Rear subframe reinforcement

**einhander** · 06-10-2003, 04:41 PM

Has anyone here purchased and installed the rear subframe reinforcement kit from Turner Motorsports? I don't relish having my subframe ripping itself apart after I install my cup kit, so I figured an ounce of prevention.....

Anyway, has anyone here had this put on? How much time did it take? I can't decide if I should take it on myself or send it to the shop. Any info would be great.

**fable** · 06-10-2003, 05:47 PM

I havent used the kit, but my subframe broke in two places last year...cost me 3600 bucks to have my mechanic weld plates in place...

Not a bad idea if your care is older like mine(1992)

**JuBu** · 06-10-2003, 07:05 PM

Out of curiosity, how can you tell if your subframe is in trouble?

Justin

**braindamage** · 06-10-2003, 08:57 PM

Originally posted by JuBu
Out of curiosity, how can you tell if your subframe is in trouble?

Justin

You will have to get under the car and do a check around the subframe mount. I've seen pictures of broken subframe mount. You can't miss it.

**mck325is** · 06-10-2003, 11:49 PM

Holy shit $3600. I bought the kit. Unless you're a very skilled welder I wouldn't recommend the DIY route. I'm going to try to get it installed this summer, probably August when I do a huge suspension uprade. I have heard of people around CHicago spending around $2k for the fix. I was expecting that to come down to around $1 to $1.5k for PM. But I haven't tried pricing this out at all yet. A big factor in the price will be how much prep you can do in advance. The entire rear half of the car should be removed for the welding.

Oh yeah, I'm going to do the rear swaybar mounts at the same time. Jim on the M3 forum also recommended having the welder do a continuous weld at the rtab mounts. It's essentially a spot weld from the factory.

.
As far as inspections, it's not always really evident at first. It can start as a hairline crack that will develop into an eyesore failure. I think if you do some searches you will probably find out a lot of info. If not here I can post a linkto some other forums the topic has come up on.

**Bernman** · 06-11-2003, 12:17 AM

There are (at least) four places at the rear of an E36 that you have to watch out for.

The "subframe tearing" that you hear most about does not seem to be very common, though it does happen to be sure. What this is actually is the body of the car failing where the bolts that attach the suspension carrier (subframe) fasten. The best picture I have of this (not my car) is this...

BMW makes plates to keep this from happening, and they were installed as standard on M3's. Part numbers are...

41 00 2 256 495
41 00 2 256 496
41 11 2 256 497
41 11 2 256 498

The other part of the subframe that fails is the sway bar mounting tabs. This is usually due to using aftermarket sway bars. Lowering your suspension or putting "stiffer" shocks will not cause this. The prevention, or repair of this looks something like this...

This is the reinforcement that I made for my subframe. I believe it is similar to a Turner reinforcement. Ground Control sells a simpler reinforcement, that is likely just as effective. The sway bar tabs are easy to reinforce and highly recommended for anyone with upgraded sway bars.

The third place that will fail on the E36 is the body (again) where the trailing arm attaches. There is no easy repair, or reinforcement for this failure, and so prevention is the best medicine. What seems to happen is when the trailing arm bushing starts to degrade, the trailing arm is no longer secure and will start to "bang" at the mounting. Over time, this banging will start a failure at the weld of the threaded rods that the RTAB carrier bolts to. I don't have any pictures of this one. The prevention is to replace your RTAB's before they wear out. For most people the best solution seems to be 96+ M3 RTAB's. Aftermarket bushings will work, but don't seem to be necessary.

Finally, the rear shock mount is a common failure item. Most people know about this one. Along the same lines, I have heard of a few cases where the body starts to crack where the shock mount fastens. Solution varies, but the best fix for this seems to be welding a duplicate of the shock tower over the damaged one. Z3 shock tower reinforcements may help to prevent this failure.

Be careful out there!
Bernman

**Bernman** · 06-11-2003, 12:28 AM

Originally posted by mck325is
Holy shit $3600...I have heard of people around CHicago spending around $2k for the fix. I was expecting that to come down to around $1 to $1.5k for PM...

The most cost effective route to adding the M3 reinforcement is to remove the rear suspension carrier yourself, and hire a mobile welder to come by and weld the parts in for you. If you go this route, you can expect to pay about $100 for the plates, and $150 to $250 for the welder. Add a little paint, and a few fasteners into the equation, and you are out about $400 for this. Expect to put in some hours removing and installing the suspension, but you will have saved quite a bit. Here is a link to my rear subframe install.

http://www.bimmerforums.com/forum/sh...threadid=71035

I did not plan far enough ahead to have the parts to be installed, however, the mountings did appear fine when I had it out. I will keep my fingers crossed

**BzAlwayzLit** · 06-11-2003, 12:43 AM

Man, you guys are tripping me out. makes me wonder now. Now I have to check

**RRdawho?** · 07-30-2003, 03:57 AM

Im tripping out too, i have 150k...

