QuestionQUESTION: I recently replaced the master cylinder 1974 MGB. I have front brakes,however, no rear brakes. When bleeding the brake lines no pressure to the rear brakes. Pulled the line of at the master cylinder no pressure from rear port. Does the banjo bolt have to be in a certain possition or do the washers provided (2) have a possible role in this? Don't want to pull the Master out if not nessary.
Jerry
ANSWER: Hi Jerry. I think you will find that the pressure differential switch has latched on. You need to unlatch it. I would guess that you fitted the switch before you bled the brakes. This is a common mistake.
The switch is screwed into the bottom of the master cylinder. You must carefully unscrew it precisely 3.5 turns (three and a half). Do not remove it completely. Next, bleed the two back brakes. When you have finished, tighten the brake differential switch and check that you have a firm brake pedal.
If you find that no fluid comes out of the nipples on the back brakes, then you have a more complicated problem so get back to me. In extreme cases the secondary piston can get stuck and you will need to unstick it.
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QUESTION: I have the Tandem brake master cylinder,this unit does not have a switch on the bottom. The unit has a plastic reservoir on top of the cylinder and the housing has nothing on exterior to set or adjust.
Jerry
AnswerOK. This type of master cylinder just has a plastic reservoir on top. There were several different designs.
If you look inside the reservoir you should see a separator. My guess is that the fluid level is below the top of the separator, the section that supplies the front brakes has fluid in it, but the section that supplies the rear brakes is empty. Fill the reservoir to the bottom of the filler neck and bleed the brakes again. If the level drops below the separator while you are bleeding, suspend bleeding until you have topped it up again.
