TC55DA - Where is 18LA loader hydr. pressure adjusted?

[Soundguy]

Also, I'll say it again... I'd have a hyd gauge and the needed adapters in hand so I could check to see what system pressure was vs pressure on the loader before i did -any- adjusting on the valve. You will also nee dthe hyd specs for that tractor.. etc. I like adjusting my loader relief pressures about 50psi under my main system relief... etc. It's easier and cheaper to repalce that loader spool block than the tractors main relief -usually-,, thus if one is to get more workout than the other.. i like it to be the cheaper/easier one..e tc..

soundguy

 

[Osconda]

Thanks guys,

I'll look for a pressure gauge at tractor supply, and check my specs before adusting anything. I'll check the at the rear remote first. Not sure where the adjustment would be for the loader.
If it's low at the SCV then I think I'll stop by the dealer and get the one they removed. They're on the way home from work. Maybe I'll just walk back to the dealer's shop and ask the Ag mechanic. He may just have a shim laying around.

 

[CJ4]

Osconda,

When you get this all figured out, please post us again and keep us informed of your discovery. I'm sure i'll need to know this for my TC55 at some point.

 

[Osconda]

I ordered one of those glycerin filled 3000PSI gauges from Northern Tool. Picked up a 1/2" to 1/4" reducer at Tractor Supply and made my test gauge to fit the rear remote output.

At idle the highest PSI is 2000. At 2000 RPMs it gets up to 2250 PSI. Looks like it's 240 PSI too low.

Now that makes sense as to while the loader feels weaker than before one of the cylinders was repaired.

I'm too busy to adjust it now. It's a nuisance at this point. Deer hunting has a higher priority at this time.

 

[Soundguy]

Hmm.. that system should run the same pressure at idle or throttle.. only difference should be the flow rate... etc.

Soundguy

 

[SPYDERLK]

Hmm.. that system should run the same pressure at idle or throttle.. only difference should be the flow rate... etc.

Soundguy

Agreed. As you say, the difference may be expained by it taking a little more pressure to push the higher volume of oil thru the relief valve. That would be a more prevalent factor if the readings were taken cold and likewise if the tractor had a particularly low idle to establish the low flow pressure.

Osconda, even a low relief pressure will not guarantee that cyls or lines on a loader wont be abused. This is because the relief is isolated from the loader circuit when the FEL valve is centered. Thats why, when you raise a heavy load and drive, the bumps you hit dont bring the arms down. That fluid is trapped until something blows. Pressure spikes FELward of the valve can go very high. Iv heard 12Kpsi. I assume thats where things start popping!
larry

 

[Osconda]

Well the tractor was cold. I just put in the gauge and started the tractor. So the fluid was cold.

Do ya'll really think I should get full PSI at idle? At least when the fluid is warm?

 

[Soundguy]

With limited exception.. positive displacement pumps make their full pressure at low rpm.. High rpm just increases flow rate ( gpm ).. etc.

Minor differences when cold are normal.. but you say a 500 psi difference from idle to throttle.. IMHO.. that is not correct..

Soundguy

 

[SPYDERLK]

I ordered one of those glycerin filled 3000PSI gauges from Northern Tool. Picked up a 1/2" to 1/4" reducer at Tractor Supply and made my test gauge to fit the rear remote output.

At idle the highest PSI is 2000. At 2000 RPMs it gets up to 2250 PSI. Looks like it's 240 PSI too low.--------------Do ya'll really think I should get full PSI at idle? At least when the fluid is warm?

You should get cracking pressure of the relief valve at idle on a deadheaded pump unless the idle is extremely slow and the fluid HOT. The pressure rises at high rpm because the relief has to be pushed open wide against the resistance of the spring in order for the high flow to pass thru it. Depending on the design of the valve the difference will vary - - 250 cold is not bad. Your numbers, and the cold operation suggest to me that your relief is set to crack very near 2000. I believe they are normally set for 2500. Before reseting I would be interested to know the Hot pressures. Im thinking the difference will decrease somewhat.
larry

 

[Osconda]

SPYDERLK,

With hydraulics running warm I didn't see any apprieciable difference. I finally picked up the "kit" from NH yesterday that contains about 6 thin washers. Cost $7.31. I was going to make a stink about it when I orderd them last week, since the dealer was the one who removed the washers to begin, with but I figured for $7 it wasn't worth my aggrevation.

When I went to pick up the washers yesterday, there was also an $8 freight charge! Dang, the freight was more than the parts. I refused to pay the freight because they never told me anything about the freight and if anything they should have paid for the parts and the freight, since I was merely correcting a problem they created......they dropped the freight charge. Good thing I didn't bill them for diagnosis and installation. I bet you guys charge a lot for diagnosis.

Anyway...I was too busy last night to actually get the washers installed but I had previously removed the large bolt that holds the spring in the drawing and found there were no washers at all in there. Should be a 5 min. job when I get home this evening.