New project came up today. I know nothing about this type machine other than what it does, or is supposed to do. Being the brave (fool) I am, I hop up into the cab, and to my surprise, it starts right up. So now what? I see a left and right joystick, each with a toggle switch on top and a trigger button on front. On the floor I see on the far right a sort of split pedal. More or less in the middle I see what I assume to be a brake. So I start moving levers and switching switches. I figure out how to open and close the claws, I found the switch that activates the solenoid for the blade motor. I can raise/lower/tilt the operating head. What I can't seem to do is make the machine move forward or reverse. I am thinking that the split pedal on the right is for that. I find no throttle anywhere. I don't know what model year this is yet. Have not opened the covers to look for any ID tags. I was told that one of the guys found some control cable mechanism had lost a bolt....no idea where, control of what, or anything more than that. Naturally, no paperwork/manuals available in house. On the surface, it seems to either lack a throttle to increase engine speed to engage a hydrostatic drive and move, or there is an unknown and unidentified control somewhere I have not located. Granted, I only spent 15 minutes with it today, but I am asked to get it figured out asap, as there is a job waiting. Anyone familiar with this piece of machinery? A quick tutorial about how to drive it around? I'm not going to be the operator, I just need to know how to drive it. oh, and this isn't one with the shredding head. It has a circular saw that cuts the tree while grasping it, then lays it down. AKA Feller-Buncher, I believe.
For anyone in the future, I'll fill out what I can on this machine. It is tagged a Blount Model 670. It is designed to operate at a fixed engine speed, with that controlled by one of a series of rocker switches on a panel to the right of the operator's seat. This particular machine is not labelled(yet), so it took some experimenting to find. The throttle control is a push-and-hold to change from an idle up to speed, as indicated on the tach, with a green band marking the proper speed for cutting. Same rocker, pushed and held the other way idles the machine back. The split pedal I referred to is indeed a F-R control. With the parking brake released, and the throttle up a bit, the transmission engages in either forward or reverse. I was able to drive the machine around the yard, forward and reverse, so it's not a dead one. BUT! The problem at hand is apparently centered on the Hi-Lo selector lever, which is located very low on the right side of the cab. There is an aluminum housing with a rubber dust boot protecting a single rod with a knob on it. It seems that it should have a H-N-L, but at this point, moving the lever has no feel of making any shift in the transmission or moving in any positive steps, or detents. I believe it simply operates a pair of sheathed cables that lead back to a shaft at the transmission that has a double ended lever clamped to that shaft, giving a rotary action to that shaft. Thus the Hi-Lo or Hi-N-Lo valving is likely internal. At this point, the machine appears ti be in high gear and that, I understand, is only used for transport. Ideally, I can find the source of binding or some problem with the cables, if that's what it is, and clear it up. I only hope there is no problem with low gear that the PO found and somehow rigged the machine to run in high only to get rid of it. If it comes down to it, for now I think I can live with low only. The job it's assigned to is far enough away that it will be trailered in, and right now the focus is on about 5 acres of a larger plot, so it won't need to move too far, too fast. If I don't get rained out, or I can manage to clear some space in one of the buildings, I'll jack the cab over so I can see just exactly how that shifter is supposed to work and why it isn't. I'll post a pic or two of the cab and controls. That is mostly just to help build this repository of information.
I have a smaller version. A 411B. Mine is electric shift on the two speed. A simple toggle. They are not speedsters by any means. High will not be over 5 MPH. A fast walk at best. Low is half that. For cutting you drive thru the tree. Last time I visited the site ten years ago you could still download all the PDF Hydro Ax manuals at Road Machinery and Supply's website. EDIT: Did you try pulling up on that knob? If my antique partial working brain remembers right some of them had a knob to lift to shift the drive.
