I bought an unfinished project '65 Fastback some years ago and am enjoying working my way through the process. Car will be a GT350 "replica" when completed. I have an unusual problem (I was a Ford technician in the '70's and am familiar with this Ford suspension design, plus I have done some research and found nothing so far to help).
The issue is the front shock absorber is misaligned outwards at the top when sitting on the front spring seat perch. If the shock absorber is positioned correctly within the upper mounting bracket, there is a gap of approximately ΒΌ" between the outer shock absorber stud underside and the spring perch.
All parts are new and nothing is bent. Reversing the shock absorber 180 degrees provides the same results as the lower flange on the shock absorber has been correctly located before production welding. Front end has the "Shelby drop", springs are of unknown spec but previous owner said that they were "performance based". Any ideas?
Are both sides the same? Does the car's front end adjust to proper alignment specs? Does a export brace bolt up proper or does it need persuasion to bolt on? Same with the Monte Carlo bar. The answers to those questions will help with a diagnoses .
Do you have weight on the front suspension? If not, the suspension is hanging and the control arms are angled down.
Is the tail of the spring in the right spot? Looks like it's past the locating tab. With the suspension in droop the angle does change putting the shock closer to the outside edge. I generally assemble everything then set the car on the ground to tighten the inner lower control arm bolt and install the top of the shock.
With the Shelby drop, are you running any negative wedge camber kits? If the springs are too long, I would expect this to occur. I generally will get everything together and set the car down as noted. Another suggestion is to use the roller bearing spring seats.
Don
gt350bp
Quote from: Bob Gaines on July 14, 2022, 09:40:03 AM
Are both sides the same? Does the car's front end adjust to proper alignment specs? Does a export brace bolt up proper or does it need persuasion to bolt on? Same with the Monte Carlo bar. The answers to those questions will help with a diagnoses .
Thanks for your reply. Both sides are identical. The car has picked up a lot of positive camber with the Shelby drop (as expected) but will adjust OK. A big light went on when I read your question about the export brace and Monte Carlo bar. The export brace that came with the car was incorrectly pressed and a nasty imitation. I now have an excellent replacement. Both the export brace and Monte Carlo bar will require spreading of the towers for fitment. Any movement in that direction will reduce the misalignment of the shock absorbers that I am concerned about. I also believe that the coil springs may be "over length" which is leading the springs to bow slightly with a corresponding rotation of the lower spring perch. Do you have any free length and spring wire diameter dimensions for OE performance coil springs so I can compare with what I have as a starting point? Thanks again.
Quote from: KR Convertible on July 14, 2022, 10:03:59 AM
Do you have weight on the front suspension? If not, the suspension is hanging and the control arms are angled down.
Thanks for your reply. Car is on a 4 post hoist, motor and trans are in and suspension is fully loaded. I will check for tension in inner bushes (in case PO had tightened arms in a "down" position and not fully loaded as required).
Quote from: 98SVT - was 06GT on July 14, 2022, 12:00:20 PM
Is the tail of the spring in the right spot? Looks like it's past the locating tab. With the suspension in droop the angle does change putting the shock closer to the outside edge. I generally assemble everything then set the car on the ground to tighten the inner lower control arm bolt and install the top of the shock.
Yes, although unclear from my photo, the tail is up against the locating tab. See my reply to Bob for what's looking like the most likely causes. Thanks for your input.
Quote from: gt350bp on July 14, 2022, 03:48:37 PM
With the Shelby drop, are you running any negative wedge camber kits? If the springs are too long, I would expect this to occur. I generally will get everything together and set the car down as noted. Another suggestion is to use the roller bearing spring seats.
Don
gt350bp
Hi Don and thanks for your input. Yes, negative camber wedge kits are installed. I think that you are right with your comment regarding over-length springs (see my reply to Bob).
You mentioned the springs are unknown. Maybe get a new set that you know are correct.
I ended up cutting my springs three times to get the ride height I wanted and use about 2 degrees negative camber. Good luck with your build and keep us posted on progress
Don
gt350bp
Quote from: gt350bp on July 16, 2022, 07:56:36 PM
I ended up cutting my springs three times to get the ride height I wanted and use about 2 degrees negative camber. Good luck with your build and keep us posted on progress
Don
gt350bp
Hi Don. Thanks for the additional information. I always expected to be cutting the springs. Do you have any free length and spring wire diameter dimensions for OE performance (or any other) coil springs so I can compare with what I have as a starting point? I appreciate that free length and wire diameter do not necessarily dictate spring rate. I really like the stance of your car. I have new C5ZZ-5560-HD rear springs in the car at the moment but also have a set of mid-eye "Grab A Track" which I will fit as the "HD" sit too high for me. I'll then look at cutting the fronts. I'll keep you posted by updating this one once I have something worth sharing!
In agreement with the shock towers being splayed inward. You may have to cut apart, spread, and re-weld them?
I had this problem with my 69 428. Bad sag and leaning inboard. When the towers were replaced, we used a quality export brace that was pre-fitted to a known good car to confirm it was correct, and had that in place during all welding.
Quote from: Cobrask8 on July 18, 2022, 07:46:49 AM
In agreement with the shock towers being splayed inward. You may have to cut apart, spread, and re-weld them?
I had this problem with my 69 428. Bad sag and leaning inboard. When the towers were replaced, we used a quality export brace that was pre-fitted to a known good car to confirm it was correct, and had that in place during all welding.
No need to re weld ,cut apart etc. to fix the typical inward sag of shock towers. I and others typically use a porta power to spread the shock towers back into stock position . I got mine from harbor freight for this specific purpose . A Shelby type export brace (original or concours quality repro) completes the fix. If you make it so the export brace drops into place in the upper shock bracket studs you know that you got it. A Monte Carlo bar helps from keeping it from coming back but of course some cars can't use that. It will typically take years for the problem to come back if at all .
I bought progressive springs along with the negative wedge camber kits from Pro-Motorsports in Utah. The springs were rated 460/600 lbs. I don't recall the spring diameter or the length. I can check the diameter tomorrow and advise.
I used 67 Mustang GT rear springs that were still available from Ford when I started my build. Strongly recommend the rollerized spring seats and Baer adjustable bump steer tie rods.
Don
gt350bp
The spring diameter is around 11/16" for the progressive springs I used. Found a couple of vendors with 65/66 Mustang progressive springsand the specs are 403/600 lb. rating.
Hope this is of help.
Don
gt350bp