Mustang II Control Arm Slip
 

I am using a Mustang II setup on my 51 AD and have had the upper control arm slip 3 times in 5k miles. I know what your first thought is, I didn't have it properly tightened 3 times. While that was probably the cast the first time, fairly confident it wasn't the second time, and I personally supervised the torquing of all 4 nuts to factory specs the third time. It is a Heidts unit. I am using factory hardware, not after market T-bolts. The spring perches have no damage or warping that could cause them to slip. I have done some searching and found that others have had this problem, one even references a "retainer" that they made, but have found no specifics on how to remedy the problem. Anyone dealt with this and found a solution that works?

Re: Mustang II Control Arm Slip
 

I have heard it is fairly common on heavier vehicles. As my dad has a nice M2 set up 35 truck frame, and a couple of friends he has in the know have mentioned it.

I have ideas on how it could be solved, but it would require surgery to the top mount.

But the simplest fix would be use 2 bolts or studs threaded into a stop. That could keep pressure on the hold down bolts or nuts.

My personal fav if the A arm mounting holes could be rotated 90*. Is to build or modify the mount you do have to use compression against the mount like C10's do. But depending on spring choices this could get complicated quick.

Re: Mustang II Control Arm Slip
 

Try using Nord-Lock washers. You can order them through Grainger, Fastenal, etc...

https://www.nord-lock.com/en-us/nord...iAAEgKl8PD_BwE

Re: Mustang II Control Arm Slip
 

Thanks whitedog. That's a very interesting solution and if it works will be easy to implement. Will definitely give them a try.