i have a 1984 Monte. I had a rear brake line blow. replaced the line, bled the master. the proportioning valve wont open up to the rear lines. i tried opening the front bleeder and stomping the pedal. after that i tried taking the line off and tapping the brass sliding valve back with a punch i made out of an old toothbrush. it didnt move with the little tap i was able to give it with the angle i have to work with. I might try jacking the car higher so i can get an actual swing at it.

how come I cant find a replacement for this valve on any of the auto parts sites?

im not 100% sure but I believe this is stock. was this added aftermarket? is this valve expected to be found on mid 80's montes?

 

I think youll find one here!

1978-88 Monte Carlo Proportioning Valves disc/drum for years 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988 @ OPGI.com
or here


84 monte carlo brake porportioning valve | eBay

 

I work at USPS on large & small mail trucks . On the smaller trucks they are a s10 frame & brakes . When they blow a rear line we have to back bleed them to center the proportioning valve . we hook up a bleeder an pump fluid back up to master ..

 

thanks for your replies. I found a replacement 1978 1988 GM A G Body New Brake Proportioning Valve Replaces GM 25509419 | eBay

I was wondering though, since I don't have any sophisticated brake bleeding equipment, would a blast of air backwards through a rear bleeder be enough to move the valve back over?

 

We have a tool at the shop that centers the proportioning valve. It's basically a piece of short threaded pipe that the end has been milled down to a smaller diameter. You remove the switch then screw the tool into the switch hole. If the center groove of the valve is near center the tool will center it up. If it isn't you may need to put a C clamp lengthwise on the valve so you can depress the button under the rubber on the front of the valve. Have all lines hooked up before you do this. With the button depressed (and switch back in valve) pump your brake pedal a few times and it should center the valve.