AKG RTAB longevity?

[FredK]

I had a set of AKG 75D RTABs on two cars.

On one, the RTABs lasted 20K miles before the RTAB on the left control arm started to develop a little bit of play. One the other, the same side developed play after around 5K miles. I greased both sets using Molykote 44, and torqued the fixing bolts with new locknuts to the proper torque. The right side is fine on both cars.

Am I doing something wrong with the installation, or are these not supposed to last a bunch of time?

[Jean]

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[Danny]

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[FredK]

A little more detail:

The first set did not have the rifling that retains grease better. The first set also had more of a light interference fit between the bushing OD and the TA bore ID, whereas the second set was more of a sliding fit.

On both installs, the RTAB bores were cleaned thoroughly with solvent to remove all traces of the old rubber bushing material. Right now, there's no clunking over bumps on the 5K mile bushings, but when you rock the left TA to check wheel bearings (as is common for tech at autocross), there is enough play to make an audible clunk.

The other suspension wear parts are the same age (AKG 75D subframe bushings, diff bushing, Meyle HD RSMs) and do not have any play.

I just want to see if this is what other users have experienced with regards to longevity. I did 7 autocrosses this season and one track day, so while the bushings were worked out a bit, it was far from the abuse that other people put them through.

[george graves]

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[Gooch]

Interesting. I'd e-mail/call AKG and see what they have to say...couldn't hurt.

[Brian D]

I'll bet the area that is getting sloppy is between the bushing and the trailing arm, right? The inner steel sleeve is still tight in the bushing? The trailing arm bore isn't perfectly round in a lot of cases and if the bushing doesn't fit tightly you will have relative movement in a short period of time, that's my theory. I actually looked at using aftermarket bushings but didn't like the options available. IMHO the only way to do delrin or hard poly bushings is with an inner and outer sleeve, like the Global West options for musclecars. I had these in the front of my Camaro and they were great, but they are a much better system than what is available for our rtab's.



This way the inner and outer sleeves are held tightly to the arm and chassis, and the Delrin sleeve is free to do what it does best, provide a smooth bearing surface.

I have Lee's rear subframe mounts and stock bushings, and I'm very happy with the results, although the solid mounts do put a lot of noise in the car. The ride is not harsh at all, and the rear is a lot tighter. I can use sound deadening for the noise, it's not insurmountable.

[caliGreen]

wow intresting... i gotta do more hw now.. was just about to grab some 75d Rtab

[gearheadE30]

Is the play on the outside or the inside of the bushings?

If you look up things that member Aptyp posted awhile back about suspensions, he had some similar issues with his RTABs. His, though, wore out the inner race of the metal sleeve, basically turning it into an oval.

Also for what it's worth, my car has developed a "THWANNNGGG" noise that it makes when changing directions, i.e. forward to reverse. Over christmas break I am planning on removing at least one of the trailing arms to see what kind of shape the bushings are in, because I am also running AKG RTABs, and I think they may be popping back and forth under load.