JeffsWorld

...what does that mean? how do you know it? if you have it, how do you eliminate it? I am trying to diagnose a left rear creaking/squeaking sound and was told it 'may' be bushing bind.

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1996 Blue-Green Chameleon Formula
1of70 Chameleon Formulas for 1996
2000 S10 LS 4.3L 4x4 PickUp
JeffsWorld

LPEdave

I'll take a stab at this, though others could me more accurate I'm sure.

Suspension is intended to support the car and must flex in particular ways to react optimally to the car's orientation and forces on it. The term "geometry" is often used to describe the whole arrangement of angles, forces, and movement of the suspension.

By contrast, bushings are not supposed to be involved in this, they're supposed to provide insulation and flexibility at the "joints" of your suspension.

When bushings get in the way and restrict movement of the suspension, that's bind.
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The "classic" suspension bind discussed here (do a search) is the bind from poly bushings in rear lower control arms. It's really a matter of understanding the movement of the suspension, to decide what type of bushing is correct for it, and of course the "best" answer is not always the most convenient or comfortable for the ride.

Dave

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1997 LPE 383/n2o Camaro Z28 Convertible
12.39@112.2, 1.76 60' (na) 11.27@124.6, 1.76 60' (n2o)
LT1 Diagnostics, New to Nitrous? Northern California Racing Club

JeffsWorld

So, the creaking could be the poly-bushings on my rear lcas. I just had hotchkis springs installed, and maybe the sound was there prior, but now it seems to be amplified. It actually is kind of embarrasssing. I have the BMR lcas w/ the rubber/poly combo. I will do a search, thanks Dave.

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1996 Blue-Green Chameleon Formula
1of70 Chameleon Formulas for 1996
2000 S10 LS 4.3L 4x4 PickUp
JeffsWorld

Chris 96 WS6

Where did you put the rubber end of the LCAs? It should be mounted to the chassis, with the poly end on the axle. Poly bushings can "creak" if they aren't lubed, and you'd hear it if it were on teh chassis side.

BigRich

i think "bind" means when the bushing has compressed so much during suspension movement that it becomes solid (no more give) and then that point of your suspension has no more give and, it's like hitting the bump stops or something for a suspension piece, which is bad.

which brings up the question of solid-link suspension pieces: how are these better? where's the give?

Norm Peterson

Normally, bind is when a bushing is being deformed in order to accommodate motion of the suspension links. In the case of rear LCA bushings, the LCA's and their bushings have to allow some twist and lateral bending to occur as the chassis rolls (and the axle doesn't). As this bushing deformation (compressing, squishing, twisting, whatever you want to call it) occurs, moments are developed at these bushings in reaction. The magnitude of these moments (and the effects on suspension behavior) depends on how stiff the bushings are.

Free rotation of the ball in a spherical joint allows free rotation (i.e. no moments can be developed).

Squeaking poly can frequently by made to shut up by making sure that the length of the poly bushing is slightly shorter than the sleeve that runs through it. In rear LCA applications, the flat faces of the poly can also be beveled a tiny bit (approximating a very flat 3-D cone shape). Both of these mods will keep the poly from rubbing against the LCA brackets while under heavy compression from the bolts. As a side effect, you end up with less bind (always a good thing when talking about suspensions).

Poly bushings can be modified in another way that will further reduce the bind. I think you'll find some discussion in the "New Idea on LCA bushings" thread, perhaps this dates as far back as March 21 of this year.

Norm

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'79 Malibu, way not stock (355, 5 speed, . . .)
'95 Mazda 626 V6 5 speed, not entirely stock either
'01 20th AE Maxima, 5 speed, stock (so far)