I've been meaning to write about this for months ....
Over the years I've noticed play in my steering and what seemed like a loose front right strut top bearing..., even after a complete front end overhaul where everything was replaced new., it still felt like there was something loose on the passenger side.
So I went to the garage where I have a spare subframe being converted to rack & pinion.., and looked specifically at the mount for the center link's idler arm. I noticed that the holes in the subframe for the idler arm bolt wasn't round and rather beat up. So I found an old idler arm and mount bolt and noticed that there was a ton of play when all the pieces were in place. Not only did the bolt not fit the idler arm hole properly and had lots of axial play.., but with the bolt in the sub frame, without the arm, you can see how this bolt is just flopping around.
The mount bolt I have looks like a standard 10mm bolt. It was purchased from the dealer years back so I assumed it was the correct part. But.., the clearance in the idler arm hole is way too much. So now I'm wondering if there was a special machined part for the idler arm that's now superceeded by a standard M10 bolt. The ETK shows a standard M10X75 bolt from the looks of it. Hard to believe.
So as a test I re-torqued the idler arm bolt on my daily driver and went for a drive. You can not imagine how much better the steering felt with the idler mount tight. There was no drifting in road grooves, no clunking on the right side when going over pot holes..., felt like a new car ! But after a few hundred miles the mount loosened and I was back to square one.
So I was wondering what you guys thought, and if it would be worth it to try to engineer a fix for this problem. Kind of like what we have for the steering box mount by Ed Raether. I think we would need to machine a small puck / disc with a hole that can be welded in place. One for the top of the mount, and one for the bottom. Then.., we would either have to sleeve the idle arm or have a special bolt made with tighter clearances.
Looking for feedback. Hope this helps a few of you out there that have been looking for a steering play culprit.
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Slop in the steering - center link idler arm
Slop in the steering - center link idler arm
Last edited by Philo on Apr 15, 2010 8:20 PM, edited 1 time in total.
I'll take some pics and post some of the clearances that I found. The subframe I have on the bench came off an M5 with 170k.., and the holes for the idler arm are waaayy out of spec. But the part that's interesting is that the bolt / idler arm relationship is not precise at all. Not very German like.., lol..