I have a 97 wrangler with a 4.0 and an automatic transmission, with NO check engine light on. Every time she gets to a temperature of 215 she doesn't want to move unless I floor it. She'll get up and go but pulls to the left really bad. Is it possible that the brake fluid is getting hot and locking the caliper? It does kinda smell like the brakes are getting hot.
Brakes sticking or transmission problem?
- Thread starter Robert76
- Start date
I would think that's more likely a seized caliper than a transmission issue. You might check the transmission fluid level though.
Once it starts acting up, splash some water on the rotors to see if one is way hotter than the rest. It will boil off if a seized caliper has heated up the rotor. Don't use your hand, it could be several hundred degrees or more. An infrared thermometer would be even better, but the water will tell you where the problem is.
To fix a seized caliper you can try flushing the brake fluid but most likely you will need to replace the caliper. Be sure to flush the fluid before installing the new caliper, otherwise debris in there may clog up the new one.
Once it starts acting up, splash some water on the rotors to see if one is way hotter than the rest. It will boil off if a seized caliper has heated up the rotor. Don't use your hand, it could be several hundred degrees or more. An infrared thermometer would be even better, but the water will tell you where the problem is.
To fix a seized caliper you can try flushing the brake fluid but most likely you will need to replace the caliper. Be sure to flush the fluid before installing the new caliper, otherwise debris in there may clog up the new one.
Sounds to me like a sticking brake caliper. The fact that it happens at 215 degrees seems like more of a coincidence.
MrMark52
TJ Enthusiast
I've got an '03 Wrangler with 108K miles. Got it at 103k miles about 10 months ago. Front disc, rear drum brakes. It needed rotors turned when I got it (front end wobble when applying brakes). I bought new rotors and pads, replaced. All good for about 2 months and right front caliper locks up going down the highway - aghhh the smell of burning brake pads in the morning. It didn't lock the wheel, but I got pulled over and was greeted with wifts of smoke from the right front fender.
Hit the brake pedal a few times, the caliper loosened up. Went and bought brake fluid and new hoses. Replaced all three hoses, completely bled brake system, to include replacing master cylinder (it was too nasty to clean, and rebuild kit not available).
Drove for 6 months no issues until one day 30 miles away from home, the right front caliper hangs up again. Smoke and smell all over again.
Limped it home, went and bought rebuilt calipers for right and left front, decided to go ahead and put shoes on rear, get drums turned. Only to find drums were not turnable, and looking inside of wheel cylinder boots I found brake fluid. Two new wheel cylinders and two new drums, more brake fluid and my brakes are rock solid today - with no signs of either caliper hanging.
Lesson learned while shopping for calipers - they are using plastic pistons in the brake calipers now, as opposed to their being metallic. I'm not sure which is better, I can see both sides of the arguments (heat retention, abrasion). But being old school, I chose to go with metal piston calipers (never had a metal caliper piston seize).
Old hoses can fail internally, sometimes failing in such a way that hydraulic pressure can move from the master cylinder to the caliper or wheel cylinder, but not back, causing the caliper or wheel cylinder to cause the pad or shoes to drag.
My advise - get a set of new or rebuilt calipers and new hoses all around (LF, RF, and rear over differential), and 2 quarts of Dot3 brake fluid. If your mastercylinder is full of muddy, dark brake fluid, rebuild or replace. Do a complete purge of the brake system starting RR, LR, RF, LF until you get clean fluid at each wheel. You should be good to go after all this.
BTW - Whenever I do pad replacements any more, especially when I get a pulsating pedal when applying brakes (meaning warped rotors) more often than not it's just easier to get new rotors so I don't have to wait on the local machine shop to turn the one's I have. My time is worth too much to have to wait around. Having everything on hand when I start allows me to get started and done - not to mention not having to worry with the machine shop contaminating the caliper bearing hubs (not a problem on TJ's as the rotor is separate).
Hit the brake pedal a few times, the caliper loosened up. Went and bought brake fluid and new hoses. Replaced all three hoses, completely bled brake system, to include replacing master cylinder (it was too nasty to clean, and rebuild kit not available).
Drove for 6 months no issues until one day 30 miles away from home, the right front caliper hangs up again. Smoke and smell all over again.
Limped it home, went and bought rebuilt calipers for right and left front, decided to go ahead and put shoes on rear, get drums turned. Only to find drums were not turnable, and looking inside of wheel cylinder boots I found brake fluid. Two new wheel cylinders and two new drums, more brake fluid and my brakes are rock solid today - with no signs of either caliper hanging.
