[mweisdorfer]

I am in the process of installing M3 subframe bushings, M3 Differential bushings, rear, front control arm bushings, and SS Goodridge brake lines (as a while you are in there).

I will update you all on my frustrations and the "ins and outs" of my experience with this install when I am done.

For now, I can tell you that I had to remove the subframe completely from the car, in order to get the 10 year old OEM subframe bushings out. There is no way in Gods Green Earth that I could have got out the old bushings and put the new M3 bushings in with out removing the subframe, much less the rear differential bushing or the SS brake lines. The Michigan winters and the salt we use on the roads in the winter rusted the crap out of & basically froze the brake line fittings and made the OEM bushings very difficult to get out. They were basically frozen in there too. I had to torch the rear, rear OEM bushings out.

I had a contraption I had made, which I had gotten the idea from a DIY done on this forum using a 3" wide x 6" long, black pipe fitting & cap. You drill a 5/8" hole on top of the cap with a carbide or cobalt bit & then put a grade 8 threaded rod with grade 8 nuts on it through the hole you drilled with and lots of washers on the other end ranging from 2 1/2 to 1". In a sense you suck in and or pull the bushing out, but you have to grind the flanges off or you can't suck it out because the flanges of the OEM subframe bushings are wider than 3". The rear, rear subframe bushings are 3 1/2" wide. The flanges probably make them closer to 3 3/4" wide. So, you can't use the tool I described above to pull them out. You are stuck burning them out and using a HD pry type screw driver bar with an 8# sludge to break out the center.

I'll get back too all of you with an update. For now my car is on jack stands. I'm going to wire wheel all the rust off and paint the subframe with a 2 in 1 (primer & paint) Rust-oleum. I really hate what Michigan Winters and Salt can do to a car. Thank God the body is good for 12 years and BMW has a special dipping process.

[Will_460cs]

Am going to tackle this soon myself.. What made you go with M3 Subframe bushings? I was going to go with Powerflex for the whole lot and keep the standard arms...

[mweisdorfer]

Originally Posted by Will_460cs

Am going to tackle this soon myself.. What made you go with M3 Subframe bushings? I was going to go with Powerflex for the whole lot and keep the standard arms...

I was debating M3 subframe vs powerflex for about 6 months. When I asked venders like ECS tuning and FCP Euro about their opinions as to what I should get and why, they both stated I would be much better off getting the M3 subframe bushings.

Why? My car is a daily driver, and I do not track the car. However, I do like to drive in a spirited manner. Both vendors listed above, stated that a powerflex type bushing would deliver a much harsher ride on "a typical" pot hole type roads that we have in the Mid-West. So, I chose the M3 subframe bushings because they both said that they would be softer than the powerflex but still allow for much better handling that OEM bushings for sure.

Again, if your going with M3 bushings, you are gonna have to disconnect all the control arms, brake lines & some electrical connections to the subframe and lower the exhaust enough to slide the subframe out. In my case, I have the 335IS mufflers attached via clamps. So, I just unclamped the mufflers and bingo room was made. I kept the sway bar on the subframe as I wiggled it out.

There are m3 bushings you can buy in a kit from ECS tuning for the control arms, and I think FCP Euro sells one too for the control arms. I have rear m3 control arms, so I opted for OEM (Lemforder) bushings in all my various control arms that are not M3.

Your gonna want to invest in a tool specific for control arms. I have one that I bought for $50.00. It's a major life savor. So easy when you have the right tools for the right job. I bought it on EBay from a guy in Great Britain. It's made of grade 8 steel.

Last like I said earlier, differential bushings and SS brake lines are absolutely a "while your in there" deal once you get the subframe out of the car.

[tlow98]

Nice work! What are you doing for springs and shocks?

[mweisdorfer]

Originally Posted by tlow98

Nice work! What are you doing for springs and shocks?

I have the Bilstein B12 lowering kit with Eibach springsalready installed about 20k ago.

[BB_cuda]

OP, did you leave driveshaft and half shafts connected to diff while it was disconnected from subframe (for diff bushing install)?

I've already had those off when I switched my diff to a Wavetrac LSD equipped one. I didn't have time to do diff bushings then but know that would have been the more practical way to do it. I will be doing M3 links, Powerflex subframe bushings, diff bushings, diff lockdown kit, and M3 sway bar all in one pop. I plan to rent Harold's tool for $65

[mweisdorfer]

Originally Posted by BB_cuda

OP, did you leave driveshaft and half shafts connected to diff while it was disconnected from subframe (for diff bushing install)?

I've already had those off when I switched my diff to a Wavetrac LSD equipped one. I didn't have time to do diff bushings then but know that would have been the more practical way to do it. I will be doing M3 links, Powerflex subframe bushings, diff bushings, diff lockdown kit, and M3 sway bar all in one pop. I plan to rent Harold's tool for $65

Yes, I took the differential out of the car. You need a special wrench to do that as you probably already know. They don't make an M3 front differential bushing for our cars, but they do make rear M3 differential bushings. I am installing those as well.

