BRAKE DANCING

I had an MGB in my workshop recently with exactly the same problems as one of your readers (Help!, October 2017). The brakes had been serviced a few months previously – one front caliper had been replaced, along with some metal brake pipes and the master cylinder – but it still felt as if there was air in the system.

I bled the brakes in the normal way, then pressure-bled them with Eezibleed, and even reverse-bled them, all to no avail. I decided to start from scratch with the rear brakes. It was only then that I discovered the handbrake cable was too tight and not fully releasing, so the slave cylinder never fully retracted. When I released the handbrake cable, I was able to get quite a few more notches on the adjuster. This helped quite a bit but was still not perfect.

Unlike your reader, the owner of the car I was working on had changed the brake servo as a precautionary measure and I suspect the replacement was not as good as the original (which he had kept). I asked for the original unit, fitted it and bled the brakes by normal method. Hey presto! Great brakes at last.

Incidentally, if the slave cylinder does not fully retract, there is the possibility of air being left inside as the bleed nipple is at the bottom instead of the top. Whoever designed this obviously thought that brake fluid was lighter than air! Herbie Mitchell