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ranchhopper

Air valve leaking

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For some reason the center air valve (yellow) leaks when its cold does anyone else have this problem? Its only below 40 or so degrees leaks pretty good out of the bottom where the exhaust port is the brakes do release but the light does not go off charges a full 120 PSI but gets pretty irritating.

 

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Posted (edited)

Pretty common once the valves are a few years old due to the hot/cold cycles the cab endures. I think it's an "R7" valve but you'd need to check as I've been away from trucks for a while. O ring kits are cheap but the valve is usually about $20.00 so not really worth rebuilding, (to me) locally.

Sorry for my inaccurate post but the valve is either a PP-1, or PP-7 and not an "R-7" as I posted earlier. R-7 is a relay valve. PP-1 is the most common to release tractor brakes and PP-7 is for charging semi trailer brakes.

 

Edited by Rob

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Hi Tom;

Most of those valves only leak during the cold months and are perfectly silent during the warm summer season.

I have several in my parts bin of all types and one of these days when I start working on trucks again, I may use a few on a couple projects.....

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