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MG MGB Technical - Big Brakes

Has anyone used the Princess 4 pots on a B? If so what were the results? And was that with the solid disc or a vented disc.

many thanks

Colin Parkinson


Princess/Ambassador four-pot callipers are a common, more or less bolt-on, upgrade using either solid (GTV8) or vented (Peugeot 505 turbo) discs, the total piston area matches quite well to the original MGB two-pot callipers so pedal travel is not an issue. The larger SD1 four-pot callipers can also be used, but there may be fouling problems with 14" wheels and there will be more pedal travel.

Geoff King

May make the pedal lighter, but you won't get any additional braking effect, that depends entirely on the contact patch between tyre and road. In fact if they lock the front with less hydraulic pressure you will actually *lose* braking effect as there won't be as much coming from the rear.
Paul Hunt 2

Hi Colin, Ive used these calipers on several Bs including one rather quick supercharged car. Ive used the dual circuit master cylinder and servo setup with solid V8 discs. The calipers as supplied by Flexolite come with an excelent pad but are not wide enough to take the vented discs without fitting spacers. Pedal travel is as Std B but they are progressive and give very good feel. I think they are a worthwhile mod especially if your std calipers are due for rebuild. Watch out for the mounting bolts as the Flexolite calipers are drilled METRIC and the stub axles are UNF. I made up some special bolts. I dont think a road car needs vented discs but may be usefull for track day use. JIM.
j soutar

This thread was discussed between 08/04/2007 and 11/04/2007

MG MGB Technical index

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