what is correct bolt size on top of rail relief valve?

[CookJ]

I've contacted 4 dealerships and none of the parts guys can tell me the actual size of this banjo bolt (pretty ridiculous!). From what i've read here, the bolt is a 12 or 14 mm x 1. 5 or 2. 0? For those of you that have capped/plugged your rail and know the actual size, can you help me out? thanks!

 

[TCDiesel]

Yes M14- 1. 25 or 1. 50 will work. Don't capped it Send it to us and I will rebuild it. The threads are recoil...

 

[CKelley1]

listen to twest, do not cap it.

 

[CookJ]

thanks twest. I believe i have a bad valve, as the truck has over 180K miles and i've run a pressure box off/on for most of those miles. I wanted to temporarily plug the valve and make a few runs to determine if there is any improvement. I've read about your modified valve and am considering this route. As i cannot be without my truck, there is no way i can send to you at this time. Will contact you to see if we can work something out. thanks