Lesson learned while shopping for calipers - they are using plastic pistons in the brake calipers now, as opposed to their being metallic. I'm not sure which is better, I can see both sides of the arguments (heat retention, abrasion). But being old school, I chose to go with metal piston calipers (never had a metal caliper piston seize).
Old hoses can fail internally, sometimes failing in such a way that hydraulic pressure can move from the master cylinder to the caliper or wheel cylinder, but not back, causing the caliper or wheel cylinder to cause the pad or shoes to drag.
My advise - get a set of new or rebuilt calipers and new hoses all around (LF, RF, and rear over differential), and 2 quarts of Dot3 brake fluid. If your mastercylinder is full of muddy, dark brake fluid, rebuild or replace. Do a complete purge of the brake system starting RR, LR, RF, LF until you get clean fluid at each wheel. You should be good to go after all this.
BTW - Whenever I do pad replacements any more, especially when I get a pulsating pedal when applying brakes (meaning warped rotors) more often than not it's just easier to get new rotors so I don't have to wait on the local machine shop to turn the one's I have. My time is worth too much to have to wait around. Having everything on hand when I start allows me to get started and done - not to mention not having to worry with the machine shop contaminating the caliper bearing hubs (not a problem on TJ's as the rotor is separate).
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I had "new" brakes put on by the dealer I bought it from. 32 miles later 3 lockers up and one severely dragging. Luckily right in front of a shop. All 4 rotors warped. And all 4 calipers junk. The brake fluid was black. Master cyl. had dark fluid (normal for a 13 year old vehicle) but the fluid at the calipers was black and gritty. The grit Locked it all up. I never saw that before. All new hoses and fluid along with 4 rotors and 4 calipers too. They just shoved in 4 pads at the dealer. Thank God they locked up in front of a shop.
Don't replace just one caliper, do both at the same time. No such thing as overkill on brakes. Go through the rears with extreme prejudice as well. Brake parts are cheap. Decades ago I attended a Bosch class for German car servicing. The instructor over and over used this phrase when he was talking about any Bosch component; "Don't be afraid to replace it". We laughed like hell knowing he was just trying to sell parts, but it is truly sound advice when it comes to brakes and suspension. BTW, we used that phrase for years after that.
MrMark52
TJ Enthusiast
I agree with all the above, and must emphasize the previous point made - black brake fluid.
If the brake fluid is anything less than clear or slightly darkened - flush, flush, flush the system. The black is brake friction surface powder that works its way into the calipers and cylinders. It is very fine (allowing it to sneak past the seals), and very abrasive. It can erode brake piston skirts and cylinders, causing them to stick. Plastic caliper pistons can warp with heat, thus compounding the issue of heat generated by a dragging caliper (probably not so much with drum brakes).
This is one case where the old saying “once you go black you’ll never go back” doesn’t apply. That fluid needs to be pretty clean.
If the brake fluid is anything less than clear or slightly darkened - flush, flush, flush the system. The black is brake friction surface powder that works its way into the calipers and cylinders. It is very fine (allowing it to sneak past the seals), and very abrasive. It can erode brake piston skirts and cylinders, causing them to stick. Plastic caliper pistons can warp with heat, thus compounding the issue of heat generated by a dragging caliper (probably not so much with drum brakes).
This is one case where the old saying “once you go black you’ll never go back” doesn’t apply. That fluid needs to be pretty clean.
I thought the black contamination was from the hose lining breaking down. Never saw fluid get like this on other vehicles. Guess the solution is to flush the whole system when you start to see any color change. If you can see it in the master cyl then it is probably a lot worse at the calipers.
MrMark52
TJ Enthusiast
Not to dispute anyone’s thoughts - but having worked on brakes since the late ‘60’s, what one will find inside of wheel cylinders is a black muck, much like a hard compressed mud.
That mud is made up from fine brake dust particles, and nothing more. You can scrape it out of the wheel cylinder.
Brake calipers are no different. They still accumulate the same muck.
Just my $.02 worth of info.
That mud is made up from fine brake dust particles, and nothing more. You can scrape it out of the wheel cylinder.
Brake calipers are no different. They still accumulate the same muck.
Just my $.02 worth of info.
Agreed. That has been my experience also, until this TJ. If I didn't have all my calipers locked up because of this "grit" in the brake fluid I would think it unlikely. But this was in the fluid itself. Not a hard sediment that stayed out. It had this "grit" free floating in the fluid.