Hmm, no I didn't try pulling it. It does seem like it should have some sort of mechanism to keep it in whatever gear you put it in, a lock of some sort. I'll give that a go in the morning. It just seems, well hard to describe, but mushy?...acts like it isn't really moving anything. Of course you can't see anything on the transmission while the cab is down to know if it's even trying to move that shift lever. Can't reach the lever from where you can see, so I'll have to get some help for another pair of eyes. Thanks for that site info. I'll check and see if they still have anything.
It appears that the cast aluminum (or Zinc alloy) housing that has the pivot for the hi-lo lever is missing some fasteners and at the exit point for the cable. Attached to the lever there is a clamp of sorts (again missing screws) that grabs a preformed collar on the cable housing. Due to the missing fasteners, the cable housing has slipped out of place and nothing is holding it. The cable is free to move in the housing, allaying some fears of a rusted, frozen up cable. All the pieces seem to be there, just not secure in their proper positions. I rounded up all the appropriate fasteners and will put it back together. Perhaps with one improvement. The pivot hole in the lever has what I believe are Delrin (HDPE) bushings, so obviously the fastener used there would have a smooth shank above the threads that provides a bearing surface of sorts. I am substituting a socket shoulder screw (aka stripper bolt, for the Tool and Die guys among us).It is precision ground and a good fit in those Delrin bushings. A Stover lock nut on the other side and it should last the life of the machine. So much for the shift control housing. On the other end of that cable there is a lever arm pinned to a shaft coming out of a gearbox. There is a fair amount of wear between the lever arm, which is welded to a round boss bord to fit the control shaft. In fact, it's quite sloppy. Major job to pull all that apart and make a new control shaft, or turn the old one true and sleeve the boss to fit it, so I intend to try and run the machine with it loose. I can shift from one position to the other (Hi and Lo) with the cab end of the cable unhooked from everything, so I believe once I have reassembled the control cable/lever housing in the cab, things should be ok. Worn a bit, but ok. If not for a hot job for this machine, perhaps I would (and probably will at some point) address the sloppy fit properly. I hate it, but it's a "get by for now" repair. Sometimes just gotta do that. I only hope there has not been any clutch damage from running in high gear all the time. This is an auction machine, so I can't say how long it's been running like this. If anyone is reading this, I could use some help finding a manual on it. The owner of this group of machines has instituted a (good) policy of getting books on everything we have when we work on it. Eventually, that will be a room full of manuals. I read some of the history of Hydro-Ax, and can't say for sure who even owns or builds them these days. My specimen has a Blount ID tag, but from reading, that may not mean a lot. Any suggestions would be appreciated.
You will only need to operate the machine in low gear. High gear is for road travel basically. High gear top speed is about 15mph, too fast to keep up with steering. There should be a rocker switch that will electronically select lower and higher hydraulic flows to act as a low gear two speed. The cable operated selector does indeed have a low neutral and high. Handle up is high handle low is low. I run a Prentice 2670 as a mulcher, it is almost exactly the same machine. I have all the manuals, about $500 worth. If you need specific info I may be able to help.
The latest on the machine is that I had the shop guys pull the trans, since it got in a bind and would nor shift into high at all, and low seemed to really be neutral, no drive at all. Shifter fork was bound up and bent some. I straightened it, worked it into low range, and with the guide rod protruding out of the case, I put a clamptite collar on it to prevent it from moving back into the case, and allowing it to slip out of low range. I had already removed the control cable and shifter box to keep the operator from messing with it. When there is time (ha!), I'll probably go back and replace that cable and see if I can free up the fork or collar on that idler gear. But for now, I definitely agree. Low speed is all we need. On and off the trailer, and from tree to tree. I have it at my personal shop now, but will deliver it back to the guys to install it tomorrow. It took less than a day to remove it, probably a bit longer to reinstall it. But it appears to be locked in low,which is what we wanted for functionality. Oh, and I did at least find an owner/operator manual for it. I've heard Service manuals are virtually nonexistent. I think we may be good to go though, and will find out tomorrow or Friday. The rockers aren't labelled very well on this old machine. I don't see anything that looks like it might have the function you describe. Could you post a pic of the page in the book that has the switch functions identified? That would help a great deal. I can make some labels for mine. Many thanks, daveyclimber
Here are how my switches are laid out. Starting from the top. Hour meter, 2 switch blanks, hvac temp control, 3 switches from left to right. AC/Heater, rear diff lock, blank. Next 3 switches, hvac fan speed switch, hi/low travel speed switch, work lights. Next 3 switches, engine speed control, blank, blank. Last 3 switches, horn, blank, hydraulic override switch. Not exactly sure what that does but it will allow me to travel with the door open and steer with the parking brake on. One the dash I have 2 switches. Left controls the hydraulic reversible fan and the right controls the saw or attachment pump. I have some spare parts I'd be willing to part with as I have no us for them . Left and right hose guards which mount down at the center joint. They are for the power unit side. New lower attachment pins for the loader arms, control computer, wiring and valves for the reversible fan. Let me know.
