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MG Midget and Sprite Technical - Rear Wheel Cylinders 72 Midget

Due to issues with my rear brakes, ie no feel in the brake pedal when pulling up to a roundabout and having to furiously pump the pedal just to get the car to stop.

I got home and the offside rear wheel was red hot which I can only deduce means an issue with the drum on that side.

Anyway I have a box of QH parts in the garage from my classic mini days and have a couple of GWC3095 wheel cylinders. I have looked up the pdf catalogue shows it as an oe part no. GWC1102 which is the part no listed on the Moss website can anyone confirm this is the right one for a 72 midget?

I will also be renewing the 'wedges' and adjuster at the same time just to avoid any issues.

If anyone else as suggestions on any improvements I can make at the same time it would be appreciated.



Normally this means:

- a spring has broken (2 normally pulling shoes together)
- wheel cylinder has popped out
- shoes adjusted too tight
- maybe wrong shoe?

can't imagine you'd ever need to replace wedges; but the ally adjuster corrodes in an imaginative manner making it almost and sometimes lierally un-shiftable, leading to chewed spanner end (ultimately need to remove back-plate and stick the end in a vice to remove).

You really need to get in there and see what's wrong...

BTW - the shoes are fitted such that the leading edge for each is the bare metal part... hope that makes sense.

Anthony Cutler

i have the same job to do on mine next week, drums, cylinders & adjusters.
I would make one of your habd brake rods adjustable with clevis ends as it makes setting the handbrake so much easier.
Also i am going to bolt the cylinder to the backplate, search the archives & you will see the mod.

Brad (Sprite IV 1380)

I am looking at getting some speedbleeders to assist with bleeding the brakes on my Midget anyone know what sizes are required.

I think its.

1/4" x 28 unf for the rear
3/8" x 24 unf for the front


Brad (Sprite IV 1380)

Shaun, yes GWC1102 is the correct Unipart wheel cylinder; the current QH replacement is BWC3095 so I think your NOS ones will be OK. I just bought a pair of QH and went through the same checking process...

David (davidDOTsmithAT stonesDOTcom)

Brad, saves experiences like you had with the easibleed and spraying brake fluid all over the engine bay and as I use Dot 4 brake fluid on the Midget this looks like an elegant solution.


So what does it actually do?
Ant Allen

Introducing SPEED BLEEDER®, the patented bleeder screw with the built-in check valve. It is truly a one-person bleeder screw. Once installed, it becomes a permanent part of the brake system. When it is time to bleed your brakes, you loosen the Speed Bleeder 1/4 turn and pump your brake pedal. When the pedal is depressed the pressure generated opens the check valve letting air and brake fluid out of the end of the Speed Bleeder. When you release the pedal and it returns to the up position, the check valve closes and prevents any air from reentering the system through the Speed Bleeder. When bubble free fluid is evident you close the Speed Bleeder. In the closed position it works just like your stock bleeder screw and prevents any brake fluid from leaking out. It generally takes about 5 pumps to purge each caliper or wheel cylinder. That is all there is to bleeding your brakes. If at a later date you need to bleed your brakes, the patented thread sealing system makes it easy to open the bleeder screw to perform the bleeding operation. It is made of quality materials and it is economical.


Still a lot more work and a lot less result than using an eezi-bleed. Easier to monitor the eezi-bleed as well. Granted, you have to pressure up the eezi-bleed BEFORE you put the fluid into it to be sure you won't spray fluid around the engine compartment, but that is something that you can learn from the experiences of others... Plus the eezi-bleed does the best job with a Spridget clutch; I doubt the speed bleeder would work as well on that.
David "no longer need all the glitz" Lieb
David Lieb

Yeah i remember that now, i read the instructions afterwards, typical bloke!
So this speedbleeder is just a one way valve at a bargain price. Think i'll stick to the old fashioned way & spend the money on a spare serpentine belt.
Drop me a mail i've made some things for you...
Brad (Sprite IV 1380)

Took the offending drum off tonight and looks like the plug that sits on the outside for checking the shoes has perished and gone hard and ended up inside the drum judging by all the debris inside it and was as hard as rock, I think it got jammed between the adjuster and shoe so that it was holding the shoe agianst the drum.

Not taking any chances and while it's apart going to replace the shoes, wheel cylinders, springs and other rubber items as I'm sure they have not been touched since 96. Just might give me some confidence with the back end.


same thing happened to me when i changed to minlites, the rubber bung ended up inside the drum.
Brad (Sprite IV 1380)

Oiling those brake adjusting screws is a regular maintainance item for me. Make sure you back them right off before oiling to ensure they're lubed all the way along.
M J Chapman

just changed my cylinders, the new clips are too large & prevent the bleed screw being fitted, a slight touch with a file on the OD gives enough clearance. They also have a slightly different profile on the throat from my originals, again a file sorted that out & they fitted without any problems.
Brad (Sprite IV 1380)

I use Speedbleeders on my autocross car. I have a set of vynal tubes set up with a tee so I can bleed both wheels at once with out any assistance. I probably could do all four wheels at one time but would have to careful not to run out of fluid. I don't think they are necessary for a street car that may be bled once a season, because of the cost. They are $10. each in the US.
J Bubela

This thread was discussed between 03/09/2009 and 14/09/2009

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