Rear torsion bar - cracking noise

EdHut · 07-19-2001, 01:01 PM

Hi all,

Ever since I bought my 1966 911 some months ago there was a small cracking noise from the right rear side of the car. At first I didn't really pay attention to it (hey, this is an old car!), but now I want to investigate it and if possible fix it myself if it turns out it's something I can do myself.

When investigating the source of the noise I found out that the suspension does not move smooth; there definitely is friction somewhere at the point where the radius arm is connected to the torsion bar.

Using the Haynes manual as a guide I think it's possible to remove the radius arm cover so I can take a look inside. I'm planning on putting the rear of the car on struts, remove the wheel, support to control arm so the shock absorber is slightly compressed, remove the radius arm cover, have a look and be surprized/horrified/relieved/...

Depending on the situation I will determine how to proceed (trying fixing it myself

or calling my mechanic for an appointment

).

Do you think this is a good approach?
Any hints of what I can expect and how to fix it are welcome?

Ed

Formerly Steve Wilkinson · 07-19-2001, 01:15 PM

I've heard that the inboard suspension point of the "banana arm" is a weak point and can fail--the banana arm cracks where it wraps around the bushing. Sure that isn't the problem?

Stephan

EdHut · 07-19-2001, 01:45 PM

As far as I can tell, just by trying to locate the source of the sound when moving the side of the car up and down a bit when standing still, it's the radius arm.

Just to be clear, I described the sound as 'cracking', but I don't think any part in particular is 'cracked'. It's more like it is caused by two moving parts not moving smoothly, perhaps because of rust or something.

Ed

Early_S_Man · 07-19-2001, 02:01 PM

Ed,

More than likely, you have severely worn rubber bushings on the trailing arms, and the noise is due to the torsion bar rubbing on the housing. Get some Neatrix bushings and put them on ... the ride will improve immensely!

------------------
Warren Hall
1973 911S Targa

Evans, Marv · 07-19-2001, 02:15 PM

Warren is right. I'm also sure you need to replace the swing arm bushings & that's a pretty big job. Lots of the time, the noise you hear is the metal on metal rubbing caused by the bushings being worn. It can be done by you & would be pretty expensive if you had someone else do it. While you have everything apart, I would also pull the torsion bars out & inspect them for cracks in the paint & rust. If they turn out to be OK, clean them, cover them with fresh grease & put them back. If you find the paint cracked &/or rust, replace them.

------------------
Marv Evans
'72 911E

EdHut · 07-19-2001, 02:58 PM

Warren and Marv, you sort of confirm my suspicions.

I sure hope I don't have to replace the torsion bars, because those will cost me more $$$ than I would like at this time.

Another question: can this job be done without removing the wheel assembly (caliper, disc, drum)?

If I pull out the torsion bars and basically disconnect the suspension, I will also have to get the car re-alligned, right? Not a thing I can do myself because I don't have the measurement equipment.

Ed

911pcars · 07-19-2001, 03:05 PM

Ed,
Used torsion bars aren't all that uncommon out there. I have a F/R set of 18/24mm I don't need, in case you're interested.

Sherwood Lee
http://members.rennlist.org/911pcars

Eric Coffey · 07-19-2001, 03:09 PM

Ed-

If you are careful and count the splines on the T-bars, and put scribe marks around the spring plate components, you should be able to return the car to it's exact configuration.

-Eric

Early_S_Man · 07-19-2001, 03:33 PM

Ed,

The Weltmeister/Neatrix bushings I was referring to are for the swing arm/trailing arm that fits over the outboard end of the torsion bar. And, no, it can be removed from the hub/control arm without any disassembly of brake rotor or caliper. You will, indeed, need an alignment afterwards.

------------------
Warren Hall
1973 911S Targa