I have replaced everything but the prop valve and the brake booster on my car, and I mean everything. All 4 calipers new, new pads around, drilled/slotted rotors, earls SS lines, new master, and the car still likes crap. It doesn't "bite" when the brakes are applied, its a very slow stopping motion. And if you give it too much pedal, they simply lockl and the car slides.
I want to know if there is a way to check the booster to make sure its working properly. I am going to be swapping over to C4 brakes in front soon and I wanna make sure the booster will be fine for these brakes. Thanks fellas

Will

 

I say its the prop valve just my oppinion

 

I second that.

 

If your booster is bad, your brake pedal will be very hard to press- alot like when the car is off and you roll it and press the pedal at that point, they are very firm and hard to stop. If the pedal does press fine but just no brake power, then it is most likely a prop valve problem- regardless of the car, put in one of the 1LE prop valves even with drums- they are much better bias.

 

Sweet, I will install a perf brakes prop valve and see what happens!

Will

 

Yeah, something has got to be done soon. The car has zero stopping power. The brakes get super hot when applied, but the car just wants to keep moving. And the pedal gets REAL hard, I mean REAL hard right before it gives and the brakes all lock. ANy more input?!>?!?!? This **** is driving me crazy

Will

 

i think im having the same problem .my car use to brake perfect then when i change my spring/struts in the front the car brakes poorly now.wat can it be i have drums in the rear though?i mean i can drive it perfect everywere but on a hard stop i have to be careful.also my brakes wont lock up no more on the street only in the rain as before sometimes they lock up in the street.please help

 

I don't see how changing the struts would affect it, unless when you had the setup apart you got crap on the rotors. But you don't have to take the brakes apart to swap struts/springs.

I will try a booster/prop valve swap and post the results by the end of the year.

Will

 

Maybe when you have the old struts the car just nose dived seeming to brake good.

 

well i know that all the wd-40 and all the build up grease fell every were on the rotors but i clean with a rag and didnt see nothing else on them.im going to try to bleed them also change the drums pad in the rear and go from there on.

 

I know my 86 Z with drum/disc used to stop better than my iroc does, and its 4wdb, with everything new. Drums can stop alright, but if theres something wrong like the prop not getting enough pressure to the cals, then it won't be changed by replacing other parts. Most of the braking is done in the front anyway. I rebuilt my rear drums once on the 86, replaced EVERYTHING, and I barely noticed any different in stopping power. just my .02 cents

Will

 

so u think our problem are the prop vavles?

 

Im waitin on Norcal to get a new prop valve . Also mia I would make sure you dont have any air in the lines. Who bled your brakes though norcal did they do it by foot or what cause they may have not got all the air out either.

 

i usually bleed them myself with a buddy

 

I bled them myself so many times... and it still stopped poorly, so I took it to this place to have them pressure bleed it and it still felt like crap.

Will

 

so basically it was a waste of time and money

 

Bingo. This braking issues has cost me too much time and money. I figure if I'm this far into it, and I'm gonna keep the car for a while. I might as well replace the only 2 things left

Will

 

Im replacing it all also might as well.

 

well i know my pedal brakes kind of low so wat can that be?bad back brakes?

 

Typically a low pedal means alot of air in the lines. But it could also have something to do with the rears not being adjusted enough. I would bleed the brakes and go from there

Will

 

im going to have the back brake done and also have the shop bleed the brakes