Why are my rear brakes so "grabby" and locking up? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TIMSPEED · 04-07-2004, 08:09 PM

Lately, when I'm coming to stop, my rear brakes will GRAB and lock the back tires and I'll start skidding. I know these are supposed to be self-adjusting, and I've tried backing up and hitting the brakes to get them to adjust. But it keeps randomly doing it. What should I be looking at to fix or lube? The starwheel?

low 84 · 04-07-2004, 08:30 PM

take the drums off and adjust them yourself

TIMSPEED · 04-07-2004, 08:34 PM

Quote:

Originally posted by low 84
take the drums off and adjust them yourself

Did I mention I hate drum brakes?

I don't have to take them apart do I? Just like move the starwheel or what?

**lolife99** · 04-07-2004, 09:05 PM

You either have a rear brake cylinder leaking and putting brake fluid on the shoes, or worse yet, an axle seal leaking gear lube on the shoes. Brake shoes don't like liquid. Check both sides. My advise is to replace them in pairs. Might as well put brake shoes on and clean or turn the drums while your at it. Pull the drums and take a look.

TwinTurbo · 04-07-2004, 09:34 PM

I have the same issue on one side, will take the thing apart this weekend.. let's hope it's the cylinder seal and not the axle...

low 84 · 04-07-2004, 09:55 PM

with the rear jacked uptry and spin the wheel, there should be slight tension, but not much. if there is too much just take the drum off and back the adjuster off a tad (use a scre dirver or break spoon if you have one and turn the little toothed wheel)and try it out.

KShortell · 04-07-2004, 10:08 PM

TIM--
Like others have mentioned, see if it's on both sides or just one side.

I had the same thing happening after my truck was repaired from being side-impacted in 1994. The rear axle seal on one side was leaking from where the left axle was replaced. The drum was being lubed, causing the other side to lock up due to imbalanced braking force.

Leaking brake fluid could have the same effect.

Good luck!

bigblock73 · 04-07-2004, 10:08 PM

I agree with lolife99, I had a similar problem and found it was a rear seal leaking and soaking my shoes.

NeCrOmAnCeR · 04-07-2004, 10:14 PM

Is this occuring during normal stops, or during a panic stop? If it happens during normal stops the answer has already been mentioned, but if it happens during a hard stop the proportioning valve is going south.

Gibble · 04-08-2004, 11:22 AM

Quote:

Originally posted by lolife99
You either have a rear brake cylinder leaking and putting brake fluid on the shoes, or worse yet, an axle seal leaking gear lube on the shoes. Brake shoes don't like liquid. Check both sides. My advise is to replace them in pairs. Might as well put brake shoes on and clean or turn the drums while your at it. Pull the drums and take a look.

I had the same problem.

Replaced the axle seals and brake cylinders (both were leaking :eek) and it's perfect now.

*Zilverado* · 04-08-2004, 12:37 PM

Another vote here for leaky axle seals or wheel cylinders - quite common in my experience.

Simple fix in either case. Axle seals take a little more time (OK, quite a bit more

), but still fairly simple. One good thing about axle seals - they are cheaper to replace than the cylinders, assuming you supply the labour.

Prerunner1982 · 04-08-2004, 12:43 PM

i have this happen but very rarely, usually during cold mornings when pavement is wet. i think i just need to adjust or bleed the brakes.

04-07-2004, 08:09 PM	#1
TIMSPEED Join Date: Jan 2003 Location: Modesto, CA Posts: 1,321	Why are my rear brakes so "grabby" and locking up? Lately, when I'm coming to stop, my rear brakes will GRAB and lock the back tires and I'll start skidding. I know these are supposed to be self-adjusting, and I've tried backing up and hitting the brakes to get them to adjust. But it keeps randomly doing it. What should I be looking at to fix or lube? The starwheel? __________________ I have a few cars... See Them Here

