Where Did I Mess Up With My Brakes

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ed1948

Royal Smart Person
Aug 6, 2016
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Quinte West, Ontario
I've only driven the 86 MCSS 300 miles before tearing it apart during the winter. From what I recall the brakes were 'ok' during hard stops.
What I've done since:
-install 3 Russell flex lines
-bleed and renew brake fluid
-service front brakes
-check rear shoes
-presently parking brake cables are loose
-right front inner pad has no backing shims due to them being damaged during past repair
-left front inner pad has 2 shims(anti noise may be another name?)
PROBLEM OBSERVED:
-during hard stop it pulls to the left
-slight tug to the left felt in the steering wheel during stop
REPAIR ATTEMPT:
Rebleed brakes (the rear were bled 6 pumps, My Son said the pedal felt firm and fluid came out freely from the bleeders)
-check front pads for seating correctly, cleaned disk and pads, adj wheel brgs.
TODAY'S TEST:
-pull to the left remains under moderate stop
-under emergency stop 1) drifts to the left and left rear locks
-pedal feels solid - no sponginess


QUESTIONS:
Would the lack of brake at the right rear cause the steering wheel to pull to the left? I assumed the tug to the left would be caused by the front brakes.
-did we bleed enough of the rear brake lines?

THE PLAN:
-raise wheels off ground and apply light brake pressure and observe if any wheels turn free
-bleed brakes paying the rear system extra attention
 
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Injectedcutty

G body LS mafia
Nov 24, 2014
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I didn't see you mention it, but what method did you use on bleeding them? I've always started with the brake furthest from the master cylinder, then work my way up until doing the driver side front last.

Did you reset the proportioning valve by pressing the little button on the front. From what you've described, it's like the pass side has air trapped somewhere.

It might be a good investment to pickup a mighty vac. You're local auto parts stores should have them in stock, harbor freight sells it too for around $40. It makes bleeding brakes much easier, as well as helps to check vacuum levels/leaks.

Hopefully this helps, I'm sure others will chime in.
 
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ed1948

Royal Smart Person
Aug 6, 2016
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I had the BRAKE WARNING last year after the master sucked air. The warning went out when we added fluid and purged the air out of the master. It's been 30 years since I've dealt with a pro valve. Let me study up on it and see if it helps.
 
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pontiacgp

blank
Mar 31, 2006
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Kitchener, Ontario
sounds like you may have fluid on the left rear brake shoe or the left rear brake and right rear brake need adjustment. Are the adjusters for the rear brakes working properly? If the left front brake was dragging the car would pull when driving not just when applying the brakes.
 
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ed1948

Royal Smart Person
Aug 6, 2016
1,286
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Quinte West, Ontario
Thanks - will check the drum brakes. The front pads are not dragging.
 

UNGN

Comic Book Super Hero
Sep 6, 2016
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Southlake, TX
I had the BRAKE WARNING last year after the master sucked air. The warning went out when we added fluid and purged the air out of the master. It's been 30 years since I've dealt with a pro valve. Let me study up on it and see if it helps.

I didn't think most G-bodied throw a warning when the master cylinder runs dry. The brake warning would have came from the proportioning valve switch, so there is likely still air in the system.
 
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ed1948

Royal Smart Person
Aug 6, 2016
1,286
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Quinte West, Ontario
#1 - air in the rear system
#2 - RR brake adjuster spring out of place not allowing self adjuster to adjust
#3 - RF inner pad problem - double shims were folded over causing funny pad wear due to cocked pad - I had removed them earlier and now I have one shim at each of the front inner pads(see question below)
Just came back from a test drive - stops with confidence (not bad for last century's technology)

Front pad rattle - what should I use between the piston and inner pad? glue?
 
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UNGN

Comic Book Super Hero
Sep 6, 2016
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When you change something on disk brakes, like rotors, pads or in your case folded shims, you need to properly bed them in. On an empty road, ten 60 mph to 10 mph hard braking reps (in rapid succession - max acceleration, brake, repeat) without coming to a complete stop should bed the pads in and get rid of the rattle. Rattles are usually from high spots. Bedding the pads in will get rid of the high spots.

If the brakes squeal under braking, grease the back side of the pads at the piston.
 

rustyroger

G-Body Guru
Mar 14, 2007
502
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Margate, UK>
You have a firm pedal without excessive travel?.
If so the brakes don't need bleeding.
If there is air in the system you will have a spongy pedal.

Try swapping the pads from left to right and see if that makes a difference.
Almost certainly your problem is with the front brakes, a rear drum not working at all has surprisingly little effect on braking stability on a dry pavement.
Double check all your work on the front brakes, and make sure you don't have a sticking or partially frozen caliper.

Roger.
 
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