• Hello there guest and Welcome to Fox Body Mustangs forum, This forum is intended to be used by enthusiasts of the Fox body Ford Mustangs (1979-1993)!
    To gain full access you must Register. Registration is free and it takes only a few moments to complete.
    Already a member? Login here then!

Hello everyone.

Ashs88gt

New Member
So I just bought my 88 gt. I'm new to the foxbody game. My question is do I need 2 adjustable upper rear control arms. I only have it on the passenger side. And the rear end seems loose when shifting hard. They were put on about 30 years ago. Should I just replace or try to adjust.
 

broncojunkie

Well-Known Member
Welcome to the group! If you're running adjustable upper control arms, both should be adjustable. They are for adjusting pinion angle, if I'm not mistaken. They may be needed depending on changes to your suspension and drivetrain. If you're fairly stock, I doubt you'll need them. If you are slammed and plan on racing, you will want fully adjustable rear suspension (that's my understanding, so someone may chime in with better info).

My main issue with aftermarket upper control arms is that they don't allow for any flex. If your upper torque boxes aren't reinforced, you risk damaging them with hard launches. If you don't need adjustables, just run stock uppers and aftermarket lowers. Or my favorite option... use the upper torque box reinforcement plates from Wild Rides and use stock upper control arms that have been boxed in (just weld a sheet of 3/16 or so steel across it for reinforcement).

Of course, you'll get different answers on this topic but I've found this works and it's inexpensive. Spherical bushings for the upper diff housing is another mod you can do to address the inherent problems.
 

Ashs88gt

New Member
Welcome to the group! If you're running adjustable upper control arms, both should be adjustable. They are for adjusting pinion angle, if I'm not mistaken. They may be needed depending on changes to your suspension and drivetrain. If you're fairly stock, I doubt you'll need them. If you are slammed and plan on racing, you will want fully adjustable rear suspension (that's my understanding, so someone may chime in with better info).

My main issue with aftermarket upper control arms is that they don't allow for any flex. If your upper torque boxes aren't reinforced, you risk damaging them with hard launches. If you don't need adjustables, just run stock uppers and aftermarket lowers. Or my favorite option... use the upper torque box reinforcement plates from Wild Rides and use stock upper control arms that have been boxed in (just weld a sheet of 3/16 or so steel across it for reinforcement).

Of course, you'll get different answers on this topic but I've found this works and it's inexpensive. Spherical bushings for the upper diff housing is another mod you can do to address the inherent problems.
Ok thanks. I'll have to take a good look at the tourqe boxes. I thought it looked odd only having one adjustable control arm.
 

347HO

Active Member
Look at the factory welds in the box area.

My 86... 4 of the 6 spot weld locations were weld to nothing.
I can only imagine how much flexing was going on under there.‍♂️
 
Top