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MG MGB Technical - Brake Pedal travel

I've checked the archive and can't find a definitive response to this.

I've now replaced the master, servo innards, brake hoses and rear cylinders. Everything is bled with no leaks.....However the pedal travel is about 3-4" The brakes do stop the car when the pedal is pushed but I can't remember if this travel is correct or whether the pedal should be rock hard. This travel is only noticeable when running, so it appears the servo is doing something anyway! As I'm not convinced that the brakes were any good in the first place I'm now paranoid that there is air in there.
Pat Gregory

Hey Pat,

How far from the "floor" is the pedal when brakes are activated?

Are the rear shoes adjusted to the point where there is just the slightest amount of "drag" on the wheels when spun by hand?

Is there plenty of vacuum being supplied to the Servo?
JR Ross

Pull on the brake handle and see what happens to your pedal feel. I bet it will be harder and higher. If it is try bedding in your rear pads a bit and then tighten up the rear adjusters
Sandy
SANDY SANDERS

should only be about an inch with the servo discharged, a bit more than that with the engine running, certainly not 3-4 inches, which must nearly be on the floor.

Do they pump up if pressed repeatedly? Then go long again if left a few moment? If so then the several MGBs I have done brakes on all do that, and need a 2-stage bleeding process. First is normal bleeding with an EeziBleed until there are no more bubbles. Then get someone to press down on the pedal as hard as they can, while you rapidly open and shut each caliper bleed nipple in turn. This always blasts an extra lump of air out, and after that they are fine.
Paul Hunt 2010

How to get the neighbours talking!!

Just been out with a ruler and measured the travel,
1.5-2" Not running. 2.5-3" running. The rear brakes were adjusted to stop and then 1/4 turn back so just off binding. I'll try Pauls bleed when I can find an assistant and update soonest.

Pat
Pat Gregory

Finally got round to this and completed the bleed. When my 'assistant' was pumping, he was also commenting on the fuid level, which can be seen from the driver's seat. All was well but still couldn't get hard pedal and still lots of air in the rears. Finally twigged that he was looking at the front half of the cylinder (i'ts in two halves front and rear) so the fluid looked full but the rear half (at the front of the cylinder) was empty. Topped up again and bled through...all now back to normal.

DOH!

Pat
Pat Gregory

Paid a lot of cash to a "specialist" in Aylesbury to bleed my system after changing the front calipers. It passed the MOT but always felt wrong and peddle travel too far. Went to adjust the handbrake and found one of the adjusted was completely useless which i replaced and now the brakes are perfect, firm no excessive travel. Take care with specialist even if in the MGOC book!
A Charman

Exactly what did you ask him to do? If it was just 'bleed the brakes' then it looks like that was what he did, and properly to boot. Saying things like 'fix the brakes' can be a blank cheque. Perhaps you should have known already that there was a problem with the rear brakes, and fixed that as well as changing the calipers. But if you are up to changing calipers I would have expected you to be able to bleed the system as well.
PaulH Solihull

This thread was discussed between 11/07/2010 and 27/07/2010

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