Morris marina pedal box

[Giovanni]

I am looking to fit a morris Marina pedal box to my pick up so that I can finally do away with the chassis mounted master cylinder. I have the pedal box and the brake pipe manifold but just need a wee bit of guidance on the pipe work. The manifold has 5 brake pipe attachments and a brake light switch. I presume two of these are inputs from the master cylinder and three are outputs to the brake cylinders. I presume that the two back brakes are linked and the fronts are separate. Am I correct in my assumption and if so does anyone know what pipe goes where, grateful for any advice from anyone who has done this conversion.

[Bill_qaz]

Have you tried Googleing marina brake hydraulic diagram ?

[Giovanni]

I have checked the internet but couldn’t find anything specific to the Marina.

[simmitc]

Is this the unit you mean:

[Giovanni]

Yes, thank you. I have searched everywhere for that diagram, it’s a lifesaver.

[philthehill]

The above drawing is of the Pressure Differential Warning Actuator (P.D.W.A.) Valve.
This when activated the switch on the P.D.W.A. valve illuminates a warning light on the dash of the Marina/Ital that warns that there has been a loss of pressure to either the front or rear brakes. The shuttle inside the valve shuts off the fluid to the faulty brakes so that some braking is retained.
Personally I would fit a single circuit master cylinder and not fit the P.D.W.A. valve.
Having the single circuit master cylinder and not fitting the P.D.W.A. valve makes for a much simpler installation and is much easier to bleed the system.
The Marina/Ital brake light switch is activated by the actual brake pedal not by the P.D.W.A. valve.
British Leyland had a spate of fitting P.D.W.A. valves and duel circuit brakes to just about everything. I found that when bleeding the brakes you had to be very careful or the shuttle of the P.D.W.A. valve would move from its central neutral position and getting it back to its neutral position was not always the easiest of tasks.
I would recommend that if fitting Marina/Ital parts a BL Marina/Ital workshop manual is obtained as all the information you require is contained within the pages.

[Giovanni]

Thanks, I assumed it was a brake light switch so really grateful for you’re clarification.