Setting up adjustable control arms

[cleetus]

How did you guys do this without ruining the tracking of the rear?

I have stock boxed lowers and double adjustable uppers. I haven't put the adjustable uppers on yet, so I'm open to advice.

 

[cleetus]

Also, I CAN'T just measure the old uppers and match it to the adjustable arms. The whole reason for the adjustable arms is to change my pinion angle downward.

 

[StreetBu]

I just put double adjustable uppers in my car with my "new" 8.5" rear end. I also needed to adjust my pinion angle which is why I bought them. I wanted to start by getting them the same length as the originals, so I bought some 1/2" threaded rod 1 foot long each. Put the rod thru the old upper and then adjusted the new upper to the same length so it would just slip over the threaded rod. Drove it afterwards to make sure that everything was ok. Now you know where your starting from and can adjust from there. Just go the same number of turns on each side when adjusting them!

 

[cleetus]

So your 8.5 was giving you problems as well?

It's weird that I DIDN'T have a noticeable problem with 3.42s, but soon as the 4.10s went in, there was a big problem. Might have something to do with a lower gear ratio... I dunno.

 

[StreetBu]

No, my 7.5 was giving me problems, Sounds like your chasing a vibration? I have yet to adjust mine, Waiting to get it up on the alignment rack so I can measure the angle at ride height and adjust as needed. Mine does have a vibration though, just had the driveshaft shortened and balanced too. Eveything else is mint so I'm hoping its just the angle [-o<

 

[cleetus]

Yep, wicked vibration cost me a transmission and driveshaft so far. I'm lucky it didnt cost me my life.

 

[StreetBu]

Mine starts around 3k rpm and stops around 4k rpm, fine before and after. I have a feeling that adjusting my pinion angle wont fix my problem. It may help, but not get rid of it all. I read somewhere (I'll try to find the site) that the diameter of your driveshaft is critical. It depends not as much on hp, but the rpm your shaft turns at. Which of course would vary on almost all of our cars as they are all different in some way. Gear ratio, tire size and transmission are the main three. I have a feeling that even though I dont need a larger driveshaft given my h.p. output, I will to get rid of this vibration with a Muncie M-21, 3.42 gears and short 25.7" tall tires :roll: :twisted: ](*,)

**Edit**

Found the article I was thinking of

http://www.carcraft.com/techarticles/ccrp_0904_drive_shaft_basics_balancing_tips/index.html

 

[BMR Sales]

How did you guys do this without ruining the tracking of the rear?

I have stock boxed lowers and double adjustable uppers. I haven't put the adjustable uppers on yet, so I'm open to advice.

The track of the rear will not be altered if you use the stopck lowers. You will need to get the uppers on and get that pinion angle set. If you have any questions please let me know.