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 MGB Technical - Rear brakes inbalance

I have recently tried to get my MGB through an MOT test.The rear brakes have got new brake cylinders and copper brake pipes fitted. However it is failing the test because they are not coming on evenly. Individually neither is better than the other. However the near side locks on first then the offside follows when they are tested together.
I've had it tested on another 'rolling road' and it passes.
Anyone have any ideas other than go and have it tested again at another test station.
Thanks in anticipation.
Martin

Adjust the breaks!

There is an adjustmet for the rear shoes
at the top of the rear plate....
HowY

Been there done that, still made no difference..
Martin


Hi Martin,

If an adjustment isn't making a difference, then something upstream could be interfering with the timing of the brake application or the amount of pressure being applied to each cylinder. Perhaps a flushing of the lines is in order.

Frank
Frank

Take it to "the rolling road" that passed it.

Maybe an air bubble in the line/wheel cylinder that's soft.

That's a fancy test. My inspector sees that the car stops and the lights work.
glg

An air bubble would affect both sides equally - unless it has a split system, you don't say what year. A difference in the springs side to side would make a difference as would more corrosion stiffness on one side, but I doubt enough to affect this test. Odd drums? Oil one one pair of shoes? New shoes? These can afect braking efficiency until they bed in. Adjustment usually only affects the travel. Was the 'other' rolling road a brake-test facility? If so then it would seem the difference is between those two rather than your brakes.
Paul Hunt

Thanks for the comments guys. Here are some replies to your useful comments;
With bleeding the brakes the lines have been pretty well flushed as I've used nearly 1/2l in the process ( didn't get it right the first time).
It's a '72 B.
'Odd drums' well the last thing I have tried is to change the drums over and next weekend I will return to see if this has made any difference. The shoes are not new but there is plenty of life left in them.

I appreciate the comments but I think it maybe another test at a different centre - unless anyone knows different!





Martin

Is it possible that you have a crushed brake line? The hard line that goes along the top of the axel from the T-fitting to each wheel cylinder can be crushed if someone tried to tie the car down (for towing, for example) by putting a chain or strap over the axle.
Paul Noble

To add to the comments about the drums....check that the drum on coming on early is round. Sometimes drums can become oval and it will cause the brakes to come on early and lock that wheel. FWIW
Richard Evans

Thanks for your comments. The car passed the re-test this morning and I am able to get out on the road with the top down...guess what, it's been raining most of the day. Such is the English weather!!
Martin

This thread was discussed between 11/05/2003 and 17/05/2003

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.