Club Triumph

I bought a pair of TRW master cylinders (GMC205, = PNB454?) around a year ago, for a Herald with disc brakes. But I've only just got round to actually fitting them... I also bought a reproduction extension piece. Put these away without thinking, but it turns out the extension doesn't fit. It fits the original (beyond rebuilding) master cylinders, but not the new ones.

TRW:

• ID = 32.5mm
  
• OD = 40.8mm
  

• OD of Plastic = 34.6mm
  
• ID of metal collar = 44mm
  

run it without the extension but take extra care when changing pads or shoes?

Quoted from glang

run it without the extension but take extra care when changing pads or shoes?

Thanks for the replies, being mindful of the fluid level seems a reasonable solution. Doesn't really make sense to me why TRW decided to change the dimensions, even the unbranded ones retain the original dimensions.

However, to give me one less thing to worry about, I'll probably change the M/C for an external reservoir type (e.g. https://www.demon-tweeks.co.uk.....loy-master-cylinders), and then mount an external reservoir on the bulkhead. Personally, I prefer a translucent reservoir, particularly for the brakes.

If youre going to fit one like that why not also buy the large reservoir that screws directly into it? Then you wont have to worry about mounting a remote reservoir but will have sufficient capacity for pad/shoes changes without risk of spillage
What about this item: http://www.jamespaddock.co.uk/brake-master-cylinder-single-line-2

posted Sun 13th Aug 2017 reply 4 of 5

The items required are
64475476  Extension small reservoir int m/cyl
64473019  Cap/Mcyl large int Alum
378763     Seal M/cyl large int
64474602 cap Assy Reservior / large 2.96 diam
supplier
Performancebraking.com
tel 01600 713117
as at May 2016
1 of each above total cost £41.39 inc vat collected Monmouthshire
Very helpful team to mee