Rear Control Arm - 86 Carrera - Bearing Issue ??

[betterair]

Can Anyone diagnose what the issue is with my control arm / brgs? Separation? Thanks in advance

[boyt911sc]

Bruce,

It looks like you have the Elephant Racing bronze trailing arm bushing(?). Is there something wrong with the rear suspension?

Tony

[betterair]

Hi Tony, Thanks for the input.

The car tracks very well, but there is a noticeable "clunk" noise on track,under hi speed cornering.It is not something that I can repeat in all corners,but occurs intermittently.
In trying to diagnose it ,I noticed the gap in the control arm fit in its bracket.

The pic above is the passenger side rear control arm/bushing .The driver side Rear control arm has the same gap that exposes the bushing on the inside of the bracket .
The cv joints/axles are approx 5 yrs old,and the rear wheel brgs do not exhibit any play that would indicate any problem..

[HaroldMHedge]

Clunks from the rear in the past for me have been a broken sway bar mount.

You could jack up the rear so the wheels are off the ground then check to see if you have any play in the trailing arm, side to side. When my inner bushings failed I had significant play in my trailing arms.

[betterair]

Harold,
Thanks.the swaybar bushings were replaced last year,which leads me back to the trailing arms.
I need to determine if the gap in-between the bracket and bushing is normal and if theres movement there.
Or if there were dust caps on ea side of the control arm that have shredded and disappeared.
Someone has to have had the same symptoms in their rear suspension.

[Jeff Higgins]

There should be shoulders on those banana arm bushings that keep them centered in the mount. They should not be free to slide side to side as it appears yours might be. Have those bushings ever been replaced?

[KTL]

Looks to me like there’s monoball spherical bearing cartridges in the arms. If the Teflon liners have worn out, there’s a void in there causing the play

[VFR750]

Originally Posted by KTL

Looks to me like there’s monoball spherical bearing cartridges in the arms. If the Teflon liners have worn out, there’s a void in there causing the play

Very true. Happened on both left and right side.

New spherical bearings are very inexpensive

COM-10T

Trailing arm has to come off the car to replace the bearing.

[betterair]

I am attaching pics of the drivers side trailing arm/brg

The brg has a shoulder on it, (2nd pic below-Inside view of driverside trailing arm) but the control arm is not even close to being centered in its bracket.
The first pic shows the outside of the trailing arm and how close it is to the bracket.The brg cannot be seen in this pic.
Also,brgs don't appear to be spherical brgs? Can any one identify these?

I will check the records i received with the car to try and determine the brand and date when the brgs were installed.
Also with the car on jack stands,I cannot budge the trailing arms in any direction to determine if theres any play due to a worn brg.

If,If these brgs were incorrectly installed,or worn,I would think I would have serious - on track control problems,other than an occasional "clunk",but that is not the case.
The car has excellent traceability,and no twitch or hitch, except when the input from my right foot gets a little overzealous-you guys know what I mean.

[betterair]

Receipt from 2006:
-"replace rear trailing arm monoball brgs" net 298.00 .
It Does not say where brgs were sourced.Rebel,Elephant?
other ?

[Mahler9th]

A trusted friend told me a long time ago that the best monoball solution he has used in those locations was back in the days he raced in IMSA, and there were still PAG-grade parts around. He worked on rsr and 935 cars.

I think the closest thing we have seen in more modern times to that are the parts sold by Eisenlohr Racing Products. He also raced IMSA back in the day and has extensive experience. Not sure those parts are available anywhere now-- I think SRP used to sell them.

Elephant Racing, Rebel Racing and of course Tarett sell these kinds of parts. Some of those folks may be selling the same parts.

When I decided to install these, I bought a set from Tarett.

I do not know how long all of these modern versions are likely to last... I consider them disposable.

I might try to see if I can get movement with a large pry bar. Or go further and with the car up on jack stands, disconnect the arms from the chassis and inspect carefully.

[KTL]

Spherical bearings are a wear item. Some people are ignorant to this or just don't want to believe it but it's true. Most of them we use on these cars wear out like I described- the teflon liner gets pounded over time from all the loading cycles and eventually creates a void between the ball and the race. Even the non-teflon bearings wear out and its usually due to dirt contamination compromising the race. We want dirt to stay away and that's why vendors like Tarett, Elephant, Rebel offer protective boots to keep out the crud. Also, non-teflon bearings should be lubed with dry lubricant like graphite or DFL spray to avoid inviting dirt attraction.

Sway bar drop links suffer the same fate and the eventually you can hear a clacking sound coming from the suspension. Another example is the bearing inserts used in the upper strut mounts. When these wear out and you also experience a major clacking sound as the ball moves up and down in the race. Use of spherical bearings in the strut mounts is a bit of a misuse since they're seeing a good amount of axial load and spherical bearings are best utilized in a radial load.

[911 Rod]

I have monoballs in my rear control arms and they are starting to wear. They sound like worn droplinks. I think the noise is coming from somewhere else.