front end rises but doesn't come back down

[latamud]

Hi,

Got a friend with a 65 coupe. He recently redid the front and rear suspension. Shelby drop. He left everything loose and drove around the block and tightened everything up wit the weight of the car on the suspension. What is happening, as he drives forward the lower control arms drop, lifting the front end up like a boat, or like a drag racer launching. Only, it doesn't come back down at all. I told him to loosen the lower control arms and drive it and tighten it up again. Well, it worked like that, but when he sped up above 30 mph it would rise again. So, I told him to loosen it up and just leave it hand tight. He says it is worse now, it rises as soon as he pulls forward.
I am now thinking it might be the alignment. We adjusted it to where it was as close to zero as I can tell and it still does this. Any ideas?

I'm also posting this on VMF for more coverage.

 

[brianj5600]

I think shelbyclone? had that problem with Granada spindles on an early. He switch to stock spindles and it went away. Tons of others use them with no ill effects. Be sure and let us know what cures it.

 

[65ShelbyClone]

My first thought was about Granada spindles being on the car too.

Different shelbylcone, BTW. I have a Granada setup, but it's in boxes.

 

[Decurion]

Ive had the same problem on 2 different cars. The first time I replaced everything, and of course the last part I didnt check was the problem. One of the upper control arm nuts that holds the cross shaft in had stripped threads and started to back out. It was pretty hard to catch because the nut can only back out a little bit before it hits the tower, especially with zerk fitting in place, but it was enough that the control arm moved around. For the second go-round I had all new parts (I rebuilt the upper arms before), but the end result felt the same. It had the same spindles (taken from the first car), but with the shelby drop, and since its a falcon I took a mustang center link and had it cut, all other parts were unmodified replacements. After a lot of work, I figured out that the fiberglass hood and fenders along with the stock mustang gt springs (higher rate than stock falcon), combined with the shelby drop that is known to increase bumpsteer, combined with the center link I apparently mis-measured, made for an awful handling car. The amount of bumpsteer I had was a lot, not to mention lopsided because of the center link being cut wrong. I put the control arms back in the original location and got a new link cut to the right size, plus cut 1/2 coil from the springs and without even getting an alignment yet, it handles 1000% better. Heres my play-by-play of what happened.
http://forums.stangnet.com/showthread.php?t=751991&highlight=bumpsteer

 

[gsxrken]

I’d search on VMF as I recall more than one post there where guys had to cut their coils after going with roller perches and/or low-friction arms and strut rods. The new coils would extend on launch and would keep the body up there, until they backed up and hit the brakes(!)
I think in each case shortening the length of the coils did the trick.