intruder

iTrader: (1)

i guess i have a problem with my pbr's,they don't seem to work very well if is wet out or a little slick when i hit the brakes the front tires lock up and the rear wheels keep pushing the car or the rear tires keep spinning after i'm stopped, it's like i don't have rear brakes at all. when i swapped the rear in my car i changed the p valve but not the master cyl could this be my trouble???

skiroulertx447

I swapped a 4th gen rear on my car and didn't change anything in the brake system. I went from drums to the lt1 discs and my fronts also lock up with hard braking and the rears can hardly hold the wheels from spinning on jackstands.
I'm eventually gonna swap in an adjustable proportioning valve.

intruder

iTrader: (1)

nobody has any idea what the problem is??????

skiroulertx447

I still have the disc drum prop valve, i was gonna switch to the disc disc prop valve but heard they were designed to not have much braking in the rear. So an adj prop valve should get all 4 to lock up if you really slam on them

JamesC

iTrader: (5)

I'd suggest using the proportioning valve designed for a specific system for the best braking performance.

JamesC

intruder

iTrader: (1)

i'm using the proportioning valve that came from the donor car the rear was in

1988-305-tbi

for best results you need an inline adjustable prop valve $50, none of the stock prop valves really apply enough pressure to the rears

JamesC

iTrader: (5)

And yet, the 1LE, GM's race car, didn't have an adjustable valve.

JamesC

Stephen

iTrader: (12)

I highlighted the problem above....

Your not taking your other foot off the gas. That woud be called a "burnout".

//<86TA>\\

iTrader: (14)

1988-305-tbi

sounds like a burnout to me, i didn't catch that part when i first read it

intruder

iTrader: (1)

yes i am taking my foot off the gas,and no it's not a burn out. i drive with one foot not 2. i come to a stop when it is slick out and the rear tires keep spinning untill i put it in neutral, they don't hold period. i had to hit the brake's rear hard to keep from hitting a deer and i flat spotted the fronts and the rear's didn't do a damn thing

l_dis_travlr

God, I love this place.

Intruder, I know its a serious problem, but that
was just a hilarious response.
Stephen, do you moonlight as a stand-up?

Now let me try to regain some composure...

How much service did you do on the brakes as part of the swap?
If the unit was setting up for awhile before you did the swap,
rust may be part/all of the problem. Are you sure that the pistons
move freely, and the caliper is free to "float" on the mounting pins?

The debate about adjustable prop valve has been raging on the
board since... well since there was a board. But what you're
describing sounds more like component failure. Start w/ some
basic inspection/prev-maintenance, then let us know what you
find. Someone here will have the right answer -- if he can
stop laughing long enough.

radical82

Rather then just buying parts at random, why not invest in a Brake pressure gauge???? Making a few hard line adapters will allow you to test the brake pressure at each port of the master cylinder, proportioning valve, and wheel cylinders/calipers.....