Brakes master cylinder and bias valve
Turbo Mini Forums

Hi I am looking to replace my servo with an early style master cylinder. Which one do I need? I know there is two types yellow band and green (I think) Do I need to also replace my bias valve? and what pipe goes to what on the bias valve does anyone have a schematic for the bias valves?. I am running metty 4 pots and standard rears with front rear split.

Thanks

If it helps ......

If it's really early style then I'd opt for the Type 1 Cooper 'S' m/cyl which has enough stroke capacity to cope with 4 pots.

If it's one of the vertical type m/cyls then I'd stick clear of the ones with a diagonal split on the outlets.

I'd go for a Type 3 dual front/rear split m/cyl if you're trying to bias front to rear braking.

On this type, the pipe outlet on the m/cyl closest to the m/cyl bolts always goes to the front brakes on a dual circuit system.

So, with a Type 4 horizontal m/cyl (presume that's the one you're using as it has the later servo), the front pipe on the m/cyl goes to the rear brakes (via the pressure regulating valve on the bulkhead - the top RH side inlet pipe when viewing the valve from the front of the engine bay) and on a vertical m/cyl, the top pipe goes to the rear brakes 9again, this could be via a PRVv).

Assuming you're not going to use the bulkhead mounted PRVv and you're not using diagonal split braking, the outlet pipe which goes to the rear brakes is the inlet to whatever bias valve you're using (either 'in-car' or on the rear subby).

The outlet pipe from the bias valve needs to be divided into two using a 'T' piece, one line to each rear brake drum/disc.

Richard.

Minivanless, but reluctantly happy living with the decision. There'll be another one day.
http://www.youtube.com/profile?user=minimadmotorman#p/u