QuestionQUESTION: I have a 2001 chrysler 300m with the 6 cylinder 3.5L. I recently had the brakes lock up on me while on the highway, I was picked up and returned several hours later with a truck and trailer. But when i started it the brakes had released and i was able to drive it home. I took it into the local garage and they told me it was the wheel speed sensor. I was just hoping to get a second opinion on this problem.
ANSWER: Hi Carlin,
You didn't say what you have done in response to the diagnosis. Did you authorize the replacement of the sensor or are you awaiting a second opinion before authorizing the replacement?
I have not heard of such a locking up due to the failure of a wheel speed sensor. After all, the ABS system is designed to prevent such a lock-up so if this were the case it would seem to be a design flaw. Not having heard of that, I doubt it is the explanation, but I have an open mind.
There is the capability to read the memory of the ABS controller to determine if it has sensed a problem of many kinds, including a failed wheel speed sensor. Was that done and is that the basis for this conclusion? If not, then if the ABS system is suspected a shop-level code reader would tell them whether the ABS agrees with that diagnosis.
There are reasons for wheel brakes to lock up which don't involve the ABS system so those would be my first thought. Mechanical binding up of the pins upon which the brake caliper is supposed to slide freely or an internally rotted brake hose at one of the wheels or a piston in a caliper sticking inside of its cylinder are all possible explanations or a master cylinder binding up, are possibilities.
Please let me know what you understand to be the basis of the diagnosis and what is the status of the vehicle/repair.
Roland
PS Please 'rate' my answer. Thanks
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QUESTION: Well I have authorized the replacement of the sensor,But I'm just concerned it may be something more serious such as the master cylinder binding.I'm hoping that it is just the sensor but when i looked over the vehicle i noticed water in the brake fluid container not an excessive amount but enough to see it is there.I am fairly certain that the garage did use the code reader as there analysis of the problem but I have heard of others having the sensor replaced and the problem still occuring and from what the outcome was it looked as though the cause of there problems was the master cylinder. I am also awaiting the vehicle to be returned as i took it in this morning so if the problem still occurs i will pursue a different garage to help me in this problem, I appreciate your thoughts on this problem as it gives me a better outlook on what the underlying problem may be. I look forward to your response on this question as you seem to have a superb sense of expertise in this field.
Thanks again
AnswerHi Carlin,
I hope that the sensor replacement will fix it for you. Are you certain about the 'water in the brake fluid container'? If so, that would be a cause for concern as the brake function will be compromised once it enters the system from the reservoir some time in the future. It might have been clean brake fluid recently added to the reservoir rather than water? Did the shop add the fluid? So check into that for sure. If you meant 'condensation', such as droplets of water in the reservoir/cap, then that might not be so concerning as it may subsequently evaporate as the weather warms. But a frank layer of water is abnormal. New brake fluid can be quite clear in color so that may expain what you saw.
Roland
