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MG Midget and Sprite Technical - Dual master cylinder on 64 midget

I've had a quick look in the archives and can't make my mind up on this.

My 64 midget has a dual master cylinder, its not the original one, (that started to bind the brakes on after 20 or so miles of use - even after it had been honed and re-rubber sealed)

So I rebuilt my spare one and this has worked fine for just over 1000 miles, but I'm now having problems with the clutch not engaging/disengaging. I've replaced all pins/pivots etc and adjusted the freeplay on the pedals as already suggested, so the only culprit to me is the master cylinder.

I believe mine is the 3/4" set up?

I've seen lots of new ones for sale at between £70 and £120 but advertised as for frogeye, early midget and mga? I'm guessing that they are the 7/8" version?

New 3/4" ones seem over twice as much money.

I've emailed a few of the sellers who say that the 3/4" version is not available new and that the 7/8" one will do?

I don't know now, but just want to get my car back useable again, and don't think that just new rubbers in my old cylinders is going to do the job.

What do you think?

John
John Collins

http://www.brakecylinder.com/spridgetbrakes.htm

http://www.gerardsgarage.com/Garage/Tech/DbrakeUg.htm
Trevor Jessie

just looked at Trevor's first link - if the later 3/4" cyl gives a >30% decrease in pedal throw compared with the early 7/8" unit, how did the factory modify the clutch to cope with the reduced slave rod movement?
David Smith

Didn't they use a different clutch slave? They certainly used a different fork.
Daniel Thirteen-Twelve

I've not long seen to this on my 1966 car. I think the answer is to get your original cylinder resleeved by a company called PastParts (in Bury St Edmunds, I think. It cost me about £110 inc postage and came back looking better than new and ready to fit. As the new sleeves are in stainless steel it should then last forever, particularly if filled with silicone fluid, and this way you retain your original part. As you say, the only dual-bore cylinders easilty available are 7/8" bore, and this way you can stay at 3/4" bore and avoind any problems. Find your way to PastParts on the web and ask them for a quote. (No connection, other than being a satisfied customer!)

G
Gus Gander

Gus,

thanks for the info, I've sent them an email enqiry, but will ring them tomorrow if I get chance, I can send them my spare one to rebuild as soon as I hear from them.

John
John Collins

John,
Contact Pastparts. They know all about these. I've had both my frogeye and Mk11 midget m/c's resleeved with them.
Neil
K series

chap on the MASC classifieds has a couple for sale (reckon he's read this thread !)
David Smith

Quick update, rang past parts today, and have just been to the postoffice to send my master cylinder off to them,

I should get it back in approx 7 to 10 days, it will be just over £100 which I thought was fair.

John
John Collins

Update, refurbed master cylinder arrived back on Friday, and I fitted it today, along with another new clutch slave cylinder, all seems well now! will give the car a longer test tomorrow.

Definately recommend past parts for service.
John Collins

John,
Glad to hear you are pleased with Past Parts. They provide a very efficient and fast service. My resleeved M/C's have been great. Incidentally, I have an MGC aswell and in the past had problems with the servo. They supplied me with a servo kit and lots and lots of advice. They were very helpful.
Neil
Neil (K series)

This thread was discussed between 19/01/2009 and 31/01/2009

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.