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MG MGB Technical - Brake Booster 1977 BGT

I am betwixt and between as to whether to refit the remote brake booster on my BGT(V8) restoration. I know that braking efficiency cannot be improved but is it worth doing for the lower pedal effort?
Comments will be appreciated.
Peter M
Peter M (member)

In my experience (I have driven the same car with and without booster connected) the difference was marginal, I was surprised how little difference it makes. We had to disconnect a friends as he had the problem where the brakes keep locking on and I had a go afterwards as well. After the first prod at low speed just to see how much difference it made, I never noticed at all, neither going back to my own car with the same system with booster working.

The integral booster, on the other hand, makes a big difference, making the brakes really heavy without assistance.
Paul Hunt

Hi Paul
Many thanks for your comments. Unless someone else chimes in with major positives I think that I won't bother re-fitting the servo.
Peter M
Peter M (member)

I guess it depends on what Paul means by 'with and without the booster connected' - do you mean with the vacuum pipe removed, or do you mean by connecting the pipe from the master cylinder directly to the three way union (ie taking the servo cylinder out of the loop)?
In my 1970 GT, the difference between 'engine on' and 'engine off' braking is huge. I also think that the servo gives you more feel, as you are pressing more gently for the same braking effort it is easier to make small adjustments to the braking effort.

Whether fluid pressure goes through the booster with no vacuum connected or goes direct bypassing the booster shouldn't be any different, I would have thought. But to clarify we disconnected the vacuum pipe from the servo and plugged the end with a spare spark plug, which should be the same as 'engine off' braking. I've never done that, but I will try. The servo must work if fitted and is part of the MOT test. Mine pass, so I presume that the testers satisfy themselves that they are working as they should, regardless of how little assistance they may give.

Remember the remote servo was only an option at one point, the remainder of the braking system being unchanged. So the brakes must have been 'adequate' without, and the MGB is unlikely to ever be accused of having over-sensitive brakes.
Paul Hunt

Pedal pressure will depend on the master cylinder. in the US 75 and later cars had the integral booster and the master cylinder had a larger bore, I believe 7/8". If your master cylinder has the same bore diameter as the non boosted system the pedal pressure should remain the same as a non boosted system, if the booster isn't working. If however you have a larger master cylinder bore, there should be a difference in pedal pressure without the booster working.
John H

Thanks all for you input.
Peter M
Peter M

This thread was discussed between 11/09/2008 and 15/09/2008

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