As mentioned before I have a 89 740 GL and after 380K miles I'm going to do front end rebuild. In 89 the lower control arms were made out of aluminum which is not available anymore. I can find all kinds of steel assemblies and even some say they are a direct replacement. So just a question here is this a common replacement . Just wondering.

 

have you considered replacing only the bushings to retain the original arms? I did this on an old Audi by removing the control arm, burning out the rubber, then carefully used a sawzall to cut the exterior sleeve to extract the old bushing. I made a press with a bunch of washers and a hardened steel nut/bolt. Put the new bushing in the freezer to shrink it a bit and pressed it in. Or... you can go to a machine shop which has a press tool :-) FCP has the bushings for about $7 a pop.

 

There is only 1 bushing in the lower control are and it is replaceable. What I am not positive about is , is the bushing the same for the aluminum arm vs the steel arm. Next is would pressing out the old bushing damage the aluminum arm as I mentioned there are 380K miles on the original arms. All of the steel arms come with the bushing installed.

 

the bushing is the same for both alum and steel control arms, however the antisway bar rod is quite different, and attaches with different hardware.

steel arm uses rod 9157725, which is attached to the arm with flange screw 965226 and washer 966814. both style rods use the same bushings, washers, and nuts to attach to the end of the antisway bar, however, each side uses 2 washer 1229303, 2 bushing 1205991, and 1 flange lock nut 971098, you can undoubtably recycle the nut and washers and just replace the bushings.

while you're in there you will want new swaybar bushings, either 2 x 1229389 (19 mm stabilizer) or 2 x 1273184 (21 mm stabilizer)


I've heard it said the aluminum control arms give a quieter smoother ride, I note they used them on the 760/960 models.

 

Thanks Pierce . I see the difference of the sway bar rod and bushings and yep it would be good to replace these bushings. Good to know that the control arm bushings are the same for Aluminum vs steel. The whole suspension system is rather simple . I changed the struts about 50K miles ago so they still look good. Seems like I'll go with the bushing replacement. Thanks

 

btw, the single most important bushing to replace is the large double conical one that connects the radius arm to the control arm. thats the one that wears and loosens up, and replacing it tightens things up significantly.

the antisway bushings can loosen up, but they mostly just make clunking noises on rough roads and not actually directly impact the 'tightness' of the driving feel

now, the strut mount above the mcpherson strut goes without saying, you should replace those when you replace the strut, and the upper strut bearing when it feels sloppy.