Blount (is or was, not sure if they sold) owns both Hydro AX and Prentice as well as a bunch of other logging equipment manufacturers. RMS has been a distributor for many years.
Cat Forestry was the latest owner but Cat gave up on the forestry market from what I hear and sold the whole forestry division along with Prentice and progress rail I believe to Weiler who makes asphalt pavers. Oh and the black button on the right hand joystick will operate the front axle locker when depressed, it is momentary.
Looks like I have some wiring to do then. And now, with the trans back in, I get a phone call that says the machine won't move at all. Guess I know where I'll be in the morning. Sounds like parts are going to be hard to find now. Great.
Ok well the guys were correct. The machine won't move. It lurches a little if the propel pedal is held about halfway down, but that's it. No forward and no reverse movement. So I made up a test gauge so tomorrow I will see what the pump is putting out. Book says max is 5420 psi, so we'll see. I'm not sure I'm understanding the layout/plumbing of this machine. The propel pedals are where in the system? It's a hydrostatic drive, so the pump is a variable displacement I suppose, but how do the pedals control the swash plate? I wish the owner manual had more detail. I'm betting the pump is running low pressure and I'll have to rebuild it. The other pumps seem fine. Everything else moves or spins like it should. And I am presuming the default position of the solenoid on the back end of the hydraulic motor is "low" speed. The coil is not open, but I don't have the resistance spec for it. I believe it's around 3.7Ω across the coil. That figures out to be a bit over 3 amps, so not a short or over-current situation. Whether this solenoid is functioning properly or not I can't tell, but I don't believe it could stop the machine from moving.
Parts are still readily available for these machines. Do lifting and steering functions work? My machine has safety interlocks and wont propel if the door is open( switch at lower rear corner of door jamb) parking brake engaged or switch fault. You mentioned an issue with the transfer case shifter. Is it stuck in neutral?
Daveyclimber, just about all of the interlocks have been butchered off of this machine with the exception of the parking brake, which is not even connected to the brake system. The brake lever must be in its disengaged position for anything to work, so the switch is still in circuit, but there are no brakes. Steering, clamps, saw, all of that works normally....and yes, with the doors open. Someone has spent a lot of time taking things off this machine. The hydraulics test point panel? Nothing is connected. Nothing. The manual shifter for the transfer case/gearbox had a faulty cable, and the decision was made to put the machine in low range and lock it there with a clamptite type locking collar. So no, it's not in neutral. It's definitely in low.
PM me your phone number if you like. I will text you a picture of the propel troubleshooting info out of my service manual. Not sure how to post pics here.
Sent
There might be a rag or blue cap in one of the propel hoses. Another one of those ask me how I know things. Simply removing the motor from the drive system and now it only lurches there is likely a blockage in the loop or containation.
