It's more than likely only one circuit will be operative so 2 wheels will have no brakes. It must be done to the letter,lives could depend on it. If you're in any doubt, get the brakes fixed by someone who knows about it. Brake work must not be skimped. You can't bleed the brakes properly until the ...

As long as the ignition is on the pump will operate. If the fuel line is ruptured the pump will keep pumping until the ignition is switched off. It will stop pumping when the float chambers are full if the engine isn't running provided there are no leaks anywhere. To test, switch the ignition on. Th...

It's to disconnect the switch from the differential piston, not shuttle valve as I thought. There's a special way to bleed the brakes as I thought so a proper workshop manual is essential. The differential piston is operated by the master cylinder piston. Now, if the system is pressure or vacuum ble...

I've just checked. It runs under the front of the slam panel.

It's to disconnect it from the shuttle valve. No air gets in and no fluid escapes even when the switch is removed as I had to do. 3 1/2 turns per the official workshop manual.

On my 77 BGT the loom emerges from the bulkhead, goes between the brake servo and wing, then under the brake master cylinder, below the fuse box, between the coolant expansion tank and wing then through the radiator panel into where the electric fan is. That's the best I can offer as it's not easy t...

Actually Ian, I checked the manual since that post and it's the pressure warning switch that's unscrewed 3 1/2 turns before bleeding the brakes. By the time I had realised the error you'd posted your reply so apologies. The shuttle valve itself will move as each circuit is bled then should centraliz...

A vacuum bleeder is supposed to be better than a pressure bleeder. I successfully bled the brakes on my 1977 BGT which has dual circuit brakes too using a pressure bleeder. By using a pressure or vacuum bleed there's no need to touch the brake pedal therefore the shuttle valve in the master cylinder...

That's correct. It's switched by relays and the 12v comes from a separate contact on the starter motor. It's a complex set up which has been discussed in depth on the forum. The resistor on rubber bumper B's is a length of resistive wire in the loom.

It's only the coil that the ballast resistor circuit affects. Surely the distributor has its separate 12 volt supply. The Lumenition Optronic on my B takes its 12v supply from an ignition controlled source on the fuse box. The voltage to the coil doesn't, or shouldn't, affect the distributor. A conv...