PMO manifold brake booster check valve.

[hdrockerroller]

The check valve that came with my PMO carburetors for the brake booster hose connection is made out of plastic. It gets brittle from the engine compartment heat and breaks.

I'm trying to find a brass version of this same fitting.
I think the size is 3/8".
Its threaded on one end to attach to manifold and and has barbed hose connection on the other end to attach to power brake booster hose.

Does anyone know where to find a replacement for this fitting?
Preferably brass, but I'd take the plastic one if that's all I can get.

[zedsn]

I just ran a barbed brass hose fitting at the intake manifold and used a metal datsun check valve that had a hose fitting on either side that I already had and it worked out fine.

[hdrockerroller]

Any idea what size fitting it takes on the barbed end and the threaded end?

[zedsn]

The PMO fitting if I remember correctly is more like a 1/2" thread and a around that size at the hose area as well.

[porscheboy1]

Does this check valve have to be used? My brake booster line is attached directly to the manifold with out it and everything seems to work fine.

[zedsn]

I do believe that you DO need a check valve.

[hdrockerroller]

I was told the check valve keeps backfires from blowing out the power booster diaphragm.

[rwest]

Just tossing this out, but could you put a hose at the carb and run the valve off to the side away form the really hot parts and then up to the booster?

[hdrockerroller]

I contacted PMO, and Richard shipped me a new one. Waiting for it to get here.
In the meantime I JB welded the broken one back together, made sure the check valve was still working, put it back on the car and its working fine.

I think ultimately, if I can find the a brass fitting for the manifold, I'll pick up an inline barbed connector check valve and move it as far back in the engine compartment as possible.

Having trouble locating the fitting at the moment though.

[zedsn]

Yes rwest. That is what I did.

[porscheboy1]

hdrockerroller. Thanks for the info that a backfire can destroy the diaphragm in the power brake unit. I'll find my check valve and install it away from the heat.

Regards,

John

[hdrockerroller]

I received the new check valve from PMO.
They have changed their setup to use an elbow that screws into the manifold and a plastic check valve that you can put anywhere in line between the manifold and power brake booster.

This is similar to zedsn's solution, except that the PMO parts are all plastic.

[Tidybuoy]

I don't have a check valve because my '74 does not have the brake booster.

However, does the check valve have to be right at the manifold? Why not connect to the intake manifold and put the check valve up front where you don't have the engine heat?

[hdrockerroller]

Tidybuoy:
The only argument I can think of for keeping the check valve closer to the manifold is to keep the pressure from backfires from traveling up the power brake booster line.