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View Full Version : Symptoms of bad RTABs?



nsk040
09-18-2017, 05:41 AM
110k miles on my RTABs. Back end feels fine and no odd tire wear. The consensus seems to be that by 100k it's basically time to replace, but I'm curious what others in my situation (i.e. no real signs of RTAB issues) have experienced when they replaced them. Were the old ones actually showing signs of wear or was the replacement more for just peace of mind?

san
09-18-2017, 05:54 AM
When my rtabs went bad, I felt like the rear end of the car had a mind of its own and it was very unstable over bumps at higher speeds - while entering or exiting a freeway. Replaced the rtabs and it's all good now. My car had 142k miles when I replaced them.


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Vas
09-18-2017, 06:02 AM
At this point, I would replace them. Rubber over time degrades and cracks.

Cost is roughly $50 for 2 of them.

https://www.turnermotorsport.com/p-350819-rear-trailing-arm-bushings-rtab-oem-rubber-e36-e46-z4-pair/

nsk040
09-18-2017, 06:14 AM
At this point, I would replace them. Rubber over time degrades and cracks.

Cost is roughly $50 for 2 of them.

https://www.turnermotorsport.com/p-350819-rear-trailing-arm-bushings-rtab-oem-rubber-e36-e46-z4-pair/

I'm definitely inclined to just do them, but also curious if people who do them at ~100k are surprised one way or the other by the condition of the old parts once off the car.

Gonna rent the RTAB tool...any other bushings that I can replace w/ that tool that are worth doing while I'm in there?

Vas
09-18-2017, 06:26 AM
I'm definitely inclined to just do them, but also curious if people who do them at ~100k are surprised one way or the other by the condition of the old parts once off the car.

Gonna rent the RTAB tool...any other bushings that I can replace w/ that tool that are worth doing while I'm in there?

Both cars that I replaced them on the rubber was dry and cracked. Upon acceleration and braking you could feel that the rear end did not stay planted and tracked straight. This is due to the change in toe which is caused by bad rtab. Both vehicles the mileage was above 100k and personally I should have done them at the same time as the FCAB.

The rtab tool works great only on those bushings.

Bludsport
09-18-2017, 07:21 AM
My car has 70K miles on it and I did a complete suspension refresh about 2 weeks ago. Of all the components I replaced, I found that the ones with the most wear were the outer ball joints on the upper control arms. At the very least, I would recommend replacing these while you're at it. Check to see if the tool you're renting comes with smaller sleeves that will fit the control arm ball joints as well. Most of them do.

nsk040
09-18-2017, 07:45 AM
My car has 70K miles on it and I did a complete suspension refresh about 2 weeks ago. Of all the components I replaced, I found that the ones with the most wear were the outer ball joints on the upper control arms. At the very least, I would recommend replacing these while you're at it. Check to see if the tool you're renting comes with smaller sleeves that will fit the control arm ball joints as well. Most of them do.

I was going to rent the Bimmerworld tool - is there a better option that can handle another few bushings while I'm in there?

san
09-18-2017, 08:15 AM
I was going to rent the Bimmerworld tool - is there a better option that can handle another few bushings while I'm in there?

Contact Shawn (elcid86). He has the rtab tool that he rents out. He should be able to tell you what you can and can't use it for.


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Bludsport
09-18-2017, 08:20 AM
I bought a tool from Harbor Freight that worked fine for 100 bucks.

https://www.harborfreight.com/ball-joint-service-kit-for-2wd-and-4wd-vehicles-63279.html

nsk040
09-18-2017, 08:35 AM
Looks like the OEM bushings require pre-load. Is this easy to do in my garage?

Sounds like the powerflex poly bushings don't have the pre-load issue, but I worry they may transfer additional force to the subframe....thoughts?

Sockethead
09-18-2017, 09:27 AM
I swapped mine at 140k. There was no visible deterioration and when flexed, I couldn't tell the difference between old and new. I swapped because it seemed like the thing to do

ELCID86
09-18-2017, 10:18 AM
Sent you a PM and link to the forum thread with the Koch Tool

Here for reference: http://www.zhpmafia.com/forums/showthread.php?17274-For-Rent-Koch-KT20312-Subframe-Bushing-tool-(plus)

Bludsport
09-18-2017, 03:33 PM
Looks like the OEM bushings require pre-load. Is this easy to do in my garage?

Sounds like the powerflex poly bushings don't have the pre-load issue, but I worry they may transfer additional force to the subframe....thoughts?

The OEM RTAB's need to be compressed a little and then shoved into the housings but I would imagine the RTAB rental tool should to that as well, otherwise what good would it do if it only removed the old ones. I'd go with the split bushings and avoid the hassle if I were you.