[mweisdorfer]

Ok. New update. I wire wheeled all the rust I could off the subframe and then took a small SS tooth brush type brush and used a home made solution of Baking Soda and Vinegar on the subframe which took even more rust off. I then used a 2 in 1 (primer & paint in one) Rust-oleum paint with 3 coats of paint. The subframe looks almost brand new.

The front, rear subframe bushings have a hole that goes straight through them like any other bushing. However, the opening of the hole differs in width from top to bottom. One opening is wider than the other. Keeping that in mind, the orientation of the M3 front, rear subframe bushing is opposite in terms of up and down vs the OEM bushings, when condsidering the location of the flange. To explain further, the flange on the OEM bushings are on the bottom, and the bottom has the smaller hole. The flange on the M3 subframe bushings is on the same side of the extra wide hole, which must go on top. The side that has the extra wide hole must go on top because it slides onto the notch located on the body. The notch on the body must slide into the wider hole of the rear, front subframe bushing, in order for the subframe to be flush to the body when it is secured to the car. Therefore, be careful not to make the mistake of putting the M3 bushings with the flange down just because the flange on the OEM bushings was on the bottom.

One last item to take into account, that is sort of related to my first post. The M3 subframe bushings going into the car are the same as an M3. The M3 E90, in its day, was renouned for its performance at the Nurburgring test track vs other sports cars, exotics and sports sedans. In fact, there werent many cars if any that could match the M3 E90 at Nurburgring Test Track. Therefore, I don't see a real need to use a Polyurethane Bushing, if the subframe bushings going into my car were a contributing factor that made the M3 so formidable against many of the world's best sports cars. Just food for thought.

[mweisdorfer]

Ok last update on this install.

The Rear, Rear M3 subframe bushings go in like the OEM bushings in that the flange is down.

Make sure you connect the drive shaft to the differential before you secure the Differiental to the car via Differiental Bushings. Otherwise, you will not be able to get the drive shaft in place, after installing the Differiental.

If you have an exhaust like a PE exhaust where you can remove the mufflers because they are clamped on, then the easiest way to put the subframe back is to slide it over the exhaust pipes and into the under cavity of the car.

Using new nuts & bolts is not a bad thing, if your from the RUST BELT (Mid-west) and your state uses salt on the roads in the winter.

A torch and an air powered torque gun are life savers. Never underestimate the power of salt, corrosion and winter.

Kroil Oil is also highly advised.

You'll need the special 50mm wrench for the drive shaft and have to get a new nut for it.

The following links below were major resources for me, other than the Bentley Repair Manual:

http://www.pelicanparts.com/BMW/tech...eplacement.htm

http://www.n54tech.com/forums/showthread.php?t=18706

http://www.e90post.com/forums/showthread.php?t=802073

[Volasko]

Congrats on the work! I pretty much did the same thing as you last winter. I second the comment about winter and road salt. Had a lot of my components sand blasted, really helped clean up rust before I re-sprayed everything. Check out my FB post:

https://www.facebook.com/media/set/?...1&l=7b96bdb1bc

[mweisdorfer]

Originally Posted by Volasko

Congrats on the work! I pretty much did the same thing as you last winter. I second the comment about winter and road salt. Had a lot of my components sand blasted, really helped clean up rust before I re-sprayed everything. Check out my FB post:

https://www.facebook.com/media/set/?...1&l=7b96bdb1bc

Wow, I assume you disconnected the shocks from the trunk. I wished I would have done that when I was working on the car. They got in the way just hanging there.

Did you do SS brake lines & change out your wheel bearings? I noticed you had pics of the hub taken apart and the PITA connections.

I broke a few steel brake lines because the freaking small 11m fitting bolt was frozen solid to the steel line & the fitting of the rubber hose. So, I made some of my own brake lines with Poly Armour PVT brake line, new fittings & an OTC bubble flare kit. REALLY EASY...

[Volasko]

Originally Posted by mweisdorfer

Wow, I assume you disconnected the shocks from the trunk. I wished I would have done that when I was working on the car. They got in the way just hanging there.

Did you do SS brake lines & change out your wheel bearings? I noticed you had pics of the hub taken apart and the PITA connections.

I broke a few steel brake lines because the freaking small 11m fitting bolt was frozen solid to the steel line & the fitting of the rubber hose. So, I made some of my own brake lines with Poly Armour PVT brake line, new fittings & an OTC bubble flare kit. REALLY EASY...

I really wanted to go the SS brake line route but my flex lines between the rear subframe and chassis hard lines were so damn fused together I didn't want to risk ruining the main hard lines (like I did with the rear subframe hard lines). I did do the rear bearings as a preventative thing while everything was apart. The rear shocks were removed from the trunk yes.

[mweisdorfer]

Originally Posted by Volasko

I really wanted to go the SS brake line route but my flex lines between the rear subframe and chassis hard lines were so damn fused together I didn't want to risk ruining the main hard lines (like I did with the rear subframe hard lines). I did do the rear bearings as a preventative thing while everything was apart. The rear shocks were removed from the trunk yes.

You can use a torch to heat up the hard line where it's fused to the rubber line and I will eventually come loose. Just don't go crazy on the torch. 7-8 sec at most per torching. I was a little reluctant at first because I didn't know how flammable brake fluid might be, but I just tried to be careful, and it worked more often than not.

