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MG MGB Technical - Bleeding....arghhh

Hi , there I was last night with my new bleed kit and rack of spanners, lying on the flat of my back under the ar*e of my mg looking for bleed screws on the rear wheels..now I tried a 6 wrench ( metric ) , too small, so I tried a 7 and guess what - to big. Bugger!

What size should I be using ( it's a 78 Roadster - with a very spongy brake pedal ) .....I am guessing some sort of imperial thing ( 3/16inchandafarthing!??! )

Cheers, Daryl.
daryl

Daryl,
Sounds more like you may just need to adjust the rear shoes and thats the square bolt at the top of the drum. you can get to this without taking the rear wheels off if you have two elbows on one arm!!! Also the bleed nipples could be anything that the previous owner fitted.....
Have fun.
TJ
67BGT
T J Nicolson

Sounds like 1/4"AF most likely (about 6.5mm)
Steve Postins

Daryl. AS TJ notes, the rear brakes need to be adjusted, preferably using the special square hole brake adjuster wrench.

He is also correct that there are several different sized wheel cylinder bleed nipples with 1/4" being one of them. MGs are not metric and a good set of AF/SAE wrenches and sockets is in order if you want to work on one properly. Les
Les Bengtson

Second Les' advice. Tried a 1/4 inch one day when I had misplaced the special (and inexpensive) brake adjuster wrench. It sorta worked and seemed to be the correct size but the special wrench makes it sooo much easier and I always take off the wheels since that makes it easier to do and see what's going on.

J.T. Bamford

Regarding rear bleeder screw size, a 9/32" spanner or socket fits my rear cylinder bleed screws. Even though they are not metric a 7mm spanner also works, not a perfect fit but it works. FWIW, Clifton
Clifton Gordon

I obtained a special spanner to undo/do up the bleed nipple. However I found that one side has a different size to the other!
I would suggest a special spanner as they fit on more flats than a normal open ended spanner.
Cecil Kimber

I only use imperial on my B tyring to use metric will strip the nuts even if they sort of fit. Lucky many parts of the "old empire" still use imperial so they are easy enough to get; even if the uk may have been swallowed up my euro land lol.
erfrefewrffre werfwerfetrtg

I have seen three different bleed nipples used over the years, two Unified National (Imperial?) and one metric. I have taken inexpensive combination wrenches and heated the box end (ring spanner end), then bent them into a "dog leg" shape to allow better fit and fuller movement when using a tube on the bleed nipple into a glass recovery jar. (The jar also allows you to see the bubbles, when present. The "old method" was to allow the brake fluid to spit out everywhere.) Les
Les Bengtson

Daryl

A little off topic but have you looked at using Speed Bleeders? http://www.speedbleeder.com/

I have them on my A and find them very easy to use. Only have to loosen and tighten them once. And you can verify wrench size before installation.

FWIW

Larry
Larry Hallanger

Bleeder wrenchs are a tool group unto themselves they come in many shapes and sizes the one I use on Bs is L shaped with a 1/4" box end with deep walls[keeps it from striping the bleeder] offsett to the inside of the L "SNAP-ON" you get what you pay for. RIC
R E L Lloyd

I'm pretty sure my rear bleeder screws are 9/32", like Clifton's are. I had to go to Sears an buy a little bag of 10 "midget Wrenches" because they didn't sell the 9/32" wrench individually. It was worth it.
GK Kendall

When bleeding my brakes I always use a ring spanner on the bleed nipple. If you position it carefully you can get enough movement to open the nipple fully and close it again. Much better than an OE spanner and you don't have to buy a special.

For adjusting the shoes I do use the special spanner and the best quality I could find.

Peter
Peter Scott

Thanks Peter. I think you just solved my missing ratchet mystery. I haven't seen it for a day or two since I adjusted the rear left brake.

I'd made a brake adjusting socket from two cheap metric sockets...drove a 1/4" drive socket into a 3/8" drive socket. I used that on a 3/8" drive ratchet for the rear brake adjustments.

Anyway, after the brake adjustment I wanted to see how the rear suspension was after changing the bushing and shock oil so I went for a short drive. I heard a little clunk from the rear one time. I didn't know what to make of it, but it didn't do it again.

Since the brake adjusting socket and ratchet disappeared at the same time, I probably forgot to remove it after turning the brake drum.

That would explain the single clunk, missing ratchet, and missing socket (which is only kept in one place).
GK Kendall

The rear bleeder screws on my GT are 9/32". As mentioned above, difficult to find except as part of an ignition wrence set.

As for bleeding, I've been using a Mity Vac and it works just great plus no need for an assistant on the brake pedal.

The Mity Vac has also been a Godsend for pumping oil into that transmission filler hole behind the radio and for filling the rack with gear oil with the radiator in place.
Steve Lipofsky

Guys, many thanks for the advice. True to form they were different sizes on either side....one was 1/4" and the other was an 8mm ( i think ).Anyway , I now have brake pressure and a tentative run up the road resulted in me stoppping nicely , which is good! Having said that, I will check it tonight to see if it has returned to the 'after six pints of stella' limpness that I ( well the brake pedal ) was experiencing before. Next thing now is to drive to a garage and get the inner wing sorted....hmmmm , that should be cheap!
Daryl

This thread was discussed between 14/08/2003 and 20/08/2003

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