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.

 

[Mudfarmtruck]

The pressure gauge is showing 30-40 psi when the control valve is open . (Lift bucket) The open centre valve has a direct connection to 1 of 2 of the hydraulic pumps . Appreciate the responses . Hopefully I can narrow this down tonight .

 

[Tinhack]

30-40 psi is typically a return to tank pressure. You're not teed off the correct line or you're teed on the down-stream or open center port. Teeing off a pressure line to a cylinder will not give you a valid pressure either until that cylinder is at the end of travel. At that point, you should get a squeal and a pressure reading of the cutoff. This pressure is typically 2200-3500 psi. Be sure your gauge can read that in the median range. In other words, your gauge should be about 5000-6000psi at maximum.

Edit: Power steering pressure lines are typically in the 700-900psi range. You also won't get that pressure until the end of travel.

 

[Mudfarmtruck]

30-40 psi is typically a return to tank pressure. You're not teed off the correct line or you're teed on the down-stream or open center port. Teeing off a pressure line to a cylinder will not give you a valid pressure either until that cylinder is at the end of travel. At that point, you should get a squeal and a pressure reading of the cutoff. This pressure is typically 2200-3500 psi. Be sure your gauge can read that in the median range. In other words, your gauge should be about 5000-6000psi at maximum.

Edit: Power steering pressure lines are typically in the 700-900psi range. You also won't get that pressure until the end of travel.

Could it be possible that I have the centre valve that puts fluid into the ports located incorrectly ? . My pressure gauge is off the “p” port .

 

[Harry in Ky]

At this point no one knows WHAT'S possible because no one knows what you have. Is this a dedicated loader valve that has the problem? Cable operated joystick type mounted under the cab? All we know is you have a gauge plumbed into a pressure line (somewhere) and it doesn't read much pressure. You still haven't identified what works and what doesn't.

 

[Mudfarmtruck]

At this point no one knows WHAT'S possible because no one knows what you have. Is this a dedicated loader valve that has the problem? Cable operated joystick type mounted under the cab? All we know is you have a gauge plumbed into a pressure line (somewhere) and it doesn't read much pressure. You still haven't identified what works and what doesn't.

its a m100x. Its a cable controlled open center hydraulic system for a loader controls are mounted in the cab. the 3 point hitch is working. The valve is leaking a very small amount, i just havent degreased it to find where.

 

[Harry in Ky]

So it no doubt has at least one remote valve on the back, totally separate from the loader valve. If you plug your gauge (or A gauge) into one of the couplers, hold that valve open, what does the gauge read? In theory, (mine at least) that's where you should have started. Typically, the loader valve will be first in line for oil flow from the pump, remote valves will be next, and three point is last. Can you follow the lines and confirm that? If the loader valve is indeed first, and it doesn't have any flow or pressure, then obviously the pump performance is suspect.