If you break a hardline, a new one can be made with Poly line and a good bubble flare tool kit. I bought 25' of line for $21.00 and the flare kit for $30.00.

Fittings aren't that much; they even make SS fittings. A new hard line will run you about $50.00 each. So, it pays for itself with one broken line and you don't have to wait 3-4 days to get one.

http://agscompany.com/product-catego...s/poly-armour/

https://m.summitracing.com/parts/otc-4504

[vladmury]

After getting the M3 subframe bushings on my 325D I get a lot of differential whine in the cabin, before with the soft bushings there was no noise. Is there any solution or just live with it?

Have you guys have the same?

I changed the diff oil but no difference.

[miker2013]

Originally Posted by vladmury

After getting the M3 subframe bushings on my 325D I get a lot of differential whine in the cabin, before with the soft bushings there was no noise. Is there any solution or just live with it?

Have you guys have the same?

I changed the diff oil but no difference.

Subframe bushings have an effect on comfort and noise in cabin, depending on how sensitive you are too it.

I am very sensitive to it and had to remove the race subframe bushings i had installed as i also noticed extra noise in cabin and a marked decrease in ride comfort after the install.

Sure it is a great upgrade and really locks down the rear end of our cars but in my experience i then had to loosen up my dampers to account for the extra stiffness in the rear end which totally counter acted the bushing install.

I am much happier with stiff sways and the koni yellows set to about 50%

I dont think there is much u can do for the whine, i noticed the same in my install. I was considering goin to the m3 bushings but said frig it and went back to the mushy stockers.

[maddmatth]

Originally Posted by mweisdorfer

I was debating M3 subframe vs powerflex for about 6 months. When I asked venders like ECS tuning and FCP Euro about their opinions as to what I should get and why, they both stated I would be much better off getting the M3 subframe bushings.

Why? My car is a daily driver, and I do not track the car. However, I do like to drive in a spirited manner. Both vendors listed above, stated that a powerflex type bushing would deliver a much harsher ride on "a typical" pot hole type roads that we have in the Mid-West. So, I chose the M3 subframe bushings because they both said that they would be softer than the powerflex but still allow for much better handling that OEM bushings for sure.

I think whoever advised you has no actual experience with these cars and solid subframe bushings, they're just going off general experience.
I went with one of the hardest poly bushings (AKG red) and it makes no noticeable difference to ride comfort. No vibrations, bumps feel the same. Combined with the differential lockdown brace there's a few cases when I can feel the gear shifts more, enough to be noticeable but not really affecting comfort.

That said, I also doubt there's any benefit from going stiffer than M3 bushings

Edit: Poster above claims he noticed the difference, TBH that surprises me. I really can't tell a difference.

[mweisdorfer]

Originally Posted by vladmury

After getting the M3 subframe bushings on my 325D I get a lot of differential whine in the cabin, before with the soft bushings there was no noise. Is there any solution or just live with it?

Have you guys have the same?

I changed the diff oil but no difference.

Wine? Explain this wine.....

A wine sounds like rear axel or drive shaft...

Did you take them off and not torque them down enough upon reinstalling them?

[vladmury]

Well the noise is present only at around 2000 rpm and when deccelerating and it appeared right after installing the M3 subframe bushings.

Its the BMW workshop who did the work so I assume it was done properly.

[mweisdorfer]

Originally Posted by vladmury

Well the noise is present only at around 2000 rpm and when deccelerating and it appeared right after installing the M3 subframe bushings.

Its the BMW workshop who did the work so I assume it was done properly.

Sounds to me like it's transmission related.

I have never heard of subframe bushings wining....

Idk

[vladmury]

Sure thing it appeared after mounting the M3 bushings.

It sounds like this

[mweisdorfer]

Originally Posted by vladmury

Sure thing it appeared after mounting the M3 bushings.

It sounds like this

The shop didn't do one or multiple of the following :

1) mark positions of the rear axel differential bolts with the differential itself. It's my understanding that you have to put it back together exactly they way you found it positioning and everything.

Maybe look for some white paint (whiteout) in this area. If not, there's a good chance they just threw it back together. OUCH

2) they didn't torque down the bolts to the rear axel to the differential to 45#

3) they didn't torque down the drive shaft to 55-6#

4) they didn't install a new insert nut on the differential between the diff & the drive shaft

5) they didn't use lock-tight on the bolts that keep the rear axel secured to the differential

6) they used the wrong fluid or not enough (maybe both) in the differential.

Check out this DIY OUT & you'll see what I mean.

Someone owes you a new Differential!!!!

Might be a great time to get an LSD. You'll probably find there's not much difference between the cost of a BMW differential and an after market LSD.

LSD's are much better for winter driving, if you have that challenge

http://www.n54tech.com/forums/showthread.php?t=18706

[vladmury]

Thanks, the subframe was lowered by removing the brake lines and flex disc between diff and drive shaft. The differential was not removed neither the diff bushings.

I have a bad drive axle which might have an influence on the noise but as I said noise can be heard at 2000 rpm and during deccelerations.