earthforce {bobcat}B250

[robert w white]

B250 just bought from Iron Planet it arrived without brakes and nor moving foward or reverse almost at all, none of which was in thier report.. loader/backhoe working fine {different hydro motor} tractor has no leakes and I changed the hydro filter and oil but no change in proformance. With engine at full reves it will creep along on flat ground but brakes do not engage. Hydro motor? servos? electric? This is a near death machine, that is someone will be killed on it if the thing is not fixed. help please! where is the Iron clad assurance?

 

[sequoyah101]

I'd start by posting their inspection here or a link to it. Iron Planet should do better than that.

Almost impossible to diagnose here without more information. Hydrostatic transmissions are hard to diagnose from my experience. I have a loader with one that has done the same kind of thing. The more you ran it the slower it got. It is better now but not great. This is after dropping $1,700 at Hug and Hall after they checked it out having advertised they are hydrostatic type equipment experts. After this I set out on a mission to learn about hydrostatic transmissions and ended up buying a $650 pressure test kit. It helped to diagnose the problem and I found the main relief valves eroded. What you really need for diagnosis is a flow meter and they are expensive, much more than the pressure test kit. I've thought about building one with a meter run and a couple of pressure gauges. $500 after that I replaced the main pressure relief valves for forward and reverse. I have never looked at the continuity of the electric system and am finding that is more important on older modern machines than I once thought. Old tractors had no electronics on them so current and voltage didn't matter as much. Next step that made a difference was finding the boost pump was loose and not giving a good charge to the injection pump. Like I said, it is better now but not up to my expectations.

If the oil is clean the swash plate motor and pump should last thousands of hours. You don't say how many hours you have on your machine. The back plate clearance is so small it can be damaged by something much less than the size of a hair. Case drain pressure is one indication that the back plate clearance may be damaged.

Sometimes it is just low hydraulic fluid level or a plugged filter. Maybe you'll get lucky like that.

Good luck.

 

[CJONE]

I have dealt with a number of so called experts. There is only 1 place that I consider experts. They actually build Hydrostats to my specs. Like Sequoyah said these units are very dirt intolerant and once it gets into the system it usually makes a bunch of trips around the HP loop doing a bunch of damage. Most replace the pump and not the motor and vise versa. Both need to be inpected and repaired as needed. AND like was already stated you need to check pressures, ALL of them. Charge pressure on stroke and off stroke, main system pressure, case drain flow, ect,ect. CJ