Here's the rundown. We had a leaky lift cylinder on the CAT941B. Removed the rod and replaced the seals (after removing that big nut on the end). Took a while to put it back together since the cylinder rod was fully extended (seemed to have pressure on it) but finally got it back together. Went to start the project the other day and the lift lever was really hard to move, was able to lift the bucket but had to push pretty hard. Now cannot lower the bucket, the lever seems like it is jammed (pushed pretty hard on it). Hydraulic fluid level was low so we added some. Bucket tilt works no problem. Could there be air in the cylinder/pump/system that is locking things up?
Sounds like you’ve got something jammed in the control spool. From your story I’m betting a piece of seal material.
Thanks for the response...So, a couple of follow up questions. Is removal/repair and diagnosis difficult? What should I be seeing or not seeing when I get in to it?
Here's a question, could an incorrect rebuild (replacement of the seals) be causing the issue? My son-in-law was the one that pulled the cylinder and disassembled it/replaced seals. Seeing as he's never done this before is there a chance that if put a seal in backwards this would cause the issue (i.e. cylinder to jam)? Is there any way to test that possibility?
He probably cut the piston seal putting the rod back in now its stuck in the control valve
As Tyler said by the fact that the lift control lever is hard to operate would indicate that something in the cylinder came apart during reassembly which then migrated down the hydraulic system and is now jamming the control valve for the lift function. To fix this will require at least two interventions. First the lift cylinder will have to be disassembled to find out what broke. Cross your fingers it was a seal, if it was something metal you are in even bigger problems. Second the control valve will have to be disassembled in order to remove whatever is jamming it. And I have left the best part until last - the control valve is located inside the hydraulic tank so that means the tank is coming off the machine and has to be opened up even to get access to the control valve. Good luck because your're going to need it. Your best bet before breaking out the tools is to get hold of a Service Manual. You will find it invaluable. Here's a link to one on eBay
I think you should look at kick out
See attached that explains how it operates to give you an idea of what to look for.
Thank you sir...
You will have to pull hyd tank and split it to access valve does lever move hard with machine not running too
So here is today's situation/efforts. Lift lever is no longer jammed/hard to move. Will now move freely, however lift cylinders still inoperable (bucket tilt still working fine). Thought maybe to check if fluid was moving to the lift cylinders. Cracked the lines at the rod end (tail?), started it up and pushed the lift lever forward and fluid came out (forcefully). Tightened them up and tried similar on the barrel end (head?) of the cylinder that was rebuilt...no fluid came out when pulled lift lever back. So I'm thinking there's no fluid getting to the cylinder. So, drained the tank and separated it. Wasn't expecting to see something that massive. Didn't see anything obviously amiss (no broken pieces, linkages etc... from what I can tell). One thing I did notice though (not in the tank of course), It appears the kick out "bar" isn't where I would think it should be. Seeing as there is a pretty heavy spring attached to that bar I would expect it to be resting against the base of the lift lever, it is not. It rests beyond the travel of the lift lever which I find odd, again because of that spring pulling on it. Could that be jammed somehow?
Some of the kick outs will flip the linkage when you drop the cylinder down
. So if the linkage is/was flipped would that stop the flow of fluid to the cylinder head?
If it is not allowing leaver to travel far enough do you have any pictures of the leavers and kick out bar at leavers
A couple of pics...one of lever at neutral, one with lever pulled back and a close up of lever pulled back - a little bit hard to see but the lever is not touching the bar, even when pulled back.
Is the bucket up or down in pictures?
Totally down/on the ground
Nige, For these Service Manuals I see there's a bunch listed with a wide range of costs. Are they all pretty much the same? I know I need one for a "80H" machine since that's what I have ser # 80H6907.
Sorry I should have mentioned the publication reference before. For your 80H machine you should search for Cat Publication reference REG00527. That was the one I linked in an earlier post above. A new paper version is currently listed at $600 with CD being priced at $430. I recommend that you stay away from the aftermarket manuals sold by, among others, Finney & Jensales.
The kick out is in the right place but as far as travel i can't tell. I'll try to explain how the kickout works the little bracket that wraps around the bar has a roller on it that the bar rides on when it gets to kick out height the roller drops into notch and lets the bar push the lever back to hold
Thanks Nige, That one you linked earlier seems a lot more appealing than a new paper version for double the cost. I'm OK with it being used, as long as it is complete (which I'll verify before I commit)
I recommend always asking the seller a direct question - "Are all the modules listed on the Index page of the binder present and correct.?" That should also include large-size fold-out drawings of the electrical schematic and the hydraulic schematic. Here's a LINK to another one. I came across 3 or 4 genuine OEM manuals when searching for REG00527.
Thanks Nige, these are even a little more reasonably priced. Thanks for the suggestions on what to ask the seller about.
I forgot to mention that also included should be the Operation Manual and the Maintenance Manual. In some of the listings you can see both of them in the photos.
It's been a while since I was able to work on the machine. Yesterday I decided to try some "redneck/yankee/shade tree mechanic" diagnostics. Here what I was looking at: Drained the hydraulic fluid/tank and took a look at the valves/workings inside and didn't see any thing obvious amiss. So since there was no fluid getting to the head of the cylinders I figured to start at the back of the tank and see if we were getting fluid out of the spool. Cracked the line on back of the tank, started it up, hit the lever and got a good burst of fluid - so fluid was getting out of the spool. So tracing the line saw where it connected to a block/splitter for the left and right cylinders. Pulled the lines from that block and was shocked....totally jammed with what looked like a shop rag....hmmmm, I guess when the cylinder was being reassembled a shop rag got inadvertently dropped in the barrel. So, now I have the pleasure of digging it out of that block. Not blaming anyone, but I wasn't there when it was reassembled. Thanks for all the suggestions. Still looking for a manual as Nige suggested (requested info from two sellers and haven't heard back, one to another)
Well who'd have thunk it.?
The one I linked in Post #6 on Page 1 still appears to be for sale. The seller is farily reputable as far as I know. I've seen a lot of stuff from them when searching for other manuals.