View Full Version : Adjustable trailing arms
I have a MK3 with 4 link rear. I am wanting to put adjustable rear arms on so I can set the angles to get semi correct driveshaft and u joint angles. I think I want to replace the lower as well as the upper. I noticed the rear has a bolt on piece that allows the use of rear coil overs. I assume this is part of the kit to allow this. Is there any modifications to this? It looks like it has a single bolt on each side to hold it. What is the best bushing material to use in these links. I also see a small hydraulic damper running horizontal on the suspension. Is this for cushioning axle wrap? Thanks for the help. 213813213814213815
StangRacer
05-16-2025, 01:55 PM
I have a MK3 with 4 link rear. I am wanting to put adjustable rear arms on so I can set the angles to get semi correct driveshaft and u joint angles. I think I want to replace the lower as well as the upper. I noticed the rear has a bolt on piece that allows the use of rear coil overs. I assume this is part of the kit to allow this. Is there any modifications to this? It looks like it has a single bolt on each side to hold it. What is the best bushing material to use in these links. I also see a small hydraulic damper running horizontal on the suspension. Is this for cushioning axle wrap? Thanks for the help. 213813213814213815
The horizontal damper is referred to as a "quad shock". The purpose of the "quad shock" is to prevent axle hop. They are not needed if you are using aftermarket control arms.
There should be no modifications required to use adjustable control arms. I would suggest using control arms that are double adjustable. In other words, they have both left and right hand threads. This way you don't have to take one end of the control arm off to adjust. Breeze makes really nice double adjustable lower arms for a reasonable price.
Ducky2009
05-16-2025, 03:39 PM
The only person I know of with lower adjustable control arms is G0-Dad-GO. You might want to ask him about them.
Flip Smiley
05-16-2025, 06:04 PM
I agree with StangRacer. I went with Breeze Automotive double adjustable trailing arms when I installed my 3 link rear suspension. They are high quality double adjustable with heim joints on both ends. They reduce or eliminate binding and are reasonably priced. I also think they improved my ride quality.
Flip
I replaced my lowers and uppers but the uppers where the only adjustable ones ,I believe I got them from LMR, the lowers I bought from a forum member they are the steel ones from Factory Five. I would recommend you change to coil overs while your at it.
I should have looked at the pictures first, you already have coilovers.
CraigS
05-17-2025, 02:28 PM
The original 4 link Mustang suspension used rubber bushings in all the connections because other wise it would bind up when the car leaned L or R. So it's not a good idea to go to all rod end type ends on all 4 control arms. Back w/ my MkI w/ 4 link Gordon Levy suggested going to Mustang Cobra upper arms because they still had rubber but it was a harder rubber than standard Mustang parts. I have no idea if they are still available. BTW the adapters that allow the coilovers also have a bolt in the center. Sorry it's been 15+ years since I worked on a 4 link so memory is faded. I 'think' you will find that the bolt that the coil over is attached to goes through the adapter and through the piece that is part of the axle.
GoDadGo
05-17-2025, 03:50 PM
The only person I know of with lower adjustable control arms is G0-Dad-GO. You might want to ask him about them.
Here is where I got my lowers control arm from for my MK-4 that has a 3-Link set up:
https://www.spohn.net/shop/Factory-Five-Racing-MK3-MK4-Roadster/
My friend David is running their adjustable uppers on his 4-Link Factory-5 33 Hot Rod with the stock non-adjustable lowers.
Hope This Helps!
CW_MI
05-20-2025, 09:42 AM
Here is where I got my lowers control arm from for my MK-4 that has a 3-Link set up:
https://www.spohn.net/shop/Factory-Five-Racing-MK3-MK4-Roadster/
My friend David is running their adjustable uppers on his 4-Link Factory-5 33 Hot Rod with the stock non-adjustable lowers.
Hope This Helps!
I was just going to post those. The "del sphere" hiem joint with the delrin bushing seems like a really great idea. I plan on using them.