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MG MGB Technical - Dual Circuit Master Cylinder

Dual circuit master cylinder without servo, I believe US spec. Anyone found a way of getting the white nylon washer out after removing the 1st circlip??

It isnt about to fall out!

Thanks

Colin
Colin Parkinson

Colin,
My car was fitted with one of these as it is an ex US car. It is so long since I replaced it with a UK single circuit cylinder that I don't remember the washer you refer to.
However, after changing I realised that the dual circuit non servo master used on UK spec RB midgets looks identical. So 1500 Midger owners might be a source of advice.

David

PS - I have nearly finished building the banjo axle you supplied parts for.
David Witham

Only way I ever found was to drill two small holes in the damn thing, and screw in a couple of very small diameter but very long screws to use as a puller. Such screws are not easily come by! And you have to be careful to not scratch the CP piston with the screws too.

FRM
FR Millmore

I believe it's the same as the late UK-spec Midget dual circuit M/C.

My method was slightly different to Fletcher's - I drilled several holes in it and removed it in pieces.

Haynes manual didn't mention the circlip behind the nylon spacer!
Dave O'Neill 2

I've assembled one of these twice because I keep forgetting the spacer behind the nylon bush. ~sigh, head slap~. Can we say "slow learner?"

I've done it both ways, drilling the thing into smitherines and levering it out with long self-tapping screws. I think the levering method works fine (again, I'm in Fletcher's camp, sure happens a lot) and if the screws strip out you can carefully drill a new set of holes to try again. If they strip out too many times, you are in the drill a bunch of holes until it breaks up mode, but then you run the risk of damage to the piston. Although, I don't think the piston does any real sealing, so if you mess it up a small amount you can turn it in a drill press with some wet dry sand paper to smooth it out. If you are really worried, get a cruddy one from the breakers and experiment on that one first.

Now that I'm almost an expert, I'm going to rebuild it one more time. You do need some kind of fixture to hold the spring back when you separate the front and rear piston link pin. Attached is a picture from my website http://www.dbraun99.com just go to the MGB Wire Wheel Conversion that turned into a Restoration and go to the restoration and suspension and then brakes section for more pictures. Sorry there isn't more text but I got texted out when I made the MG TD15470 restoration site!

good luck!
dave

Dave Braun

Lyndsay Porter talks about smashing it into many pieces with an ice-pick and hammer.
PaulH Solihull

"Although, I don't think the piston does any real sealing, "
Yes it does, the seal under the nylon bush is the rear seal for the piston. Without it, all the fluid will run out the back of the cylinder when the pedal is depressed. And the piston is chromed to act as a bearing in the nylon bush, as well as a sealing surface. Faults in the piston surface can cause sticky pedal and leaks.

FRM
FR Millmore

Nuts, Fletcher... well, one more thing to double check...

warmly,
dave
Dave Braun

Thanks guys I guess it is coming out in bits!!

Picking up seal kit tomorrow. Hopefully the plastic seal is supplied?

Colin
Colin Parkinson

Yes it is in the seal kit. And it has come out in many pieces!!!

All I need to do now is get the 2nd circlip out!! Will have to think about that one.

God they make these things difficult for us mere mortals!!!
Colin Parkinson

I modified a pair of long-nose pliers specificly to do that job. I ground hooks on the ends, but also had to grind the outside to fit inside the bore and the inside to clear the rod IIRC.
Dave O'Neill 2

dave I have done exactly that. And it is now in it's component parts!

CP
Colin Parkinson

Just out of interest it is all back together, but here is a picture of the tool I made to hold the piston in.
Makes life alot easier!

CP

Colin Parkinson

This thread was discussed between 23/09/2011 and 08/10/2011

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