[M-Steep]

Test post for pic upload from iPhone.

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UPDATE 4-3-2015
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Text added. Pics to follow.

M-Factory LSD and AKG Bushings Install Notes

I installed an M-Factory LSD and AKG polyurethane (95A) subframe and diff carrier bushings on my 2009 335i vert. I learned a tremendous amount from all of the great DIY info on this forum (especially Rob1976, CalWaterboy http://www.e90post.com/forums/showthread.php?t=661459, and windymissile), but I also learned a few things on my own as I went. Here - in no particular order - are some of my observations and tips for those also wanting to do these installs.

1) Jacking notes: Even a decent low-profile, high-lift "race" jack has too little reach/height to lift and/or support the subframe or diff high enough to get the car on jack stands at suitable height (about 18" off the ground, from garage floor to floor pan of car). You'll need blocks to use on top of the jack lift pad. Choose wisely to ensure blocks are of suitable size and material to securely stack and support what you're lifting. I used square blocks cut from 2x4s (about 3 1/2" x 3 1/2" x 1 1/2" actual size). Laid flat on the jack lift pad, they stacked securely and were big enough and stout enough to support the various assemblies I lifted.

2) Proper tools: I will admit that part of the reason I like DIY is that I love to buy new tools. But even if you prefer to get by with what you've already got, there are a few, inexpensive pieces that made things a whole lot easier for me once I figured it out. And some are better than inexpensive, they are straight out cheap.

Get a set of external Torx sockets, for the half shaft bolts (E14) and subframe mounting bolts (E18). Normal 12 or 6-point metric sockets just don't fit well enough for the torque you're gonna be applying (especially working on your back like I was). You can get a nice 10-piece set - made in USA by Lisle Corp! - from O'Reilly Auto for $36. Works a treat - you'll be glad you did.

Stout circlip (snap ring) pliers will make removing the side carrier bearings in the diff housing MUCH easier. Do yourself a favor and get a pair of Knipex like these - $27 bucks on Amazon.



A PVC reducer coupling for 3"-to-1 1/2" pipe is dead-on perfect for pushing out the carrier bearings and reinstalling new bearing seals. About $5 at Home Depot with center cap I added to make it easier to smack with mallet.

A steel coupler for 1 1/2" conduit with a cast iron plug screwed into one end is also dead-on perfect as a drift for reinstalling the bearing races on your new LSD. About $6 at Home Depot for both pieces.

Half-shaft bolts are kinda hard to get a socket on because CV boot and axle interfere. I used a 3/8" drive torque wrench with a 4" extension and normal depth Torx E14 socket. A longer or shorter arrangement just did not work very well. With the setup mentioned, I could comfortably torque three bolts on lower side of half-shaft flange (with parking brake set to hold shaft from turning), then release parking brake, rotate remaining three bolts to lower side (1/2 rotation of axle), reset parking brake, and torque remaining three bolts to spec.

A decent dial gauge is only about $35 bucks on The Amazon. This one checked out to be accurate and produce repeatable readings.

3) Subframe bushings: Dropping subframe enough for removing OEM bushings is pretty easy - except you really do have to disconnect the brake lines. I hate brake fluid. When you drop the subframe, just drop 1/2 at a time (front / rear), using a jack under the half you're dropping, otherwise you may *really* "drop" the whole damn thing. You will have to loosen the mounting bolts for the half you're not working on to allow enough drop on the half you *are* working on. But leaving one half always connected is safer and will help maintain the proper fundamental alignment of the subframe.

Bushing press tool kit that HP Autowerks rents is SWEET for subframe bushings - a must have, I would think - but the threaded rod in the kit is too big for either the OEM or the AKG *diff* bushings (and any other aftermarket, I suppose).

*Torque specs*: Recommended torque value for mounting bolts with AKG poly subframe bushings is MUCH lower than OEM: 35-40 ft/lbs vs 73.7 ft/lbs. Check with the manufacturer of your aftermarket bushings for recommended values AND you may need Loctite on those subframe mounting bolts. Oh, AND

You are supposed to use NEW bolts. ALL subframe mounting bolts are SINGLE-use bolts (there are four of one type that install through the four bushings and four of another type for the thrust plates/rods on the front) . All eight will only cost you about $50 bucks total online; that's worth it, 'cause it's holding *the entire rear subframe* onto your car!

4) Differential mount bushings:
An 8" length of 1/2" threaded rod with nuts and washers (about $3 at Home Depot) works very well to press out the OEM diff bushings; used a 2 1/8" hole saw ($12 at Home Depot) as receiver sleeve to press out two (small) front bushings; used the receiver sleeve and thrust bearing from HP Auto kit (with 1/2" threaded rod) to press out single rear (large) bushing.

