I have a 99 K2500 crew cab that I've owned since new. The anti-lock brakes have been acting up lately (coming on for no apparent reason as I'm nearing a full stop). I really don't have any idea what might be going on (I've had a couple guys I know mention the anti-lock computer)

Any ideas on what it might be? I really don't have time to tear into this and can't afford not having the truck for several days but I'm also afraid what I might be looking at ($$$) if I take it someplace to be worked on.

I hate working on the brakes on this truck (actually getting the rotors apart for turning is the part I really hate). The engineer that designed these damn things should be shot.

I hope someone helps because i've got the same problem with my 97 K2500 extended cab long box........ I know what you mean about the front rotors (i have the 8 lug wheels)..... but my neighbor does my brakes for $10.00 a wheel :thumbsup: I ain't stupid...... WELL worth the $20.00 for me

There is a TSB or even a recall for you snow belt folks, there is a rust buildup where the ABS sensor is inserted into the hub and it forces the sensor out some, the sensor gives the ABS computer false readings. I don't have the info right here at hand, but over at www.fullsizechevy.com you can find it or if you have some kind of online data system available to you, you could check it out there.

Document ID# 1205328
1999 Chevrolet Chevy K Pickup - 4WD


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Antilock Brake (ABS) Activation At Low Speeds (Clean Wheel Speed Sensor Mounting Surface) #02-05-25-006A - (Nov 26, 2002)
Antilock Brake (ABS) Activation At Low Speeds (Clean Wheel Speed Sensor Mounting Surface)
1999-2000 Cadillac Escalade

1995-1999 Chevrolet Silverado (Old Style)

1995-2000 Chevrolet Suburban, Tahoe (Old Style)

1995-2003 Chevrolet Astro Van, Blazer, S10

1995-1999 GMC Sierra (Old Style)

1995-2000 GMC Yukon, Yukon XL (Old Style)

1995-2001 GMC Envoy, Jimmy

1995-2003 GMC Safari Van, Sonoma

1995-2001 Oldsmobile Bravada

This bulletin is being revised to change model information. Please discard Corporate Bulletin Number 02-05-25-006 (Section 05 -- Brakes).

Condition
Some customers may comment on ABS activation at low speeds, usually below 8 km/h (5 mph). Upon investigation, the technician will find no DTCs set.

Cause
The cause of this condition may be an increased air gap between the wheel speed sensor and the hub reluctor ring due to rust and debris built up on the sensor mounting surface.

Correction
Measure AC voltage and clean wheel speed sensor mounting surfaces.

Raise the vehicle on a hoist.
Disconnect both the front wheel speed sensor harness connectors.
Place a DVM across the terminals of each sensor connector.
Rotate the wheel with hand speed and measure the ACmV's. The reading should be at least 350 ACmV's.
If the reading is between 200 and 350 ACmV's, remove the wheel, caliper and rotor in order to gain access to the speed sensor.
Remove the wheel speed sensor and plug the hole to prevent debris from falling into the hub during service.
Clean the speed sensor mounting surface on the hub to remove rust and corrosion.

Important
Make sure that the sensor sits flat on the hub. If the sensor flange is distorted, replace the sensor.


Apply a thin layer of bearing grease to the hub surface prior to sensor installation.
Install either the original sensor or a new one in the hub and secure the sensor. Ensure that the sensor is seated flush against the hub.
Install the rotor, the caliper and the wheel.
Place the DVM across the sensor terminals and recheck the voltage while rotating the wheel by hand. The voltage should now read at least 350 ACmV's.
Warranty Information
For vehicles repaired under warranty, use:

Labor Operation
Description
Labor Time

H2412
Sensor, Wheel Speed (Front Both) - Replace
Use published labor operation time




GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
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Document ID# 1205328
1999 Chevrolet Chevy K Pickup - 4WD

I have a 99 K2500 crew cab that I've owned since new. The anti-lock brakes have been acting up lately (coming on for no apparent reason as I'm nearing a full stop). I really don't have any idea what might be going on (I've had a couple guys I know mention the anti-lock computer)

Any ideas on what it might be? I really don't have time to tear into this and can't afford not having the truck for several days but I'm also afraid what I might be looking at ($$$) if I take it someplace to be worked on.

I hate working on the brakes on this truck (actually getting the rotors apart for turning is the part I really hate). The engineer that designed these damn things should be shot.

I never did get a reasonable explanation of what it was doing but that same thing cost me a little over 3 grand when I had to have it fixed on my 94

Thanks T-man.

You have got to be kidding me ... is there actually a recall for this, or just a bulletin. Everyone I know has this same problem, and has the same solution ... take out, clean the face, and re-install. I've been complaining for years (major safety), because nobody realizes how much longer it takes to stop the truck with those things activated.

I cussed at mine, because I couldn't get the brake shield off (two days, on four bolts!). Everybody I asked gave the same response ... take out, clean, and re-install. It worked, but I sure was moaning over two days labor ... that should have been courtesy of Mr. GM!

Anyhow ... sorry to gripe. What you have read will fix the problem. I would not get into new sensors, but just pull the old one's out ... clean the face, and the sensor overall real well ... apply some hi-temp brake grease ... and re-install. Worked good on mine ... and about a dozen other friends I can think of.

Neal

As always, this site comes through again! Thanks a ton guys. I'll give this a shot on Saturday.

Mine didn't have that simple of a problem, wish it had. Mine had a failure of a part inside the distribution box looking deal. Man is that thing expensive.

Just an FYI

The failure inside the dist. box thingy ... is why you'll here companies pushing for brake fluid flushing now. It didn't used to matter that brake fluid absorbed water, and rusted components ... you just replaced brake lines, calipers, cylinder, etc ... they were relatively inexpensive. Now you start talking that big ABS distribution box ... things aren't inexpensive anymore, and rust corrosion is a BAD thing!

Neal

That's a bulletin and does not entitle you to any free repairs from GM or their dealers. Consider it a "heads up" on how to resolve a specific problem.

Don't waste your time printing it out and running back to your local dealer, you wont make any friends there. ALL GM dealers world wide have access to the same information and it's up to the dealer personnel to use the system to help find solutions to problems.