Hello, and thanks in advance for the help! I have an old Bantam C451 Excavator that I recently acquired to torment my wife and make huge messes on my property. It seemed to be running and moving fine when I purchased it although I did not do any digging with it. It had a hose blowing fluid everywhere so we kept it to a minimum. I replaced a number of hoses and rebuilt the dipper cylinder and both boom cylinders. I also replaced the injectors in the 4-53 and cleaned up the entire fuel system and she runs like a top. So here is the problem... Now that everything is buttoned back up, I can't seem to build much hydraulic pressure. After an extened time, the cylinders try to move a little but can't seem to really do anything. Also, I do not hear the engine loading at all with the pressure. The bucket cylinder, which was not disassembled will also only move a few inches, so it does not appear to be due to the air in the system. Side note: During the process of tuning up the engine, I did pull the clutch lever to disengage the hydraulic pumps (it had that feeling that it had not been disengaged in about a decade). The clutch does appear to engage and I can hear a small audible change in the engine. I checked the hydraulic filter and cracked the cap on the filter resevoir and indeed fluid is being pushed around the system. So my first suspecion is that the clutch is not fully engaging. I will figure out how to inspect that. But I am also not sure how to test the hydraulic system. There are 3 hydraulic pumps (Commercial Shearing) and the 3 pressurized output pipes have what appears to be pressure test ports on them. I would like to know more about how this system works. All three outputs go into various blocks of the sectional spool valves. This has me wondering if the sectional valves are connected internally so that each pump adds to the flow or are they kept separated so that each pump runs its designated functions? Are the sectional spool valves rebuildable without removing them? Side question..... when I rebuilt the dipper cylinder, the gland nut has a 1/4-20 bolt running straight into it. I assumed this was to lock it, but after thinking about it, I can't see how this would do anything. The bolt is currently drippng a little bit of fluid, even though I can't get the cylinder to move. Is this bolt supposed to have a gasket or sealing washer on it? Any ideas? Any other advise or help is much appreciated! Thanks clint
Good day Do you have a user or service manual, the clutch between pumps and motor is a little strange. Kind regards Uffex
No I dont have a manual. There are some print parts manuals out there, but nothing that looks particularly useful.
I have seen that where for cold starting you want to give the engine a chance to spin fast enough to fire off, then shut down and re-engage once the engine is warm for a spline clutch
By some luck I just found a hydraulic diagram on ebay - I bought it, but I can see enough of it in the picture to be helpful. I didn't realize there is a suction filter and a return filter. This may be as simple as low fluid level. If the suction filter draws up from 1/2 way on the tank or so (and it may based on the digram and general arrangement), it may have just been struggling to get enough oil.
worth a shot and worth inspecting the return filter in case there is organic goop in the tank
I guess it depends on what type of clutch you have. Some are dog clutches some are over-center clutches. The dog clutch you have to shut down to engage or they make an awful racket. The over-center you have to push past the resistance to go over center which through mechanical linkage holds her engaged. I'd imagine that is what you have. Good luck.
As far as I can tell its a standard auto style friction clutch. I can see the throwout bearing engage with the arms / tangs. I just can't quite see the friction material or the shaft, it appears the shaft rides inside a tube (that the throwout bearing slides on).
Pics, pics are worth a thousand words
Good day According to the diagarm you have three gera wheel pumps, there areno releif valves in the diagram. I suppose there was not a standard schematic included? Kind regards Uffex
I have not idea, I just found this and purchased on ebay... will be a few days I am sure before I get it. Not sure if there is more to the diagram on the back side or additional pages, but that is certainly helpfull even as it is.
Bantam.pdf Shared with Dropbox www.dropbox.com Joe H
That is fantastic! thank you!
