I'm trying to fix an issue with my 94 Del Sol which continues to have "soft" brakes which I think is due to my prop valve leaking via the eyelet. I've installed 2 used valves which were previously working on donor cars but leak in my car. Before installing the valves I blew air into each of the 4 brake lines and was able to see the brake fluid coming out of each brake line eyelet which attaches to the caliper.

Could a leaking prop valve be related at all to a bad master cylinder?

 

No, proportioning valves leak due to pressure leaks after the master cylinder, master cylinders leak from the internal seals. It is not likely possible that you have both a bad master, and a bad proportioning valve.

You should first start off when you started having "soft" brakes.

You should also define "eyelet". From what I can gather, "eyelet" means the "hole the brake fluid comes out of in the line. If you have a fluid leak at a line fitting, the flare is damaged and does not seal on either the line, or the sealing part (in the case, a proportioning valve).

Why were you doing any of these repairs? You need to give us the back story if you want real answers.

 

It started after a rear caliper piston locked and the entire caliper was replaced. After bleeding, I now have a leaking prop valve from the pressure relief hole. The problem is this is a discontinued part for a 1995 Del Sol Si so my only alternatives are used valves and the last 2 both leaked.

If anyone has part number 46219-SR2-003 - I need one!

 

Del Sol 1725 Rear Disc Brakes SI Brake Proportioning Prop Valve Civic 93 97 | eBay

 

Thanks for the heads up Danny!