99 SLT brakes grabbing at low speed.
Thread Starter
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Amateur
Joined: Dec 2009
Posts: 48
Likes: 2
From: Powell River, BC
99 SLT brakes grabbing at low speed.
I have a 99 SLT, 5.9L that has an intermittent brake issue. Doing a search hasn’t turned up any posts with the same issue. It happens when moving at slow speeds, like moving around in the driveway/parking lot kind of speeds. Hasn’t happened when slowing for stop lights etc. When moving slow and just applying the brakes lightly, the brakes will just suddenly lock up. It doesn’t happen all the time, maybe 20-30% of the time. It feels like it’s the front only, rears are adjusted & lots of meat on the shoes. I replaced the rotors (as one was slightly warped anyway) and both calipers/pads but the problem has come back. There were some slight divots on the rails the pads slide on & I filed them all smooth & greased them when I replaced the calipers. Calipers pins are well greased too. Could it be a master cylinder issue? I’m kind of at a loss on this. TIA for any advice.
THE ULTI-MOD
Joined: Jan 2007
Posts: 19,797
Likes: 36
From: Union NJ
my 02 used to do something similar, but it was ONLY on the first stop of the drive, and only when it was wet (first thing in the am with dew on the brakes, after/during a heavy rain). I chalked it up to wet rotors, you step on the brakes normally and dont get the response you expect so you increase pressure (instinctively) by this time the rotors have been wiped dry and grab with almost normal force, but you have increased the force seen on them and you feel like the brakes are grabbing ALOT harder than you expected.
does this sound about right for your situation?
does this sound about right for your situation?
Veteran
Joined: Jun 2012
Posts: 340
Likes: 1
From: Lindsay, Ontario, Canada
my 02 used to do something similar, but it was ONLY on the first stop of the drive, and only when it was wet (first thing in the am with dew on the brakes, after/during a heavy rain). I chalked it up to wet rotors, you step on the brakes normally and dont get the response you expect so you increase pressure (instinctively) by this time the rotors have been wiped dry and grab with almost normal force, but you have increased the force seen on them and you feel like the brakes are grabbing ALOT harder than you expected.
does this sound about right for your situation?
does this sound about right for your situation?
Thread Starter
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Amateur
Joined: Dec 2009
Posts: 48
Likes: 2
From: Powell River, BC
I don’t think it’s the same as what you guys are describing. It will do it more than just the first time in the day (its our daily driver) and again always at slow speeds. It does it moving forward or reverse.
Veteran
Joined: Jun 2012
Posts: 340
Likes: 1
From: Lindsay, Ontario, Canada
Take a good hard look at the front flexible hoses. If you start running out of things to check, one last ditch thing I would do is unbolt the vacuum booster and see if anything is binding there.
Problems like this can be a PITA to find, good luck.
Problems like this can be a PITA to find, good luck.
Thread Starter
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Amateur
Joined: Dec 2009
Posts: 48
Likes: 2
From: Powell River, BC
The booster was replaced when I first got the truck approx 1 yr ago. The hoses look ok externally, no leakage or signs of cracking, but I guess there could be internal issues with them. I might just replace them anyway if nothing else works. Thanks.
Record Breaker
Joined: Apr 2010
Posts: 1,745
Likes: 50
yup rubber hoses often disintegrate from within, with no outward signs of issue. they aint that expensive, on a 20 yo truck I'd have replaced them long ago anyway as a matter of basic maintenance.
and that 99 is newer than anything I currently drive by a couple of years...….
and that 99 is newer than anything I currently drive by a couple of years...….