Right Rear brake locks up - The 1947 - Present Chevrolet & GMC Truck Message Board Network

skokie · 12-21-2006, 07:40 PM

I was driving down the road and had to slam on the brakes and the right rear locked up before any of the others. Is this normal? Truck is a 68 drum all the way around with power. Wheel cylinders, shoes, and shoes are all new.

Thanks

CPNEJR · 12-21-2006, 08:01 PM

not sure but i know that the rears will lock before any others because of the weight transfer to the front

*rage'nrat638* · 12-21-2006, 08:02 PM

sounds like one of your adjusters is backed off..if your wheel cyl's are new.
or you might have a bad wheel cyl anyway???

**Green Machine** · 12-21-2006, 08:42 PM

Misajustment side to side, adjuster(s) not working, stuck park brake cable, air in one side or stuck cylinder, both primary shoes put on one side, or primary and rear shoes reversed, leaking brake fluid or leaking axle seal instead of making brake slicker, actually makes it grab. Pull both sides apart and check, the question is, is the right side working too well, or the left side not working good enough ?

cdowns · 12-21-2006, 08:47 PM

alot of people dont bother to clean and lubricate the adjuster threads while doing a brake job causing improper operation// i'd also try bleeding the 2 rear cylinders again if you're going to have an air bubble in the system it will go to the left rear more often than not

skokie · 12-21-2006, 08:48 PM

Thanks for the ideas guys. Ill start with the bleed on the back 2 and go from there.

skokie · 12-22-2006, 01:57 AM

I didnt bleed either side out but what I did was head down the street in reverse and tap the brakes. Somebody told me thats how you adjust drum brakes. All I can say is it worked. I took it down the road and locked em up. All 4 went at the same time. Did it about 5 or 6 times same result.

Longhorn Man · 12-22-2006, 04:18 PM

screw cleaning the adjusters, replace them when doing the brakes.

**jerry moss** · 12-22-2006, 06:14 PM

anytime you replace cylinders, you MUST bleed the system, i'm surprised they work at all if you didn't bleed them.

70GMCer · 12-22-2006, 07:01 PM

The right rear locked up on me and turned out to be the axle seal leaking. Also, the rear brakes are NOT supposed to lock up first. If they do, the rear of the vehicle will swing around and you'll spin out. That's the purpose of the prop valve.

Longhorn Man · 12-22-2006, 09:13 PM

drum/drum brakes don't have a proportioning valve.

PanelDeland · 12-22-2006, 09:26 PM

Adjusters are easy.I determined after just a few months they always quit adjusting.It was always the threads rusting up.So now I clean them every time I am in there and use a little bit of anti-sieze on the threads only.Since I started doing this I haven't had any problems.

70GMCer · 12-23-2006, 07:15 AM

Prop valve does with power brakes......Mines original......

12-21-2006, 07:40 PM	#1
skokie Registered User Join Date: Oct 2003 Location: San Jose Ca. Posts: 3,334	Right Rear brake locks up I was driving down the road and had to slam on the brakes and the right rear locked up before any of the others. Is this normal? Truck is a 68 drum all the way around with power. Wheel cylinders, shoes, and shoes are all new. Thanks __________________ RIP to my son Dylan. 5/17/2002 - 8/18/2018 If you want to know more about rare forms of pediatric cancer or if you want to help fund pediatric cancer research, please check out the website for the non-profit I started. https://slothforpedcancer.org 68 build thread http://67-72chevytrucks.com/vboard/s...d.php?t=223234

12-21-2006, 08:01 PM	#2
CPNEJR Registered User Join Date: Sep 2003 Location: Franconia,N.H. Posts: 1,029	Re: Right Rear brake locks up not sure but i know that the rears will lock before any others because of the weight transfer to the front __________________ (Only) Member of the CPNE Fan Club Aint that the truth 67 C-10 350 with 3-speed tranny and 308 gears swb step 82 Z28 Camaro 355 small block over 350 hp and a borg warner super t-10 (blown engine) 72 Chevy K20 Suburban (future project) 70 Chevy K20 now 68 GMC K2500 2003 Chevy 2500hd ccsb 4X4 (daily driver)

12-21-2006, 08:02 PM	#3
rage'nrat638 Account Suspended Join Date: Mar 2003 Location: THE FALL GUY CHICAGO IL Posts: 5,883	Re: Right Rear brake locks up sounds like one of your adjusters is backed off..if your wheel cyl's are new. or you might have a bad wheel cyl anyway???

