Brake Proportioning Valve issue

[Chasenfeathers]

Hey guys need some help.

 

I recently installed all new brake lines on my 03 Silverado. While doing this I had a screw up. I took off the vacuum cap on the proportioning valve and the cap fell into the engine bay somewhere gone for ever. SO I hillbilly rigged it with a normal trimmed vacuum cap held on with a zip tie. That cap is now dry rotted and I have air in the system.

 

Does anyone know where I can order a replacement cap with out buying a brand new valve? 60+ bucks seems high for a little rubber cap.

 

Any help is appreciated, maybe I should just stop being a tight @ss.

 

Thanks in advance.