Fork holds air, until compression.

[Fire Lord Jim]

Fork is a Manitou R7 Platinum. Both legs hold air. I put the shock pump on, pumped, and left the pump on; each leg stays at the originally dialed pressure. But with a couple of rebounds on the bike, and the shock is spongy and won't return. Any suggestions? Am I about to rebuild my first shock? Thanks.

 

[blackburn1973]

Yes, I believe you are. Is the pressure still correct when you test it after a couple of rebounds? And can you pull the shock back to fully extended or is it stuck in depressed mode?

 

[Fire Lord Jim]

I can pull it back to extended, so not stuck. I am going to fill a trash can with water, and look for air bubbles during compression.

 

[Fire Lord Jim]

I filled the trash can with water, aired up and then dunked the shock. No bubbles. I compressed and rebounded the shock several times: no bubbles. I turned it over and lather rinse repeated upside down: no bubbles. Now I am thinking that it takes a larger force than I can apply by hand to let the air escape.
If this helps, the rider likes to do standing, pedaling wheelies, and then smack the front down hard.

 

[dmkalemba]

Captain Obvious says, are you sure the rebound isn't set all the way to slow, or somehow stuck there? I did overlook that once my self...have no idea how it happened, but...

 

[blackburn1973]

You should definitely check the above. If there's no leak my assumption (w/o knowing this fork build at all) would be that you've got an internal gasket that's leaking and not keeping the oil and air separate which is what allows the fork to maintain tension.