GM knee shocks? NOS there 80 years old! Rebuild NOS?

[ng8264723]

So I am b uilding a 1939 Pontiac Woodie.  It has the knee shocks.  How do I know if they are good?  It is not ready to drive.  I want to erebuild or eval and replace everything.  How do I check a knee shock?  Should I buy NOS? they are actually cheaper then a rebuild but are old!

[Bloo]

I am not sure which version of "knee action"  a 39 uses, but either way you are probably better off with rebuilt ones from a reputable rebuilder. The weak point was the seals, the problem with bad ones is that you have to keep refilling the fluid as it runs out on the ground.

 

My guess is the NOS ones would leak.

[Guest]

I would suspect rebuilt shocks by Apple Hydraulics would outlast NOS 100 to 1.  After 60 years in the old car game I believe the only good and usable NOS are solid metal items.  Anything electrical or having to do with oil or gasoline should be rebuilt.  You are really buying a core.  Sitting on a shelf for many many years is harder on an item than normal use.    IMHO

 

 

 

[Rusty_OToole]

Go ahead and use them. Fill with knee action fluid or hydraulic jack oil. If the seals are bad it will leak out. If they don't leak, or only a little, they are fine. If you work them by hand you should feel resistance when pulling up.

[39BuickEight]

Any they may stop leaking after the oil gets moved around in there.  3 of mine did.

[51dyno]

If they have drain plug ,remove oil and if rusty oil flush with mineral spirits . refill and see if they leak . Might be best to call apple for a recommend and best oil on todays market  . 

[PFitz]

Don't use them until your sure they are not rusty inside. Rust is an oxide and it's a hard abrasive. You'll be pumping that through the small spring loaded valves that control the energy absorbing action. When the valves wear they won't work as they should. Call Apple Hydraulics - nice people to deal with !!!!

 

Paul

Edited September 24, 2018 by PFitz (see edit history)