Brakes don't work - The 1947 - Present Chevrolet & GMC Truck Message Board Network

blowermtr · 10-18-2002, 02:49 AM

I did the conversion to pwr brakes and from drum to disc/drum set up on my 67/68 chevy. Every thing worked great except... the rear brakes. I have replaced the master cyl. 3 times, the booster, all lines, calipers, wheel cyl, and took the prop valve off an 81 chevy. The fronts are great but i can't even get pressure to the rear to bleed them. Please help me stop.

Mike D

67/68 slammed, blown C10 so close

guitarman · 10-19-2002, 06:01 PM

You probably have a crimped line or trash in the distribution block. Pull the lines from the rear drums and at the distribution block and use compressed air and try to blow them out. If after that you get no air flow replace the rear lines or the distribution block or replace both they are cheap any way.

crazy longhorn · 10-19-2002, 06:14 PM

You might also check for a collapsed rear brake hose. good luck.......longhorn

Spoof · 10-22-2002, 09:53 PM

I'm sorry if this is vauge but...the proportioning valve (at least on 71 models) has a reset button on the front of the valve. It needs to be pulled out and retained while the brakes are pumped I believe, this will reset the proportion of braking power between the front and rear brakes. I don't have my service manual handy so I can't elaborate or even know if this could be part of your prob. Good luck any how.

guitarman · 10-28-2002, 10:26 PM

Spoof, that's a new one on me I don't think that factory GM p-valves are adjustable.

1-PU70 · 10-30-2002, 10:41 AM

There not adjustable but when you bleed the braks sometimes the light in the cabe coimes on and the switch inside needs to be centered .

Alex Hayley · 11-04-2002, 02:19 PM

How do you center that switch?

10-18-2002, 02:49 AM	#1
blowermtr Registered User Join Date: Oct 2002 Location: Beaufort, SC/ Georgetown, TX Posts: 13	Brakes don't work I did the conversion to pwr brakes and from drum to disc/drum set up on my 67/68 chevy. Every thing worked great except... the rear brakes. I have replaced the master cyl. 3 times, the booster, all lines, calipers, wheel cyl, and took the prop valve off an 81 chevy. The fronts are great but i can't even get pressure to the rear to bleed them. Please help me stop. Mike D 67/68 slammed, blown C10 so close

10-19-2002, 06:01 PM	#2
guitarman Do it well or don't do it Join Date: Apr 2002 Location: Georgia Posts: 457	You probably have a crimped line or trash in the distribution block. Pull the lines from the rear drums and at the distribution block and use compressed air and try to blow them out. If after that you get no air flow replace the rear lines or the distribution block or replace both they are cheap any way. __________________ Try to be the person your dog thinks you are. Excellent paint and body site: http://www.autobody101.com/ Visit my Web Site http://home.attbi.com/~agfosteriii

10-22-2002, 09:53 PM	#4
Spoof Registered User Join Date: Jul 2000 Location: Victoria,BC, Canada Posts: 1,300	I'm sorry if this is vauge but...the proportioning valve (at least on 71 models) has a reset button on the front of the valve. It needs to be pulled out and retained while the brakes are pumped I believe, this will reset the proportion of braking power between the front and rear brakes. I don't have my service manual handy so I can't elaborate or even know if this could be part of your prob. Good luck any how. __________________ 71 GMC 1500 LWB

10-28-2002, 10:26 PM	#5
guitarman Do it well or don't do it Join Date: Apr 2002 Location: Georgia Posts: 457	Spoof, that's a new one on me I don't think that factory GM p-valves are adjustable. __________________ Try to be the person your dog thinks you are. Excellent paint and body site: http://www.autobody101.com/ Visit my Web Site http://home.attbi.com/~agfosteriii

10-30-2002, 10:41 AM	#6
1-PU70 Registered User Join Date: Apr 2000 Location: Bradenton, FL Posts: 1,036	There not adjustable but when you bleed the braks sometimes the light in the cabe coimes on and the switch inside needs to be centered . __________________ 1970 CST/10 402,700R4,3:73 posi,AC,PS,PB,TLT,PW,Buckets with heaters

10-19-2002, 06:14 PM	#3
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	You might also check for a collapsed rear brake hose. good luck.......longhorn

11-04-2002, 02:19 PM	#7
Alex Hayley Registered User Join Date: Jul 2000 Location: NC Posts: 987	How do you center that switch?



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