TallTim

iTrader: (2)

Greetings suspension gurus

Forgive me if this has been discussed a bunch here but I thought some pics and the video would help others understand the situation I've created for myself and help others deal with it.

I think I know where I am going with this but I want some validation.

Some years ago I cut the rear springs to change the stance of the car. The rear lip is at about 26" now.



In another thread you will read about my 700-R4 rebuild struggles, putting the torque arm back in is also part of that story.

To on reinstalling the torque arm I see that at rest it likes to sit way higher than its front bracket, like 1 3/4" higher.



With hand force I can bring down the front of the torque arm and bolt it into the bracket. But this causes rear end dynamics at the rear as in the video. You see the nose of the diff drop and the rear body rise.


I believe this is why they make LCARBS which I do not have but should get to reposition the geometry to not be under tension when the torque arm is bolted in.

Does this make sense?

Thanks! Tim.

QwkTrip

iTrader: (22)

This is normal with springs installed. The springs are behind the axle centerline, so spring force on the axle pad causes the axle to rotate, pushing the torque arm up into the floor pan. Installing the torque arm restores suspension geometry.

DynoDave43

iTrader: (11)

I was thinking back to this Klowny video where he's replacing the torque arm. When he disassembles the front mount, the arm springs up. Just like QwkTrip is describing I believe. Start at about the 2:40 mark.


That isn't to say that you don't need lower control arm brackets after cutting the springs. Just that this behavior alone is not an indication of trouble.

TallTim

iTrader: (2)

Thanks for the vid DynoDave. But I don't see his arm lift like mine. When he pulls the clamshell apart the arm just stays in position. I had to put some body weight onto my arm to pull it back down into the clamshell.

There are no clearance issues anywhere so I guess I am ok.

Plus on the test drive afterwards I got 4th gear back on my year-long trans rebuild so I'm a happy guy now.

Cheers.

QwkTrip

iTrader: (22)

Results will vary. It all depends how much force the springs are applying to the spring pads when the torque arm is removed. How much axle droop, how long are the springs, spring rates, etc.... If you drop the car on the ground it will get even more difficult to pull down the torque arm because the springs will be applying even more force.

TallTim

iTrader: (2)

"If you drop the car on the ground it will get even more difficult to pull down the torque arm because the springs will be applying even more force."

I believe this is the first time I've had the car sitting on 4 ramps while working on the torque arm so that must be why I struggled with it this time around.

Thanks again.

QwkTrip

iTrader: (22)

Helps to be fat sometimes, Just hang on and it drops like a rock....

sofakingdom

iTrader: (1)

The springs are trying to rotate the axle at all times, because their perches are off to the rear of its center. All the force that they apply is trying to do that, specifically in the direction that raises the TA's mount end. Reducing the spring force on the perches to as low as possible is the secret.

The way to deal with the TA is, put the car up on 4 stands, under the chassis; let the rear axle hang as low as it will go; jack it up under the pumpkin an inch or so, just enough to lift it up off of the extension stop of the shocks; with a 3rd pair of stands, support the axle tubes - NOT the pumpkin, NOT the shock brackets, NOT any other part, THE AXLE TUBES - just enough to keep the shocks slightly compressed. This eliminates as much of the force tending to rotate the axle that's applied by the springs, allowing the TA to almost float freely.

DynoDave43

iTrader: (11)

By god you're right. I just watched a video within the past week where the arm did just what you describe. I thought sure that was it. No I have no idea where I saw that. Sucks getting old.