Brake compensator valve

[Andrew1967]

I've got an unboxed NOS rear brake compensator valve for my pick up project, but I'm not sure if it's for the 5/8 or 3/4" bore wheel cylinders.

Is there any easy way to differentiate between the two types without stripping it. I have two rusty old valves that have different spring lengths and presume this must be what makes the outlet pressure different.

Do the casting numbers mean anything ?

Cheers

Andrew

[Spider]

There were something like 7 different pressure shut offs.

All these used all the same parts, as far as I am aware, the only part that changed was the spring (which is internal). I don't have descriptive references for the springs, so even if you did pull it apart, I couldn't say which is which. Unless someone else can suggest something, you can have it tested to find out what it is.

[Andrew1967]

That's interesting Spider and probably has compounded my problem

Prior to starting the thread, I looked in the Lockheed reference manual and only found two different numbers, one for early and one for later (post 69) cars. There are several numbers for different types of compensator valves though.

Anyone else able to help ?

[Spider]

I've just had a look to see if I had something to offer that maybe more helpful, but there is quite a lack of published data on these valves.

Here's some factory info on the variety of valves fitted in Aust production;-



(hopefully that's legible) I may have a similar UK list, though at a quick look, if I've got one, it may take me a while to find,,,,,

There's shut off pressures at;-

220 PSI (not in that list, used in some SPO models)
250 - 300 PSI
370 PSI
390 PSI
420 PSI (not in that list)
430 PSI (not in that list)
450 PSI
And I have a nagging recollection of a 480 PSI type, again not in that list and for SPO Models

I would think similar units were fitted in UK production.

[Andrew1967]

Well presuming pick ups were the same as vans, that'll mean I need whatever to make a '390'

Thanks for that posting Spider - things are never as plain as they seem !

Got plenty of time to get this correct though