Well, P&S, it was doing the lurching before, from the beginning. If you ran the engine speed up, and hit the forward propel pedal, in about 5 seconds it would sort of jump forward a few inches, then a few more, and repeat this until it was actually moving, albeit sort of rough. It was definitely in high range though. I was able to drive it around the yard, stopping and starting, and once it was at full temp it seemed to fully engage and take off more normally. Once it cooled down though, it was a repeat of the jerking and lurching. I could see it being a problem with line blockage or something like that. Once the oil thinned out, it seemed to do a little better.
Was not aware of existing condition. Daveyclimber, to post pictures if you so desire, just click upload file and select picture. Then choose thumbnail or full image and click post reply.
Today, a limited bit of testing took place. It's difficult to do the recommended tests when most all of the ports are inaccessible, and the bulkhead where all the test points are hosed to has been stripped of all connecting hoses. Really aggravating. If I has the time, I'd hose all of them back up so that in the future the next shmuck would at least be able to throw some gauges on without being a contortionist or knocking the cab over time after time, ad nauseum. Anyway, as far as what got done today, working with an old CAT hand who's pretty sharp, we tested the pressure from the propel pump. The way we did this was done not so much by the book, but by instinct and book combined. There are three lines from the propel pump and the propel motor; Forward, Reverse, and Case Drain. Step one; d/c and cap off Reverse port at pump. Step two: Connect 10kpsi pressure gauge to Forward port at pump. Step three: Remove Case Drain from Propel motor and connect service hose to catch pan. ( this is where I start questioning our procedure. I have no idea what is supposed to come out of the Case Drain port of the motor; I'm thinking not a lot. It's normally routed back to the reservoir, but I don't know. Especially with all the custom hosing on this machine.) So, essentially I have dead-headed the propel pump into a 10,000 pound gauge for this test. Cab is lowered, mechanic in the cab. Cranks normally, for this suicide machine, and I read about 600 psi at low idle. A quick touch of the propel pedal drops it to virtually zero. No working tach, so just guessing on these speeds. We bump the speed control up to its naxt notch, I'm guessing around 1500-1550. Pressure hops lively to around 1k. Run the speed on up, and the pressure follows. Now we go for it. Engine speed up to normal op speed (really need to fix that tach!) Pressure hops on up to around 3200 psi. Then the op hit the propel pedal lightly, the pressure went on up rapidly to about 5400 psi. I'm taking this to mean that the propel pump itself (base pump) is fine, capable of producing proper pressure. I don't have a flowmeter, and with it deadheaded into a gauge that would be pointless anyway. Maybe later I'll add one to the kit, and can check things while they are running. I also believe the pilot system is functioning properly, as the idle pressure is low, as it should be, but with throttle up, it jumps right up to proper pressure to run the propel motor. Since I got the readings I did, I decided not to test for the same pressures from the reverse side. The drive problem seems identical whether it's in Forward or Reverse, so I didn't see the point. This test also indicates to me that the circuit that includes the pedals is ok as well, since the system responded in the way it did: drive pressure jumped up immediately to where the machine ought to be trying to move. So, the next question is about the motor itself. It's a variable displacement swashplate design, and I question exactly what controls the angle of the swashplate in order to keep it where it should be on the speed/torque curve, and what sort of problems are possibly or likely to cause a failure of the type I see here (no move). Since the normal test lines have been removed (but can be put back, easily, at a minimum what ports on the transmission should I be looking at? And how much oil should be lost through the Case Drain? Or does the fact that I have ample drive pressure indicate there is some obvious (though not to me) problem that will need to be addressed through a teardown. It's not a difficult R&R, but the guys obviously won't be happy since they just had it out to pull the gearbox for me. Or since I am short on time, should I just buy another propel motor? You guys are more help than you probably realize, and I can't express well enough my appreciation for your assistance.
I think I'd still try to disconnect the drive lines at the transmission and see if the transmission yolks turn freely or jerky. And then reattach one axle at a time. The front axles take more abuse on these machines. Maybe you have an axle that is wonky and binding or the front brakes are stuck somehow. It's great you have extra help. I usually have to monkey around by myself. Power tilt on the cab would be a nice feature. I always thought the pilot inputs and associated valving controls swashplate condition but I'm not well versed in hydraulics either.
