sway bar slide
 

Hello a few weeks ago I installed a Hotchkis sport suspension sway bar on the back of my 1967 GTO. Today I had it up on the hoist and noticed that the sway bar is sliding from side to side. This is evident by the grease relocation on each side of where the sway bar is attached the the rear axle. Look closely and you can see where it is sliding back and forth. Is this normal?? It seems like I have been experiencing torque steer recently. Could the two be connected somehow? If so How? Three pictures attached.

thank you in advance
alan

Might want to give all your rear control arm bushing a close look. That seems to be a lot of movement.

Check control arm bushings. If they are good try 4 of these.

https://www.grainger.com/product/29N...g!431367529106!

Think about what is happening to the sway bar, which is rigidly mounted to the frame, when the axle articulates in motion comparatively to the frame. There is going to be some movement of the sway bar at it's connection to the axle.

Now that's not to say the rear bar isn't partly to cause for your new steering issue. You've added more rate to the springs back there when the axle isn't moving directly up and down. On hard acceleration, the pinion gear wants to climb the ring gear, which acts on the axle itself and tends to lift one side. This is why you see drag racers using air bags on one side in the rear.

This motion does transfer to the front of the car where any bump steer issue in the front can come in to play and cause what fwd drivers would call torque steer. The a body suspension does inherently have a good amount of bump steer in it and certain alignment setups can make that worse.

CONFUSED, Rear sway bars normally attach to the rear lower control arms and do not need the U shaped Brackets at all on the rear.

The bar if designed right bolts solid to the sides of the control arms.
I have used shims between the lower arms and the outside edge of the sway bar so that the rear bar does not have any side to side movement.

Tom V.

The pictures almost look like you are talking about the front sway bar.

Tom see link below. These are similar to the HR parts n stuff and the BMR. Bolts to axle housing and has brackets that go to the frame or control arms.

https://www.hotchkis.net/product/196...k=&yr=&md=&sm=

I’d call Hotchkis and ask. Like Tom said, I’ve never seen rear bars that attach that way. Reading the copy in the link, it says “... designed to pivot..” - so that may be what it’s supposed to do?

Thanks Mike and Chris, Learned something new about "A-Body" parts today.

I really doubt that you could ever break a HO Racing rear sway bar but whatever.

Thanks again

Tom V.

Agreed, could've had something to do with that chatter issue as well.

http://forums.maxperformanceinc.com/...d.php?t=830810


Frank

I had a BMR bar on my '65 and it would move about 1/2' side to side. It never seemed to affect anything negatively that I could tell.

Makes you question if the rear end has an issue that is causing it to walk around.

One thing that can cause the rear axle on a "A-Body" to move around is if the upper and lower control arm bushings are shot. Same deal for the upper rear axle housing bushings.

I had bushings made from Bullit-proof Plexiglas and they will not fail due to impact or deform over time. They are a bit stiffer vs the Poly stuff though or the Rubber parts.

Tom V.

Ford was throwing out 2" thick sheets of the stuff 24" X 40" long.
When it gets a bit scratched then the cameras installed in the CRASH PIT cannot film the crash properly,
so they scrap the sheet. A sheet costs hundreds of dollars. You do NOT want a Rear Suspension System
with a lot of slop or you will get as was said Chatter.

On my BMR it clamped to the housing then the ends were connected to spherical links attached to the frame. The rear end itself doesn't move around, I think what's happening is if the left corner of the chassis goes down like in a turn it'll push the bar slightly to the right and vice versa. It doesn't move that much but would leave a grease mark on the bar like the OP's. When driving straight it wouldn't move at all side to side.

If this were me--and it isn't--I'd hang the bar from the body/frame above the axle, with links dropping down to the axle or the control arms. This would drop the unsprung weight considerably.

As is...I'll continue with my heavy-ass HO Racing rear bar that stretches from arm to arm like the OEM bar.

Check the upper cross member. If not equipped with reinforcement bars, it can flex, crack, or remove itself from the car.

YOU THE MAN MR CROCIE. We have been dancing around that possible torque steer issue and it never entered my mind to ask if he had installed the crossmember reinforcement brackets that GM used after the crossmembers cracked on the early cars.

(And I have installed those brackets on my car.)

Tom V.

If you read the thread on chatter you will see "Put it on the lift and try it, this will tell you."

"Please report back", never heard a peep, next thing you see is this thread, lol.



Frank

Is that the bar that bolts to the rear trailing arms or the frame?.....if it’s bolted too the arms I would bet some movement .....definitely take a gander at the uppers to make sure they are intact!

AGREE WITH WHAT YOU ARE SAYING, TO CLARIFY FOR YOU:

He is a not using a GM sway bar mount system (where the bar mounts to the lower control arms).
The Sway Bar has heim lengths from the ends of the sway bar to the rear axle.

BAR DOES NOT MOUNT TO THE LOWER CONTROL ARMS.

Tom V.

Hotchkis makes a bar that mounts to the axle housing with end links that bolt to the rear trailing arms.......see link below.... can’t tell in his pick if he’s using this particular one, but it looked like it.... looked at them a few time myself

https://www.hotchkis.net/product/196...&md=1089&sm=20

Some other brands of anti roll systems mount the bar to the axle and the end links attach to the frame .....bmr, hr parts etc...