New guy needs help with brake problem - The 1947 - Present Chevrolet & GMC Truck Message Board Network

gmc-rob · 05-28-2002, 04:01 PM

I bought a 1972 Chevy Cheyene 10 a few months ago and am trying to get it road worthy. When I first got the truck it braked really well (it has power brakes) but the rear brakes locked up first. The truck needed to have a saftey inspection and to pass it needed new rear brakes, so after putting on new drums, shoes, parking brake cables and all the other rear brake springs it now skids the front tires first and it does not seem like the rear brakes are working. I did not replace the wheel cylinders or hoses so the fluide part of the system was not opened so there should not be any air in the system. To make sure I took it to a brake place and they used a power bleeder to bleed the brakes but the rear brakes still do not want to skid, even in gravel when before they would easily lock up on the pavement. I think they are adjusted properly and I backed up and stopped alot to set them up, what am I missing??? I would really appreciate some advice, thanks. ROB

Low69CST · 05-28-2002, 04:14 PM

Maybe your back brakes aren't seated in good yet. Which makes them not work and puts 100% of the braking on your front which is skidding your tires. Have you double checked everything in the rear brakes?

Gordo · 05-28-2002, 04:30 PM

Is it possible the proportioning valve tripped?

gmc-rob · 05-28-2002, 06:36 PM

The tripped propotioning valve sounds about right, how do I reset it?? Thanks.... ROB

Longhorn Man · 05-28-2002, 07:41 PM

The prop valve isn't your problem. You had done nothing hydroulicly, so there is no reason for it to be the problem.
Jack up the rear. Supprot safely. Remove one or both rear wheels. Remove drum.
Look at the little star gear thingy at about the 6 o'clock position. Are the teeth shill there? Move the little lever down to strike the gear, does it make contact? If not, replase the gear. (that is your adjuster and assosiated parts)
If it is all good, then look at your drum, there should either be an access hole, or a blank that is ready to be knocked out. Install the drum after ensuring the hole is free.
Position the drum (by spinning rear axle if you have too) to where you can see the gear. Useing a lang flat head screwdriver, reach in and spin that gear the same way that lever would have spun it. That will tighten up your clearance. Do not tighten it to the point that there is shoe contact with the drum. (more likely than not, there will be a lot of spinning on that little gear)
Go to the other side and repeat.
Once the tires are on and tightened, drive down the street (or open lot) in reverse pumping the brakes. Eash time you hit the brakes, it adjusts just a little, but will not over adjust. You should feel the pedal get firmer, and have less travel.
Go and lock up your tires, try it in gravel if you like, but they will skid on pavement now.
99.99% chance this is your problem. It is the #1 problem after doing drum brakes. Many people think the self adjusters will do huge adjustments, but in reality, it is for very fine increases in adjustment only.

**JIMs70GMC** · 05-28-2002, 08:35 PM

Have to agree with longhorn, had same problem after replacing rear shoes. Jacked up the back of the truck and while spinning the tires I adjusted the brakes until i heard them drag. Did both sides, now I can get the rears to lock-up and only put 5 or 6 clicks on the emergency brake pedal before it gets tight.

gmc-rob · 05-28-2002, 09:08 PM

I tried to adjust the shoes by turning the adjuster (which is new so it has teeth) then putting the drum on and spinning the drum, I adjusted so the shoes just barley rubbed (I put on new drums also). I could not do it like you said longhorn because for some reason this truck has 2 slots to check the front and rear shoe clearance but does not have one to reach in and adjust the adjuster, I even have the special screw driver for that but the backing plates on this truck does not have a slot? Does it need to be punched out? Thanks long horn for the advice, this is sure a great board. ROB

Longhorn Man · 05-28-2002, 09:23 PM

Actually, it is on the drum its self.
About 1 and a 1/2 inches long by 3/4 inch tall.
Since they are new, you'll need to punch out the blanks. Probably has just the corners holding them on.
However, if you adjusted till they bareley rubbed, I guess this is the .1% of the time.
Bummer.

*Fast68Chevy* · 05-28-2002, 10:09 PM

you adjust them through the slots in the front, youll only need one slot, dotn need both, i do it with simply two screwdrivers, one medium sized #2 and one tiny to hold back the star lock lever, you only need to lift back the plate when tightening(spreading out) the shoes
the teeth will move from top to down on the side of the adjuster facing you when you are loosening them and opposite direction when tightening, use some plumbers pipe thread dope on the threads ot keep it from freezing up anymore in the future

gmc-rob · 05-29-2002, 01:15 AM

Thanks for the advice everyone. ROB

Brad · 05-29-2002, 04:28 PM

I've got several of these adjusters if you need 'em. Both rh & lh, just pay for shipping.

05-28-2002, 04:30 PM	#3
Gordo Registered User Join Date: Jan 2001 Location: Killingworth, CT. USA Posts: 3,378	Is it possible the proportioning valve tripped? __________________ 1971 C10 swb stepside 350/700R4/3.73posi (retired as of 4/22/03) 1998 S10 short bed 2002 S10 Blazer 1942 Oldsmobile 1958 Massey Harris Pony 1951 Wife Killingworth, Connecticut May those who love us, love us, any of those who do not love us, may God turn their hearts. And if God is unable to turn their hearts, may he turn their ankles so we may know them by their limping. A man who works with his hands is a laborer; a man who works with his hands and his brain is a craftsman; but a man who works with his hands and his brain and his heart is an artist.