The AKG rear diff bushing (big one) installs from the BACK side of the subframe and is VERY difficult to install in a 'vert; bulkhead reinforcement is in the way of mounting hole. I had to drop subframe WAY low (hanging by a few threads) and pound on that bitch bushing until it was in and aligned enough to fully press in.

The AKG front diff bushings (two) install from FRONT side of subframe; they press in fairly easily - I used an old c-clamp.

E93 up in air, ready for install:

[sirdaft1]

Love to hear how install goes ^^^

[windymissile]

Good luck!
WM

[M-Steep]

Thanks guys. Install is complete and went well. Just trying to sort out pics to upload my two-bits worth of experience, riding on the work of others like ya'll (yes, I speak Texas!).

[sirdaft1]

Originally Posted by M-Steep

Thanks guys. Install is complete and went well. Just trying to sort out pics to upload my two bits of experience, riding on the work of others like ya'll (yes, I speak Texas!).

How long did it take you?

[Chitown335i]

Which LSD....and was it LSD only into your original pumpkin....what build date is your car since different build dates have different diffs. (Small,large,Bolted welded)

[Jaronbwall]

Really interested in the results or short DIY for the install

[Chitown335i]

The shimming part has me most concerned

[Donalde3]

Originally Posted by Chitown335i

The shimming part has me most concerned

+1

[M-Steep]

Thanks for replies, all. I need to get my info posted up.

In the meantime, I installed an M-Factory helical LSD, and AKG subframe and differential bushings (95A).

Took me about two days, spread over about a month.

Removal was about 4 hours; subframe bushing install was probably about 4; actual LSD removal/install (new unit), took about another 4. Reinstall was maybe another 4.

M-Factory vendor has install kit; doesn't include shims yet, but will.

[M-Steep]

BTW, I have an 09 AT, "small" (med 188) bolted diff. And yes, I work slowly!

[M-Steep]

About shimming - I researched how-to and parts, but did not (yet) change my setup.

Found a source for 50mm D, 3mm thick c-clips, and possibilities for 50mm/45mm D, .01mm shims.

It's not hard, you do want a decent dial gauge, but they are not expensive.

[Chitown335i]

I have the same lsd comming....interested in the DIY for sure....except mine in large bolted....(08/06) build dste

[sirdaft1]

Did you swap this by yourself? I just swapped out LSD's in my e30 track car today with a buddy and couldn't imagine doing it by myself. Those diffs are bulky!

[Chitown335i]

I am taking the pumpkin to a shop to install the lsd ~300 to put it in including fluid etc. ....how hard was it removing the pumpkin....is there much of a difference between small and large bolted.....

[M-Steep]

Originally Posted by sirdaft1

Did you swap this by yourself? I just swapped out LSD's in my e30 track car today with a buddy and couldn't imagine doing it by myself. Those diffs are bulky!

I did, and yes, that bitch is heavy! I had an assist to put it back in, but did most on my own.

Just gotta lift with your legs!

[M-Steep]

Originally Posted by Chitown335i

I am taking the pumpkin to a shop to install the lsd ~300 to put it in including fluid etc. ....how hard was it removing the pumpkin....is there much of a difference between small and large bolted.....

I can't answer as to all differences, really, but external dimensions are similar. Removal was not difficult, but tedious, because of the half-shaft bolts. You have to manipulate the hand brake and rotate the respective half-shaft every three bolts.

[Chitown335i]

Originally Posted by M-Steep

I can't answer as to all differences, really, but external dimensions are similar. Removal was not difficult, but tedious, because of the half-shaft bolts. You have to manipulate the hand brake and rotate the respective half-shaft every three bolts.

Pardon my ignorance....I don't have much experience with drive-train work....since I need to only remove the pumpkin to take it to a shop this is my main focus....

Put the car on stands (well in my case I am fortunate to have a buddy with a lift in his garage lol) and keep the car in neutral?

[M-Steep]

The pumpkin attaches to the rear subframe via three large bolts/bushings, two at the front and one at back. Back bolt is through casting in rear cover plate.

At front of pumpkin, splined shaft engages with driveshaft and is secured by a large flanged nut.

At each side of diff, half-shafts - really the axles - attach to axle stubs via six bolts. The axle stubs are splined to engage with the differential inside the pumpkin, and install through and are supported by the carrier bearings (one in each side).

[M-Steep]

Trying to post this all up using my iPhone. Perhaps not such a good idea. Pics are showing up in random spots. Sorry if this is not clear.