kbdecatur

My upper control arm bushings went south so I had some polyurethane bushings installed. I’m really not liking the stiffness and the ride height. It actually lifted it up. It’s so stiff it’s like a low rider. Has anyone else had this problem? 72 convertible cutlass. I have 15x8 wheels on it now.

ELY442

Did you tighten up the control bushings up in the air or on the floor?
I have polyurethanes in my upper and lower, front and rear control arms. I feel like changing it back to rubber because it rides very hard. It feels like my tires are made out of stone. The potholes in NYC is not making it any easier for me.

kbdecatur

It was definitely in the air. I’m having the same issues hard ride and I hate it. I’m thinking about the same thing going back with rubber.

oldcutlass

How much air pressure in your tires?

kbdecatur

30-32 psi

boese1978

If you torqued them down in the air as you state that was a mistake. They need to be torqued with the weight of the car on the suspension. I have poly in my 68 vert and love the ride, not harsh at all and handling is much improved.

jensenracing77

It is very rare that I hear of someone that likes the polyurethane bushings. You for sure need to loosen them and re-torque them with the weight of the car on them before fully deciding you don't like them.

boese1978

cornering or whipping through a round a bout will show you the diff between rubber and poly. Tight!

Dockolds

For the windy roads I like to drive my 10 on here in south central KY....the poly works great.
www.somernitescruise.com

kbdecatur

Is there a specific way that it needs to be done? Or do is loosen them all up and see what happens?

Orlando 1

I've been driving on poly in my 69 and 68 Cutlass for over 20 years, I'll never go back to rubber. I also used poly when I installed the heavy sway bar in front and rear. My next step is putting stiffer 1 inch drop springs.

boese1978

You need to have the car ( full weight, motor trans etc) sitting level on all 4 wheels and then torque the control arm bolts to spec.

Fun71

Loosen nuts/bolts, ensure vehicle weight is compressing the suspension, tighten nuts/bolts while vehicle is at correct ride height.

boese1978

You will like the 1" drop, mine are from BMR, I love the ride ,I won't use rubber again either.

jensenracing77

When you tightened them down with the car in the air it clamped them in that position. All you need to do is loosen all of them and AFTER all of them are loose, tighten them back up with the cars weight on them. Don't just loosen and tighten them one by one or it will have nearly no affect.

boese1978

I bounced my car by hand a bit before tightening the bolts to settle everything into place and ensure nothing was binding........

kbdecatur

ok one last question on this. What about the shims that are in place. Would that keep it from settling right?

jensenracing77

Also a good idea to roll the car just a little to be sure the front tires are not binding slightly with the floor

jensenracing77

Any shims should be for alignment. After changing the bushings it is a good idea to get it aligned. No need to loosen that part, only the large nuts on the bushings and the lower control arm bushings.

Fun71

Are you referring to the upper control arm alignment shims? If so, leave them alone.

kbdecatur

Thanks guys!!!

Schurkey

ABSOLUTELY NOT.

RUBBER bushings need to be torqued with the suspension at normal ride-height. Poly bushings DO NOT need to be torqued at ride-height. They're not bonded like rubber bushings, the suspension can be torqued in ANY position.

If the control arms are stiff moving up and down after installing Poly bushings, THEY WERE INSTALLED WRONG. First Guess: Control arms were bent during installation of the bushings. If the ride height changed, it's likely the springs weren't installed properly.
I won't use rubber if I can source Poly bushings.

boese1978

Read the instructions that come with the poly kit, clearly states to torque with weight of car on the suspension.

boese1978

"The FSM will state that the final tightening of the components needs to be done with the car at the correct ride height" <<<<taken from Poly bushing inctallation instructions.

Fun71

The instructions may say that, but I found it is not required, at least not on the rear control arm bushings that I installed. If you look at the way the bushings are manufactured, you will see what Schurkey said above.

The factory bushings have the rubber bonded to both the outer shell and the inner sleeve, and the inner sleeve is slightly longer than the bushing so that it is pinched between the control arm mounting ears. This means there is a limited arc of movement as the rubber can "stretch" only so far, and therefore the bolts need to be tightened with the suspension loaded so that the arc of movement is centered.

The poly bushings that I used are made differently, with a polyurethane insert pressed into the outer shell, then the inner sleeve is pressed into the poly bushing. This allows the inner sleeve to rotate 360º instead of having a limited arc of movement, which means the bolts can be tightened without having the suspension loaded.

Perhaps some poly bushings are manufactured differently? I don't know as the only ones I have experience with are the PST rear bushings.

edit:

The Energy Suspension installation instructions don't mention anything about having the car at normal ride height when installing front busings:

https://www.energysuspensionparts.co...sion/17019.pdf

• Re-torque to hardware to factory specifications.

Schurkey

THANK YOU! You saved me a lot of typing.

BONDED (rubber) bushings have to be torqued at ride-height. The rubber needs to be in a "neutral" position, because as the control arm goes up and down, the rubber is stretched clockwise and counter-clockwise. If you torque the suspension with the control arms fully "down", the rubber never flexes in one direction, but flexes twice as far the other way. It will spend almost it's entire life stretched to near-maximum design limit in one direction, occasionally relaxed as the suspension arms drop, and wound-up to twice it's intended motion when the arms raise going over a bump, or leaning on corners. The bond between rubber and steel soon rips, and then the bushing is ruined.

NON-BONDED (Polyurethane, Del-Alum, etc.) can be torqued with the suspension at any position. The Poly doesn't twist, the steel sleeve just rotates within the bushing insert--which is why they tell you to grease the thing during installation. It's one of several reasons that Poly bushings are easier for a D-I-Y to install than rubber.