locking brakes

[bucketmouth64]

Son has a '01 dodge dakota and has had problems with front brakes locking up. Had a brake job last summer. First time (about month ago) he had it towed to dealership and brakes were not locked up when mechanic looked at it, he oouldn't find the problem. Second time (last week) brakes locked up and he drove vehicle home after sitting at side of road to see if they would free up. They didn't until he got home and let vehicle sit in driveway. He brought it in to dealership and they still don't know what the problem is. Mechanic thinks calipers need replacing. Service manager thinks something else is going wrong because both brakes are locking up at the sametime which isn't typical of bad calipers, which he still isn't ruling out. Something common to the front brakes must be going out. He thinks it might be the brake booster. He showed son if it happens again how to release pressure off master cylinder to free the brakes. He says if this is the case then he says booster needs to be replaced. Any of you mechanics have an opinion of this or have encountered this problem? Nice to get some other opinions to get this figured out.

[Macgyver55]

I've found a few over the years that the pedal was not returning all the way causing the brakes to pump up. I've also found a fair amount of brake hoses bad that would collapse and not let pressure release. Never found two bad at the same time though.

Also, likely not your problem, but I just worked on a custom hot rod a few weeks ago where the guy had done a disk brake conversion on a 40 Ford. After driving a while his brakes would start dragging worse and worse until he would have to stop and bleed off the pressure. After some checking, I finally ended up taking off the master cylinder. I found that the actuator rod between the booster and master was too long. We shortened it by 1/16 of an inch and its been perfect since.

[Gus]

I have an 02 Dakota and have had mine lock up on me also. First time it happened I had just purchased the truck and was doing a panic stop test, just to get a feel for the braking capabilities. Both fronts locked up that time and I had smoke billowing from them by the time I figured out what was happening (remember it was still new to me and I didn't know the truck all that well yet). 10 minutes of sitting and they had freed up, dealer never found a problem. It took a year for it to happen again and that time it was only one side. Again, sitting let it release and it hasn't happened again since, which has been about 2 months. I was planning on replacing the calipers, but I have no idea if that will be the ultimate fix. My bro in law had the same thing happen and replaced his calipers and has not had it happen since. I'm hoping that's the cure I'm looking for, but since it happens so infrequently I haven't really jumped to put money on it yet. Otherwise everything works great. So 2 times in a year's time. 02 Dakota.

Sorry I don't have a cure for you, but if you find a solution, please post it up so I'll know what worked for you. I'll do likewise. It seems like a somewhat common issue with these trucks, just by using google I see a fair number of posts on the issue.

[Scott K]

Is this only happening in heavy traffic, or after some hard breaking, or on really hot days? I have seen where the brake fluid will expand, and hold the brakes on after driving in stop and go traffic, what I have done, was to adjust the brake booster pushrod down a couple turns, and this allows for enough expansion and wont lock the brakes up. A couple turns shouldnt effect the brake pedal hieght much, but before you drive it after making an adjustment, check the pedal and how well it holds the truck.

This may not be your problem, just saying I have ran into this sort of thing in the past, and this corrected it.

[jeffreyd]

it sounds like the master cylinder to me, i would not mess around too long without changing it out. i will do some research and see what i can come up with. the other thing is the slide pins may need to be greased, cleaned and lubed. have you done brakes on the unit recently? did you replace the pad slide guides, clean and lube caliper pins?

[Jeremy airjer W]

What does the rubber seal under the cap for the reservoir look like?

[bucketmouth64]

it sounds like the master cylinder to me, i would not mess around too long without changing it out. i will do some research and see what i can come up with. the other thing is the slide pins may need to be greased, cleaned and lubed. have you done brakes on the unit recently? did you replace the pad slide guides, clean and lube caliper pins?

Son had a brake job done last summer at the dealership. They replaced rotors. As far as guides and lubing caliper pins, couldn't tell ya. Isn't that part of a brake job?

[bucketmouth64]

Is this only happening in heavy traffic, or after some hard breaking, or on really hot days? I have seen where the brake fluid will expand, and hold the brakes on after driving in stop and go traffic, what I have done, was to adjust the brake booster pushrod down a couple turns, and this allows for enough expansion and wont lock the brakes up. A couple turns shouldnt effect the brake pedal hieght much, but before you drive it after making an adjustment, check the pedal and how well it holds the truck.

This may not be your problem, just saying I have ran into this sort of thing in the past, and this corrected it.

I think both times it happened when it was hot outside. I believe normal braking and each time it happened on a highway.

[jeffreyd]

suppose to be but a lazy mechanic might have not replaced them. to me sounds like the calipers are hanging. has he added fluid to the system when it was low? if he used the incorrect fluid that could affect it also. lots of what ifs. might be time to take it in to a dealer and have them check it.