Well, I've had the transmission out, and on blocks sitting on the shop floor. Turning the yolks took very little effort on both front or back, and and everything was smooth. I'll also say that turning the input shaft via the splines was also very smooth and took little effort while the output yokes showed very little backlash, which was a little surprising to me, considering the hours on the machine. This didn't feel any different in high or low gear. The splines on the propel motor/gearbox interface showed very little wear and also were smooth as glass where they made contact. Virtually no step where the contact/no contact areas met on the splined shaft. When the machine was pushed into the shop, there was no noise, no excessive effort required, nothing unusual, so I don't think there is anything going on in the axles. But I'm not ruling out anything at this point. Since the gearbox locks the front and back together, if there were a problem with either, it should show up any time the machine was rolling, I'd think. I'm glad for the help too. I have serious back issues (plus a few others)and only am involved in this work formally as a consultant. Sure, I'll do some light work. I don't mind getting greasy, but my back (and broken hip from about 4 years ago) really limit how much crawling around on the floor I can do without really regretting it for a few days afterward. So I have an agreement with my customers to have a helper when I need it. I'll do electrical work, troubleshooting, design work, and other not-too-physical stuff, but heavy work I leave to the younger crowd. I did my time.
Hope this is not your situation , but pushing a hydrostatic drive machine without disconnecting the drive motor from the drive line or relieving the pressure valves can cause pump/motor damage. On the hydro ax having the transmission in neutral would be the easiest.
Yes, I know this. The gearbox shift selector that was thought to be the original problem was in neutral. Part of the problems faced and fixed up to this point were to lock it into low, and I made sure everyone involved knows that means no more pushing the machine. I know the mechanics in the shop know you can't back-drive a hydrostatic setup, but I am a little concerned with the field guys. That said, however, they are instructed not to attempt repairs in the field. So hopefully that will not become an issue. I should probably put a big red tag on the dash to remind them.
Looks like I'm in for a new propel motor. Found a source, but price is high and lead time I can't live with. The guys are pulling it tomorrow and I'll start teardown to see if I can find the problem. I'm convinced it is a hard part failure. The source I found told me the seal kit, about $530 rarely fixes anything. It's nearly always a mechanical problem. They sell all the bits and pieces so hopefully I find out what's wrong and can get the parts soon enough. I'm running out of time. I don't want a used one, but I'd take a factory reconditioned one if I could locate it on the shelf, so if anyone has suggestions on sources for that, I'd appreciate it. I can rebuild this one, unless the case is damaged or something serious like that, but I'd rather not have to. From the exploded views, it's a pretty involved motor. Guess I'll find out tomorrow. Guess I better clean off one of my workbenches this evening. it should be interesting. At this point, I'd even consider renting a machine if I could find one, just to get out of this bind.
Well well. Upon teardown, I find a missing seal ring (or they call it a piston ring, more properly) out of 9 that is completely missing. It's about 7/8" O.D. 1/16 thick and 3/32" wide. Sometime in the past it went crunch. The bore it was is suffered some linear scoring, and what some call the swash plate (they call the valve plate, and the mating seal surface also got a few small scars from eating the bits of ring. I believe this is what gave the machine the "lurch" or "cogging" behavior when we tried to move it. One of nine cylinders produced little to nothing force-wise. Kind of like a V8 running as a V7, except a v8 has a flywheel to spin it on past the dead hole. This motor pretty much stopped when it got to that "cylinder. I had a nice, hour long chat with the service manager about what when wrong and why, and he assisted me selecting the proper replacement parts. Nice guy. Even stayed past whistletime to help. It certainly appears there will be some tricks to get everyting lined back up to reassemble, and given time I'm sure I could get it together, but he offered to school me on how it's done. So I have a list of parts I am going to try to rush in so I can reassemble this beast and give it back to the shop. It's 2-3 hours to reinstall, so not too bad. My worry is not finding all the crunched up bits of ring. I was told if they weren't right there, they probably made it to the tank and they would be stuck in the gunk so not to worry. But I will. I'll flush out all the passages and fish with a magnet and blow with air....everything I can think of. It would be bad to have a loose piece get tangled up in this. But then, the clearances are <0.001 in most of these fits, as new, so even on a used motor the pieces would have to be pretty small to get anywhere. Plus if there were any in the motor, likely they would have already been through it and made it to the reservoir. I'm hoping, anyway. Just for entertainment value, I'll post a couple of pics for those who haven't torn into a bent axis hydraulic motor.
