I have a 2006 Thomas 153 which is leaking hydraulic fluid into the the final drive. i am wondering if it makes sense to try to rebuild and reseal final drive motor or just install a new one. Any advise from past experiences would be greatly appreciated
If the leak is on the hydraulic side. One common problem is a clogged case drain filter. The clogged filter will cause back pressure on the seals to internally blow causing the Hydraulic Fluid to internally leak. Before you decide which path to go i would verify if it is a problem with the case drain filter. Rebuilding is usually half the cost of new which is a good way to go.
Thanks for your advise i will check the case drain filter.
But bear in mind replacing the filter won't fix the leak if that is the problem. The shaft seal will still need replacing.
I do not see a filter and I shot air through the line and there is no restrictions. I have already replaced the shaft seal. This unit started leaking at very low hours 240.
Usually shaft seals that fail are a result of High Pressure or a Pressure Spike. With you not having the filter i think something else maybe happening. Dirty oil and Contaminants can also cause issues. The dirty oil or contaminants can actually get under the shaft seal and literally grind a groove in the shaft causing a leak. 240 Hours on a rebuilt Motor is not a lot of Hours.
I have a T133 that the chain case was filling with hyd. oil. It's possible the wheel motor just needs seals but in my case they replaced the wheel motor. They took the wheel motor out and sent it to a shop more experienced with them. There was internal damage and it was less expensive to put a new wheel motor in. If you caught yours in time, it may just need to be resealed which will be quite a bit less expensive.
I replaced the seal and it did not help I am now wondering if the fact that i changed over to Amsoil 10w30w synthetic when i first got the unit may have something to do with it. I use Amsoil in all of my vehicles and equipment but maybe its to slippery for the drive motor.
Also a damaged valve plate in the hydraulic motor will cause the case drain to pressurize. To check the case drain, disconnect the hose somewhere near the tank and put the end into a drum, run it at WOT for 1 minute then shut down. Measure the amount of oil in the can, if you have more than a quart then the motor needs to be looked at. You will have to lift the machine off the ground to do this.
I think it's possible the synthetic oil may have caused the issue if it isn't compatible with the conventional oil or what the OEM specifies for hyd. oil. Is the Amsoil 10w-30 recommended for hyd's? Hyd oil is different than engine oil but some machines do specify to use 10w-30 engine oil. I don't know what caused my wheel motor to start leaking but I wouldn't change to synthetic oil just for the sake of changing to synthetic oil. I change the hyd. filter pretty regular though. Did you take the wheel motor apart and inspect it? Did you replace just a wiper seal or the pressure seal(s) in the motor? It's hard to say what is causing the leak but having the motor inspected by a competent hyd shop would be the logical next step.
I am going to drain the Amsoil and go back to a 10w30w conventional oil
I am unaware of the set up on a Thomas, but don't overlook a leaking brake piston seal if it has hydraulically released brakes.
Would that make it leak out the final drive motor into the final drive?
Again I am not familiar with Thomas set up on the drive motor, but yes if the brake is integrated with drive motor it could leak into the final.