I’m in the process of refreshing the rear suspension on my 1967 S3 SE. It was raced in period, and the owner at that time installed threaded sleeves and smaller diameter springs on the rear. He later reverted to stock rear springs. I’m planning on going back to smaller diameter springs, therefore I want to make use of the sleeves that are already there. However they appear to be threaded SAE, 18TPI to be exact. I have both SAE and metric thread gauges and the metrics simply do not line up. Meanwhile I cannot find 18TPI spring perches or locknuts. Everything is metric these days. I’m looking for information that may help me solve this dilemma.
Picture is not the best for this purpose but it (just barely) shows the threaded sleeve, with one threaded ring at the base. The original spring perches were trimmed for clearance by the prior owner.
Your adjustable spring perches appear to be a domestic product.
First suggest check RD Enterprises. He sells both strut tubes with threads and he sells slip over tubes with the threaded nuts. I think you have the “slip over” threaded tubes.
“Do-It-Yourself Elan Rear Strut Adjustable Spring Platform Kit
Install these tubes on your original strut tubes, remove or cut down the original platforms and install 2-1/4” ID springs. You’ll have extra tire clearance and adjustable ride height. Kit includes two threaded tubes, platforms and jam nuts.
Ref. 26R D 0008-KIT Tube/Nut Pair $200.00
12" springs available in 90#, 100# and 110# rates $200.00/pair "
Anze Suspension sells Penske shocks that I believe are all imperial inch sizes. If you are capable of measuring the diameter of the tube threads, he might have something on the shelf for you. If not he can turn a set.
Thanks for the replies. I plan to reach out to RD, as it is quite possible the originals were sourced from him. I hadn’t thought about having someone machine a set…
