Suspension - Popping Noise, Front End
90bmw14 Group 31 Front SuspensionBulletin Number 31 02 90 (3088)
Woodcliff Lake, NJ July 1990 Service Engineering
SUBJECT: Popping Noise from Front End
MODELS: E30
Situation: Some vehicles may make a popping noise when turning or hitting bumps. This noise may be coming from the mounting points of the front sway bar to the subframe. It can be caused by rustproofing material that has penetrated between the rubber bushing and the metal of the sway bar, bracket or subframe, causing them to stick together instead of moving freely.
Correction: To eliminate the noise, any rust preventative must be removed from all metal to rubber contact points where the sway bar mounts to the subframe. This can best be accomplished with a solvent such as Brakleen(R) which does not leave a film.
Remove both, sway bar bushings and brackets. Depending on individual preference, you may choose to disconnect one sway bar end and remove and clean the bushing and bracket for that side before remounting and doing the other side.
Thoroughly clean the inside of the mounting bracket, subframe, sway bar, and the inside and outside of the rubber bushing with the cleaning solvent and a rag. Once all traces of the rust preventative have been removed, wrap the sway bar with one layer of Teflon(R) pipe thread lubricant tape, then reinstall the bushing and bracket. Do not lubricate any of the parts. If difficulty when reinstalling is encountered, use only clear water to wet the parts so that they go together more easily. Tighten the mounting bolt to
22 N-m (16 ft.lbs.).