Pics as promised:
That piston ring either left the motor through the case drain or it went back into the hydrostatic pump as it is a part of the closed loop drive. It would be wise IMO to remove the pump and disassemble it to check for damage and flush or replace the propel hoses. If pieces of that ring stayed in the loop, repeat failure can be instant. I would imagine your parts supplier would concur. If that machine has an access port in the tank it would also be a good idea to open it and inspect for debris. Change the filters and esp the hydrostat charge filter.
In order to clean the system properly, you really need a filtration cart. I've blown hydraulic pumps and motors in the past. When I do, I connect the lines into a loop with extra fittings and start flushing one way and then connect everything in reverse to flush the other way. A decent filtration cart will provide enough GPM to flush particulates downstream and then catch them in either the coarse (40 micron) of fine (usually 2-10 micron) filters. As per advice from a hydraulic shop, I usually flush with diesel fuel first. Then I keep a barrel of mixed diesel and hydraulic oil from former flushes. After the flushing with the second fluid, I suction everything out as well as possible and then fill with new oil transferred via the filter cart. New fluid is not always as clean as it should be. I also regularly hook up the filtration cart to my machines and do a regular preventative maintenance on the fluids. This way I can also run my fluids longer as there is no particulate contamination. The fluids never really go bad. We are only given change intervals to get rid of contamination.
P&S, I've already gone through the pump, replaced a few parts and have pressure in excess of 6 ksi both directions after a quickie going through. Hoses are all clean. There was no damage. Two of my service advisors where I buy my parts agree that odds were that the pieces of the ring went on through and ended up in the reservoir. There is no reverse flow on this motor. The pump has two outlets, one for each direction of the motor. When there is no propel command, there is a bypass straight back to the reservoir. At any rate, the pump escaped any damage. The filters have already been changed, and the old ones tossed. I really wanted to open them up to see what they had caught, but missed that chance. I do plan on going fishing in the reservoir and hopefully find the remains of the ring, ideally in large pieces. I do hope it has a larger access port. At this point, it seems that if I can get my hands on a set of piston rings, I'll be able to limp by this job anyway. I'll be looking for a buildable core in the mean time and will take my time and go through it with a fine tooth comb so I'll have a spare to swap in if this one bombs on me. I see a few parts with minor wear, but nothing serious, or out of service specs.
Muncher, I couldn't agree more. But at this point in building up our shop, we don't have that luxury yet. I'll just have to do the best I can. In our fleet, I'd estimate >50 pieces of equipment, with nearly all equipped with hydraulics. I'd love to have a flush cart, but it's not in the cards presently. Maybe I'll just build one. I'm sure I have all the needed components. It would be nice to add that to our PM program.
