solid steering rack mounts
 

Hey guys. I have owned my 86 928s for almost 2 years now. It has always had a little vibration in the steering wheel at higher speeds (85+). I thought that my tires might be out of balance so I had that checked. the car was smoother, but still not fixed. I figured my tie rods might be worn ( I recently replaced them on my wife's mercedes to stop a similar shimmy problem) I wanted to test the tie rods first, so I jacked the car up and grabbed the tire to wiggle it and see if there was any "clicking" from the tie rods. what I did notice was that the entire steering rack wiggled up and down in it's mounts.

I ordered the solid steering rack mount kit from 928Motorsports. The mounts took about 2 hrs to install. The hardest part was getting the old rubber mounts out after the bolts were removed. I had to tear each old mount out using a pair of vise grips. The new ones slid right in place with a little Mobil red grease, 1 mount took a few taps with a soft mallet. I went for a test drive after. What a difference! absolutely no vibrations , I took it up to about 110 - (on a closed course with professional driver :) ) and the steering feels super tight and responsive. In short I am happy as a Clam.

mike

There's an alternative way to accomplish the same outcome and it costs about $1. Clean off all the old rubber from the existing bushing. You'll see something like this.

http://forums.pelicanparts.com/uploa...1180901465.jpg

Find a washer that will fit over the inner steel bushing. I think it's about 3/4" ID. You need a washer about 1/8" thick. The SAE sizes are thicker than the regular hardware store type. If you can't find a thick washer, use two of the regular ones. It has to be thicker than the protruding inner part of the bushing. Put the washers over the top and bottom of the bushing like this.
http://forums.pelicanparts.com/uploa...1180901880.jpg

Re-assemble the rack to the cross member. I was trying different washer thickness when I took these pics. Some show aluminum washers I made and others have hardware store washers. Not critical.

http://forums.pelicanparts.com/uploa...1180901991.jpg

Thanks, Louie. I see a small drip that appears to be coming from my steering box so I may be replacing the rack soon...and I'll do your fix while I'm in there.

Harvey

Any thoughts on using something more compliant than aluminum?

Suspension plastic, whatever that is?

Why is it rubber in the first place?

they (like most suspension pieces) were rubber encased due to cost and making a softer ride and long life (as opposed to steel bushings and the like).

Polyurethane bushings (for what-ever application) didn't become popular until the racing community needed a bushing that didn't bind, but was very unforgiving when stressed.

As for the 928 rack bushings, I suspect the intent was to limit bumps and vibrations up through the steering mechanism into the hands of the driver.

Remember, the 928 was a grand touring car, not a race car. Big difference......


-----http://www.pelicanparts.com/support/smileys/pc2.gif

The solid ones don't seem to have any negative effect. The result is more precise steering.

Thanks Louis.

repeat what Louis said-----

glad to see something of value on here...... finally.

Thanks Louis as well.

Hey, sorry to revive this thread - just thought I would post a video I made following Louis' solid rack mount idea.

Hope its useful - https://youtu.be/odfC8GUL0rU

Its part of my 928 rebuild project, all recorded on Youtube :)

Todd.

I got a set of Delrin bushings from 928s RUS. My perception - much less work, and very inexpensive.