Clutch master cylinder replacement

Technical advice Q&A

Topic author
Collfryn
Posts: 26
Joined: Fri Feb 10, 2017 1:32 pm
Location: Mid Wales
Great Britain

#1 Clutch master cylinder replacement

Post by Collfryn » Sun May 19, 2019 1:43 pm

I'm rebuilding my 1967 late Series 1 2+2. The pedal box and rear brakes are all Series 2 and it was fitted with the longer hydrostatic slave cylinder. All seem to be original - maybe part of the changeover to Series 1.5/2 cars?? The clutch master cylinder attached to the pedal box is a cast iron Girling model (which I'm pretty certain is a replacement) and has only one seal at the rear of the piston. Having refurbed the cylinder I wasn't 100% confident with the bore so I purchased a replacement, non oem cylinder. On swapping out the pushrod on the new cylinder, the piston assembly came out. It had a groove on the piston, but there was no rubber seal in it. The body feels like it could be aluminium.

My question is, should the replacement cylinder have a seal fitted to the piston, as well as the rear seal? In the photo below, Ive fitted one that was in the refurb kit I bought for the old cylinder.The sectional view of the cylinder in my manual shows a piston sealing ring and rear seal, but the cylinder is a different type with a port at the rear. Is this what was fitted to 3.8 cars?

Image
Richard Marsh
1967 Series 1 UK RHD 2+2

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cactusman
Posts: 2053
Joined: Wed Nov 14, 2012 11:09 pm
Location: Hertfordshire
Great Britain

#2 Re: Clutch master cylinder replacement

Post by cactusman » Sun May 19, 2019 4:16 pm

Simple answer....yes....the second seal should be there....it is not a pressure seal but should stop any fluid that passes the main seal leaking out....
Julian the E-type man
1962 FHC
1966 MGB....fab little car too

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Topic author
Collfryn
Posts: 26
Joined: Fri Feb 10, 2017 1:32 pm
Location: Mid Wales
Great Britain

#3 Re: Clutch master cylinder replacement

Post by Collfryn » Mon May 20, 2019 8:45 am

Thanks Julian. I'll contact the supplier and suggest they check their stock
Richard Marsh
1967 Series 1 UK RHD 2+2

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