Yes the pump has two outlets. Under operation one propel hose is the pressure hose and the other is the return hose which is basically the suction hose for the main rotating group . When the opposite direction is commanded that just reverses. That it why it is called a loop and why I am always concerned about containation when dealing with one of these type systems. There is a charge pump located inside the main pump that serves to keep the loop full by replacing oil lost from normal leakage to case drain and what oil is removed by the flushing valve on the motor , as well as providing pressure to control. The flushing valve lets oil out if the loop so it can replaced with cooler oil. With the failure on that motor you posted , you could have diagnosed internal motor failure by running the motor case drain hose into a bucket and measuring the flow out if that hose in gal per minute at neutral as the charge pump creats that flow that is going around that missing piston ring and into the case drain When the pump is in neutral, the pressure is equal in both propel hoses and that pressure is from the setting of the charge pressure relief valve. When the pump is in neutral there is no flow in the loop, it is static. I wish you luck patch repairing that 51 Saeur Danfoss motor. I have not had much luck fixing those things with out buying the whole rotating group which as far as I know is the only way to replace the pistons and that dog bone is tricky to get in right with those rollers. This is likely not an issue on what you are dealing with here but I have also found internal leakage between the valve plate and the head where the valve plate had worn into the head. Keep in mind that I have no formal training on hydraulics , just on the job training and I am only trying to help out.
P&S, I appreciate the explanation, clarification, and suggestion. OJT is something that there is no substitute for. I tried to locate some sort of spec on what the flow from the case drain should be but could turn up nothing. You are quite correct in that the only way to replace the pistons (in particular) is to buy the output shaft. The pistons are held in place by pressed in rings on the end opposite the cylinder. If I had to, I could build the tooling needed to remove and replace them, but they are not available as separate items. Since you obviously are familiar with these motors, let me ask about the solenoid mounted on the valve segment end of the motor. Which direction is the normal operating position, "up" or "down"? Or is this F and R? I realize this changes the displacement and hence the flow, but the machine this is going on has been really cut up as far as controls, wiring, and lots of hosing. Assuming the solenoid is not ever energized, where does that leave the valve segment? I would not think it should just float. Or is this something that is (or I should say ought to be) normally switched manually from the operator position? It does have the connector and at least that part of the harness, but of course, following it back to the control is practically impossible. I can get power to it if needed, and switch it if that is required or desired. I suspect that one of the rocker switches on the panel did control it. Also, the nut that I imagine held the coil in place is gone, so if it is intended to be reversible, that's not possible at present and I'll have to make a nut. I'm learning that getting parts for this Hydro Ax is nearly impossible. I've been warned about the dogbone and reassembly, and that if I call this particular service manager he will give me some tricks, but I can see that it will be awkward, to say the least. I see a bit of frustration in my future.
Well, a little update to the saga. I was able to get the rings overnighted to me. I cleaned everything up, polished all the scratches that were there. Really was not bad at all. Took a few tries to get the pistons and dogbone all aligned when assembling the cylinder block. The old arthritic hands and fingers just don't cooperate like they used to. But I did get it together and delivered. After a few test runs around the shop they decided to go take down a handful of trees and see how well it sawed and grabbed. It did very well. Unfortunately it has been raining on and off for a week or two and the operator drove into a soft spot and sunk it to the frame. End of tests. I left the scene at this point. The plan was to anchor an old milsurp 6x to a tree and winch it out. I don't know the details, but it seems to have propel issues again. I have a feeling they just pulled it out with it not running and not in neutral. That makes me think there is now some motor damage again. So I'm on the hunt for another motor (used, but running hopefully), since getting parts seems to be a difficult problem to overcome, although I did find what appears to be a good supplier here in-state and within reasonable driving distance should the need become desperate. They say they stock a lot of Danfoss parts, among other makes. I just hate that the damage could be from something as simple as dragging the machine out of the mud. I had already told everyone involved that the machine could not be moved with it in gear, as I had locked the transfer case in low. They would not have been able to drop the driveshafts very easily, because it was sitting on the belly pan and sinking further. But they could have opened the lines or removed the locking collar I had out on the transfer case and taken it out of gear....or something. But the pressure was on, and I'm betting no one gave it any thought. I'll have to find out. They will be pulling the motor on Monday. To Be Continued...... I'm kind of bummed about it. It was looking like a success story.
