MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - rearwhweels locking up

The rear wheels are locking up before the front wheels when cold. I just changed from drum drum to disck drum, standard new Lockeed callipers with Brembo disks, Mintex pads, rear 3/4 cylinders. So I need smaller cylinders! Do the 1500 midget 11/16 cylinders fit the 1963 back plates?

Flip
Flip Brühl 948 frog 59

Flip, I think I'd let the front pads bed in some before I started changing things. Could just be that the fronts aren't really braking at their best and once the pads bed in the balance should return.
Bill Young

If you find you still need to change the balance, the answer to the question on the 11/16" cylinders is MAYBE YES - BUT:

There was a difference in rear wheel cylinder between all-drum Spridgets and disc brake models, single acting and double acting. If you have the later double acting ones fitted, then the change is simple, BUT:

These wheel cylinders are one of a range identical in design apart from the bore size, which ranges from 5/8 to 7/8 (I think I have seen 15/16 too)in 1/16 steps.

In order to reduce the likelihood of mixing up the cylinders on the same axle, there is a roll pin which protrudes from the rear and engages with the backplate, and this roll pin is in a different position for each size of wheel cylinder.

When you change cylinder size, you will therefore have a mismatch between roll pin and backplate which will have to be addressed. While the simple way is to remove the roll pin, you also remove the protection that you/someone may in the future inadvertently be supplied the wrong cylinder and end up with different sizes on each side. For that reason it is preferable to either modify the backplate (plug & redrill) or fit backplates off the original application
Paul Walbran

Bill,

I did bed in the pads the hard way on a circuit, 2 cycles of 10: braking max from 70 to 20 mph. The balance warm is ok! As I use the car on the public road I would like a good balance when cold. I agree with you, Dust will make the drums les efficient. But this is not what I want.
Paul,
Thank you for the information, I use to tap the rollpin hole to accept a bolt witch I glue as well, (I was never able to make a safe fixation with the circlip). Do you have BLMC numbers of smaller cylinders?

Flip
Flip Brühl 948 frog 59

GWC1139 is what I have it down as. However, GWC1129 is listed as Midget 74 onwards, so there may have been a type somehere!
Paul Walbran

Thank you,

I located the parts here in Holland with www.thepart.com
A nice site for BLMC dealers (as well for you and me)

Flip
Flip Brühl 948 frog 59

Sorry for answering so late: I was sailing and there was fog on the North Sea. So I was sailing longer than expected. While sailing I woke up one night thinking about oval drums. I came home today. Before I screwed the new cylinders in I did control the rear drums for ovality: Thy were oval. I changed them for round ones and yes! The front locks up before the rear on a dry surface.

Flip
Flip Brühl 948 frog 59

This thread was discussed between 17/05/2010 and 24/05/2010

MG Midget and Sprite Technical index

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