brakes when cold or wet.

[rocklandxjer]

90xj06---
do you want the brakes to lock up?

they aren't supposed to

 

[fitbmxseries1]

90xj06---
do you want the brakes to lock up?

they aren't supposed to

yeah i was thinking thats not the safest thing on the street.

 

[8Mud]

Just a few possiblities, but some things I've seen before. Drums or discs will get a light coat of rust on them. First couple of stops can be pretty grabby and sometimes squeeky. Rear drums full of dust, sand, mud, salt whatever can get grabby.
If there is any kind of brake fluid leak (at the rear cylinders), the pads or shoes can swell, don't really know if it's the brake fluid itself or the moisture the brake fluid absorbs or the junk that sticks to the brake fluid and acts like sand paper. But they will grab, especially the rears.
I've had rear shoes, grab in the beginning then fade away to almost nothing. It turned out to be a leaky rear axle seal, the junk that stuck to the oil would stop me just fine a couple of times (sometimes to good), but when the junk wore off or got heated up, the shoes would slip from the oil.

 

[fitbmxseries1]

i just tore my rears apart today and discoverd the passenger side is worn WAY more then the driver side, and needs to be replaced but i dont have the parts now and no place is open any more so i just cleand and greased up a few parts, seems to be working now but the real test is when it rains. if this doesnt fix it i may try to replace the cylenders when i get new drums and pads.

 

[Flash]

if your replacing the brakes get the hard ware kit for both sides and the adj too

the grabbing problem when first applied is aether brake fluid or axle lube getting on the brakes! it sound completely wrong, but the fluid caused the brake shoe to be come softer and cause it to be vary grabby! if they get socked they will be grabby all the time.

Replace the shoes clean every thing up good, wash you hand before you install you brakes shoes with all new hard ware and they will work better the ever!
moisture amplifies the oil on the brakes problem

when the rear brakes are remove, lift the dust seal on the wheel cylinder and if they are not completely dry underneath, replace them!!!

 

[YosemiteXJ]

pk when my brakes get wet or cold the work great. if you hit the peddle they will lock up nicely. but then after a couple stops that lock up ability vanishes. i have a new master cylinder and pads and shoes.

i was just wondering. its strange tho it doesn't do it in the rain. but if you spray them with the hose.

You said that you have a new master cylinder. One of the causes of your symptoms is brake lines that need bleeding. Could you have air in the lines? I would bleed first the master cylinder, then all of the brakes... it is easy and quick, and could solve your problem.

 

[fitbmxseries1]

if your replacing the brakes get the hard ware kit for both sides and the adj too

the grabbing problem when first applied is aether brake fluid or axle lube getting on the brakes! it sound completely wrong, but the fluid caused the brake shoe to be come softer and cause it to be vary grabby! if they get socked they will be grabby all the time.

Replace the shoes clean every thing up good, wash you hand before you install you brakes shoes with all new hard ware and they will work better the ever!
moisture amplifies the oil on the brakes problem

when the rear brakes are remove, lift the dust seal on the wheel cylinder and if they are not completely dry underneath, replace them!!!

it was very dry inside of there no oils or brake fluid just dusty but i cleaned that out with some brake cleaner, and after driving it agian they started squeaking......... could be the front but every thing was replaced just recetnly up there so im thinking its the rear.

 

[Jeepski]

I have had this locking problem ever since I moved from Colorado to San antonio. I also had front axel work done right before the trip. I drive a 99 also. Only the front brakes lock, and they only do it for the first few stops when the jeep is cold and especially when it is wet outside. This sometimes happens when the jeep is less cold and the conditions are wet. One of the calipers was sticking so I had those replaced and the rotors turned a couple weeks ago. The problem persists. I've had a few close ones as a result of this. It's pretty sketchy to slide through a skid for forty feet to stop at thirty miles an hour. I've met ice that's easier to stop on than dry asphalt with cold brakes on my jeep. I think the next step is to try and re-bleed.

 

[Garden Spyder]

HyJack.. I have brake problems also, and thought I would add to an existing thread.
Before going to Colorado mountains a few months ago, I replaced the discs on front and put on new pads, after being out in Co. for a few days, my front end started to grab like there was a gear binding up, or bearing locking up, and it only did this going forward, not backward (verified by jacking up the front end and manually turning it.)
Then I replaced hub assemblies to eliminate that as being a possibility, changed diff oil and inspected the gears, which were like new, replaced calipers, replaced hoses, and still it does the same thing. I had a stroke of luck to see what was happening when I jacked up the front end and turned the wheels again and could see the caliper jumping when the wheel locked up. to release it, I had to turn it backwards, and it turned perfect backwards, but turned it back forward again, and it kept ratcheting.
someone mentioned master cylinder, but I am wondering if it doesn't have something to do with glaze,(not sure what that is) or some of this other stuff you guys are talking about.

 

[Matthew Currie]

HyJack.. I have brake problems also, and thought I would add to an existing thread.
Before going to Colorado mountains a few months ago, I replaced the discs on front and put on new pads, after being out in Co. for a few days, my front end started to grab like there was a gear binding up, or bearing locking up, and it only did this going forward, not backward (verified by jacking up the front end and manually turning it.)
Then I replaced hub assemblies to eliminate that as being a possibility, changed diff oil and inspected the gears, which were like new, replaced calipers, replaced hoses, and still it does the same thing. I had a stroke of luck to see what was happening when I jacked up the front end and turned the wheels again and could see the caliper jumping when the wheel locked up. to release it, I had to turn it backwards, and it turned perfect backwards, but turned it back forward again, and it kept ratcheting.
someone mentioned master cylinder, but I am wondering if it doesn't have something to do with glaze,(not sure what that is) or some of this other stuff you guys are talking about.

Make sure the pads are engaged correctly on the rails, and the rails haven't lost a big enough chunk to cause them to hang up.