Hydraulic pump problem

[davesisk]

Hi and welcome!

Don't run the engine without the hydro-static drive pump primed. You'll burn the pump up in about 60 seconds due to cavitation. Even if it is an old pump, you should have a bleeder port on the left side (looking at the pump from the front...back of it attaches to the engine). You might not have fitting on this port (I didn't)...it might just be a hex allen screw.

Unplug the spark plug wires, open the bleeder port. and turn the engine over with the starter about 10-15 seconds at a time, then stop for a minute or so, then repeat. (You don't want to burn up the starter either!) Continue this until you get nothing but oil (no air) out of the bleeder port.

Btw, I have a 1990 PT-1418...13 years old and still running! (Although I do have to do some patching up periodically... /forums/images/graemlins/wink.gif)

HTH,
Dave

 

[toy]

i think in a variable volum pump there is a plate that spins like a wheel , when you push down on the tram it causes the plate to shift to an angle, as it spins at an angle the plate causes the pistons to work back and forth thus causing the pistons to pull oil into the cylinders and pushing it out to the wheels. If the small variable volum pump works the same way that larger ones work, and that plate isn't angled to the max then the pump isn't on full stroke and if it isn't on full stroke then it isn't giving you a full volum of oil that the pump should put out. The metal from the breakdown of the variable volum pump could have also caused damage down stream from it, I hope the problem isn't something that will cost you extra. The oil in your tank might be contaminated , but the filter should catch anything coming out of the tank. Check the oil in the tank and see if it has metal particles in it. If it does you might want to drain the old oil out and clean the tank and refill it.

 

[J_J]

If you suspect the wheel motors, you can check each of the wheel motors by removing hoses, and inserting an adapter to connect the two hoses togather. If you develope full pressure and volume, then you will know which wheel motor is at fault . I also feel like the repair company should have hooked up and tested the unit before you paid in full.

J.J.

 

[toy]

Have you got your machine going yet? I haven't looked at the wheel motors but according to the schematic it shows only two hoses on the wheel unit and does not show a return hose to the tank, however it doesn't show the tram pedal valve in it either, but it looks like to me if one wheel unit was bypasing the oil would go to the other wheels and still pull. By the wheels turning the wheel units is not locked up I wouldn't think, you don't mention the engine bogging down when you try to tram it, so I wouldn't think that the oil flow was blocked off. It sounds like the pump either has a problem or the tram valve is not sending flow required to stroke the pump. As I said though I am not looking at the machine and the schematic leaves a lot to be desired, and my machine might not be exactly like yours. Hope you get it to going soon.