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MG MGB Technical - Brake Master Cylinder/Servo Seal

Is there any sort of seal between where the late dual line brake master cylinder joins to the servo.

This is the two screw flange which is bevelled on the MC, and fits into a neat hole on the servo.

I have been told one is not required because there is nothing to seal, air or vacuum wise, but I just need to know before screwing up, probably in more than one sense.
Tom

Having just done this, there is only one seal involved. This the rubber boot supplied with the servo kit(!) that goes over the end of the Master cylinder. It is then retained in place by a metal shroud, confusingly described as a "seal retainer" (I say confusingly 'cos I spent some time looking for a non-existant retaining clip). The Master cylinder bolts directly to the servo in metal-to-metal contact. The part of the seal not hidden by the shroud forms an airtight seal between the "nose" of the Master cylinder and the servo. It also serves to seal around the pushrod to save the MC seals from having to work against the "suck" from the servo. You may want to rub off any "galling" that has formed on the pushrod and give it a quick coat of silicone rubber grease to enhance its life in this area.
T J C Cuthill

I've just found what you are talking about in the bag of old seals, so many thanks.

I'm sure the seal is part number AAU9165A Connecting Seal, but Moss UK say they are no longer available.

However, I'm told they are in the major overhaul seal kit for the servo but at £50 a set, that's some expensive seal.
Tom

How did you two get on parting the master cylinder from the servo.

I have one of these set ups on my bench part stripped with a view to fitting it in my car when I do a LHD to RHD convertion. I have not been able to part the master cylinder from the servo and I am concerned about using too much force. Is there a trick to this?

Yes I have undone the nuts!

David
David Witham

I'm afraid I didn't split it, but if T J C Cuthill can't answer your question, I'll ask the chap who did.
Tom

Just answered my own question.

The seal is in the MC overhaul kit.
Tom

This thread was discussed between 29/07/2003 and 04/08/2003

MG MGB Technical index

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