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Does anyone know the torque specs for the middle carrier bolt and the 3 18mm bolts that hold the rear trailing arm in place?

Also, what would happen if you use regular silver anticeize and also what would happen when you use oem rtab's and you pre-load?

Thanks
 

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Just want to make a point about 'preloading'.

People have it backwards. If you tighten things up before lowering the car then that is preloading, not the other way around.

You are 'preloading' the bushing before actual load is placed on it, which is a common mistake when installing OEM CAB. If you tighten the bracket to the underside of the car before actually placing 'load' on them this will lead to premature failure as the bushing will be under constant stress once the weight of the car is placed on them. Therefore you do not want to preload OEM bushings.

The poly bushings don't care as pointed out because they cannot be 'preloaded'.
 

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great this whole preload crap is confusing me now...i want to upgrade to oem M3 RTAB on my 330CI.....so do you guys mean that the 3 bracket bolts should be tighten with the car on the ground and not supported by jacks?...i cant see how the thru bolt can be tighten once the car is on the ground...someone clear this up for me.
 

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The pre-loading uses a special BMW tool, but if you use powerflex or RE bushings, there's no pre-loading. That only applies to OEM bushings.

Edit:
Here's the tool:
 
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Just want to make a point about 'preloading'.

People have it backwards. If you tighten things up before lowering the car then that is preloading, not the other way around.

You are 'preloading' the bushing before actual load is placed on it, which is a common mistake when installing OEM CAB. If you tighten the bracket to the underside of the car before actually placing 'load' on them this will lead to premature failure as the bushing will be under constant stress once the weight of the car is placed on them. Therefore you do not want to preload OEM bushings.

The poly bushings don't care as pointed out because they cannot be 'preloaded'.
You seem to be a bit confused yourself. The 3 bracket to body bolts have nothing to do with preloading the bushing. The bushing through-bolt is the only bolt of significance in this regard but unfortunately, due to the fact that it is recessed in a pocket and covered by the bracket, it can't be tightened after the car has been lowered onto the suspension.

In order to keep from pre-loading the bushing, the through-bolt must be tightened while the bracket is oriented at a specific angle relative to the trailing arm (the same angle that the bracket makes relative to the TA when the car is resting on the suspenion). Then, when you bolt the bracket back up to the body, you will notice that in order to get the bracket to sit flush against the body you must apply enough force to twist the bushing. The bushing is now pre-loaded while the suspension is at full droop with the wheels dangling in the air. If you installed the bracket at the correct angle though, the load on the bushing will be relieved when you lower the car back to the ground and the bracket to TA angle is returned to its static resting value.
 

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crap...looks like i have no choice but to get powerflex bushing....i would rather go OEM since i heard some bad reviews on the powerflex bushings :(
You can make your own tool, the Bentley manual gives the specs that need to be met. It's really not that difficult to get the correct bracket angle when torquing the bushing through-bolt.
 

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I just did my suspension last week and bought the RTAB tool for the bushings. Well worth the money! Took hardly any time at all to pull the bushings. I have mine and will sell it to you if you want. I paid $100, if you want it, send me a PM.

I know this isn't the place to sell stuff, but I thought it was appropriate because if you're reading this, you're probably about to do it.
 

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crap...looks like i have no choice but to get powerflex bushing....i would rather go OEM since i heard some bad reviews on the powerflex bushings :(
I got Rogue Engineering (the softer type, not the race) and have been more than satisfied with them, no special tools needed and were very easy to install.
 

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You seem to be a bit confused yourself. The 3 bracket to body bolts have nothing to do with preloading the bushing. The bushing through-bolt is the only bolt of significance in this regard but unfortunately, due to the fact that it is recessed in a pocket and covered by the bracket, it can't be tightened after the car has been lowered onto the suspension.

In order to keep from pre-loading the bushing, the through-bolt must be tightened while the bracket is oriented at a specific angle relative to the trailing arm (the same angle that the bracket makes relative to the TA when the car is resting on the suspenion). Then, when you bolt the bracket back up to the body, you will notice that in order to get the bracket to sit flush against the body you must apply enough force to twist the bushing. The bushing is now pre-loaded while the suspension is at full droop with the wheels dangling in the air. If you installed the bracket at the correct angle though, the load on the bushing will be relieved when you lower the car back to the ground and the bracket to TA angle is returned to its static resting value.
TxZHP04 is correct. The bentley manual confirms it. I have attached what the bentley manual (3-series 99-05) says about preloading the trailing arm.
 

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You seem to be a bit confused yourself. The 3 bracket to body bolts have nothing to do with preloading the bushing. The bushing through-bolt is the only bolt of significance in this regard but unfortunately, due to the fact that it is recessed in a pocket and covered by the bracket, it can't be tightened after the car has been lowered onto the suspension.
I'm not confused. I wasn't talking about the specific procedure for RTABs. I was responding to the comment that you should preload all bushings for BMWs.

The RTAB is the only bushing that I know of that you need to preload.
 

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I just got some Meyle HD rtabs and Vorshlag limiters...

Anyone know if I should be concerned with the preload? The rtab sure resembles an oem closely. I have the newer style with the split casing and it doesn't flange out on one side..

Any input appreciated, Ken
 

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Discussion Starter · #57 · (Edited)
I'm not confused. I wasn't talking about the specific procedure for RTABs. I was responding to the comment that you should preload all bushings for BMWs.

The RTAB is the only bushing that I know of that you need to preload.

My 5 series requires pre-loading on one of the front control arm bushings as well. PITA as far as I am concerned.

A simple flat bar of steel will do the trick as pointed out below in the Bentley manual:

TxZHP04 is correct. The bentley manual confirms it. I have attached what the bentley manual (3-series 99-05) says about preloading the trailing arm.
 

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Thanks this DIY helped me a lot....Bimmerworld.com has the same tool to rent
 
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