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Bleeding Brakes!!!

Having a problem with the brakes on my LE.
There is what seems to me to be excessive play in the brake pedal.
This is not new, but seems to be worse now than it has been.
The brake pads & linings are all fine.
A new master cylinder was put in over the winter, and last weekend, I replaced the flexible hoses with Goodrich braided hoses in case there was a weak hose.
None of this has made much difference.
The brakes have been bled in accordance with the Haynes manual, loosening off the warning switch and also having the engine running.
Immediately the brakes are bled, the pedal is fine.
Next time the car is used the pedal goes nearly to the floor & needs pumping up .
No fluid leaks visible and no apparent loss of fluid .
Anyone got any ideas?

Hi John

Firstly i assume that the brakes worked fine before and what have you replaced?

Bleeding the brakes on a B (especially the earlier single system) is a nightmare - Abingdon had a special rig designed as it is such a problem.

Are you using and eezi bleed or vacuum bleed system. I personally found that the vac system is better as it draws the air bubbles out.more easily

Perseverance is the key 😀

If it ain't broken don't try to fix it as if you do it will definitely break

I pressure bled my roadster when I fitted the Goodrich braided flexes and copper brake lines and that worked well.

Interested to know how the vacuum assist works though?


I used a combo of both but the vac system is great at pulling the air bubbles through plus you can empty the reservoir of old fluid rather than pushing it all the way through the pipes 😀

If it ain't broken don't try to fix it as if you do it will definitely break

Could be a servo issue so worth checking that over as well. When my failed the servo was filling with brake fluid. When mine let go it was causing the sinking in the brake pedal and lack of pressure

It's not losing brake fluid, so I think the servo is OK. However, the problem may be in the front nearside hub. We currently think that the brake disc is pushing the piston back into the calliper when the wheel is rotated but we are still investigating.

Problem solved with a new (S/h not available new) front hub from MGB Hive. Not a bad bit of kit for £25, especially as it included the wheel bearings.
So, the problem with the brakes wasn't actually caused by the braking system at all!!!

So what was wrong John, obviously not a warped disc but was it wheel bearing related?

If it ain't broken don't try to fix it as if you do it will definitely break

Well, we put a new wheel bearing in over the winter and had to put a new spacer in .this was worn when we looked at it last week. We haven't stripped the wheel bearing out of the hub, but when we do, I'm expecting to find some wear on the bearing surface of the hub. These aren't available new for non- wire wheeled cars, but it's not the sort of thing you'd expect to fail. This hub was replaced during the rebuild when I first bought the car .I think that corner took most of the impact, but that shouldn't have anything to do with it as I rebuilt the crossmember albeit using second hand parts except for the brakes of course.