Track Car Build Woes - Z3M Solid Subframe Install

[modifiede30]

Having some issues while installing the rear subframe back into my Z3M track car. I removed and installed TMS solid aluminum rear subframe bushings, as well as the adjusters for the TAs and new TA bushings. Went to reinstall the setup and having several issues with fit. Here's a few items I'm struggling with:

1 - The subframe tabs from the TAs are hitting the hard brake lines on the left, and on the right, the subframe carrier (the large round cap at the top of the bolt).
2 - Unsure if it is because of the above, but the entire subframe is sitting about 3/4" too low and won't rise any further - if it did, the 2 brackets would be higher in the rear end. It appears the TMS bushings are slightly shorter than stock
3 - If I can get past the above 2 issues, and the subframe does pull up another 3/4", the 2 brackets that bolt to the chassis and under the main subframe bolt are then too high on the chassis to meet the bolt holes in each side.

Anyone else have this issue? TMS only sells one type of solid bushing, so not sure how it could be the wrong bushing.

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[bluptgm3]

Are the Tailing Arm Adjusters new to this installation?
I have heard that they can interfere with sub-frame installation, as the sub-frame conceptually is the same as an E30 it is different.
Looks like the brake lines need to be reconfigured.
Did you purchase sub-frame bushings specifically for the Z3M?
Can you install shorter bolts for the RTA adjusters? Smaller diameter SFB washers or shave them down?

As a side note, do you have any sort of rear sub-frame/trunk floor reinforcement installed? Dual ear differential cover?

I think you need to contact Randy Forbes.


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[modifiede30]

Realistically if these are supposed to be "stock" replacements, all of these adjustments shouldn't be needed - these are pretty material changes. Having to run new hard brake lines is a huge PIA. The other items are less an issue, and can be worked around if I need to cut a washer down to clear the TA bolts. But even this seems unusual for this setup and I'm surprised its not been posted as an issue by others who have done this install. I can't help but think there's something else going on here.

[jimmypet]

I have not been under a Z3. I do know there are subtle differences between the E30 and the Z3 / 318Ti subframes.
Are those large washer looking plates part of the chassis or do they slip off?

If they slip off, I would try it just taking them off and see if the subframe nests into place.

If they are part of the chassis I'd just take a cutoff wheel and D shape them to allow clearance for the subframe to slide past.

With solid bushings they are not going to do anything anyway.

[modifiede30]

I'll probably remove the big washers if I can get the main bolt out of the chassis that's holding it up. At this point my main issue is getting the brake lines rerun so they aren't crushed by the subframe tabs on the left side. I think the tabs on the right nearest the subframe bushing is going to hit the chassis seam just above it, but it shouldn't interfere with the adjustment at all so I'm not too worried about that issue.

[Gofast]

That gap is designed into the suspension; the OEM mounts have it when the the car is raised and the suspension unloaded.
Some of the aftermarket poly bushings have shoulders on the ends that fill that gap, but it looks like your metal bushings are just a direct copy of the OEM.

https://www.bimmerforums.com/forum/s...shing-question