KOEHRING BANTAM T451-C4516006250 EXCAVATOR Parts Manual PDF Download This KOEHRING BANTAM T451-C4516006250 EXCAVATOR Parts Manual PDF Download provides detailed service information, step-by-step repair instruction and maintenance specifications for the machine model. It includes detailed illustrations, diagrams and instructions to help you to perform the required... service-workshopmanual.com Bantam T-451 C-451 Excavator 522 Log Loader Factory Parts & Maintenance manual $23.76,Factory parts and Maintenance manual has step by step procedures. Real good shape. OEM.*We offer a money back guarantee. Buyer to pay $0.00 shipping in the U.S. We can combine shipping to save you www.cardinalbest.com Might be a manual here, or maybe not. On line manual sellers seem to be a dodgey lot. Joe H
Interesting that it lists the individual pieces to build/rebuild the buckets. I wouldn't think that's very common on excavators.
Good day If you have no hydraulic functions I would be inclined to suspect the clutch, I would guess this has been used to centralize the drive to the pump splitters. If the pump splitters have a lube chamber, you could possibly pull a dip stick load the hydraulics and see if the gear wheels are turning. Kind regards Uffex
I drained the fluid and pulled the suction filter - its about a 20" long fine screen mesh filter. It had some goo on it and there was a couple gallons of slimy gooey stuff in the bottom of the tank. I am not sure if it was enough to clog the filter, but if it did, the relief valve is at the top of the filter and would have been above the level of the hydraulic fluid (the hydraulic fluid was well below the sight gauge and minimum level - about half a tank). I am hopefull that this was the issue, its not quite a smoking gun but certainly within the possiblity. Since all the functions were reacting the same, I doubt that it was a pump since they have seperate duties and based on the diagram, seperate valve blocks and bypasses. So what could be affecting all three pumps equally ? Either the fluid (level and/or filter) or the clutch is the only thing I can come up with. So now here is the question, now that the fluid is drained.... Is there anthing I should service while it may be a bit easier? Should I pull a pump and replace the seals? (probably best to leave it alone, but its tempting when not having to deal with fluid pooring out everywhere.
Hang upsidedown and get a few rolls of paper towels to mop all that goop out of the tank. Hoping that new fluid does the trick! It was circulating before maybe some relief valve is jammed open.
The tank is clean now. The challenge is that it all goes down to a 2x4" cross beam/resevoir that has one 1/2 npt drain plug in the middle side. I filled that with diesel and drained, then filled again with diesel and left overnight. Hopefully that softens the goo enought to drain well out of the drain plug. I suppose the little that is left will go through the pump and should get picked up at the return filter pretty quickly.
I wonder if a little diesel biocide would be helpful to get the stragglers. Certainly a few return filters.
Curious what would cause that thick sludge? Almost looks like grease got mixed with the oil. I think it would definately be part of the problem and wouldn't flow very well through the hyd. lines.
Not sure, but I don't think its uncommon for pertroleum to do that. Even heating oil tanks form sludge. Probably heat and oxidation. maybe water.
typically when you get a layer of water, bacteria / algae arrive that eat the parrafins in the petrolium, most types of oil can get it but those that remain cool very much more so.
Doesn't water usually settle at the bottom over time? The oil didn't look to have much water in it.
settles to the bottom right quick. could be slimy sludge or could be grease, maybe someplace grease getting pushed into a hydraulic component?
I suggested maybe grease in my 1st response.
After completely cleaning the tank and filter, I exhausted a brand new barrel of ISO 46 and still didn't get to the min level. I fired it up, but I did not play around much becuase the main boom was under a gantry (and the cylinders are still full of air), however, the bucket moved fine, which it would not before. I shut her down and went off to get a few more pails of hydraulic fluid. By the time I got back it was pooring rain.. But based on my quick test, I am pretty sure I solved my problem.... which turned out to be slime in the tank clogging the filter, combined with low fluid level which was below the bypass valve on the top of the filter. So the pumps were struggling for fluid. Once again... can not overstate the importance of clean filters! and I am that guy that has extra filtration and spare filters for everything and it still gets me!
We demand video proof