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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - Master cylinder

I have just purchased a TRW Lucas master cylinder which only cost £70 plus carriage. However I have since been told by another company they had trouble with this unit and recommend Lockhead. I spoke to the supplier who was a bit put out and said he had sold many units without a single problem. I have asked MGOC and their MC is made by Caparo AP and also Moss whose unit is made by XRN. It seems that everyone has different suppliers.
I was wondering if anyone has experience with the TRW unit? I dont really want to take chances with the brakes. Many thanks
Graham V

I also recently purchased a TRW master cylinder, but have not yet installed it. It says on the box that the warranty is void if DOT5 fluid is used. Has anyone had experience with the TRW master cylinder and DOT5 brake fluid, which is what I intend to use....?

Thanks, George

G Goeppner

George
I spoke again with the company that warned me against the TRW. It turns out that they only use Dot 5 fluid and it appears this is why they experienced problems. They thought I should be fine with Dot4.
So I think you should not be tempted using it with dot 5 and going against the manufacturers recomendation. The brakes can be a nuisance if they dont work!

If it helps, from google I found a posting in a Triumph TR6 forum that refers to issues with compatibility of dot5 with the seals due to surface finishes and fluid not providing enough lubrication. If you want to read it:- www.british-cars.org/triumph-tr6-bbs/silicone-brake-fluid-200907110047292057.htm
Graham M V

Thanks for the link Graham, it was interesting reading. I don't understand how so many people have success with DOT5, and not just with British marques. Maybe I'll just put Lockheed seals in my new TRW mc and see how it goes.

George
G Goeppner

I'm always more than a little bemused when people say that there are problems with X brake cylinder. These are safety critical items, and the manufacturers make them to the tolerances required, otherwise no-one in their right minds would sell them because of the liability issues involved. That goes right the way through the supply chain. Caparo AP, TRW, Lockheed etc are serious companies, so they don't produce cr*p (at least in brake cylinders - brake light switches come under a different discussion). Maybe the brands are different, but I rather suspect that a smaller number of actual (asian) specialist manufacturers are supplying the brands concerned.

That the distributors limit the application support to normal brake fluid rather than silicon is, I suspect, a result of having limited experience and data to say that they are OK. It is, after all a fluid, that is not used in mainstream applications, and they probably have limited test budgets and resources like all the other manufacturers in the world! That doesn't mean it won't be entirely satisfactory in practical use. Again it wouldn't be sold and promoted if it was suspect, because of the liability issues involved (particularly in North America).

I have been using Silicon fluid for 20 years, and (as in any normal moving part) have had to replace seals at about 10 year intervals - but the car was my only one for years. That's routine maintenance.

As to comments in the british cars thread about aeration of the fluid, how on earth do people get away with rubbish like that. For aeration to occur, there has to be air in the part of the system where it doesn't belong and should be bled out anyway. The problem is not the aeration, it's the presence of air in the system in the first place!



dominic clancy

This thread was discussed between 02/03/2010 and 04/03/2010

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This thread is from the archive. The Live MG MGA BBS is active now.