This is why I hate Urethane

[Size1]

Yep. Just had a look and the mount is stuffed. Actually it looks very bad, probably because it is still under load. The transmission mount is OK but I will need to change that soon too because of the extra work it has to do at the moment.

 

[Size1]

Does anyone know where I can get the mounts from locally. Meek are shut till the 16th and i have emailed bill at stealthautomotive, but I am impatient. Bad time of the year to choose to do maintenance I think.

 

[TME_Steve]

I got mine from Jonson....

Paul, i've seen solid spension urethane go crap but yeah I would guess the holes don't help, still hate the stuff.... Solid rubber would be my preference for this application....

 

[Size1]

What do you guys think about the prothane inserts from the eclipse, any good?

 

[naughtika]

they're the ones we all used..

 

[Size1]

Thanks, Ill get some from ebay then.

 

[Size1]

Finally had the time to change the mount today. It took alot longer than I expected! Anyway the car feels much better now, most of the vibrations are gone. But I can still feel some especially when braking, though I am not convinced that it is from the rotor's or pads yet ( going to do them anyways). It feels like it is coming from the drive train has anyone got some suggestions?

 

[naughtika]

if it shudders/vibrates while braking, it could be your rotors needing re-surfacing..

does your steering wheel slightly shudder or you can feel the vibration through it?

 

[Size1]

I do have that vibration too slightly, but this feels a bit different. There is a bend near my place that I can recreate this vibration while not braking. It improved by changing the rear roll stopper, but it is still there. I think I should check out the transmission mount. Should have done this before!

 

[Kenneth]

I have a theory on this.
When you use a solid front roll stop, it pushes the engine up at the front and down at the rear. Or tries to. Standard rubber mounts handle this to a degree because they have sufficient movement that they don't break and rubber is better at going back to its original shape.
Either that or the engine and gearbox mount are tired and letting too much weight settle down on the roll stops.

I noticed this because I have a solid front mount also and when doing up cross member from the front first, it was very obvious.

Either way, I think it is not the urethanes fault, more the application being incorrect.

Well this isn't technically a suspension post but it's more commonly used for suspension than anything else.

I'm robably going to get flamed for this but for those who don't know I hate urethane for most applications it's used for. Eg Engine mounts (as you can see below) and most suspension mounts. The exceptions are those which have very little lateral or vertical load and no twist apart from perpendicular to the mount.

For example, urethane mounts on our front upper wishbone where it bolts to the car I'd be OK with (hence they are still in my car). Swaybar D rubbers I'm OK with as well as there is not too much vertical load applied to them. However, lower control arms, no thanks.

The reason being Urethane deforms much more plastically (as opposed to elastically) than rubber, meaning it doesn't spring back properly. The problem is deformation of the mount over time (a relatively short time) and then things move like they shouldn't.

Anyway, I couldn't find just how old this rollstop was but it is certainly less than 3 years. And check it out! and that's without an engine in it so add another 5mm or so deflection with the engine hanging on, probably 10mm under load. The tailshaft was hanging mighty low I must say. Now that half my vibrations are gone, back to getting that SAYC diff angle correct....

 

[TME_Steve]

All my urethane mounts distorted significantly, and they're all now replaced

the rear roll stop was worst followed by the gearbox then the top mount, anyway, Paul and I have now come up with a a solid rubber solution for the rear roll stop, see this thread all about it

Also, stiffer maine engine mounts are available from meek, although still not solid, better than stock though and more compliant than urethane.