I have been going over all my brake components replacing everything. My car is a 91 crx hf. I have 1990 integra ls rear brakes, and 91 crx si front brakes. I noticed that my prop valve is still stock. Its a 1725 one. I went to the junkyard and got a 3540 prop valve off of a civic ex. Will this one work well? Or do i even need to change it

 

An adjustable one is best, you need an AP Twin Bore. It's expensive, but the only way to do it properly, anything OE is pure guesswork, though picking one from a car whose brakes are as close to your brake setup as possible will get you most of the way there.

If you had drums, you definitely should get a disc prop in there, otherwise they'll be doing less work than the drums were.

 

maybe i could use a crx si prop valve. i have si front brakes and the rears are almost the same as an ls arent they?

 

I'm not too hot on US models and their brake systems, I'm only really familiar with UK models.