L175 lift cylinder piston o ring

[RootedRural]

I recently bought an L175. It has some hydraulic issues where it'll go up (with higher throttle) but then slowly leak down. I pulled the cylinder cover and found the main lift piston was completely seized in the bore with old hardened oil and rust.

I finally got the piston out, cleaned the cylinder bore with EvapoRust down to bare metal, and installed a new O ring (K7561-54370) and white backup ring(32200-37380). White ring first towards the open side then the o ring on top of that. Re lubed everything but it was a tight fit going back in, so I gave it a few light taps with a mallet to get it sunk in.

I put it all back together, and it worked great for about a minute. Then it started leaking down again, I pulled the piston back out and found the brand new o ring and back up ring were broken. Thoughts?

 

[TheOldHokie]

I recently bought an L175. It has some hydraulic issues where it'll go up (with higher throttle) but then slowly leak down. I pulled the cylinder cover and found the main lift piston was completely seized in the bore with old hardened oil and rust.

I finally got the piston out, cleaned the cylinder bore with EvapoRust down to bare metal, and installed a new O ring (K7561-54370) and white backup ring(32200-37380). White ring first towards the open side then the o ring on top of that. Re lubed everything but it was a tight fit going back in, so I gave it a few light taps with a mallet to get it sunk in.

I put it all back together, and it worked great for about a minute. Then it started leaking down again, I pulled the piston back out and found the brand new o ring and back up ring were broken. Thoughts?

I would say you pinched or tore one or both during instsllation. Install two new ones.

Dan

 

[North Idaho Wolfman]

Hone the cylinder or replace the liner.
And just to be clear the Orientation is, o-ring (30) is to the outside of the flat ring (31).

 

[RootedRural]

Just to follow up, rehoned and put new rings on. So far so good, thanks!