**BimmerBoy** · 07-30-2003, 04:16 AM

Mine subframe ripped out in 2 places a few years back. A way to know when you have a torn subframe (well in my case) was that everything i would shift, i would hear a thump coming from a rear. The car was fixed with some "home made" plates, after that I bought the bmw plates and had them welded in for peace of mind.

**Franchise** · 07-30-2003, 04:29 AM

SHIT! my car also has 155k miles and is a 93..i hear a thump...

damn this...its scary stuff...

anyone know a welder in the bay area?

how bout a group buy from the welder?

what do u think rich...we could have him meet us behind cingular....

**RRdawho?** · 07-30-2003, 04:38 AM

Hahaha, dude...this is gonna be much more expensive than the fender roll/ fan delete meet....

**Franchise** · 07-30-2003, 04:45 AM

i know

check my new thread in this e36 forum...i need to know what the hell i need.

**Dnz** · 07-30-2003, 07:36 AM

so fixing is expensive and preventing is expensive.. all e36 have this problem potentially? what are the odds that someone has this..debilitating/leeching/famine inducing problem?

**RRdawho?** · 07-30-2003, 01:24 PM

I believe only the M3 series came with subframe reinforcement plates, so us regular 3 series guys are left to fend for outselves...

**ponq** · 07-30-2003, 02:07 PM

Damn
I wish I never saw this thread.
150,000 miles and a scary bump sound on the rear driverside wheel.

**Reck1ess** · 07-30-2003, 02:19 PM

yeah the surrounding of my RSM on the right side broke through. had to weld that part in and it cost me 2500!!! i'm officially broke so i won't be doing any more mods to my car. Bernman, you sound like an expert in this area. should i go ahead and do all the preventative stuff? damn i wish i had the tools to do this... cuz the mechanic's just too expensive... maybe if i tell my dad what to do, he can do it because he has some tools but he's all the way in LA... my head hurts.

**Reck1ess** · 07-30-2003, 02:24 PM

Bernman, u're in pleasanton? isn't that not far from berkeley? I'm new to the nor cal area and here for college. man can you check out my car one day and tell if anything else is going to break? i'm so paranoid at every freakin sound my car makes.... a week ago i had to replace the waterpump, radiator, fan blade, and fan shroud. i think my car is dying.. probably sell it and get a reliable civic

**Reck1ess** · 07-30-2003, 02:25 PM

my dad's 94 civic lx has 300k miles and all we do is replace oil. heh the price of driving a luxury car..

**Bernman** · 07-30-2003, 04:33 PM

Not sure that I am an expert, but I have had most of the suspension out of the car, and know something about what has a tendency to fail.

If you want to come down to Fremont (where I work) some day, we could do lunch and I can point out what to look for. Shoot me an email or PM and we can arrange something.

As for repairing this. Your least expensive route will be to do the rear suspension removal, and hire a mobile welder to come and weld in the plates. After that, you get to put the suspension back in. The actual welding should not cost you more than $100 to $200. The reason this repair costs so much is that removing and installing the rear suspension can be very time consuming, and it does not take all that many hours at $75-$100 per to get to $2500...

Good luck!
Bernman

**Dnz** · 07-30-2003, 05:42 PM

its something that happens only later on in a cars life tho, wont happen anywhere near 65K miles right?

**BimmerBoy** · 07-30-2003, 08:48 PM

Originally posted by Dnz
its something that happens only later on in a cars life tho, wont happen anywhere near 65K miles right?

It around 65k you should be alright, not to discourage you, but i think i read that some people experienced this around 20k. But 95% of the time, it is with higher mileage.

**Dnz** · 07-31-2003, 05:14 AM

Ive heard that a 4 door version as opposed to a coupe has a stiffer frame, is that going to in any way make it more or less likely to have the subframe problems?

**Dnz** · 07-31-2003, 05:15 AM

And in terms of prevention, basically anyone with an e36 should be gentle when going over speed bumps etc right?

**BimmerBoy** · 07-31-2003, 06:03 AM

Originally posted by Dnz
And in terms of prevention, basically anyone with an e36 should be gentle when going over speed bumps etc right?

Not only over bumps, but also you should not powershift that often. What happens is that there is a lot of strain put on the mounting points when the car is under load, and when you accelerate hard and shift the the load on the rear end releases and goes right back on, in other words there is load, no load for less then a second, and load again (not sure if that made any sense to you, i just cant think of any other way to put it at the moment), its similar to when you take a bend tab of the coke can back and forth, it gets easier and easier to bend until it breaks. What the reinforcement mounts do is spread out the load, so not to much strain is put on a small area. Hope that it helps and sorry if it sounds confusing.

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