Hi All - first post - excellent forum by the way ! Firstly this is an old machine approx 1994 - 5 ton. Has been good but with a leak from the hydraulic tank (split seam). I have lived with it leaking fluid for a while but the performance got so bad a few days ago and the fluid was perhaps only half full - I drained the tank and welded the leak. here my troubles began - on re-filling the tank I can only get track movement and dozer blade up/down - no arm/bucket action at all. The servos are totally inoperative and lifeless........... I have checked the safety switch - fine. Could it be an air lock in the servo pump ? I have and I know I should not have adjusted the valves that are directly on the main pump body - there are three. In the absence of a manual and in a needs-must situation I was stuck. I tried various combinations of all three valves and short of them disabling my tracking and dozer and cutting out the engine I cannot get my servos back to life. I am sure it is probably something simple - as this is a pre "electronics" machine but I cannot sort it and it is driving me mad :Banghead The Pel-Job company was bought by volvo and this is basically an early Volvo EC55, but without the crazy electronics. I can post some pictures in the morning if thats any help to you folks I am using the machine to move a chunk of welsh mountain from one place to another and still have about 1,000 tons to go so I need to get the old girl back to life. The Volvo agent wants around $250 dollars to put a guy on site before he wields a spanner...... Fingers crossed someone here can help me:beatsme Jon.
pictures to help understand my problem.... Hopefully these images will make things a little clearer........... If anyone can offer any thoughts it would be much appreciated Because I am still:Banghead
It sounds to me like you have an airlock in the servo pump. You are correct in that you should not have played with the valves but you have, so we will have to live with it . Hopefully you have them back where they started as you made a note of how many turns you moved each one ( raised eyebrow awaiting, but not expecting a response ) I dont know the proper procedure to purge the pumps but I would recommend you DO NOT run the machine until you are pretty darn sure that you have oil in those pumps. Crack the pipes one at a time and see if you have oil, bare in mind oil at the fitting might be oil in the pipe NOT neccessarily in the pump, its going to be messy and you are going to loose some oil but its the only way I know to check. When you think you have it cured start the machine and keep it on low revs while you check each and every operation. I dont want to scare you but I believe the life span of a pump with no oil is shorter than the time you can hold your breath under water and the results are about the same if you open you mouth while there.
Bled the pump............I think ! Thanks for the reply - I feel as if I've spent a week on this - in reality about two full days ! I disconnected the various pipes from the pump and reconnected - filled manually with oil from top most connector. Started her up and no difference - still no hydraulic pressure to the servos - my next test will be to crack the connection at one of the servos itself......... Normally when the machine starts no matter what position the accelerator lever is in it always starts with a slow rev for approx fifteen seconds - then seems to build up pressure and then settle to whatever you have the accelerator set to............. Now it just starts straight up to whatever the accelerator position is, with no hesitation whilst it builds pressure if you know what I mean.......... As I said it tracks okay, and dozer goes up/down but nothing else.......... To make matters worse the grading bucket is fully loaded almost fully extended half way inside my dumper Does anyone know a friendly hydraulics guy in south wales, UK ? Thinking about pushing it down the side of my mountain right now.......... Got the adjustments pretty much back where they were by the way (small valve block).... Any more ideas ?
I am still confident that you have an airlock. The machine was working ok prior to you shutting it down and draining the hyd tank, which you repaired and refilled with oil. I know what you mean about the slow build up of pressure and your not getting it now. I suspect you have a main pump and that at present is serving the tracks and blade, the servo pump is airlocked, imho I cannot recommend or advise cracking a pipe on the servo pump, but I know what I would probably do.
Hi there Joncat, where abouts in south Wales do to live? I lived in south Wales for about 3 years, and know a few good fitters around there! First of the 3 valves look to control the swash on the pump! the pump itself is a straight forward gear pump, as are most servo pumps! have you checked if you are getting servo pressure at all? should be about 40psi on the larger Volvo diggers, not sure about the minis, but could find out! Crack of the out put pipe on the servo pump (not running) until a fair bit of oil runs out! this should be all you need to bleed the pump! If oil flow out well check your servo pressure,If you dont have a gauge crack of the pipe and start it to see if any oil spews out! but let me know where you are any way see if i can get any one to help you! cps
Hi cps - much appreciated advice - I'll get on it first thing. I don't have a pressure gauge but there is nothing at the servos from feel if you know what I mean. I am in Bridgend, Llangeinor to be more specific - CF32.......... Thanks again ! Jon.
