850 lift cover Stuck Check Valve

[LarryMaine]

Am rebuilding my lift cover & cylinder. Have replaced pivot pin, cylinder piston and washer and O ring. Replaced all o rings. Removed and cleaned control valve, replaced relief valve. Will measure and adjust clearance for draft and position control. I removed the check valve plug on side of lift cover, and check valve components should have just come out, but they are stuck in place and it does not move at all. Not talking about the valve seat, I mean the check valve pilot assembly, ball, spring, etc. that are in front of the seat. Any suggestions on how to get it out without damaging it (replacement check valve parts are not available anywhere). Thanks all, Larry.

 

[shaun wallace]

The plug with 11/16 wrench size is out? the part with nub on it pulls out, has spring and ball, Next part is back pressure bushing,has plunger and spring behind it. Uses 3/8-24 threaded rod to pull. Use socket and washers with nut to pull. DO NOT use slide hammer it will break it. Have seen very few failures of back pressure valve but after 60+ years it could happen.

 

[LarryMaine]

Yea, I knew most of that, the problem is I have the plug cap off, but the check valve assembly would not come out. It is out now because I used PB Blaster, Propane Heat in cycles, and lightly hammer tapped the cover. Then I used a punch to loosen the assembly, then I used a vise grips to pull out the assembly using the little knob at the end. The assembly and the hole needs a good buffing to get rid of the rust, and will work on pulling the check valve seat and back pressure valve tomorrow once I get the right bolt. If I buff the interior then I should be able to pull out the seat without much problem. Thanks again, Larry