Test DIY

[Dave M]

I’d lived with the slop for a while now. The vehicle has seen @300,000miles and, as one might imagine, quite a few shifts along the way. Shifting was adequate, but the annoyance factor made this job a priority. Since we needed a new exhaust and flex disk, It seemed like the right time.

The following is intended as a guide for those who seek to regain as much of the original shift feel as possible. I am by no means an ace mechanic and much of the procedure requires relatively basic tools and knowledge. Part numbers or ETK diagram numbers are provided where possible. I purchased the majority of the linkage parts are from the dealer, while exhaust and driveshaft components were purchased from BMA.

Exhaust Removal Notes

All of the manifold to downpipe nuts co-operated so no struggling here, just a long extension (6-8”) on a ½” drive and a regular socket. The brackets that clamp to the rear muffler were the rustiest thing I encountered and provided more of a challenge. I ordered two more and butchered the old ones to expedite removal. Again, instead of wraslin with the rubber hangers, I quickly cut them with my trusty dremel tool and lowered the exhaust. Depending on your set-up, it might be wise to separate the exhaust pieces prior to removal to ease managing them under the car (read heavy).

Regardless of whether major exhaust components are being replaced, plan to purchase the following;
- All four rubber hangers (2 x # 18 21 1 712 838) (2 x # 18 21 1 105 638)
- Two goldy-brassy looking rear muffler clamps, 3 pieces each (2 x # 18 21 1 178 343 - 2 x 18 21 1 178 340 - 2 x 07 11 9 927 022 ).
- Manifold to downpipe nuts (6 x #1 737 774) and Gaskets (2 x #1 716 888).

You may also want to replace the exhaust clamps if your system is not welded and, of course, inspect mufflers/cat/welds/clamps for weak spots and holes.
Oh yeah, great chance to easily change your O2 sensor (Universal type requiring wire splicing, which I had a pro solder for $20 – BMA # 15716)


Driveshaft Removal Notes

Remove the rear transmission support to gain better access to the driveshaft to flex disk and flex disk to transmission output flange (behind flex disk) bolts (19mm). 13mm socket for all trans support hardware. The inner 2 nuts on the rear trans support are attached to rear transmission rubber mounts and can be a bit of a pain to turn as the rubber may want to twist along with the bolt.

Mark the driveshaft flange and trans output flange with paint or scribe to ensure you install the assembly the same way. My 91 525im had all the bolt heads facing toward the rear of the vehicle. The ETK illustrates the three bolts from the transmission output flange to flex disk mounted with heads toward the front end. Also, the three bolts from driveshaft to flex disk are shown with ‘spacers’ on the bolt head side. Not sure what the purpose is, but everything seemed to work fine as shown above and I figured one shouldn’t fix something if it ain’t broke. I have seen photos of e34s with all three bolts facing the same direction and heard others on the board mention it as well. Maybe someone else can enlighten us.

Con’t

With the vehicle securely mounted and rear tranny support removed, a 19mm socket with breaker bar and 19mm open end wrench was adequate to free all six bolts without hassle.




Still More

Shown above is the driveshaft (flex disk still attached) removed from the tranny output flange. Note the amount of paint required to mark the position of driveshaft to tranny output flange, make sure you have a few cans available. Since you’ll spin the driveshaft without it attached to the tranny (in gear), break all bolts prior to removing the driveshaft. Once broken, I carefully bent the driveshaft to the side of the vehicle and removed the driveshaft to flex disk bolts in a more comfortable position. Purchase, at minimum, new lock nuts for all six driveshaft/flex disk/tranny output bolts (Nut PN 07-12-9-900-047) (Bolt PN 26-11-1-227-659).

[PhilH]

Testing, testing.