[jkunnari]

My Farmall 350 (1957) hydraulics has been over the past year gotten to be less responsive i.e. slower to raise loader arm/bucket. After running for awhile it has recently gotten to where there's no hydraulic action on any of the 3 main controls i.e. loader arm, bucket, 2 pt. quick hitch. I've drained the hydraulic oil reservoir, cleaned the metal cone screen, refilled the reservoir with fresh (Fleet Farm) Case IH Trans-Hydraulic fluid. Still no hydraulics at all. Ideas? Hydraulic pump vs. Hydraulic Regulator/Safety value in bypass mode or other. Recommended sequence to identify the cause. I don't see obvious fluid leaks. Thank you

 

[BigT]

Howdy jkunnari, welcome to the tractor forum.

The safety valve may have debris stuck in it holding it open, but not likely. If it's an easy job to take a look at it, go for it.

I presume that this is an old pump. The hydraulic pumps have aluminum housings, which are what is usually worn out if internal wear allows the tips of the gears to wear into the housing. There is not much that new bushings, or end plate machine work will do.

You could give the pump a flow/pressure test to check its performance. The pump's ratings are 10 GPM @ 1600 RPM 1200 PSI. Install a hose into the pump output and flow test it into clean buckets. You will need a helper to control the engine, so you don't make a mess. You could also install a pipe "tee" with a 1500 psi pressure gauge into the pump output and check pressure, but you will also need a valve to apply backpressure to test the pump. Don't deadhead the pump.

There are aftermarket pumps available for about $600.

 

[jkunnari]

Howdy jkunnari, welcome to the tractor forum.

The safety valve may have debris stuck in it holding it open, but not likely. If it's an easy job to take a look at it, go for it.

I presume that this is an old pump. The hydraulic pumps have aluminum housings, which are what is usually worn out if internal wear allows the tips of the gears to wear into the housing. There is not much that new bushings, or end plate machine work will do.

You could give the pump a flow/pressure test to check its performance. The pump's ratings are 10 GPM @ 1600 RPM 1200 PSI. Install a hose into the pump output and flow test it into clean buckets. You will need a helper to control the engine, so you don't make a mess. You could also install a pipe "tee" with a 1500 psi pressure gauge into the pump output and check pressure, but you will also need a valve to apply backpressure to test the pump. Don't deadhead the pump.

There are aftermarket pumps available for about $600.

Thanks BigT, I'll work on getting the pipe "tee" with a fitting I can attach/detach hose with pressure guage. I think I can fabricate that with parts from local Mills Fleet Farm store. As you said, to be sure guage rating is at least 1500 psi. This should at least point me to whether there is pump flow or not. Then I can go from there. I have priced new pumps in the range $625 approx. I think I'd go that route rather than a used, since those may be similar in age/use as mine (I think it's original 1957). Thanks again. It'll be several weeks before I get up to family homestead where it's stored to continue troubleshooting. I'll give updates as I know more.
Merry Christmas

 

[mrfred]

More than !likely your unloader valve needs attention. It is located in front of steering column on the left side. Left hood will have to be removed. A service manual wood help you alot. Four bolts hold the cover on the valve. The valve unit does not have to be removed from the tractor. Be careful after removal of the four bolts as the cover is under strong spring pressure

 

[jkunnari]

More than !likely your unloader valve needs attention. It is located in front of steering column on the left side. Left hood will have to be removed. A service manual wood help you alot. Four bolts hold the cover on the valve. The valve unit does not have to be removed from the tractor. Be careful after removal of the four bolts as the cover is under strong spring pressure

This hydraulic regulator / safety value you describe is high on my list to look at. 1st I'm going to verify whether hydraulic pump is producing flow. If it is, then the regulator / safety value is next. I've read to remove the top plate, it's recommended to remove one bolt at a time replace with longer bolt, snug down. Then loosen the longer bolts gradually alternating one at a time. If there's possibly a weak or broken spring in there, the bypass may not reset, is 1 possibility. I've got an "I&T" Farmall 350 shop manual. However, the details in that are limited. I have a couple Binder manuals on order, since 11/30 that should give more detail. They've been USPS black hole, since 11/5.
It'll be in Jan. 2021 before I'll be back where the tractor is to continue troubleshooting. Will post what I find out. Thank you all!