All of a sudden, the lift doesn't. All other functions are fine, bucket tilts and forward/backward motion just like before. With the machine powered off, I can move the lift pedal and the linkage moves but does not feel right. When I manipulate the tilt pedal, there is slight resistance and the pedal will spring back to center when released. When I manipulate the lift pedal, it will go either down or up with very little resistance and stay in that position when released._____ I've removed the seat to see the pump and all. I can see that the linkage connected to the control valve assembly is moving but I cannot see where or how the linkage connects to the control valve assembly. The Service Manual shows a nearly worthless picture that seems to depict the lever being connected to the control via a pin. _____ Is there any way to check this without removing the tubelines (the step in the manual before the linkage "pin")? I'm not a mechanic but I can find my way around a toolbox. Still, removing this assembly appears to be a task that is beyond my comfort level._____ Thanks in advance.
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Thanks, Tazza; no way I'd have ever thought of that. I did not get a chance to try this today after work, had to seed an acre and a half of pasture before the rain with a lawn spreader (note to self - don't do that!). I'll give it a shot tomorrow.
Wow, sounds like you were a tad busy, you gotta do what you gotta do though.....
Hopefully it as easy as the lever, if so, you won't do it again
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Hopefully by now you've found the problem but in case you didn't, the linkage for the lift arm controls passes underneath the pumps. Right in the middle of this bellcrank under the pump is a pivot pin that is welded to the top of the chaincase. Could be that this is broken off. The rod ad the valve connects with a piece of roller chain link, it looks like a master link from a piece of roller chain, probably exactly what it is. Could be that the link fell out or broke? The fact that you can easily move the pedal and that it stays in whatever position you leave it leads me to believe it is the linkage to the valve. It will not be fun to access this linkage at the valve but it is possible to install it without removing the lines from the valve. Good luck and keep us posted.
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Forgot to add that if the pivot under the pump is broken then you will need to remove the pump to fix it...
Thanks much, spitzair, I believe that I did find the issue. The linkage bar that sits under the hydrostatic unit does appear to have lost its pivot point. However, the Bobcat online parts diagram shows a bolt that passes through the bar from underneath. I can see the hole that this bolt must pass through on the left side of the hydro I cannot see a hole under the bar so I would assume that the bolt sheared off just below the bar. I've got no idea how to get it in there and it's too late to crawl under the thing tonight. I'll have to check that tomorrow.
There is a bolt that screws through the chain case fron inside the chaincase up to under the pump. Not a great idea, as if it loosens when working on it, you need to crack the chain case up to work on it.....
Yep, the bolt sheered off at the top of the chain case. Great! _____ But I've got a plan to get this bugger working again. My neighbor will help me take the rops off with this skidloader and, if I can't rig a temporary pivot block to get the arms raised under power, I'll disconnect the arm hydraulic hoses and lift the arms with his loader. I plan to use an engine hoist with the hydraulic arm to lift the hydrostatic pump. _____ I do have one question, though. The service manual explains to disconnect the hoses from the pump; lots of work a very messy. Is it possible to lift the thing enough to get the chain case open and this pivot bolt replaced without taking the hoses all off and removing the pump completely? _____ If I really do need to take the hoses off, the manual says to use caps and plugs to keep the connections clean. Anyone know of a cost effective (aka cheap) source for these and what size it would take? _____ Thanks a lot, folks.
flyerdan
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Cap plugs are one of those ubiquitous items that are everywhere and nowhere. You'll find them on every hose or component that has an opening, even on the ends of hdmi cables. However if you go to purchase them in lots less than 5000 per they're practically nonexistent.
As to finding some, I would ask at dealers or shops that work on a lot of hydraulic equipment, they undoubtedly receive a lot of stuff that arrives with the ends capped, they should have a surplus of them and might be willing to part with some.
Failing that, using some plastic bag material and rubber bands will keep the mess in and the contaminants out. Won't be as robust as a proper cap plug, but should be ok with reasonable care.
As flyerdan said, if you need to pull the pump and hoses, rubber bands and plastic bags and rags will help keep the mess down somewhat.
Remove the main drive motor hoses at the motors, leave the pump end on, they are hard to access.
When i have done this sort of work, i did find i didn't need to lift the arms, not sure if it would be easier with the up in the air or not. If you do, make sure it is vell supported and that you install a jack under the rear of the machine to stop it tipping backwards.
I'm wondering, if you remove the engine, and the front pump mounts, if you can tilt the pump up enough to access the plate to get access to the broken off bolt. With the engine in place, i don't think you will get the required angle.
