The definitive subframe strategy thread

[Z3MUSN]

Glad to read Randy, the one and only Oz, is active and hopefully feeling much improved vs last spring/summer.

Randy are you back to work? My 99 is needing some Randy magic...

also, in the pipeline my 98 w34k miles intact but plan to do as preventive

To everyone - stay safe

[Randy Forbes]

Glad to read Randy, the one and only Oz, is active and hopefully feeling much improved vs last spring/summer.

Randy are you back to work? My 99 is needing some Randy magic...

also, in the pipeline my 98 w34k miles intact but plan to do as preventive

To everyone - stay safe

Yes, a LOT better feeling than even a year ago. Thank you!

I've been dipping my toe in the water...

[Z3MUSN]

Good good for ya!

Let me know when you want me to throw money your way 💵💰

[Randy Forbes]

Good good for ya!

Let me know when you want me to throw money your way ����

That's what makes it so hard to quit, people wanting to give me money...

[Meeners]

That's what makes it so hard to quit, people wanting to give me money...

Hence why great dancers/escorts stay in the game. We call that game the "trap"

[Mjreier]

Help needed. I’m new to z3’s and the forum. I’m about to pull the trigger on one of 2. Both 2001 3.0 manual. What is concerning me is they drove completely differently.

The one in “ok” shape drives great. Felt tight, good acceleration, etc. it’s a Florida car shipped to minnesota. It has a few mechanical issues such as a cam sensor, leaky window, etc but overall the engine sounds and smells good. It’s faster too as it’s yellow. Ha. I did notice what appears to be reinforcement underneath but I’m not finding active links on this site showing what completed work looks like.

the other is mint. Looks like a new car, mechanically seems perfect. But it drives a bit mushy and I noticed a weird wobble under light acceleration. The only thing I can compare it too is the wobble of death that happens to some Jeep wranglers at speed. could be tires. But I couldn’t tell.

my question, are there driving symptoms of a car that has a frame issue? I’m going to re-inspect both cars armed with some of the info from the forum. Thanks for being a great resource.

[adonnan]

Supposedly the shop is starting to mock up the dual ear diff conversion this week. Probably could've gotten by with a single ear reinforcement, but armchair engineering tells me two is better than one and I could care less about racing rules. Here's what a somewhat docile driven m coupe mount looks like after 170k. I wonder how long it's been starting to tear...



Randy, where do we source the paint and sealer, etc?

[Randy Forbes]

Your local autobody paint supply store will have everything that you need.

The brand SEM now makes a few different colors to match the E-coat in aerosol cans.

[ProductUser]

You can also take some scrap pieces of metal to the auto paint store as they should be able to create something very close to what you need.

[AHS]

Aloha,

Not to raise the dead here by bring up this old thread, but I just purchased a '99 Z3 2.8 5sp with 85k miles and no signs of broken welds in the trunk. I do get the feeling from the descriptions of the vehicles that have suffered this failure, IE supercharges, chipped, aftermarket exhaust, etc, that the vehicles were run hard and put away wet. What are the chances of this failure happening on a vehicle that was not driven like the driver just stole it every time that it was driven?

I see a mention of bushings being part of this problem. If I replace the bushings now, would that help prevent any future frame breakage from happening?

Thanks from an old guy that has no interest in "seeing what the vehicle, can, could, or will do". aloha.

[Mr Bingley]

Aloha,

Not to raise the dead here by bring up this old thread, but I just purchased a '99 Z3 2.8 5sp with 85k miles and no signs of broken welds in the trunk. I do get the feeling from the descriptions of the vehicles that have suffered this failure, IE supercharges, chipped, aftermarket exhaust, etc, that the vehicles were run hard and put away wet. What are the chances of this failure happening on a vehicle that was not driven like the driver just stole it every time that it was driven?

I see a mention of bushings being part of this problem. If I replace the bushings now, would that help prevent any future frame breakage from happening?

Thanks from an old guy that has no interest in "seeing what the vehicle, can, could, or will do". aloha.

Replace the bushings with polly and keep an eye on it.

[JustinHalverson]

Aloha,

Not to raise the dead here by bring up this old thread, but I just purchased a '99 Z3 2.8 5sp with 85k miles and no signs of broken welds in the trunk. I do get the feeling from the descriptions of the vehicles that have suffered this failure, IE supercharges, chipped, aftermarket exhaust, etc, that the vehicles were run hard and put away wet. What are the chances of this failure happening on a vehicle that was not driven like the driver just stole it every time that it was driven?

I see a mention of bushings being part of this problem. If I replace the bushings now, would that help prevent any future frame breakage from happening?

Thanks from an old guy that has no interest in "seeing what the vehicle, can, could, or will do". aloha.

