Longer Springs for Rear Bilstein Coil Overs

[FFMark3MN]

I am attempting to raise the rear ride height of my FF MK3 about 1", and I am struggling with how to accomplish that given no more room to raise by adjusting the threaded collar on the existing rear coil-overs. The threaded adjustment collars on the Bilstein's are at the top of the allowed travel. The ride height should go up 1/2 to 1" to make room for new FF Halibrand 17" x 9.5" rims and new rubber (275/40/17). I finally have the car up and unloaded on the lift today (where it now sits), and was able measure the springs this morning. They are 10"L x 1 7/8" ID, 250# rated. "Factory Five" is still visible on the springs as is the part number #12590, which matches an invoice found in the documents passed on to me from the original owner.

I purchased this car from the original owner, who had it built for him, so I don't have the history of his efforts to address this issue. Consulted with FF via email and they advised to install longer springs (e.g., 12"L vs existing 10", making sure to match ID" and # rating). Today I spoke to tech supports at both Summit Racing and JEG's, and neither have a 12" spring with 1.875" ID (they only had 2.5" at 12" L). Attached is a picture of the rear coil-over with the car/spring fully loaded to show what I am trying to describe.

I just Googled the topic and found some old threads about spring length issues with Bilstein's but couldn't find clear posts on how to resolve. The original kit was shipped in Feb. 2005. Any guidance on where I should go next?
Rear Bilstein Coil Over Spring.JPG

Thank you.

[CHOTIS BILL]

Why not make a 1 or 2 inch thick spacer? Or try a businesses like Pegasus. They have 2” ID springs that should work but may need a spacer ring to make up the difference in dia.
https://www.pegasusautoracing.com/gr...roupID=SPRINGS

Bill Lomenick

[FFMark3MN]

Bill, hadn't thought of adding a spacer. How would you recommend that be constructed? Looked on Pegasus and didn't see any springs in 2" that were near 12"

[CHOTIS BILL]

It has been a long time since I made any but they are make kind of like the spring adjusting ring but with the threads removed. The ID needs to slip over the threads and OD the same as the large OD of the nut. One end of the spacer has a lip that centers on the spring ID just like the nut and the other end has a counter bore to clear the lip on the nut. Most machine shops should be able to turn them up is you give them a simple sketch with the dimensions you want or take the parts with you and show them what you need.

Good luck,

Bill Lomenick

[skullandbones]

Hi FFMK3MN,

My MKIII setup is 275/50/17 on 9x17 Cob**R wheels. The shocks are at the end of their adjustment but it works. But I have another issue I would like to resolve which is the angle of the LCAs and the shock locations. I mention this because, it's caused me to think a lot about the situation. For your purposes, you could do a minor modification to the shock bracket to get the solution you need for your particular issue. If you cut the outer shock bracket off (cut off wheel is easiest), you can relocate it about 1.5 inches higher and reweld it on the bracket. Use the outer bracket hole as a guide and redrill the hole in the FFR bracket and the OEM bracket as well. This way, you wouldn't change the movement of the Bilsteins and get your extra adjustment needed. If you move it up enough you can gain a little adjustment range if things change later. This is a much cheaper way to do it. On the Milling machine or CNC, they are going to charge quite a bit per hour. Bills solution is fine, I just like the simpler way. I could do this in my garage. You may be able to as well. Good luck, WEK.