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TR2/3/3A tr3 petcock

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sp53

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Hi all this is perhaps another dreamer post, but my petcock on the engine on my tr3 is leaking very slightly and I was thinking that the radiator pressure is only four pounds and the sediment is right there. So perhaps it would just stop after awhile. I took it apart and cleaned it, but it still leaks. I mean the thing is solid brass. It is not like it has a rubber seal or anything.
Steve
 
First question, is it leaking through the valve, or where the valve screws into the block? Those are straight threads, there should be a fiber washer to seal between the valve & block even though some of the parts books don't show it.

The valve relies on a taper fit between the rotating barrel and the housing, which can easily become damaged and leak. If the damage is only minor, you may be able to stop the leak by disassembling the valve again, and using a mild abrasive to lap the joint. I also found that the factory springs were rusted to uselessness, and found a stainless spring that I could cut to length as a substitute. Some silicone "stop cock lube" will help, too, both with sealing and making the valve easier to operate. (Eg, Dow Corning 111)

BTW, the pressure inside the block goes considerably higher than 4 psi, due to the flow of the water and the restriction through the head and thermostat. Some folks have reported measuring over 30 psi!
 
To keep the one on the bottom of the rad as well as the one on the engine above the starter looking original, I removed both, drilled and tapped a small pipe thread plug inside both brass bodies. This stopped them leaking.

This way they still "look" original but if I need to drain the rad or the block, I un-screw the whole brass piece as if it was just a single solid brass plug.

Don't tell the VTR judges.
 
Thanks you guys are good. And yes Randall I replaced the spring also, but it still leaks right at the guts. I really like Don’s solution. Do you guys think if I modified it by just filling the end of the brass fitting with silicone I would have any problems?
Steve
 
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