Still no joy......... Okay folks, latest situation : Pump seems to be working but nothing at the servos - in fact nothing at the central pipe that comes out of the right hand side of the small valve/connection block, no pressure on there at all when engine running. If I crack it open a fair way there is a fair dribble of oil but no pressure coming out..... If i disconnect the pipe and run the engine there is a good flow of fluid out of the end of the pipe - as if it is flowing into the connection ! I have tried a range of adjustments again to no avail and all i did was empty and refill the hydraulic fluid............ Machine still tracks and dozer still travels up/down.......... If you need any more photos folks I'll put them up - even some video if needed - that should be a laugh ! Any more ideas, I am running out of hair and patience ! Does aservice manual for one of these old Pel-Job machines still exist anywhere - I have googled without much success............ Desperate now - oh and did I mention also broke............ Jon
It is difficult to tell from the pictures and no way am I a hydraulic or pump specialist. It looks to me as if the silver lump in your pictures is probably a gear pump. Ignore ( for now ) the three valves and pipes you have been trying, which I assume are the goldish coloured bits with a pipe coming out on a 90* elbow. Have you cracked the pipes above ( with a T ) and below that lump that looks like a pump to make sure you have oil there. Remember cracking a joint might show oil, but it could be oil in the pipe trapped against an airlocked pump. Remove the pipe and check which way the oil is coming, your thumb and a couple of cut down 4 pint milk containers will work a treat at saving some of the oil. This is with the engine OFF On edit, on that silver lump is the pipe underneath a.." U ".. its hard to tell from the picture as the edge of the machine obscures it slightly?
Hi jon, you said you have checked the saftey switch but did you check power going to the soloniod valve that cuts the servo out?? this will be mounted on the line somewhere before the line splits to the two servo levers! I am thinking along these lines as it seems strange that it stopped altogether, maybe welding the tank shorted the wire or something! (stranger things have happened) Maybe you have checked all this, there is alot pointing me this way, you re getting oil flow and you seem to be getting pressure! It would be the most common thing, as servo systems are fairly straight forward! I lived in Glyn-neath near Neath for about 3 years, so not to far from were you are! worked mostly around South Wales, In Hirwaun and around the rhonda valleys.
Hi cps - I think you may be onto something............ There is a solenoid valve on the side of the tank. Will investigate in the morning. Got a tractor from Hirwaun on Thursday ! Thanks again, Jon.
Getting there............ I have removed the solenoid valve - hoping it would be kaput and solve my problem. I stripped it and cleaned it and now when I apply 12v to it there is flow of fluid not straight through back to tank but to the big bank of valves It seems now the challenge is to get the settings right on the three adjustables on the servo / main pump so that it actually works. I have tried some quick wiggles with not much success so I will have to start from a point and move on......... Anyone know if there are any manuals anywhere folks ????:beatsme Thanks again, Jon.
false dawn - I thought there was progress but no, I was wrong ! Despite all indications no real change - servos do zilch still, so I can only assume that they are getting no hydraulic pressure........... Bit too definate for me though, I would have thought whatever the problem is there should be at least SOME pressure as the pumps are good and I have spent another hour going through a range of adjustments on the three adjustors in the photo above............ The only electrical control element seems to be an interlock on the left hand side "pod" that has a contact switch that is activated by the switch being in position and a "normally open" cut off switch........... I am powering the solenoid with a direct 12v feed ........... Could there be another electrical cut-off solenoid / switch / sensor somewhere that is stopping flow to the servo controls ? Heres a plea to any hydraulic gurus out there ! Jon.
I have never worked on one of these machines, but I am scratching my head about something here. What I'm seeing in the pics looks like a typical excavator set up with a charge pump bolted onto a single stage hydrostat pump. Again, I know nothing about this machine, but the charge pump is normally used for "control" pressure and the hydrostat pump provides oil/pressure that works "all" the machine functions. If this is the case with this machine, the part I'm curious about is your original post where you stated that "on re-filling the tank I can only get track movement and dozer blade up/down - no arm/bucket action at all." If the hydrostat pump is working the drive and blade, doesn't that tell us the charge pump and hydrostat pump are working? And that the problem is with a component that locks out only excavator functions? :idontgetit
I agree - but what component is the question ? I have just pulled a pipe from the left hand servo control and when running the engine at about 25% and operating the servo and placing my finger over the port the pipe was connected to I can feel positive / negative pressure when I move the servo - but only very slight pressure, but there is SOME pressure there but not a lot - obviously not enough to switch the big valves to actually power the rams ! The investigation continues ! Jon.
Sorry I don't know your machine to help, but I have worked on some mini-ex's that the drives and blade would work with the "safety lever" in the locked out position. I'm wondering if your's is the same way. Since the drives and the blade operate, that seems to tell me the charge pump is providing "control pressure". It sounds like you have a malfunction of a component or valve that is related to the safety lever that applies or takes away control pressure from the joystick controls. I have no idea what or where it is though, I'm just trying to get the hunting dogs on the right rabbit trail. Anybody else want to jump in here and direct the hounds? :beatsme
Yeh - call off the dogs ! I pulled the control panel apart, mess of spaghetti wiring including some burnt together - very old burning I add ! I cut away the old nasty unwanted stuff - lights, clock (!) etc and low and behold we have life............ The main dipper arm is a little low on power but I amsure it is just one of my crazy valve adjustments. thanks to all you guys for your support. I am going to get this tidied up, new glass and painted and buy something bigger - around 10 ton I think, got too much work for a small machine like this methinks. I am soooooooo happy ! Thanks again, Jon.
