How to tell if strut insert is good?

Dauner · Dauner's Garage

Looking to purchase some low mile used Bilstein inserts for my 89 carrera 3.2 (Boge struts). There are sets available in the classifieds every now and then, but i don't know what test to have a seller do to verify they are still in working order?

Thanks,

Mark

Driven97 · 06-26-2014, 05:22 AM

Not 100% check, but the shock shaft should fully extend on it's own under no load. Shock oil is not compressible, but a shaft takes up volume as it enters the shock. So there's a floating piston with pressurized gas on the other side that can compress to take up the volume. That pressure then pushes the shaft back out.

If the gas or some of the shock oil leaks out, you lose pressure and the shock will not return all the way, or even at all.

If you want to look deeper than that I would suggest putting the shocks on a shock dyno and seeing the forces.

faverymi · 06-26-2014, 07:33 AM

Wear items.

Don't buy used inserts. You will be sorry later on. And you gonna have to do it twice.

Buy new and enjoy.

uwanna · 06-26-2014, 07:48 AM

Quote:

Originally Posted by faverymi

Wear items.

Don't buy used inserts. You will be sorry later on. And you gonna have to do it twice.

Buy new and enjoy.

Not so fast! If you can find used Bilsteins cheap enough you can send them to Bilstein
and have them rebuilt to good as new for a very reasonable fee. Used to be $50 or so each. BIG savings over new!

gamin · 06-26-2014, 08:36 AM

If you have bilstein shocks now why not send them out for rebuild? Why buy some old used shocks when you already have used shocks that could be rebuilt?

Driven97 · 06-26-2014, 08:42 AM

Chuck at ER also has the ability not just rebuild but also revalve Bilstein struts to your specific application if desired.

Dauner · Dauner's Garage

I should have been more clear. my current inserts are Boge, not Bilstein. Looking for some HD Bilsteins to do a quick improvement over what I have, and if they wear in couple years have them rebuilt.

Loud and clear on the buying new. Been waffling on that one. I was aware of the rebuildability factor which was weighing in on my decision...

Things have gone downhill fast this spring summer. Now most bumps in the road initiate a fast feeling of "wubba wubba". I'm assuming it's the inserts. bushings are in rough shape as well (assumption), but wouldn't give that "your front suspension is shot" feeling with road bumps.

Torsion bars I'm assuming are OK as fast sweepers feel normal. When I pull the inserts, I'll get a good chance to look at everything.

recently replaced (last winter) my ball joints and installed Turbo Tie Rods (wow, that was a bummer (tie rod removal and boot install). see my threads. Could do it now much faster, but the first time was no fun). possible (actually likely) that by stiffening that portion up, the inserts are seeing more impact?

Thanks for the replies!

mark