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MG Midget and Sprite Technical - 1500 Type 2 Brake Master Cylinder Problems

Well after spending the past few working sessions making up and installing shiny new brake pipes I went to bleed the system today...

Ran into something of a problem... The master cylinder doesn't seem to be sucking any fluid through the system.

I removed the cylinder and stripped it and it all seemed fine, rubbers were in good nick and with a bit of fluid in the cylinder it would squirt some out the end.

However when it is installed there is nothing...

Any ideas gang?
S J Dodd

Also I can't seem to find anywhere that still sells this type of brake cylinder...

Any ideas on that one, Moss and the MGBhive both say no longer available and I can't even find one on eBay...
S J Dodd

Are you using an eezi-bleed?
Dave O'Neill2

I would be but because I have the remote reservoir I cannot attach the eezibleed to it as the cap on that system isn't big enough to fit the reservoir...
S J Dodd

I think you have a dual circuit master, is that so? If yes, and it is shot then I believe you have to convert to a single circuit system.
Graham P

I have the single circuit system but it has a banjo connector so there is one brake pipe going down to the front drivers side wheel and then the other pipes goes round to the other side to do the front nearside and the rear brakes...

It seems my only option is to get a new cylinder with a non remote reservoir... Unless anyone has a source for the one I have at the moment...?
S J Dodd

Can you not get new seals and see if it makes a difference? An old seal might well push fluid out into atmospheric pressure but not manage to move a whole set of brake pistons. It's a cheap possible cure - if the bores are good in the master there's not much to go wrong unless you've left a component out.
Nick Nakorn

Some years ago I chenged my M/C for the later see-through type and found I could not get any pressure.
In the end I pumped the pedal for a minute or two and the seals bedded in, bled it, and all has been well since.

I dont know if there is something on the seals or inside the bore that prevents normal quick bedding in with these new cylinders, but I have heard of someone else solving their problem the same way.
JB Anderson

OK cool, I'll have a look at getting the refurb kit and give that a go first then before forcing myself to splash out on a new M/C :)

Thanks for your help guys, much appreciated!
S J Dodd

If one hasn't had the opportunity to get the master cylinder out on the bench and clean it really well and polish the bore it's sometimes the case that a bit of grit can get under a seal and prevent it sealing. A few pumps sometimes doslodges it and sudenly all is well!

Nick Nakorn

it's always worthwhile scrounging or buying spare m/cyl caps when the opportunity arises so you have a variety for the easibleed kit...
David Smith

ISTR gunsons in their manual for the Ezebleed note that other size caps are available if required.

Could try giving them a call.

richard boobier

Well the master cylinder is out now so I guess a strip down and full clean as well as replacing all the seals has got to be worth a go...

If that doesn't work I guess it's time to buy a new one instead!

Thanks again for your advice!
S J Dodd

let us know how you get on with the seals
Nigel Atkins

Well the new seals arrived on Friday (I think) and I installed them...

Still no joy though :(

My gut feeling is that there is some sort of blockage between the filler pipe and the chamber...

Gonna hopefully take it in to my local mechanic and see what his thoughts are before ordering a new master cylinder...

Bit of a pain but you gotta expect these sort of things with an old car I guess :)

Thanks for the advice anyway guys!
S J Dodd

What was the condition of the bore of the cylinder like?
Nick Nakorn

Looks fine... No pitting or anything...
S J Dodd

This thread was discussed between 13/04/2014 and 28/04/2014

MG Midget and Sprite Technical index

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