Excellent, glad you got the old girl going again.
:ban from future diagnostics, will stick to pulling the levers Well thought out explained and exercised :notworthy :drinkup
Hi jon, Glad you got it going! I bet you are happy! Not sure if there is another valve, but on a jcb js130 the driver ripped EVERY wire of it in a tip (no belly gaurds) 3ft of water!! I powered the valve and no good! by-passed its hydraulics and it worked! Did it work when you power the valve direct?
Now Rob,that's a bit drastic there, don't 'ya think? Logic would obviously lead one to think this, as I would as well, since the machine operated previously and all he did was drain the tank. Upon re-fill, there had to be an air pocket somewhere related to the tank being drained. I just couldn't get past the drives and blade working, thus, started scratching my head, sort of a "2 x 2 wasn't coming up to 4" in my mind. I'm just glad he fixed it, I had no idea what to tell him to look for on the machine which is why I jumped in so late. I was kinda clueless on this one.
Thanks dont feel quite so stupid now. Still a very nice piece of diagnostic work, especially on an unknown machine. Shows a mind that can think things through logically in my book. :drinkup
Guys, I have a Peljob EB22, with exactly the same problem! nothing from the servos, but the blade and tracks work fine. It has been stood doing nothing, and when I started it up, this problem. I've followed your discussion, and there is no reason to suspect an airlock, rather that there is a valve somewhere that controls flow to the servos. But where?
Hi Ian there should be a valve on the servo line before it splits to go to both lever blocks! Not sure where, but if you follow the servo line from the pump you shold fine it! check to see if there is power to the solenoid! if there is power the valve may be stuck!
cps, thanks, I'm making progress, (with help from Volvo in Duxford, they are very helpful, considering they don't seem to have inherited the basic service info from Peljob). There is a micro switch under the lifting arm supporting the left hand servo lever, when the arm is down and the switch closed it should feed the solenoid that that opens the valve allowing hydraulic power to the servos. Problem is the switch is dead, if I jump a 12v pos feed from the battery every thing fires up. So the problem is electrical, I'm guessing that the relay that supplies power to the micro switch is dead. Which relay? That could take a bit longer! Anyone know where there is a workshop / service manual for an EB22.4 that needs a good home?
Hi Ian, welcome aboard. There cant be too many relays hidden behind the seat on that old girl If you have a spare relay.................ok forget that If you can find something that works but stops after you pull a relay, then you know that relay is ok, try swapping this good one with the others one at a time to see if you can find the offending one. Check the markings on each before swapping though.
I'm not very familiar with excavators, just learning the ropes myself, as above try swapping and take note of where the relays came from if no joy then remove all relays and check for continuity from switch to relay spades with a multimeter a fault after an idle period, a broken wire is less likely, so you should trace the right relay Seems more like poor contacting fuse, stuck relay, eroded relay points , ie relay 'clicks' but doesn't make contacts, connections, etc......... removing all fuses/relays and reseating may do the trick. See how it goes, a few more tricks can be tried with the meter if the basics don't work, don't forget percussive maintenance can show up a dicky relay :bash Is the switch supplying a relay coil, or is it like you said supplied from a relay? A lighter wire to the micro switch, than to the pilot solenoid could indicate that the switch feeds a relay coil, and this relays output goes to the pilot solenoid.
Guys, thanks for your help, for the record and in case it helps someone else in future, it was the starter switch. The micro switch/safety switch is fed directly from the starter switch. Go get a mortgage then off to Volvo for a new switch, and it all works.
Well done Ian and thank you for the result, it is always handy to know what the final outcome is as it will indeed assist others in the future. If a new switch really is expensive, you have just found yourself a very good anti theft switch. Take a wire from the live side of the ignition ON and run it through a seperate switch on your dash before connecting to the micro/safety switch. With the switch on you will have power so long as the ignition is on but if you turn that switch OFF
Hi Ian, You maybe could get a switch from a local auto electric place, durite or something like that, not much to them! Or have you got it already? How much if you dont mind me asking! I got one for a telehandler this week for £12
hi here a proud owner of a Peljob 12.4 from 1994 same problem but it comes and go when the mini stops working i have to use dozerblade or tracks for a second and then it works again but it can appear 10 times a minute so it is very anoying the valve what is beeing controled by the microswitch in the armrest is out of the system i have coupeld the 2 hoses on there together so created an open channel for the rest it beats me thanks in advance Manfred