MG Sports Cars

One of the properties of plastic parts is that they are "plastic". In other words as an amorphous solid the material can continue to flow from a high pressure area to a low pressure area, the rate being dependent on the pressure. You can see that in Graham's old bushings where they have gotten thicker on one side and thinner on the other. Finding a composition that resists this flow adequately yet is still compliant enough to absorb shock loads and has sufficient ductility in shear is sort of the holy grail of suspension bushings. A hard rubber is fairly good at it but has limits. Polypropylene was once considered the cure all but it really hasn't turned out to be all that and some formulations are better than others. By and large longer lasting has meant stiffer, with Delrin at the upper end of the scale.

In practical terms what this means is that you find the hardest formulation of poly that you can live with and change out the bushings when they approach metal-to-metal contact, or install delrin and live with the squeaks. Maybe install grease zerks. But each time you remove compliance from the suspension you get more harshness. This applies to the tires as well. So the road to good handling might be paved with loose fillings and other bolts and nuts.

It's a highly loaded component. 500+ lbs on each bushing as a constant load and several time that as impact loading. Of course it will take a beating. Just one of the compromises inherent in the coil-over design. It's why they are used primarily for racing or custom applications where they are likely to have more frequent replacement. You'll note, even the stock MGB spring coil sits on a rubber seat IIRC. Well, maybe it doesn't, I'm not sure anymore, but it should.

Jim

I talked with Moss yesterday and according to them the problem was solved in early 2019. I am interested in this because I am going to change to either a Moss unit or the Hoyle unit. It looks like both have had problems. Hoyle uses Autobush when they supply Polybushes. I think this is only for the A arm inner bushes. I am presently waiting for an answer. GAZ supplies the shocks and springs for both units along with the bushings. I do not know what bushings they use. If you go to the Autobush.com website they claim that their bushes only use a compound and grease secured from an American supplier, because of reliability issues. They guarantee there bushes for two years from date of purchase, which is the identical length of time for the GAZ shock unit supplied by Hoyle.
BTW I posted a picture of the current GAZ unit on MG enthusiast web site, so take a look and see if it any different than those supplied with earlier units as per Graham and others.
In summary, I have read somewhere on the internet that GAZ had a fire and that is what caused these problems, but I have not been able to verify that. To my mind, I think that Moss and Hoyle have any problems sovled as of now, but I don't know about longevity. Certainly, any coil over shock bushing should last longer than one or two seasons. They all support the weight of the car. Some are subjected to more load than others--the farther outboard the less the weight or force on the bushing. That is probably why the Hoyle and the Guzman units have less or no problem as apposed to Moss.
There ya go, just my two cents.

That's why we used solid spherical rod ends on the coil-overs in the MG Roadmaster and my roadster which operate at a 2:1 ratio. I think the Roadmaster has 9 seasons on it now.

Jim

Quote:

BTW I posted a picture of the current GAZ unit on MG enthusiast web site, so take a look and see if it any different than those supplied with earlier units as per Graham...

Here's the shock info that I have on file
Moss Coilover front suspension #268-208
GAZ Part# GP8-1129
MOSS Europe Part# TMG49025
MOSS USA Part# 268-199

Graham, This looks the same to me as I posted on the other web site. I did query Moss Europe and got this answer:
Since posting this picture of the Moss Coilover shock unit, I emailed Moss Europe for an explanation of what happened.

Here is my email:

Comment: Regarding your part no. TMG40750G (and similiar). I notice that you sell a replacement upper and lower bushing kit for this part number. May I ask why? I have read on the internet horror stories of bushing failures in very short times ranging from destruction to the hollowing out from load and consequent distortion of the bushing hole. These claims and your substitute bushing prompts my question. Please let me know what the present status is of these coil over kits. This and some others are presently on backorder--Is these because of bushing failures? Thank you for your help.

And their reply:

Hello James,

For years we have offered alternative bushes as (A) replacement and (B) upgrade.

Problem then occurred in 2009 with Gazzmatic poly bush supplier (Powerflex) as their factory burnt down. Gazzmatic found another supplier (they did not want to use superpro) but their bushes were not as good.

They have been trying out new design bushes over the years using bottom bushes such as fitted to Peugeot expert but these suffered distortion.

They have since used a bottom bush which is as used in their Jag range which has cured the problem,

We cannot build anymore kits at the moment as we are out of stock of 5/16unf bolt.



Regards

Mick Pratt

Technical Support

Moss Europe Ltd

Unit 16, Hampton Farm Business Park.

Bolney Way. Feltham. Middx

TW13 6DB

Quote:

They have since used a bottom bush which is as used in their Jag range which has cured the problem

Part no?.... kit?.....
At least, the bottom bushes are easier to replace than the tops!

Graham,
Spot on on the ease of replacing bushings. Perhaps if you email Moss they will tell you the part no. of the bushing they now use. They do have the SuperPro and the part no.s are TMG49025ASPK for the top, and TMG49025BSPK for the bottom. They are listed on the Moss Europe web site.

Thanks for the SuperPro info, James. Have sent an inquiry off to Moss UK.

As a follow up to conversations with Moss (UK), it appears that GAZ has released an updated shock with a revised bottom eye/loop that precludes using the TMG49025BSPK SuperPro bushing...this part will only service the old shock eye.
Here's photos of the original shock and bush (right) vs the new design shock and bush.(left)







Edited 1 time(s). Last edit at 08/27/2020 06:06PM by ex-tyke.

I have just acquired the late build Moss Gaz coil over shock kit. The bushings are indeed different. Please see the picture for the look of the new lower shock bushing.

I am getting old and hate to learn new things. I just learned how to resize pictures so that they could be posted on this site. I use an Android computer now after years of using Microsoft. I like the computer but the picture resizing (I thought) was a challenge. I did as Curtis suggested and downloaded a free resizing program and the above post is a example of that. I will post more pics of the shock as I take it apart for analysis.
Suffice to say that this shock and the bushings are significantly different than the earlier examples. I do not know whether this mod of the lower busing solves the problem of bushings wearing out, but according to Moss it does. It is a pity, as Graham has just revealed that the new shock does not accept the Superpro busing replacement that Moss Europe sells. It is a bigger pity that they do not mention it on their website.

Graham, Do you know if the upper replacement bushing kit from Moss Europe fits the latest shock offering from Moss? The lower one certainly doesn't fit!

MOSS rep indicates that Superpro Part Number: TMG49025ASPK will service old and new shock.
[www.moss-europe.co.uk]

Which Moss rep? Kelvin?

Quote:

Which Moss rep? Kelvin?

Nope.....inquiries went to Moss UK (Mick Pratt)

Hopefully, it was good intel.

To all that uses Gaz Coil over shocks.
Me too have Gaz coil overs on the front suspension and a 4 link suspension with Gaz coil overs on the rear axle. The car is still on a rotissery so I have no experience or data about the lifetime of the bushings. I will investigate with Gaz in the UK about this issue. That is where I got the shocks from.
In the meantime I will keep looking for further news about this issue.
I have the Hoyle front suspension but not road tested it. The A arms are fitted with poly bushings from Australia.
Werner

Werner, Welcome to the conversation. I don't believe that you will have the same problem with Hoyle front suspension which uses a different shock. I don't think there have been any issues with the Hoyle front suspension shock bushings. In my conversations with Hoyle they use Autobush at present for the A arm bushings but previously have used the SuperPro from Austrailia. If you are interested stay tuned for more information on the Moss Suspension bushing probems, history and what is being supplied.