Coil Over Bushing Failure

[restorejag]

I completed my MGBGT in July with a 302. I used the Moss coil over kit  part # 268-218.At 600 miles
I noticed the shock bushings were starting to fail.I called Moss who sent me new bushings ,they are also started to fail. At this time Moss has not come up with a solution.
Has anyone else had this problem with the kit.This car is used for normal driving.Any ideas on solution?

Thanks

Mike

[mstemp]

Mike,

How about Prothane or Energy?

http://www.energysuspension.com/assets/files/energysuspension-catalog.pdf

Interested in what you do as I have about 300 miles on my Moss kit. Guess I better have a looks!

Mike

[restorejag]

They are poly bushings,the springs are set at the lowest setting also the valve.I would think the
bushings that come with the kit should work.
Mike

[mstemp]

Mike,

I recall mine looking like poor quality when I installed the kit, especially when I pushed them through the new large hole in the subframe for the upper mount. Sort of reminded me of WallMart products and thinking how long is this going to last. Not all urethane parts are the same.

[DiDueColpi]

Hey Mike,
I run into this problem with urethane bushings all the time.
They hold up well and do a superior job when stress vectors are varied and transitional.
However when subjected to a constant load they deform or "flow" and fail.
A better choice is a good old fashioned rubber bushing or a nylon or composite bushing.
If noise is not a concern then a full metal setup would be best.
Cheers
Fred

[pspeaks]

Fred, you think then that urethane is not a good choice for normal street driving?  Moss has been selling that suspension modification for years; surly they must know there's a problem by now.  I was giving it serious thought for my GT but right now I'm replacing my radiator with an aluminum cross flow and making some changes to my steering so I guess I have a little time  to think about it.

Paul

[DiDueColpi]

Urethane is just fine in most instances Paul.
Sway bars, control arms, suspension links etc are all good candidates for urethane bushings.
The problem crops up when the bushing is subjected to a constant unrelenting pressure.
Such as supporting the weight of a car through a coilover set up.
Unless the bushing is unreasonably large the urethane will deform and continue to deform until it finally breaks.
There are other materials much better suited to this situation.
Cheers
Fred

[pspeaks]

Thanks Fred, I guess my plans are back on track.  I haven't installed them yet but I have a front and rear urethane set.  Still a little concern about squeaking and the correct grease to use.


Paul

[ex-tyke]

Installed the Moss coilover last Winter and have put 4K miles on since...so I'll definitely check for bushing wear when it goes on the Winter blocks....as I recall the bushings are Ozzy made.(SuperPro?)

[mstemp]

Graham,

I think the bushing are the ones on the shocks. Those were the only black ones on my kit and looked to be of  suspect quality. I am sure Mike A will let us know if that is correct.

[classic conversions]

What size are they ID and OD I may be able to help you.

[restorejag]

Thanks to every one for there input.I have contacted GAX technical who wanted the photos .Have
not gotten a responce at this time.I will let everone know when I do.
The bushings are the ones on the shock.
Bill I will let you know the size if I can ,it may be hard to do on the failed ones.
Thanks again
Mike

[classic conversions]

Coil over bushings as per e-mail This is the way they should be.

[restorejag]

Bill,
I do have the sleeve,it is 1/2id 3/4od.1 3/4 long.They use a poly spacer in between the bushings.What material are yours made from?
Mike

[classic conversions]

Then there is low quality bushing, all QA 1 US built shock use the bushing I picture. My front end kit that was installed in 2005 still has the original bushings in the shocks.

Get a better quality bushing.

[mstemp]

Mike A,

Did you ever get a response from Gaz? While my car sat over the winter the bushings have failed. Found this yesterday when the car was lifted to work underneath. Less than 350 miles!

Mike

[BlownMGB-V8]

Simple polyurethane tends to be something of a biodegradeable compound and needs certain fairly specific stabilizers to give it any kind of a usable lifespan. Those stabilizers tend to be specific to the application also and it seems to be pretty easy to be off just a bit on the formulation, which results in a reduced service life. Either there is something of an art in getting the formula just right, or certain chemists believe in planned in obsolescence, but a service life of less than five years does not seem to be all that uncommon (in some cases considerably less) while a lifespan of over ten years is not infrequent in superior compounds. The durometer or hardness seems to be a factor as well with softer parts tending toward earlier decomposition.

By now Urethane parts have been around for something like 2-3 decades so we're beginning to see a track record. Based on that the best is to pick those products that have a history indicating that they should be able to meet your requirements. Durability of urethane *can* be better than rubber but that isn't saying it always will be.

Jim

[NCtim]

So what have we learned to date? Any news from GAZ or Moss on this issue. I am planning on the Moss coil-over for my car also.

Tim

[BlownMGB-V8]

What I've learned is that in general, expecting a urethane bushing the size of a shock end to support nearly 1000lbs and absorb shocks for 100K miles without deforming is not really very realistic. If any *can* do it, they are made of an exceptional material indeed and we need to identify them.

(approx. 500# at wheel x approx. 2:1 ratio at shock)

Jim

[mstemp]

Jim,

They are not lasting 500 miles so there is more to it than that. Gaz had to change suppliers a few years ago due to a fire that consumed the original source.
Energy makes a suitable replacement.

[BlownMGB-V8]

It's a lot to ask of any bushing.

Jim

[mstemp]

Funny QA-1 have no issues according to Bill! Also it's how they are sold so one expects them to work. Gaz does employ Engineers so I expect them to work no mater what you believe should be used. If rubber works in lots of OE Coilover application I believe Polly can be formulated to function for more than 500 miles! Oh and Jim if you were the one who made the purchase and now had to rip it all apart you too might be a bit pissed.

Should anyone want to buy the Moss setup, order three sets of Energy 99105G bushings to use in place of what comes in their kit. Three are needed because one set needs to be cut up to get the extra length in the lower bushing, this is also what Gaz did. Or source one that has a wider spacing. Another option may be the nylatron bushing Moss sell for the lower control arms. Not sure of noise etc though. Other than the bushings I am happy with the kit. Moss has been stand up guys on this and they are working on a fix as well right now. From what they say Mike A and I were the first to have the issue.

[302GT]

I had GAZ shocks with my Hoyle suspension kit. The bushings failed in about 1500 miles; same for all replacements. I finally went to QA1 shocks and the bushings have held up well for over 10,000 miles. I also like the QA1 shocks better because the adjustment only stiffens the rebound; the compression damping is fixed and relatively soft. With the adjustable GAZ shocks, the compression and rebound are adjusted together. To get acceptable rebound damping, the compression damping was much too stiff causing the car to jump sideways on bumpy corners.

[mstemp]

Larry,

With your replacement bushings on the Gaz, were they all Gaz or did you try another manufacturer?

Thanks,
Mike

[302GT]

I used GAZ replacements. I considered trying another type but then a shock shaft bushing wore out on one and I gave up on them.