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MG TD TF 1500 - Brake master cylinder

I have helped club members after 3 total brake failures after fitting brand new master cylinders. Attaches pics of two different types.
The tiny main seal seems to give up very quickly.
The cylinder dimensions are exactly the same as original including the position of the fluid holes from the reservoir to the bore.
The lower type piston (AP) can be machined back to the same size as original and the more substantial OE seal used.
The spring seat from the new one is reduced in diameter by 20 thou and smoothed off to use as a cup filler.
Of course if you still have your old cylinder you can just swap them over.
Ray TF 2884

Ray Lee raybar2(at) tiscalidotcodotuk

Ray. A lot of people have bought new TRW master cylinders, having seen issues reported with the AP version. As you probably know its the TRW cylinder that MG Octagon sells. Are you saying that there is an issue with the TRW cylinder as well?
Dave H
Dave Hill

The TRW cylinder seems to be the one to go for, only AP cylinders have failed.
2 cylinders failed totally (pedal to the floor and no brakes).
On stripping down no reason could be found except the primary seal was very floppy.
I rebuilt one and it worked for a bit then dumped all fluid through the rear seal. This was possibly because there was no lead in taper at the start of the bore and I may have damaged the seal.
Both owners very reluctant to use AP again as you can imagine.
As I said, the new cylinders replicate the original so OE parts can be used. My car has had one of these cyls for over a year and performs perfectly.

PS I always fully bleed master cylinders before fitting to check operation (and save time)

Does anybody know how I remove my email address from the "started by" list
Ray TF 2884
Ray Lee

Does anybody know how I remove my email address from the "started by" list
Ray TF 2884
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Jim B.
JA Benjamin

Check this out. The original cylinders and at least the early repro cylinders used the top drawing components. There were issues with rebuild kits for them a few years ago, that Bud K. straightened out. Other than that, I know of no problems with the original style and early repros in the US. George
George Butz

the TRW piston seems to be yet another type but uses the later seal.
Maybe we were just unlucky with the AP cylinders. It does not inspire confidence in a singe line brake system.
Ray TF2884
Ray Lee

See reactivated thread 'Tight m/c rebuild'. Bud
Bud Krueger

I doubt three failures are coincidence. Single systems are inherently risky- I nearly crashed into my parent's garage years ago with MC failure. Seems suppliers/TRW should look into this. George
George Butz

It is the AP cylinders that failed. So far the TRW's from the Octagon Car Club are OK.
It is strange that the 3 fails we had plus 1 other are all that have been reported.
Ray TF 2884
Ray Lee

This thread was discussed between 24/08/2016 and 25/08/2016

MG TD TF 1500 index

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