Body Bushing Torque

[DarkForce]

Need the specs on body bushing torque - just finished installing all of them. Seems like I remember the spec being in the 50 to 55 # range but it's been many years since I looked at those numbers so I could very well be way wrong.

It wasn't to bad of a weekend. Got the last two bolts for the KB rear brace in, installed a set of boxed lower control arms and ATR sway bar, installed a 340 pump, and did some cleaning / painting underneath on the project car.

 

[darkfa8]

gm

my '88 GM G-body Shop manual: 60 ft. lbs. as the upper limit

After intalling my poly body bushings with a impact gun, when i checked them with a beam-type torque wrench they were at 35-45 lb. ft. I then torqued them down to 60 lb. ft.

 

[DarkForce]

Thanks darkfa8.....I torqued them to 35# just to get them to settle in. Tomorrow I'll get out the Snap-ons and finish the job.

I was going to use poly bushings but decided to do something a little different. Bushings #1, 7 are solid plastic (for stiffness), bushings #2,3,4, 6 are stock (for noise damping in passenger compartment), bushing # 5 is gnx (for good luck). Plenty of bracing and suspension stuff being done too to make the car more for the street than for the track. How have the polys performed for you?

 

[darkfa8]

..

i can't say the poly bushing "perform". They do provide a good solid connection between the chassis and the body.

I have a better feel for the car and what it is doing. However, my rear upper control arm bushings and entire front front end bushings (sans sway bar endlinks) are stock, old and tired.. so I can't give you a good critque because the rest of the "system" needs to be replaced.

 

[DarkForce]

A couple of weeks ago I replaced the shocks (all totally worthless & leaked down) with Bilsteins and put poly end link bushings on the sway bar but kept the rubber centers. This made a MAJOR difference in how the car handled. Hope to have the rear upper control arms boxed and installed in about two weeks.

The big problem I have to deal with now are the dry rotted tires. Even though I'm making the proper suspension changes, usually tires give the biggest bang for the buck. After a tire swap and a chance to see how the car handles, a new set of springs may be needed. The car is going to be lowered about 1.5".

 

[DarkForce]

Almost forgot, put the diagonal braces and the brace of the GPs that goes from frame rail to frame rail in the front end too.

 

[Evan H]

I put in the poly bushings and new rear upper and lower control arms with poly bushings and the car has never felt better in the 8 years I have owned it. It is lowered 1.5 in the front and one in the rear. I love it !!! But the down pipe is really low. Pte Frt mnt.

 

[DarkForce]

Evan H, did you cut/replace the front springs or use drop spindles?

On the rear lower control arms, I used poly in the rear and stock bushings in the front. This way I know it won't bind but from what many people are saying, there is no real proof the polys are binding. It is just that anytime the suspension is designed to flex at angles not parallel to the direction of the car I have a hard time dismissing the possibility of binding. Probably just over cautious again, haha.

 

[Cartech Preston]

Originally posted by DarkForce
Evan H, did you cut/replace the front springs or use drop spindles?

On the rear lower control arms, I used poly in the rear and stock bushings in the front. This way I know it won't bind but from what many people are saying, there is no real proof the polys are binding. It is just that anytime the suspension is designed to flex at angles not parallel to the direction of the car I have a hard time dismissing the possibility of binding. Probably just over cautious again, haha.

There is quite a bit of proof that polyurethane binds. I have seen it bind myself. Doug at GW will tell you the same thing. The stock GM bushings will also bind at certain positions in their travel. Feel free to make a test rig yourself.

At any rate. If you use ruber at one end and poly at the other, there shouldn't be an issue.

 

[DarkForce]

What made me make the final decision on using a combination of poly and stock bushings was a local wheel and frame alignment shop. These guys are some of the brightest and most down to earth guys you'll ever meet. They do all the really trick suspension work for many of the street rods and they've seen and done it all!

They had the same comments about what would happen if polys were used all the way around on the rear lower (and upper) control arms - things are going to bind at some point and it may even structurally damage the suspension over a long period of time.........