From digest.v7.n1337 Wed Mar 18 17:33:53 1998
From: Neil Maller <neilmaller_at_worldnet.att.net>
Date: Wed, 18 Mar 1998 14:01:39 -0500
Subject: Re: <All> Strut shaft nut tool (was thump solved)

Raymond M Wong <rmw3_at_acsu.buffalo.edu> wrote:

>The way I torqued the nut I actually was torqueing the strut shaft. I had
>a 1/2" to 3/8" reducer on the torque-wrench and then attached a 3/8" to
>1/4" reducer on the that. I held the nut in place with a 19mm socket and
>inserted the 1/4" drive extension with 9mm socket.
>
>This worked for the first strut, when attempting to do the second one I
>snapped the 1/4" reducer, so I just tightened by hand. This turns out to
>be not enough...thus hollow thump over bumps.
>
>I then tighten the nut on the second strut while it was in the car. I did
>this with a sparkplug socket (very close to 19mm) and a 1/4"
>minibreakerbar. I tighten the nut via a wrench on the hex shaped
>sparkplug socket. I couldn't torque it so I just compared threads with the
>first one that I torqued.

Removing, and even more so, properly replacing and torquing the large nut on the top end of the front damper shaft can be difficult. The issue is that you end up turning the whole shaft, rather than unscrewing the nut form the shaft. BMW dealers have some kind of special tool, big surprise. Raymond described above how he improvised such a tool, but his problem was using a 1/4" drive tool which won't handle the torque.

Bob Stommel told me how to make a tool easily, and I've since taken his idea one step further.

First, buy a 1/2" drive deep socket in the right size, it's 22 mm for my E36 M3. I got mine at Sears for $10 (yeh yeh, spare me the Craftsman tool diatribe). Using a bench grinder - or if you've got all weekend, a file - grind flats on either side of the top end of the socket to accept an open end wrench. I found that 15/16" was a convenient size. Pass a 6" inch long 3/8" drive extension down through the modified socket, fit the appropriate allen drive 3/8" socket on the bottom end.

The allen drive goes into the hex recess on the strut shaft end, while the now concentric deep socket engages the shaft nut. Use a ratchet handle or breaker bar on the 3/8" extension to stop the shock shaft from turning, then an open end wrench on the flats of your modified socket to turn the nut.

As an added refinement, instead of an open ended wrench I use a crowfoot wrench (also Sears, so sue me!), which I can then drive with a torque wrench when tightening the shaft nut. It helps to have 3 hands when using this setup, so I plan to have the crowfoot welded on to the socket to make things a little easier.

This tool works equally well on stock or Bilstein front struts. (For Konis there's some additional work you have to do, email me if you need to know.)

Neil
96 M3