Randy Forbes posted many years ago (so long ago I suspect he doesn't remember) that he had never seen a car come in with spot weld failure that had poly bushings installed prior to the failure. That may no longer be true, but when it was posted, I decided to reweld (plug welds) a couple of failed spot welds and install poly bushings. That was six years ago. I drive an M roadster with some "spirited" driving but I'm not abusive. The repair and poly bushings seem to have held up fine.

So... replace the bushings, keep an eye on it, and stash away enough $ for the RF repair should the spot welds start to fail.

[pine1000]

Randy Forbes posted many years ago (so long ago I suspect he doesn't remember) that he had never seen a car come in with spot weld failure that had poly bushings installed prior to the failure. That may no longer be true, but when it was posted, I decided to reweld (plug welds) a couple of failed spot welds and install poly bushings. That was six years ago. I drive an M roadster with some "spirited" driving but I'm not abusive. The repair and poly bushings seem to have held up fine.

So... replace the bushings, keep an eye on it, and stash away enough $ for the RF repair should the spot welds start to fail.

How noticeable are the plug welds? Got any pictures?

[ProductUser]

Visible spot welds are only a small subset of spot welds used to secure the cavity that supports the rear diff cover. Like many, I had a few spot welds that I was monitoring, thinking that all is okay. That was until I looked under the car to see a crack coming from those pulled spot welds.

[JustinHalverson]

How noticeable are the plug welds? Got any pictures?

Plug welds on driver side.(the apparent roughness is accentuated by the grazing light I used to make thewelds visible)

spot welds.jpg
Red = rewelded, failed spotwelds. Yellow = New plug welds, Aqua= failed spot weld repaired from under car.

I thoroughly cleaned up the area around the failed spot welds with a dremel tool, then drilled additional holes for new plug welds between the failed spot welds. I had a highly competent welder (nuclear qualified) come to do the welding. He mentioned that he had to "chase some cracks" that developed while rewelding the old spot welds, but had no problem with the new plug locations. The difference is obvious in the photo.

Six years and 15K miles and everything remains intact.

[WB-MZ]

Randy Forbes posted many years ago (so long ago I suspect he doesn't remember) that he had never seen a car come in with spot weld failure that had poly bushings installed prior to the failure. That may no longer be true, but when it was posted, I decided to reweld (plug welds) a couple of failed spot welds and install poly bushings. That was six years ago. I drive an M roadster with some "spirited" driving but I'm not abusive. The repair and poly bushings seem to have held up fine.

So... replace the bushings, keep an eye on it, and stash away enough $ for the RF repair should the spot welds start to fail.

I installed Poly subframe bushings on my 2000 M Roadster about 15 years ago when I had my H&R springs, Koni shocks and new trailing arm bushings installed all while the trunk floor and diff mount was pristine. I have taken my car to a couple auto crosses and track a couple times but I don't abuse it (no burn outs or donuts). Last year when I was doing one of my usual checkups I found a couple popped spot welds. So I promptly called Randy and ordered one of his kits and also called Matt at VTmotorworks in Pleasanton CA to do my install. I was referred to Matt by Randy and he was also the guy that originally installed my suspension anyway so he knows my car. Poly subframe bushings probably help BUT don't necessarily STOP the spot welds from popping.
IMG_0954 (002).jpg

IMG_0972 (002).jpg

[AHS]

TNX for the replies.
I have done a little more research on the subject since writing, and my take away is as follows.

This is a nice vehicle, but it's hardly worth spending thousands on fixing the frame. After all, it's no classic Corvette.

Even replacing the bushings seems as if it's a major undertaking, and in reality, would cost more than the vehicle is worth at this point if you needed to have the service preformed. Maybe 20 years ago I would have dove right into changing the bushings myself and thought little of the amount of work involved, but today, not so much. hi.

I'm must admit that I'm disappointed that BMW let this issue go. Seems obvious that they must have been aware of the issue after a couple of years of production and then chose not to address the issue until the next model design. Of course I'm assuming that the issue was addressed at that time.

IMO, this puts BMW right on the same level as every other manufacture, in that, screw the consumer is the reasoning when the bottom line is concerned. Risk vs cost with a little consumer R&D thrown in. There was a time when I thought that BMW was somewhat above that BS, and that the product quality was the first order of business. After all, is quality not the number 1 reason we buy BMW's?

Saying that it only cost a few thousand getting the fix, like it's a tune up, is ridiculous. For sure I never would have purchased a Z3 had I been aware of the issue. I look at it as I was lucky that the Z3 that I purchased had no signs of damage. I very easily could have unknowingly purchased a vehicle with major damage. I've owned BMW's for years and have never heard of frame issues. Granted, I'm new to the Z3 scene, but who'd even think that any BMW would have a frame issue? I mean really.