Thanks, flyerdan, Tazza, I'll check around and see if I can find some plugs/caps. ----- The reason for removing the rops and lifting the arms is to allowworking from the side, especially if I can do the job with just lifting the pump instead of removing it completely. Any, yes, putting a jack under the rear is an excellent idea. ----- While I've got the thing apart, I am also planning to remove and clean out the gas tank - from what I can see, there's plenty of built-up crap in there as well as some dirt and grit; hopefully that'll help prevent the fuel shut-off from clogging so often. Also, I'll flip the pintle bars to stop the forward creep (I can see that the are worn on the one side). ----- Is there anything else that that any y'all think I ought to check while I'm in there? As far as I can tell, everything else seems to be working properly.
If the pump does come out, replace or at least, check and grease the universal joints.
Look at the control block too, there is a hose that connects to the bottom and loops up, this hose fails and leaks, it's murder to get into and change on a 743, i don't remember the setup on the 732, but i'd assume this hose is still there.
If you are getting into the chain case, you may want to swap the oil in it too and mop the sludge out of the inside, be careful, there can be some spiky metal in there.
Thanks again, Tazza; I'll do that. And it looks like no easy out for me. The service manual says there are four bolts holding the pump to the chain case and I can only see three of them. It appears that the fourth one, on the right rear, is underneath two of the hoses. So, I'll have to remove the hoses and realized that I should have degreased and power washed the inside of this beast before taking the rops (with the ignition switch) off. And the service manual tells me to drain the system but does not give any hints as to the best way to do that. Is there a way to drain most if not all of the fluid without it just coming out every connection?
I drain fluid by running the machine at idle and pumping it out the aux couplers, when it spits i shut down.
The bolts can hide under the fuel or oil tank too. You take the pump put with the mounts still attached. Two at the front where the hydraulic pump is, the two at the rear mount to the frame where the fuel tank sits. Remove the 4 large drive motor lines at the motors, the line to the hydraulic pump and the charge hose(s). Lift the whole thing out with 4 hoses attached, it is heavy, but managable.
Keep note of the washers under the mounts. They are there as shims to get the correct ehight.
Thanks, Tazza. I wish I had drained it before I removed the rops (and the ignition switch!). I just removed the hoses and let it drain and that seemed to work with minimal mess. _____ I spent the whole day today cleaning what appears to be 40 years of crap form under everything, getting the hoses detached, and trying to figure out how to get that fourth bolt undone - I finally got a wrench wedged onto the bolt under the bracket by reaching in from the engine compartment. I think I've got the pump all detached but I am having trouble getting it out _____ The service manual says, "Fasten chain hoist to hydrostatic pump assembly and lift the pump while sliding the pump forward." Yeah, right! _____ There are two hydro lines (for either the left arm or the aux) that run between the chain case and the pump that the rear bracket needs to clear. The front comes up no problem but the rear just does not want to come up high enough to clear the lines AND there's a elbow for a hydro line on top of the pump that hits he welded framing that the cab back plate bolts to and the two meet no matter how I try to lift the pump. I tried removing the elbow, but it still hits the frame before loosening enough to come out. _____ When I try to just lift the rear of the pump, it only comes up a little then the front starts to rise (and the elbow hits the frame), as though there's something still holding the rear down. The manual does not say that anything else needs to be disconnected but I am afraid to force it. I am assuming the pump disconnects from the engine kind of like an automotive driveshaft and transmission and will just slide apart but I hate making assumptions, especially potentially costly ones. _____ Any advice would be greatly appreciated.
It should slide forward, up and out. The fitting on the top of the pump can be a pain, but it doesn't need to be removed.
Is the engine still in the machine? if it was out, it may help. It is possible the coupling is holding it in a little stopping it from dropping enough.
Every machine i have had has had masses od crud in the bottom of it, my dad gets the job of scraping it all out!
I was scanning the forum for the first time in a while and found this thread unfinished. I thought that odd because I was sure I finished it. At any rate, with the help of the knowledgeable and helpful Tazza, spitzair, flyerdan, and my ever so kind neighbor Adam, I got the bloody thing done.
The actual issue was the nut came off the bolt on which the lift linkage pivots and that bolt then unscrewed itself low enough to cause the linkage to disconnect. That bolt needed to be screwed back in (up) and a new locking net applied.
Had I known that, I believe that I could have reached the bolt without completely removing the pump; just detaching the pump from the frame and tilting enough to get my arm in there and tighten the bolt. That would have been good to know because it was nearly as hard to get the pump back in as it was to get it out; fortunately, Adam was not afraid to use sufficient persuasion (jump on the dang thing) to get it back into position. Also, I still have some leaking connections that need to be addressed as I am dripping fluid all over the place.
Still, it went back together and works like a charm. I had to drain the chain case as it was mixed with enough water to make it look like well-creamed coffee, using a drill-powered pump that I got from Northern Tool for a reasonable price. Again, thank you, fellows, for your expert guidance.
Glad you got it sorted out.
Lucky you did the chain case oil too, it is the most neglected part, as no one ever checks it.