Tony, you will likely find that same ring gone from the same piston. I have tried the same thing in the past , thought it was fixed for a little while. The solonoid on the motor is either off or on. Just can't remember which is turtle and which is rabbit. It only affects ground speed . All directional control is from the pump .
Very possible. But a new factor is a blown hydraulic hose. There is oil sprayed everywhere. I have been told that it acts smooth and normal moving forward, but not reverse. I theorize that a blown hose would not supply normal pressure to one side of the motor, and if it were the "reverse hose", it might act like it is described. In the morning, I have a guy who will spend some time with our pressure washer getting the mud off it and I'll knock the cab over for him to clean the oil spray down. It's a long shot, I know. It was moving fine until it sunk. Turns out they dragged it out with a track hoe, but I still don't know if it was running and they were trying to walk it out at the same time. No way to know when the hose blew, if that's what it is. Just have to wait until it's all cleaned up now. Meanwhile, I've found a reconditioned motor in stock that I can hotshot in if I have to, but negotiations are underway with an individual willing to come in and just do the cutting and stacking. He has a larger machine anyway, so it would probably help get back on schedule or closer. So the pressure to fix it may ease off so I can do a more thorough job of failure analysis. So meanwhile, I move priorities to the Volvo Artic. Manifold repaired, rebuilt turbo. Runs great. Now they are telling me something is up with the transmission. They found what they thought was a relay that had had a meltdown, but it was a flasher unit. Don't know of any connection with the transmission to the flashers. Or for a fact that it served that function on this truck. No docs available. Wish I had a schematic. At least on the artic, we have a Terex and a Cat as backups. We have no backup for the Hydro Ax. It will get fixed, it just moved down the list for now.
Oh, P&S, on that solenoid, it controls where the valve segment is positioned by means of the servo piston. At one extreme, the motor is at minimum displacement, and there is an adjustable stop bolt to determine that (called minimum displacement limiter). Factory set. At minimum displacement, the available torque is at its lowest, but the motor speed is at its highest. I guess that would be the default position for transport, and the solenoid would be energized. Otherwise, the solenoid is not energized and the hydraulic controls move that servo piston and hence the valve segment, varying both the speed and torque. That's basically the operating description in the technical documents I have downloaded from Danfoss.
I don't want to be a bother, but I am trying to diagnose a prentice 2764 hydro ax and sure could use an operators and/or service manual. I need to remove the battery and I cant get the cab jacked up. There seem to be some pins that I have to rotate but it's a Monday and I seem to stupid to figure it out.
I have learned that if one turns the battery isolation switch on it works better. Operator error. Now I just need to figure out how to operate it.
Did you get the cab lock pins figured out? Once I found the "open" position on mine I took a centerpunch and made some index marks.
I did notice the notches in them and I think I have them clocked correctly, but the cab still wont budge. I may have them in the wrong position. I no longer need access to the battery so that's on the back burner. Now I just need to learn how to operate it and figure out if the lack of mulcher function is operator error or if there's actually a fault.
I can tell today isn't monday. The hydro axe works fine if you know how to operate it. Thanks for trying to help Mr Wells. Push the buttons and play with the levers until it starts coochin! Oh, and safety first!
Yeah those disconnects can be such a bother. And they can save your tail. Once you get used to them, you'll be fine. I add them to any machine I work on that doesn't have one. And I make up a little label to put near the ignition key when possible as a reminder (or informer) for the users. I'm confident that it has saved a few batteries and perhaps even a few machines over some time. I'd venture to say that a recent machine fire we had (a Diamond Z grinder) would most likely have been avoided had the operator used the disconnect. They did not, and we nearly lost the machine. Glad you got it going! Now the fun begins. I'm sorry I can't give you operating pointers. I ran ours only a little for testing. We have a couple of good hands who are pretty good with woods machinery, and they take care of the use of them. About the only thing I can say is that you should always use low gear for actually cutting and bunching. High gear is only meant for roading. But if you find the books on it, it's in there.