E36 question re broken subframe mounts

No, not trying to start a Bimmerforums thread .

Pretty much every buyers guide warns about the broken rear subframe mount (well, where the mounts break/pull through the sheet metal) but I'm wondering how common an occurrence they are. According to a couple of threads on the above forum and another one, the world as we know it will come to an end if you auto-X or track a non-M E36 and haven't got the reinforced mounting plates that the M3 already has.

Given the cost of having those fitted, the price difference between an OK 328is and a ratty-ish M3 more or less disappears so I'm wondering if they're so common that considering an M instead of an E36 is would be a good idea.

I spend quite a lot of time at the track with the BMW club. In the last 10yrs I've seen a few that needed some repair. They were caused by driving hard with bushings that were already worn to the point of excessive play. It is certainly worth looking for before buying a car - but it's pretty rare on a street driver that has had proper service on the bushings.

The fix... it's the same work to get in there to repair as it is to fix preventatively so if the car you get is fine - keep driving. It is a fearsome thing only to the kind of people who pay someone else. For anyone who has ever welded sheet steel... its dropping a subframe and welding in some patch panels.

So... summary... it is an issue. It is not a pandemic. It is not the end of the world to fix but there are a lot of E36s out there. Buy one in good shape and reinforce it at your leasure or wait until it breaks (if the bushings are good it probably never will).

E46's have a similar problem with the rear subframe mounts tearing. I'm not saying it never happens but according to the Internet mine should have fallen out and killed a van full of orphans a long time ago (its at 153k now).

After a fair amount of autocross runs and three track days its still fine. But I don't drive like an idiot on the street so that probably evens things out a bit. I say if its lasted this long without failing and you don't go dumping the clutch at every stoplight it'll be fine.

In reply to Giant Purple Snorklewacker:

Well, I haven't welded in about 15 years so I guess I'd better practice on something slightly less critical... That said, the reinforcements didn't exactly look that hard to weld in.

Gas tank has to come out which is a major PITA because of all the vent hoses and it goes up over the driveshaft, dual pickups, dual senders. Effing stupid design IMHO. Yeah I could fill a novel with 4 letter words about the e36 fuel system.

I have heard that all cars 96< got the reinforcements.

My front passenger mount was really bad and I actually had to do some rebuilding of surrounding sheet metal before I could even weld in the reinforcements. I should have replaced the whole piece of subfloor that the mounts attach to but didnt know you could buy that piece at the time. Will probably have to go back and put one in in the future if I keep this body. Suppposedly this new subfloor part is much heavier that the stock part that cracks. 92 4d 325i 254K

They can even fail on the "reinforced" M cars. I know a guy with a '95 LTW and his has the extra reinforcement plates welded in, it's a good idea if you plan on tracking the car. His haven't failed but he sees enough that do.

I saw on one of the BMW forums that someone used some high strength industrial adhesive rather than welding. If its not already too far gone that might be a good option. No heat so you can leave the fuel tank in place, and fewer chances for rust if you live somewhere that might be a problem.

I've seen two subframe mount stud failures come through the shop, I see several hundred e36's per year.

Backing up what GPS said, yes it's a problem, no it's not the apocalyptic nun-killer.

Rear trailing arm mount pockets are also likely to tear as a result of hard driving on worn bushings, they're significantly easier to reinforce.

The welding work on both areas can be done with the fuel tank in place, I chose to do it this way and used a slab of sheet metal as a heat shield.

ansonivan wrote: Backing up what GPS said, yes it's a problem, no it's not the apocalyptic nun-killer.

well then, what are we going to use to kill the apocalyptic nuns?

BoxheadTim wrote: In reply to Giant Purple Snorklewacker: Well, I haven't welded in about 15 years so I guess I'd better practice on something slightly less critical... That said, the reinforcements didn't exactly look that hard to weld in.

buddy of mine from college had his brothers E36 for a while that had this problem. a shop quoted him something around a grand to fix the problem, he was what i would call an amateur welder, and he stuck it back together and it give him another problem as far as i know

Joshua wrote: They can even fail on the "reinforced" M cars. I know a guy with a '95 LTW and his has the extra reinforcement plates welded in, it's a good idea if you plan on tracking the car. His haven't failed but he sees enough that do.

