Help me diagnose 630 problem plz

[mrp010]

I have a 1980ish bobcat 630. It is new to me and I am a skidsteer noob. It runs great and functions fine for about 15 minutes or so. Once good and warm it starts to hesitate to turn and eventually won't turn at all. Makes a loud whining noise when trying. I have the manual and it looks like it could be a few different things. But none of the trouble shooting tips say anything about it just happening when warmed up. All the fluids were recently changed and the levels look fine. Any advice would be much appreciated. I just want to try to narrow it down and see if it's something I can fix or if it needs to go to the shop. Thanks Mike

 

[OldMachinist]

Sounds like the sintered bronze filter in the port block is clogged. Remove and replace or clean.

 

[mrp010]

Sounds like the sintered bronze filter in the port block is clogged. Remove and replace or clean.

That was one of the things I was considering but wouldn't that affect the drive in all directions? That and the by-pass valve. Like I said it will go good in forward and reverse but it wont with one side going forward and one side going reverse. Could it be the replenishing valve?s? But again why would it still go in forward and reverse and just give me grief when turning. Thanks Mike

 

[antfarmer2]

That was one of the things I was considering but wouldn't that affect the drive in all directions? That and the by-pass valve. Like I said it will go good in forward and reverse but it wont with one side going forward and one side going reverse. Could it be the replenishing valve?s? But again why would it still go in forward and reverse and just give me grief when turning. Thanks Mike

Takes more power to turn fix it and see how much more power you have

 

[mrp010]

Takes more power to turn fix it and see how much more power you have

Ahh. Makes sense. Thanks to you both. I'll give it a shot.

 

[mrp010]

Sounds like the sintered bronze filter in the port block is clogged. Remove and replace or clean.

Well I got a new filter in it. Didn't fix my problem tho. Any other ideas? Bypass valve maybe? More serious issues? Thanks Mike

 

[jerry]

Well I got a new filter in it. Didn't fix my problem tho. Any other ideas? Bypass valve maybe? More serious issues? Thanks Mike

Have you changed the main hydraulic filter? Sounds like the hydro pumps need attention though. It does take a lot of snort to do the spinning around maneuver though.

 

[mrp010]

Have you changed the main hydraulic filter? Sounds like the hydro pumps need attention though. It does take a lot of snort to do the spinning around maneuver though.

I was told all the filters were replaced about 10 hours ago, and they do look new. I'll check them tho. It's not just trying to spin, it's turning at all, makes a whining noise and just won't go. Goes forwards and backwards with no problems.

 

[mrp010]

Sounds like the sintered bronze filter in the port block is clogged. Remove and replace or clean.

I replaced the bronze filter, not the issue evidently. The old one looked to be in good shape. Any other ideas before I go to the stealer ship? Any chance it is the bypass valve or am I way off base?

 

[Tazza]

I replaced the bronze filter, not the issue evidently. The old one looked to be in good shape. Any other ideas before I go to the stealer ship? Any chance it is the bypass valve or am I way off base?

Kinda depends on just how confident you are, you can pull the pump and inspect it for wear and repair what needs it.
The bronze filter is generally the issue with what you described. The oil gets hotter and thinner, the filter restricts the oil flow and the oil cavetates (tiny bubbles). You get little to no power and the drive pump heats up quickly.
If you are brave enough to dig into the pump, let me know and i can give you details of what to expect and how to go about repairing it.