I'm still happy with the vehicle, but now concerned about the frame braking, for no other reason than it's now 22 years old.

Aloha.

[ProductUser]

Your points are shared by many. Enjoy your Z3 cruising the twisty roads of Maui while I bake in the world's largest manmade pizza oven called Phoenix

Aloha.

[Mr Bingley]

I'm must admit that I'm disappointed that BMW let this issue go. Seems obvious that they must have been aware of the issue after a couple of years of production and then chose not to address the issue until the next model design. Of course I'm assuming that the issue was addressed at that time...For sure I never would have purchased a Z3 had I been aware of the issue. I look at it as I was lucky that the Z3 that I purchased had no signs of damage. I very easily could have unknowingly purchased a vehicle with major damage. I've owned BMW's for years and have never heard of frame issues. Granted, I'm new to the Z3 scene, but who'd even think that any BMW would have a frame issue? I mean really.

Well it's not for lack of trying that you weren't aware of the issue before you bought--it's not like we don't have a big sticky thread at the top of the forum page devoted to warning people about it before they buy--doing the research was on you. BMW's are beautiful, wonderful machines, I've owned several between cars and motorcycles over the years--I still do for that matter. BUT, and it's a big BUT, I have yet to encounter one that didn't have an Achilles heal--a fatal flaw--something big, expensive, and outrageous, that ruins it. It is simply the way of the marque. Frustrating, to say the least. The S54 had the sopt weld problem and it spun rod bearings for C****t's sake! We don't own these cars because they're practical--that's Volvo. We don't own them because they're mechanically flawless--that's Honda and Toyota (boring but flawless). We don't own them because they're the best German engineered sports cars--that's Porsche. We don't own them because they're sensuous--that's Jaguar. We own them because they are the ultimate driving machines (well, ok, that's actually Ferrari, but we cant afford them). All of which is to say "sucks to be us." But we're here anyway because we love our cars.

[AHS]

I suspect that I may have put too much blind trust into the product that I have trusted for years. I never had a BMW suffer anything that couldn't be repaired with a few minor parts. Of course I'm older now and haven't driven a vehicle like I just stole it for many years. I guess that part of my driving history stopped when I started buying Mercedes and BMW's. The Jags never ran long enough to do any real driving.

Nice run down on the vehicles, but you forgot the one modern roadster that re-started the whole roadster craze again. The best for reliability, fun to drive, a look, and in a class of it's own. The Miata. Now there's a vehicle that a driver could drive like they just stole it 24/7/365 and it would take it for years and years. I speak from personal experience from days gone by.

Aloha,

PS to the fellow in AZ. I hope that you're staying safe up there. I can not imagine what the people of the west are going through. Maybe I should follow suit and say that it's not like there weren't warnings of impending doom. Kind of a hollow thing to say no, kind of like we have a sticky that you should have read.

Take care, and really, keep yourself and family safe as possible.

[BimmerBreaker]

PS to the fellow in AZ. I hope that you're staying safe up there. I can not imagine what the people of the west are going through. Maybe I should follow suit and say that it's not like there weren't warnings of impending doom. Kind of a hollow thing to say no, kind of like we have a sticky that you should have read.

Take care, and really, keep yourself and family safe as possible.

...just curious, what are we going through in AZ exactly...?

Also didnt some Miatas have crank keyway issues, causing the engines to come out of timing? I dont think any car is perfectly reliable... And its not like every Z3 has trunkfloor failure

[BUCK57]

Seems if 2020 hasn't been interesting enough , ..... History repeating itself discussing the dreaded Z3 subframe issue on the eve of fast approaching Halloween!!

2020 has been scary enough!!!

I'm going RF subframe!

Ironic!!!! As I age, the M has become the go to toy ................ Mind bender!!!!!! Ya get it or ya don't!

[Badger56]

Seems if 2020 hasn't been interesting enough , ..... History repeating itself discussing the dreaded Z3 subframe issue on the eve of fast approaching Halloween!!

2020 has been scary enough!!!

I'm going RF subframe!

Ironic!!!! As I age, the M has become the go to toy ................ Mind bender!!!!!! Ya get it or ya don't!

I’d much rather talk about the frustrations of the Z3 than current events inside the DC beltway. At least we have fixes for our problems and truly enjoy the Z3 experience.

[OlatheksM]

Hello all,

I just joined the board but have been reading for years. Just thought I would pass on my story. I bought mine in 2002 (still have it). After 2 years the frame had it's issue. I didn't know it until a mechanic found it. When I took it to BMW they actually stood behind it and did the fix no charge. Seems I was one of the few. Car is going through a complete refresh now, just light stuff, and has 54,000 and lives like a queen.

Pete

[khammack]

Looks like you are one of the lucky ones. Hope your luck continues!