05-28-2002, 08:35 PM	#6
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	Have to agree with longhorn, had same problem after replacing rear shoes. Jacked up the back of the truck and while spinning the tires I adjusted the brakes until i heard them drag. Did both sides, now I can get the rears to lock-up and only put 5 or 6 clicks on the emergency brake pedal before it gets tight. __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm

05-28-2002, 10:09 PM	#9
Fast68Chevy Account Suspended Join Date: May 2000 Location: IL Posts: 0	you adjust them through the slots in the front, youll only need one slot, dotn need both, i do it with simply two screwdrivers, one medium sized #2 and one tiny to hold back the star lock lever, you only need to lift back the plate when tightening(spreading out) the shoes the teeth will move from top to down on the side of the adjuster facing you when you are loosening them and opposite direction when tightening, use some plumbers pipe thread dope on the threads ot keep it from freezing up anymore in the future Last edited by Fast68Chevy; 05-29-2002 at 04:48 PM.

05-29-2002, 04:28 PM	#11
Brad Out of the carpool lane. Join Date: Jan 2000 Location: Clark Co, WA Posts: 5,672	I've got several of these adjusters if you need 'em. Both rh & lh, just pay for shipping. __________________ 1968 C-10 SWB, 5.7 Vortec/700R4/3.73 posi, Torch Red 1968 Camaro, 250/Powerglide, all original (No, I'm not gonna drop a 350 in it!...Jeez!) 2000 Honda VFR in the faster yellow! 2008 Husqvarna TE-610 1967 C-10 SWB 'Six Appeal'-Gone but not forgotten...

05-28-2002, 04:01 PM	#1
gmc-rob Registered User Join Date: Apr 2002 Location: Saskatoon,SK Canada Posts: 41	New guy needs help with brake problem I bought a 1972 Chevy Cheyene 10 a few months ago and am trying to get it road worthy. When I first got the truck it braked really well (it has power brakes) but the rear brakes locked up first. The truck needed to have a saftey inspection and to pass it needed new rear brakes, so after putting on new drums, shoes, parking brake cables and all the other rear brake springs it now skids the front tires first and it does not seem like the rear brakes are working. I did not replace the wheel cylinders or hoses so the fluide part of the system was not opened so there should not be any air in the system. To make sure I took it to a brake place and they used a power bleeder to bleed the brakes but the rear brakes still do not want to skid, even in gravel when before they would easily lock up on the pavement. I think they are adjusted properly and I backed up and stopped alot to set them up, what am I missing??? I would really appreciate some advice, thanks. ROB

05-28-2002, 04:14 PM	#2
Low69CST Registered User Join Date: May 2000 Location: Frankfort, Kentucky, USA Posts: 2,163	Maybe your back brakes aren't seated in good yet. Which makes them not work and puts 100% of the braking on your front which is skidding your tires. Have you double checked everything in the rear brakes? __________________ '69 CST Short fleetside Lowered, 400 small block, 700R4, 4 wheel disc brakes, front sway bar & rear camaro sway bar (in progress) '87 V10 4x4 Short Fleetside Quad Suspension and Dual Tanks

05-28-2002, 06:36 PM	#4
gmc-rob Registered User Join Date: Apr 2002 Location: Saskatoon,SK Canada Posts: 41	The tripped propotioning valve sounds about right, how do I reset it?? Thanks.... ROB

05-28-2002, 07:41 PM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	The prop valve isn't your problem. You had done nothing hydroulicly, so there is no reason for it to be the problem. Jack up the rear. Supprot safely. Remove one or both rear wheels. Remove drum. Look at the little star gear thingy at about the 6 o'clock position. Are the teeth shill there? Move the little lever down to strike the gear, does it make contact? If not, replase the gear. (that is your adjuster and assosiated parts) If it is all good, then look at your drum, there should either be an access hole, or a blank that is ready to be knocked out. Install the drum after ensuring the hole is free. Position the drum (by spinning rear axle if you have too) to where you can see the gear. Useing a lang flat head screwdriver, reach in and spin that gear the same way that lever would have spun it. That will tighten up your clearance. Do not tighten it to the point that there is shoe contact with the drum. (more likely than not, there will be a lot of spinning on that little gear) Go to the other side and repeat. Once the tires are on and tightened, drive down the street (or open lot) in reverse pumping the brakes. Eash time you hit the brakes, it adjusts just a little, but will not over adjust. You should feel the pedal get firmer, and have less travel. Go and lock up your tires, try it in gravel if you like, but they will skid on pavement now. 99.99% chance this is your problem. It is the #1 problem after doing drum brakes. Many people think the self adjusters will do huge adjustments, but in reality, it is for very fine increases in adjustment only.

05-28-2002, 09:08 PM	#7
gmc-rob Registered User Join Date: Apr 2002 Location: Saskatoon,SK Canada Posts: 41	I tried to adjust the shoes by turning the adjuster (which is new so it has teeth) then putting the drum on and spinning the drum, I adjusted so the shoes just barley rubbed (I put on new drums also). I could not do it like you said longhorn because for some reason this truck has 2 slots to check the front and rear shoe clearance but does not have one to reach in and adjust the adjuster, I even have the special screw driver for that but the backing plates on this truck does not have a slot? Does it need to be punched out? Thanks long horn for the advice, this is sure a great board. ROB

05-28-2002, 09:23 PM	#8
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Actually, it is on the drum its self. About 1 and a 1/2 inches long by 3/4 inch tall. Since they are new, you'll need to punch out the blanks. Probably has just the corners holding them on. However, if you adjusted till they bareley rubbed, I guess this is the .1% of the time. Bummer.

05-29-2002, 01:15 AM	#10
gmc-rob Registered User Join Date: Apr 2002 Location: Saskatoon,SK Canada Posts: 41	Thanks for the advice everyone. ROB



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.