Bolt in Delrin CAB

#1

I have heard that the recommendation for securing the offset delrin control arm bushings basically involves drilling a hole through the lollipop and affixing a bolt into the CAB. Is this fully permitted by the rules? What have others done to secure (if necessary) the CABs? I am guessing that it is either covered by rule 9.3.8.9 which allows replacing the suspension bushing material (i.e., the bolt is part of the replacement procedure) or possibly 9.3.8.12 which allows reinforcement of the control arm pickups (if the lollipop is one of those pickups).

Advice?

#2

I doubt that anyone will protest you for drilling and tapping your control arm bushing in place. I think you will find that many others have done the same thing.

I would suggest using a 3/16" or 1/4" drill and then tap the hole and use a hex head set screw to hold the bushing in place. You can set the screw so that it is slightly countersunk for a clean professional look.

#3

Since I haven’t done this yet, I assume the process is as follows? Pardon my horrible drawing.

#4

kioneo wrote:

Actually a pretty accurate drawing.

I went to Orchard Supply and picked up a #3 drill bit, 1/4-28 NF plug tap and two 1/4-28 x 3/4" long, grade 8 hex head bolts.

With the bushing in place drill through the bracket into the bushing 3/4 to 1" deep, including the thickness of the bracket. Then tap the hole 3/4" deep.

I did a minor countersink with a bigger bit so the head of the bolt would seat flush against the bracket.

Hope this helps.

Chris

CAB1.jpg680x510


Post edited by: m3donnelly, at: 2006/08/30 23:40

#5

My car came with the offset OEM M3 CAB installed, without the bolts. I assume the bolts keep the bushing from rotating? Is this a common problem because of the offset hole?

Thanks,
Sasha

#6

the other alternative is a bushing with a retaining plate to keep the bushing in place - we have these on our car. Ed

#7

edavidson wrote:

[quote]the other alternative is a bushing with a retaining plate to keep the bushing in place - we have these on our car. Ed

[/quote]

Who makes them and what is the price? thanks

#8

$79 for the pair. They have 2 sets left. 1(800)-291-5340
http://www.suspension.com/bmw2.html

#9

Carlton’s bushings rotated so definitely do something to keep them secure. In typical Carter-engineering fashion, I drilled a small hole and ran a sheet metal screw into the side of the bushing. Your drilled-tapped-bolted in setup is much better.

Carter

#10

You really should drill and tap them. Long Long ago before I worked at Bimmerworld I had some of those that ALWAYS were twisted out of position. The problem was poor tolerancing on the bushing itself to where it couldn’t fit snugly enough to stay put. The ones with the backing plate are from RTRS.

Shortly after coming to BW, we dropped that line and started making them all by our ownselfs out of that blue nylon. It’s slightly stiffer than delrin and impregnated with oil for better low speed high load friction reduction. We hope it will provide better long term wear. It really is better to keep them in place with a set screw.

Anyway back to work on my 318, it runs like crap right now but should be ready for VIR in a few weeks.