Hydraulic bleed down fast on c-175

[Torino 14]

Hydraulics will not hold. The deck will go from full up to down in less than a minute.

[TT-(Moderator) 1,147]

It's probably a bad cylinder seal but it could also be a bad control valve seal.

[Torino 14]

Stupid question. Should the guilty party be leaking?

[Save Old Iron 1,568]

The guilty party COULD have an external leak but the hydraulic fluid may be leaking past an internal seal on the control valve or the piston seal of the cylinder. No EXTERNAL leak would be seen. If it were an external leak at fault, nearly all the fluid in the lift cylinder would have to escape to allow the attachment to move that far. There would be a BIG puddle of fluid if it were an external leak. An internal leak just bypasses the fluid under pressure past the sealing orings to the unpressurized side of the system and returns the fluid to the low pressure side of the system. No visual leaks are seen.

[Torino 14]

Is there a way to know the guilty party if there is no external leak?

[Butch 194]

The guilty party COULD have an external leak but the hydraulic fluid may be leaking past an internal seal on the control valve or the piston seal of the cylinder. No EXTERNAL leak would be seen. If it were an external leak at fault, nearly all the fluid in the lift cylinder would have to escape to allow the attachment to move that far. There would be a BIG puddle of fluid if it were an external leak. An internal leak just bypasses the fluid under pressure past the sealing orings to the unpressurized side of the system and returns the fluid to the low pressure side of the system. No visual leaks are seen.

Huh?!

[mrocket49 23]

Here's a link to a schematic of the lift cylinder. http://www.partstree...-72R10046-00022 The cylinder is a two-way hydraulic cylinder which means it has pressure in both directions. If the o-rings leak, the oil just gets pushed back into the transaxle (which acts as the reservoir). there were two different cylinders, I think you identify which you have by whether they are held together with a snap ring or an "e" ring, but I can't remember off-hand right now.

As long as it's not a welded lift cylinder, they are easy to rebuild but the kit from Toro is around $60.00 and you don't get much more than o-rings for the money. Some people on here have figured out the sizes and bought the o-rings individually for less.

[Save Old Iron 1,568]

T,

if you have no major external leaks, the troubleshooting becomes a matter of how much work is involved in checking out the two possible suspects (lift cylinder or the control valve). The "tools" needed to troubleshoot become more expensive than the fix.

The control valve is easier to rebuild than the cylinder but the control valve is much more difficult to access and remove from the tractor hood stand area.

One method to save time / money / aggravation would be to remove the lift cylinder from the tractor and take it to a hydraulics shop to have it tested. If it tests OK, your control valve could be the culprit.

If you really want to get into isolating the guilty party for the sake of learning or familiarizing yourself with hydraulics,start with the lift cylinder. Raise the plow blade or mower deck to max height and block it up so it remains elevated. Remove both hoses from the lift cylinder. Plug both the inlet and outlet port ON THE CYLINDER with appropriate block off fittings. Remove the blocking for the blade or mower deck. The accessory may initially move a bit due to air trapped in the cylinder caused by removing the hoses. If the blade or mower deck floats to the floor, the cylinder has a significant leakage past sealing o rings internal to the cylinder. If the blade or deck remains elevated, the cylinder passes the test and the control valve will need to be inspected / rebuilt.

http://www.nhc.ru/pa...da3a928ec694d41

[Torino 14]

Tnks, for the info guys. I will report back.

[Torino 14]

Finally getting around to this. I have an extra WH lift cylinder I got for another project that I can use. Of course if it still leaks down it is not telling me anything, if it does not then I know it was the cylinder. It came to me without any fittings. How do I make sure that it is clean enough inside to install it? How do I install it (I know how to install it I am wondering about the fluid once I take it off)? Do I fill the cylinder with fluid before installing? Do I need to release the pressure in the system, if so how?

[Whmaverick 54]

Hello, I totally disassembled my hydraulic system on my 77 C-160 auto cleaned, primed and painted then reinstalled the entire system, "dry" , when it came time to get it running I asked my local dealer tech guy and he said to simply block the axles to free the wheels, then add 10W-30 motor oil, with the engine running, work the motion control lever back and forth as well as the lift lever up and down until the fill level is at the f mark and all systems are working properly. HTH (hope that helps)

[Torino 14]

Old Iron somehow I missed post no.8. I was on a new laptop with Windows 8 (which so far I don't like) and sometimes it jumps around on the page and I guess it flew by your last post. I am going to try your suggestion of blocking the deck and see if it bleeds down so I know if it is the cylinder or the control valve and go from there.

If it is the cylinder what do I use to clean it out before installing?

[Torino 14]

It was the lift cylinder.

[Save Old Iron 1,568]

That's great T. Glad you could identify the culprit. The o'rings in the cylinder do take more abuse than the ones in the control valve.

Did you get to take it apart and do any work on it?

[Torino 14]

No, I happen to have an extra one so I tried that and it worked. Since the rebuild kit is so much I am not sure what I will do with the old one. Some say having it rebuit is right much cheaper. Any thoughts?

[Save Old Iron 1,568]

Since it probably all stems from a worn o'ring on the piston, getting a seal kit would be the least expensive option. I don't have any numbers for the parts but I believe a search here will bring them up. Invest $15 to $20 and a few well chosen and muted curse words when re-assembling and bingo - done.

[Butch 194]

Torino I bought my cylinder parts from Toro. Not cheap for what I was getting. I could have gone to my local hydraulic shop

and got the parts for next to nothing.

[mrocket49 23]

http://www.partstree.com/parts/?lc=toro_consumer&mn=01-17KE02%2C+C-175+Twin+Automatic+Tractor%2C+1982&dn=810272R1-72R10046-00022

Part #2 in the diagram. $59.00