12-21-2006, 08:42 PM	#4
Green Machine Senior Member Join Date: Jul 2004 Location: Estherville, Iowa Posts: 3,371	Re: Right Rear brake locks up Misajustment side to side, adjuster(s) not working, stuck park brake cable, air in one side or stuck cylinder, both primary shoes put on one side, or primary and rear shoes reversed, leaking brake fluid or leaking axle seal instead of making brake slicker, actually makes it grab. Pull both sides apart and check, the question is, is the right side working too well, or the left side not working good enough ? __________________ 1968 C10 307 3spd Long Fleet ------ http://67-72chevytrucks.com/vboard/s...d.php?t=201103 1970 C10 305 Super T10 Long Fleet --- http://67-72chevytrucks.com/vboard/s...d.php?t=202285 1971 C20 383 TH350 Dana Posi ----- http://67-72chevytrucks.com/vboard/s...d.php?t=206894 2001 GMC Sierra 1500 C3 6.0

12-21-2006, 08:47 PM	#5
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Right Rear brake locks up alot of people dont bother to clean and lubricate the adjuster threads while doing a brake job causing improper operation// i'd also try bleeding the 2 rear cylinders again if you're going to have an air bubble in the system it will go to the left rear more often than not __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

12-21-2006, 08:48 PM	#6
skokie Registered User Join Date: Oct 2003 Location: San Jose Ca. Posts: 3,334	Re: Right Rear brake locks up Thanks for the ideas guys. Ill start with the bleed on the back 2 and go from there. __________________ RIP to my son Dylan. 5/17/2002 - 8/18/2018 If you want to know more about rare forms of pediatric cancer or if you want to help fund pediatric cancer research, please check out the website for the non-profit I started. https://slothforpedcancer.org 68 build thread http://67-72chevytrucks.com/vboard/s...d.php?t=223234

12-22-2006, 01:57 AM	#7
skokie Registered User Join Date: Oct 2003 Location: San Jose Ca. Posts: 3,334	Re: Right Rear brake locks up I didnt bleed either side out but what I did was head down the street in reverse and tap the brakes. Somebody told me thats how you adjust drum brakes. All I can say is it worked. I took it down the road and locked em up. All 4 went at the same time. Did it about 5 or 6 times same result. __________________ RIP to my son Dylan. 5/17/2002 - 8/18/2018 If you want to know more about rare forms of pediatric cancer or if you want to help fund pediatric cancer research, please check out the website for the non-profit I started. https://slothforpedcancer.org 68 build thread http://67-72chevytrucks.com/vboard/s...d.php?t=223234

12-22-2006, 04:18 PM	#8
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Right Rear brake locks up screw cleaning the adjusters, replace them when doing the brakes.

12-22-2006, 06:14 PM	#9
jerry moss Born Psycho Join Date: Feb 2001 Location: brentwood,cal,usa Posts: 4,862	Re: Right Rear brake locks up anytime you replace cylinders, you MUST bleed the system, i'm surprised they work at all if you didn't bleed them. __________________ jerry moss 72 cheyenne super K20- tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,tow hooks,bumper guards,toolbox,aux. fuel tank,posi front and rear,plus other goodies!!! SOLD 69 suburban K20-tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,4 inch all spring lift,4 speed, 14 bolt full floater, dana 44 HD,warn winch,posi front and rear,tow hooks,plus other goodies. 73/80 chevy/gmc K20 SB400,turbo 400,205,tilt,a-c,gas hog. 77 K/5 cheyenne blazer-daily driver/beater. SON HAS IT NOW BRENTWOOD,CALIFORNIA

12-22-2006, 07:01 PM	#10
70GMCer Senior Member Join Date: Apr 2005 Location: Joppa, Maryland Posts: 4,408	Re: Right Rear brake locks up The right rear locked up on me and turned out to be the axle seal leaking. Also, the rear brakes are NOT supposed to lock up first. If they do, the rear of the vehicle will swing around and you'll spin out. That's the purpose of the prop valve. __________________ 1997 GMC Sierra Ext 1965 Mustang

12-22-2006, 09:13 PM	#11
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Right Rear brake locks up drum/drum brakes don't have a proportioning valve.

12-22-2006, 09:26 PM	#12
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	Re: Right Rear brake locks up Adjusters are easy.I determined after just a few months they always quit adjusting.It was always the threads rusting up.So now I clean them every time I am in there and use a little bit of anti-sieze on the threads only.Since I started doing this I haven't had any problems. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

12-23-2006, 07:15 AM	#13
70GMCer Senior Member Join Date: Apr 2005 Location: Joppa, Maryland Posts: 4,408	Re: Right Rear brake locks up Prop valve does with power brakes......Mines original...... __________________ 1997 GMC Sierra Ext 1965 Mustang



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