open hydraulics

[Harry in Ky]

So this is an M100, cab tractor? Has a loader with mid mount cable controlled two spool valve under the right cab door? The hydraulic pumps are under the cab just below the seat? You have a gauge in the pressure line leading to that valve? The loader currently doesn't function at all? Yes/no so far?

Steering, PTO, and transmission circuits (all supplied by the other pump) seem to work okay? So what did the dealer shop claim they did to solve the original problem? You stated it worked ok after that for a while.

 

[oldnslo]

it first started having issues with the FEL, slowly creeping down . Took it into the dealer because I was just flat out busy , (huge mistake). Seemed fine at first then eventually it stopped working all together . I pulled the valve apart to find some parts missing (heater plug) . So I got a re seal kit and installed it. Still nothing .

What is the “heater plug” that was missing?

I hooked up my pressure gauge , haven’t been able to get much for pressure . When I ran the unit in the winter , I did notice sort of a wheezing coming from the pump area. It sounded like cavitation , so I checked my plumbing, new filters , all new oil . The pump isn’t making the noise now, so I’m wondering if the pump is cooked ??

Does the pump housing get significantly hotter than the inlet line to the pump?

Which doesn’t make sense because my 3P system works . I will see if I can put the 3P system under load to see if it can actually lift anything . Appreciate all the responses . Thx

I made the assumption that the 3 point working meant it was lifting a load.. so yes check to see if it will lift a load.

 

[Bentrim]

A basic review of hydraulics.
1 a pump moves oil it does not create pressure.
2. a valve controls how oil is directed.
3. In an open center system oil MUST not be stopped. If flow is stopped a big bang will happen wether a hose, pump, drive shaft, or relief valve.
4. The load applied to the system determines the pressure within the system.
5 for a load to leak down the cylinders are first suspect, valve second, and never the pump.
The cylinder have a seal on the piston between the ends of the cylinder. The piston moves and subjects
the seals to wear, so oil can leak from one end to the otherm with no oil leaking out of the cylinder.
The valve is sealed from leaking oil out of it by O rings, there are no internal O rings in a valvem the spools and lands are matched to assure a sealm oil finishes this seal.
6 A gauge placed anywhere between the pump and load will read working pressure. If the relief valve is activated it will read system pressure or maximum available pressure, If the system pressure cannot be attained then there is a leak somewhere, pump is shot, or the inlet to the pump is restricted.
7. It is normal for all systems to slowly leak down, there are no perfect seals. That said during operation it should be negligable.
8 There are valves made that use poppets to seal any oil returnm but they are very expensive and usually used on combines.
9 If you feel the loader cylinder are causing your leak down take a pipe, screwdriver short bar, etc and place it against the cylinder you will hear a hissing as the oil bypasses the piston. If you suspect the valve again use the "tool" and listen for a hissing of bypassing oil.

 

[kenhar]

Low or no hydraulic pressure, I change the hydraulic filter. If it doesn't help it doesn't hurt either.