No bucket tilt function on Bobcat 753

[bob6104]

I was using the Bobcat the other day and after hearing a "clunk" the grapple tilted down. I am unable to raise it. The right pedal does nothing. Any thoughts? I was detaching the grapple this morning, trying the right pedal just for the heck of it and once (and only once) when I pressed it down with my heal on the right pedal the Bobcat arms went down. (I swear I didn't touch the left pedal!) I'm going assume that this repair will be beyond my shade tree mechanic abilities, but I would like to get an understanding of what some of the possible solutions might be so that I can speak intelligently to the mechanic. Many thanks! PS: Another strange thing is that now the Bobcat will roll away on a hill unless I set the parking brake. This was never the case before. Normally it will roll for less than a foot before stopping itself.

 

[Acoals]

I was using the Bobcat the other day and after hearing a "clunk" the grapple tilted down. I am unable to raise it. The right pedal does nothing. Any thoughts? I was detaching the grapple this morning, trying the right pedal just for the heck of it and once (and only once) when I pressed it down with my heal on the right pedal the Bobcat arms went down. (I swear I didn't touch the left pedal!) I'm going assume that this repair will be beyond my shade tree mechanic abilities, but I would like to get an understanding of what some of the possible solutions might be so that I can speak intelligently to the mechanic. Many thanks! PS: Another strange thing is that now the Bobcat will roll away on a hill unless I set the parking brake. This was never the case before. Normally it will roll for less than a foot before stopping itself.

Have you lifted the cab yet?

 

[bob6104]

Yes. Don't see anything unusual.

 

[Acoals]

Yes. Don't see anything unusual.

If you can do it safely, actuate the pedals, carefully watching the linkages operate. Compare the side that still functions with the bad side. Carefully examine the valve and the actuator arm as it operates. If you could do it running I would be listening to the fluid as well, but that is kind of hard to explain.

Make sure the machine is level and blocked and the boom is either down completely or locked up with the orange lock bar before you do much of anything.

 

[bob6104]

If you can do it safely, actuate the pedals, carefully watching the linkages operate. Compare the side that still functions with the bad side. Carefully examine the valve and the actuator arm as it operates. If you could do it running I would be listening to the fluid as well, but that is kind of hard to explain.

Make sure the machine is level and blocked and the boom is either down completely or locked up with the orange lock bar before you do much of anything.

Thanks for the response. The wind, rain and snow finally let up so I was able to get out and take a closer look. I don't see any difference in how one pedal operates compared to the other. When it is running and I operate the right, tilt pedal I hear something, probably the pump make a faint noise. I operated the tilt pedal when the cab was up and the engine running (with seat bar up but pressing down on the plunger that the seat bar would normally push down on. It tilted down once but then I couldn't get it to do much after that. Another strange thing is that with the cab down, sitting in the seat with the bar down the pedal does nothing. If you put the bar up and lean forward and depress the plunger that the bar normally depresses the pedal will make the bucket tilt back and forth maybe a half an inch. Does this help at all?

 

[Acoals]

Thanks for the response. The wind, rain and snow finally let up so I was able to get out and take a closer look. I don't see any difference in how one pedal operates compared to the other. When it is running and I operate the right, tilt pedal I hear something, probably the pump make a faint noise. I operated the tilt pedal when the cab was up and the engine running (with seat bar up but pressing down on the plunger that the seat bar would normally push down on. It tilted down once but then I couldn't get it to do much after that. Another strange thing is that with the cab down, sitting in the seat with the bar down the pedal does nothing. If you put the bar up and lean forward and depress the plunger that the bar normally depresses the pedal will make the bucket tilt back and forth maybe a half an inch. Does this help at all?

That indicates that the problem may be in the linkages, or at least that is a good place to start. Those older Bobcats have a bunch of moving parts and bushings, all of which wear over time. One thing to do would be to find wear the linkage actuates the valve itself. Disconnect the linkage there, or as close to the valve as possible, and try to manually actuate the valve. It may be hard, you may need to use a prybar or something. The idea is to test the hydraulic function by temporarily eliminating the control linkages.

Make sure you have help, and be completely clear of the loader arms when you do this. I can't over emphasize caution, particularly if you don't have much experience with mechanics. That machine can kill you in an instant if you forget something.

 

[bob6104]

I like the idea of isolating the problem from the linkage. I found a diesel mechanic who is coming over next week and I will share the idea with him. He mainly works on trucks so I'm sure he'll be interested in any ideas you have. I read in another post about a similar issue that the problem could be a blown valve in the hydrolic cylinder that operated the tilt in the front of the Bobcat. What do you think about that idea?

 

[Acoals]

I like the idea of isolating the problem from the linkage. I found a diesel mechanic who is coming over next week and I will share the idea with him. He mainly works on trucks so I'm sure he'll be interested in any ideas you have. I read in another post about a similar issue that the problem could be a blown valve in the hydrolic cylinder that operated the tilt in the front of the Bobcat. What do you think about that idea?

I don't have any thoughts on that idea, other than that I doubt there are any valves in the tilt cylinder.
Diagnosis is something that needs to be done in a systematic way. We have to first figure out if the problem is hydraulic or mechanical before we get tangled up talking about hydraulics.

 

[Tinkerer]

The cylinder parts list would show it if there is one.
I would suspect a piston may have come off one of the cylinder rods.

 

[spitzair]

Is your tilt pedal linkage still connected to the valve spool? From what you’re describing it sounds to me like the linkage got disconnected at the spool, then dropped down and when you had it move the lift arms that one time it probably pressed against the lift spool which is below the tilt… at least it is on the older machines I’m used to. The linkages are really just pieces of flat bar tied to the hydraulic spool valve with a simple pin. If that pin fell out it would explain the clunk you heard too. The fun part of the deal is that the control valve is very buried in the right side of the machie and getting to it could be difficult…

 

[bob6104]

Everything looks connected and the pedal moves the linkages the same way that the left peddal does. I have a mechanic coming over later today and he'll verify this. Thanks!