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MG Midget and Sprite Technical - Brake Master Cylinder Identification

I have one of the Lockheed metal ones on my 1975 1500.
I'm after a set of replacement seals.

I ordered some, part number KL71535. However these are for the original cylinder that would have been fitted. The instructions mention that the kit will not fit the later model version of this cylinder which is identified by a groove machined into the body which mine has. The original has a flat nose to the piston, mine has a concave head and I believe a narrower bore.

My cylinder has no other identification markings on it, and I'm struggling to identify it to work out which replacement seals I need.


and another pic, with the machined groove between the flange and tin can


and the instructions that mention a different model


Google Moss's catalogue, go to Brakes, then Master cylinder& pedal Sprite/Midget 1275-1500. Your cylinder I think, is item 44 type 1 and the kit is next to it.(item 45)

b higginson

Oh so that's the groove everyone refers to, I thought it was some semi-hidden groove on the push rod tubing, no wonder I've never been able to get into our local Masonic Lodge.

ask the guy on the counter if the seal kits actually work for any length of time or if there is trouble with them - I don't know the answer now but they used to be a pain.
Nigel Atkins

Thank you Bernie, that looks like it. I missed it when I looked at my paper catalogue.

Nigel - the Master Cylinder doesn't leak at the moment as far as I know. But the brakes haven't been used yet.
My idea was to replace the seals whilst I have the pedal box out of the car. But if the replacement seal kits are poorer quality then maybe its worth leaving the originals in for now.

I'm back at Moss on Saturday to pick up some more stuff so I'll ask the question....


Could you bench test the m/c perhaps, put fluid in seal it off and put it under pressure for a few minutes and see if there are any leaks.
Nigel Atkins

yep - changing it later with the pedal box back in and the wing on is a PITA
S G Macfarlane

Yes I can imagine trying to get circlip pliers into the piston when itís mounted would be a right pain

The paper catalogue doesnít list the seal kit for cylinder with groove, online one does.

No, I just canít read properly! The paper catalogue does list the repair kit for the cylinder with a groove in it but itís a different part number.

This thread was discussed on 09/01/2018

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