04-07-2004, 08:30 PM	#2
low 84 Registered User Join Date: Jan 2002 Location: Houston, TX Posts: 2,144	take the drums off and adjust them yourself __________________ '51 F100, backhalf with a narrowed 9 and coil overs, 18.5" mickeys, monte front clip, +400" sbc in the works '05 1500 Crew Cab RIP '84 swb 5/7 drop, solid cammed 408 w/ fully ported dart heads, th350 w/ 10 inch hughes, 12 bolt w/ 3.73 richmonds and a locker '80 swb 4x4 in progress: 7" lift, 350 th350/np205, d44 and 1.5" ORD tie rod, 14BFF w/discs , armored diff covers, 40" MTR's

04-07-2004, 09:05 PM	#4
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	wheel cylinder or axle seal You either have a rear brake cylinder leaking and putting brake fluid on the shoes, or worse yet, an axle seal leaking gear lube on the shoes. Brake shoes don't like liquid. Check both sides. My advise is to replace them in pairs. Might as well put brake shoes on and clean or turn the drums while your at it. Pull the drums and take a look.

04-07-2004, 09:55 PM	#6
low 84 Registered User Join Date: Jan 2002 Location: Houston, TX Posts: 2,144	with the rear jacked uptry and spin the wheel, there should be slight tension, but not much. if there is too much just take the drum off and back the adjuster off a tad (use a scre dirver or break spoon if you have one and turn the little toothed wheel)and try it out. __________________ '51 F100, backhalf with a narrowed 9 and coil overs, 18.5" mickeys, monte front clip, +400" sbc in the works '05 1500 Crew Cab RIP '84 swb 5/7 drop, solid cammed 408 w/ fully ported dart heads, th350 w/ 10 inch hughes, 12 bolt w/ 3.73 richmonds and a locker '80 swb 4x4 in progress: 7" lift, 350 th350/np205, d44 and 1.5" ORD tie rod, 14BFF w/discs , armored diff covers, 40" MTR's

04-07-2004, 10:08 PM	#7
KShortell Registered User Join Date: Oct 2003 Location: Chesapeake, VA Posts: 734	TIM-- Like others have mentioned, see if it's on both sides or just one side. I had the same thing happening after my truck was repaired from being side-impacted in 1994. The rear axle seal on one side was leaking from where the left axle was replaced. The drum was being lubed, causing the other side to lock up due to imbalanced braking force. Leaking brake fluid could have the same effect. Good luck! __________________ Semper Paratus

04-07-2004, 09:34 PM	#5
TwinTurbo Registered User Join Date: Sep 2003 Location: The Netherlands Posts: 994	I have the same issue on one side, will take the thing apart this weekend.. let's hope it's the cylinder seal and not the axle...

04-07-2004, 10:08 PM	#8
bigblock73 yeller Join Date: Oct 2001 Location: Twin Cities Posts: 13,824	I agree with lolife99, I had a similar problem and found it was a rear seal leaking and soaking my shoes. __________________ Jeff 73-87.com 73-87.com Facebook page 73-87 cab corner 6x9 speaker brackets for sale 67-72 cab corner speaker brackets for sale 47-54 cab corner speaker brackets for sale Last edited by bigblock73; 04-07-2004 at 10:15 PM.

04-07-2004, 10:14 PM	#9
NeCrOmAnCeR Registered User Join Date: Feb 2004 Location: Hodgenville, Ky Posts: 735	Is this occuring during normal stops, or during a panic stop? If it happens during normal stops the answer has already been mentioned, but if it happens during a hard stop the proportioning valve is going south.

04-08-2004, 12:37 PM	#11
Zilverado Account Suspended Join Date: Nov 2002 Location: Winnipeg, Manitoba, Canada Posts: 798	Another vote here for leaky axle seals or wheel cylinders - quite common in my experience. Simple fix in either case. Axle seals take a little more time (OK, quite a bit more ), but still fairly simple. One good thing about axle seals - they are cheaper to replace than the cylinders, assuming you supply the labour.

04-08-2004, 12:43 PM	#12
Prerunner1982 Registered User Join Date: Oct 2002 Location: Edmond, OK Posts: 5,904	i have this happen but very rarely, usually during cold mornings when pavement is wet. i think i just need to adjust or bleed the brakes. __________________ Jon 1982 Chevy Silverado 350/th350.... RETIRED 1993 Jeep XJ 2 door(Cherokee) 4wd 4.0ltr/AX-15 (5spd)/NP231 .... Oklahoma Roll Call

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