They can fail on any car that was beat on with bad subframe mounts. If you keep them fresh - you won't likely have an issue regardless of reinforcement. It is the excessive movement that causes the fatigue. If the subframe stays where it is supposed to the stress on the area is properly spread out.

AngryCorvair wrote:

ansonivan wrote: Backing up what GPS said, yes it's a problem, no it's not the apocalyptic nun-killer.

well then, what are we going to use to kill the apocalyptic nuns?

Ball-peen hammers. $2.99 at Harbor Freight.

Baaack from the dead!! So how difficult is this job of repairing subframe bolts?

After reading what SupraWes wrote, the gas tank was difficult.

Reason for asking;

Seller said: Now for the reason I am selling it, the rear end needs fixing. There is 1 bolt holding on the rear end the other 3 ripped out of the sub-frame. Someone that is good with a welder & the time & knowledge to fix it can get the job done but unfortunately I don't have the time or place to fix it. Another option is taking it to a frame shop. Or you can use it as parts. How ever you want to do it, its not drive-able. It was a daily driver until it broke.

http://dallas.craigslist.org/mdf/cto/3978693030.html

The gas tank is no biggie. It's plastic and held in by 2 straps. Remove the whole rear subframe and diff and it comes right out. To make it even easier... use the in-tank fuel pump, and a few feet of fuel hose at the front of the rail to pump it empty first.

Then, assuming you can weld... repair away.

BUT... $1500 is about right for that car with 200k+ miles and everything otherwise in pretty good shape. It's too much money for a car you have to do significant structural work before you can drive it. I would offer him $800. I've bought one for $500 that ran and drove (although rust was a factor in that price).

In reply to Giant Purple Snorklewacker:

Good on ya for the input. I'm working on the lady on the pricing. She has it at a repair shop. Luckly, it's a stone throw away from my boss's house, which has a lift and a variety of welders.

In reply to DukeOfUndersteer:

Have you researched the fixes? You are going to be patching the crack, then reinforcing the area. There are nice laser cut plates available from AKG for not too much money for the sheet pan, the top of the subframe, swaybar tabs and the control arm cups.

Then, replace everything bushing related with solids or nylon/delrin... etc. Factory rubber is too vague for race track use, and a gen-you-wine pain in the ass to press in.

In reply to Giant Purple Snorklewacker:

Yep, still reading in on the fixes. If I do go thru with buying it, I was planning on doing poly-everything. Got a press in the shop as well.

Thanks on all the info. AKG? Guess I need to Google them.

So I would be adding these new subframe mounts once the existing cracks have been filled?

Duke,

Like GPS said, its not a big deal if you know how to weld.

I am typing from my phone now, but this is what I used for reinforcement

http://forums.bimmerforums.com/forum/showthread.php?t=1955967

Of course, mine was not ripped and more preventative, so you need to see how bad the sheet metal is under there.

In reply to Slippery:

Cool, okay. I am going to look at the car this afternoon to see what I am working with. I do know how to weld, so I will see if it is something that can be tacked back together.

Just get a 318ti.. different rear suspension, no chance of ripping out the subframe

mad_machine wrote: Just get a 318ti.. different rear suspension, no chance of ripping out the subframe

sigh Not the point at all...

Well, I went and saw it last night. It looks basically totalled. Don't think I can save it. I bet Jesus can't even save it. The bushings look completely deteriorated, front portion of the subframe has been rubbing on the exhaust, wheels are toe'd in by like 10 degrees.

lot of bushings in the rear of an E36. That much toe is not surprising if the bushings are gone

Well, after talking to a couple people, it can be salvaged and fixed in a weekend. Only problem is I have to get it before this weekend as I leave again and it will probably sell if I don't get it.