Odd Brake Anomaly

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1952Chevy

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I have recently(but only occasionally) encountered a very odd issue with my brakes. Something I've never encountered before with any vehicle.

When I first start the truck and go to pull out of my driveway, as I slightly apply pressure to the brakes, my front drivers side locks up. It could possibly be both fronts, but for sure front drivers. This occurs at the slightest application of the brake pedal.

After I get down to the 2nd stop sign from my house(about 4 blocks) everything seems fine. Today it is rainy, and I believe the last time I noticed it it was also rainy. Instead of slamming me forward today I could hear the front drivers tire skidding, so ABS did not engage. I'm not sure if this requires a certain speed to engage or not. I do know the last time I drove in icy conditions the ABS worked.

I have also noticed that my pedal returns very slowly after I let off of the brakes at all times.

This is a 99 K2500 Burb with hydroboost. I completely replaced the front brakes this fall(pads, rotors, calipers, brake hoses) as well as flushed new fluid to all 4 corners of the brake system.

I've done quite a bit of brake work, and this just has me stumped. Any help is appreciated.
 

HotWheelsBurban

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Might be a combination of things. Have you ever replaced the hydro boost unit or front brake hoses? On my crew cab, when the booster went out, it was doing really weird stuff, and I know it's hard to get good quality rebuilt units consistently. On my Suburban, the right front brake locked up, and I replaced the hoses and calipers on both sides. That took care of that issue!
 

1952Chevy

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Might be a combination of things. Have you ever replaced the hydro boost unit or front brake hoses? On my crew cab, when the booster went out, it was doing really weird stuff, and I know it's hard to get good quality rebuilt units consistently. On my Suburban, the right front brake locked up, and I replaced the hoses and calipers on both sides. That took care of that issue!
I haven't personally touched the hydro boost, other than when I replaced the power steering lines due to leaking.

I had the front right caliper siezed up last summer, that's when I replaced both calipers, rotors, pads, and hoses.

My thought process was that it is likely something in the hydroboost or master cylinder.
 

Pinger

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I have recently(but only occasionally) encountered a very odd issue with my brakes. Something I've never encountered before with any vehicle.

When I first start the truck and go to pull out of my driveway, as I slightly apply pressure to the brakes, my front drivers side locks up. It could possibly be both fronts, but for sure front drivers. This occurs at the slightest application of the brake pedal.

After I get down to the 2nd stop sign from my house(about 4 blocks) everything seems fine. Today it is rainy, and I believe the last time I noticed it it was also rainy.
Mine does the same - just the brakes being 'grabby' cold. As soon as there's heat (and a bit more speed to arrest) they're fine.

Instead of slamming me forward today I could hear the front drivers tire skidding, so ABS did not engage. I'm not sure if this requires a certain speed to engage or not. I do know the last time I drove in icy conditions the ABS worked.
There is a minimum engagement speed for ABS I think.
I have also noticed that my pedal returns very slowly after I let off of the brakes at all times.

This is a 99 K2500 Burb with hydroboost.
Mine's a C but otherwise the same as yours and the pedal is never lightening quick on returning - but not so slow as to cause concern.
 

1952Chevy

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Mine does the same - just the brakes being 'grabby' cold. As soon as there's heat (and a bit more speed to arrest) they're fine.
But it's just the left front, if they were just super grabby it would make sense, but it's only the one and its skid marks, that corner of the truck diving, and throwing me forward.
 

Pinger

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But it's just the left front, if they were just super grabby it would make sense, but it's only the one and its skid marks, that corner of the truck diving, and throwing me forward.
It could still be 'cold/grabby' - just one wheel affected. Could be pads sit closer to disc on that side than on the other, that side exposed to wind/rain (from memory, mine are worse in wet weather), etc, etc.
Providing it only occurs when first moving, I wouldn't worry about it (but do understand/appreciate your curiosity!).
 

Erik the Awful

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Make sure your pads and shoes are clean, and that your rears are assembled correctly and bled. Do the brake hoses look good, or do they have cracked outer rubber?
 
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