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MG MGA - Master cylinder extension

I have just removed my master cylinder, and have a new one in stock to fit.
I have the 1600 Mk2, so the master cylinder comes with the reservoir extension on top. The replacement doesn't have an extension and I was originally intending to swap my extension on to the new one. But I now find the "lid" on the new m/c will not come off without a good deal of persuasion, as the cork gasket doesn't want to leave either surface.
A new gasket is easy enough to get hold of, but having read the archives, I am wondering if its best to leave things alone, and not fit the extension.
Opinion seemed to be that the only purpose of the extension is to save regular having to check the fluid level as the brake pads wear. That's not a problem with my low mileage. So I was wondering if that is still the general view?

Makes life nice and simple!

Thanks, Graham
Graham V

Hi Graham
my 1600 (Mk 1) also has the flat master cylinder cover and I have wondered why the later high volume cover was deemed necessary.

I have just replaced a set of brake pads and when I checked the master cylinder, there was still plenty of brake fluid in there, even though the brake pad material was well worn down.

Perhaps if the rear brake shoes became worn down at the same time as the front pads, then the fluid level could drop low enough to allow air into the system?

I do have a Mk II deeper cover in a cupboard somewhere but I haven't decided to fit it yet.

I have though just flushed out all of the systems old Dot 4 brake fluid with new fluid because we are just about to set off on a trip through the Alps.
Although the brakes are working well just now, I realised that the brake fluid could have been in there for 10 years or so.

I think the prospect of "10 year old brake fluid" vs "Dozens of downhill Alpine hairpins" gave me the incentive here😁!

Colyn

Had a torrid time with the horribly misnamed "Easy-Bleed" kit!
Set at the recommended pressure it wouldn't push enough fluid through to bleed the system, but if I raised the pressure, it pumped fluid all over the top of the master cylinder🤐.
In the end, I only used the plastic tubing from the kit and I had borrow my wife's Rt foot to operate the brake pedal.
This was only made possible by "Live-pausing" the "One-Show" and by showing her that, by careful placement of a coaster, you can in fact place a wine-glass on the dashboard of an MGA 😊.

Colyn Firth

Colyn

That's the potential problem with Eezibleed. I now never put any fluid in the bottle. It means topping up the M/C after each wheel bleed. Takes a bit longer but saves the mess you suffered. I once removed the Eezibleed cap on the M/C before removing the pressure source. Sprayed fluid everywhere. Fortunately silicon. I now have a rust proofed engine compartment.

The Dot 4 type fluids should be changed every 2 years. Naughty boy for leaving it that long. Bit like not going for your 2 yearly SpecSavers appointment!

Steve
Steve Gyles

I have had occasional dabbles with other easy bleeding methods but I always return to my standard set up. This is the simplest of all single handed methods consisting of the old style pipe with a non return valve with its end covered by fluid in a small coffee jar. I top up mc after about 5 to 10 pumps. My wife got fed up with really old style two handed bleeding years ago! By the way my set up is drums all round although I don't think that makes any difference.
The only bleeding problem I ever have is with the clutch but even then I use same approach when it can take a few goes over a couple of days. I always think it's never going to work but it always does in the end.

Paul
Paul Dean

Thanks for the responses

Colyn, if it works for you that's good enough for me! As I say, I did go through the archives, and I just wanted to check there were no negative views.

I would imagine it's only wear with the disc pads that should affect the fluid level. I'm thinking that if the rear brake shoes are adjusted reasonably regularly, then there should be no drop in fluid at the master cylinder for wear at the shoes?

I was planning on using eezibleed, I have used it before with mixed results, and certainly am nervous about leaks, which I have had my fair share of. But I am not sure I will have luck with the clutch hydraulics just with HID pumping the pedal. Time will tell

Thanks, Graham


Graham V

I would boil the old m/c in a pot of water to loosen the cork bond.
Art Pearse

This thread was discussed between 14/06/2017 and 15/06/2017

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