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MG MGB GT V8 Factory Originals Technical - Brake Help

I built my V8 from a roller chassis and I'd never driven the car prior to putting a V8 in it. During the course of the building of the car, I overhauled the master cylinder(but not the slaves)

During a panic stop several months ago, the rear wheels locked up, although it seemed the fronts were working well. Assuming I'd assembled something wrong in the dual master (77) I rebuilt the master cylinder again. It does the same thing - locks up the rear brakes.

Does anyone else have this experience? Can the rear slaves on the drums stick? I jacked up the rear wheels and they turn fine when I release the brakes. Any advise or experiences would be welcomed.

Hi Phil,

The good news is that there does not seem to be anything radically wrong with your car. I don't know whether you have uprated your front brakes to cope with the V8, but if you did therein probably lies the cause of the problem. Factory V8's used Roadster rear slave cylinders so that the improved front brakes did not cause the rears to lock up early. I'm not an expert, but the improved brakes cause more weight transfer to the front wheels thus reducing the load on the rear which leads to the premature lock-up and consequent instability. When building my V8 GT I used even smaller rear wheel cylinders from a Mini 1275GT, and have had no problems. You may choose to put a brake balance valve in the rear circuit so that you can fine tune the brakes. Good luck.
David Daw


To add to David's comment, there is a smaller rear cylinder available for racing purposes to deal with this problem. With so many non Stock braking systems being used it would be a good idea to use a brake balance valve to maintain the right balance between front and rear.


This thread was discussed between 15/04/2001 and 17/04/2001

MG MGB GT V8 Factory Originals Technical index

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