Brake Problem...any ideas?
07-06-2009, 08:57 PM
#1
Brake Problem...any ideas?
I was driving home from dinner tonight and as I am pulling up to the house, I feel the ABS activate. 
I was not on the brakes hard at all, my speed was from maybe 15mph to stopped. I tried to repeat it, and it is a repeatable thing. Recently I changed all the pads, as well as the rear rotors. When I compressed the calipers, I opened the bleeder so I didn't force fluid back through the ABS check valve. I have a dual piston caliper depressor, so there was constant pressure on the pistons, which allowed no air into the system.
Has anyone experienced this? It feels like there is air in the lines, I just haven't gotten around to bleeding them yet. Even still, wouild air in the lines make the ABS activate at low speeds when there is absolutely no wheel slip? Some input would be greatly appreciated, as I will be driving this thing to work in the morning.
I was not on the brakes hard at all, my speed was from maybe 15mph to stopped. I tried to repeat it, and it is a repeatable thing. Recently I changed all the pads, as well as the rear rotors. When I compressed the calipers, I opened the bleeder so I didn't force fluid back through the ABS check valve. I have a dual piston caliper depressor, so there was constant pressure on the pistons, which allowed no air into the system. Has anyone experienced this? It feels like there is air in the lines, I just haven't gotten around to bleeding them yet. Even still, wouild air in the lines make the ABS activate at low speeds when there is absolutely no wheel slip? Some input would be greatly appreciated, as I will be driving this thing to work in the morning.
07-06-2009, 09:02 PM
#2
One thing that I just remembered, yesterday when I hit the brakes, again, normal driving, I felt the wheel jerk to the right slightly, like the left front caliper took a split secong longer than the right front to compress. I figured that the caliper was in need of a rebuild. Would this play into the whole ABS issue that I am seeing now?
07-07-2009, 11:58 AM
#5
The common thing that causes pre-mature ABS activation on these trucks is an excessive air gap between the front speed sensors and reluctor wheel caused by rust and dirt build up between the sensor and it's mating surface, but since this started happening after you did the brakes and opened the system, it may not be the case here. If there's air in one of the calipers, it may be possible that one is grabbing more than the other, causing the wheels to spin at different speeds and activating the ABS....just a theory. I'd bleed the brakes first and go from there. If you get all of the air out of the system and you're still having the problem, remove the front speed sensors and clean them and their mating surfaces. Blow any debris of the reluctor wheel if it looks dirty when you look at it after removing the sensor.
07-07-2009, 04:05 PM
#6
...I will be doing this next, as well as greasing the guides that the pads are mounted on. I think that will resolve the issue. Thanks Budhayes.
07-07-2009, 04:07 PM
#7
Totally separate issue, I will go ahead and hijack my own thread, I am having a multiple misfire detected after installing the heads /cam. The only thing that I think MIGHT be causing that is a plug boot resting on a primary. Would this cause a misfire or should I look elsewhere (besides going over all connections 5 times.
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07-08-2009, 10:42 AM
#9
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Definately a +1 to Budayes on his reccomendation. The most common cause of this is the corrosion or contamination bulld up on the reluctor ring or the eye of the ABS sensor. Most of the time it won't activate your ABS lamp either, so it may leave you guessing without a starting point. Also, excessive slack in your wheel hub (bearing) can cause this to happen too. While this is not as common as the corrosion, it does happen. I would remove your wheel and tire and inspect the ABS sensor and see if you have any excessive dirt or contaminate.
Not long ago, my truck did the exact same thing and it ended up being grease from my CV Axle boot. My CV axle was getting hot on a long trip and the grease liquified, and was squirting out a small minute pinhole in the boot. It squirted all over the rotor and subsequently made it way to the ABS sensor, so everytime I hit the pedal it would go into the anti-lock shudder. After a 10 min. cleaning it works fine now.
Not long ago, my truck did the exact same thing and it ended up being grease from my CV Axle boot. My CV axle was getting hot on a long trip and the grease liquified, and was squirting out a small minute pinhole in the boot. It squirted all over the rotor and subsequently made it way to the ABS sensor, so everytime I hit the pedal it would go into the anti-lock shudder. After a 10 min. cleaning it works fine now.
07-08-2009, 12:23 PM
#10
Totally separate issue, I will go ahead and hijack my own thread, I am having a multiple misfire detected after installing the heads /cam. The only thing that I think MIGHT be causing that is a plug boot resting on a primary. Would this cause a misfire or should I look elsewhere (besides going over all connections 5 times.
(I had that code after installing my baby cam and my truck was running fine, no real misfire, a little tuning and softening up the misfire monitor and all is good
)