Dark Blue Rotors = Dragging Brakes? - PeachParts Mercedes-Benz Forum

retmil46 · #1 04-12-2010, 02:06 AM

Ok that's probably semi-rhetorical. On the 05 Jeep, a few times in the past two weeks when trying to back out of my parking space, it felt as if something were holding it back, and I'd get a momentary shudder when I applied light throttle to get it moving. Couple days ago, there was enough resistance it actually stalled that diesel engine at light throttle in reverse!

Thought at first it might have been due to low fuel level and parking nose down on a slope - didn't reoccurr after filling the tank.

But this morning I checked the brake rotors - all four were a dark blue, and there were small chips missing from the edge of the outside brake pad on the drivers rear wheel.

I'd say dragging brakes big time. No wonder my in-town fuel mileage has went to crap of late.

Any thoughts or comments?

mpolli · #2 04-12-2010, 02:25 AM

You can verify with an IR thermometer. Usually , though, only one gets stuck. Usually not all 4 at once. At least I never heard of it. People with Toyotas wish they had this problem...

pawoSD · #3 04-12-2010, 06:50 AM

Yikes, master cylinder failure? ABS malfunction? Dark blue is bad....

layback40 · #4 04-12-2010, 08:23 AM

$$$$$$$$ is the worry. All 4 makes it sound like master/ABS problem.

soothappens · #5 04-12-2010, 08:34 AM

Could be San Antonio traffic !! Lately with all the construction you need to use your brake pedal more than your throttle !

Seriously though I agree with PawoSD And layback sounds like your master cylinder is not releasing due to " four " blue rotors.

With the mileage it should still be under warranty no ??

dannym · #6 04-12-2010, 10:03 AM

The bluing of the rotors is definitely a sign of overheating. And possibly compramising the integrity of the metal. Not good at all.

Danny

4x4_Welder · #7 04-12-2010, 10:29 AM

Can you post a pic? Some rotors I have seen turn what looks like a dark blueish color but it's just the metal composition.
If you make a lot of swift stops, that'll do it too. Double check with an infrared pyrometer, they are under $40 now and an invaluable diagnostic tool. If it's only one that's abnormally hot, then the brake hose for that wheel is most likely bad.
If the fluid in the master cylinder is dark, flush it thoroughly and it may clear up the issue.

DieselPaul · #8 04-12-2010, 10:40 AM

After a drive put your hand on the wheel, easy way to check for dragging. Either it'll be kind of room temperature, maybe a little warm because you're in texas... or you'll rip your hand away because you're burning the skin off your fingers. The heat from the brakes will transfer into the wheels really easily if they are locked up. Just an easy place to start. Also drive through a tunnel of some sort at low speed with the windows down, you can hear the brakes dragging as you go along. It'll be a metallic scraping noise.

retmil46 · #9 04-13-2010, 10:52 PM

Well, believe it or not, looks like it's just due to SA traffic!

Took it by a local shop I used last year for my initial TX inspection, just wanted to get their opinion on what I would need to replace. Gent came out and looked at the rotors, listened to my description of what had been occurring. They offered that since they had an opening, they'd throw it up on the rack and pull the wheels and check it out, 20 minutes tops, for no charge, since they considered that to be a safety item. If nothing wrong, they'd throw the wheels back on and I'd be on my way.

They pulled the wheels off and their shop foreman checked it out, then they brought me back to have a look first hand. Gent said he saw absolutely nothing wrong - dark blue color just indicated to him heavy use of brakes and due to type of rotor material, asked me if I was in the habit of riding the brakes (which I'm not). Loads of material left on original pads, even wear on all, no indication of warpage on the rotors, no evidence of hanging - nothing wrong.

I described to him what had been going on, and his immediate response was that the one thing that did fit that scenario was the parking brakes being misadjusted or hanging, asked how often I used the parking brake (essentially never).

His opinion was that unless I was really concerned about the possibility of the parking brakes hanging, his opinion was the vehicle was good to go as is, and if I wanted I could bring it in one day and leave it so he could have time to pull the hubs and check the parking brakes. They were good to their word, put the wheels back on and sent me on my way, no charge.

Damned surprising these days, to get service like that. Shop is Belden Automotive on Fredricksburg Rd, couple of lights north of Wurzbach Rd.

He opined that the engine stalling out was due to the low fuel level in the tank and parking nose down on a slope, nothing to do with the brakes. I usually don't let it get below a quarter tank, but that day it was right above the low fuel warning - since I refilled the tank that afternoon, it's behaved normally. Could be that ALL the instances of shuddering were due to low fuel level and the fuel pump sucking up some air/foam.

But given the history of what Chrysler has pulled with these vehicles, I'm going to play it safe. I need to get it inspected this month anyway, wanted to get the brake system flushed (fluid is 5 years old and black) before all this occurred, and have the tires rotated. I'm going to drop it off Thursday and have them do all this plus pop off the rear hubs and check out the parking brakes.

Just freaked me out, I've NEVER had a vehicle have the brake rotors turn that color under ostensibly normal use, unless something was fubar. One year and 6K miles ago, when I first moved down here, those rotors were still nice and bright. Guess the weight of the vehicle, plus all the stop and go driving, including the jackasses that keep cutting in front of me and then slamming on their brakes to make an immediate right hand turn (

), have taken their toll. When I described to the mechanic my normal commute to work and how heavy the vehicle was (4300 lbs), he opined that it could be the stock brake system was a tad underpowered for that heavy a vehicle in this type of driving.

Gent that I know up in Charlotte with another 05 Liberty CRD, also has an 02 gas version. He said that he switched the 02 over to cryo treated slotted rotors with Akebono ceramic pads, and the improvement over the stock braking system was dramatic. Looks like I might need to consider that upgrade myself. Those blue rotors just don't give me a warm fuzzy.

JohnM. · #10 04-13-2010, 11:23 PM

I wouldn't take his word for it. There's so many whacked out mechanics out there, some that still run reputable shops. If your rotors are blue....your brakes are dragging for some reason. Even after heavy periods of brake use...your rotors shouldn't be anywhere close to bluing.

retmil46 · #11 04-14-2010, 12:09 AM

Like I said, blue rotors don't give me a warm fuzzy, even if it is due to metal composition. At the least, it says those brakes are being overworked for the type of driving I'm doing, at least in my book.

I'm thinking the slotted rotor upgrade is going to get done sooner rather than later.

retmil46 · #12 04-14-2010, 12:23 AM

Quote:

Originally Posted by 4x4_Welder

Can you post a pic? Some rotors I have seen turn what looks like a dark blueish color but it's just the metal composition.
If you make a lot of swift stops, that'll do it too. Double check with an infrared pyrometer, they are under $40 now and an invaluable diagnostic tool. If it's only one that's abnormally hot, then the brake hose for that wheel is most likely bad.
If the fluid in the master cylinder is dark, flush it thoroughly and it may clear up the issue.

That was basically the mechanics take on it - type of metal, asking if I was in the habit of riding the brakes, etc. With the drivers in SA, unplanned swift stops are the order of the day - as I mentioned, people down here are in the habit of just zooming along in the middle lane, then at the last second cutting over in front of you in the RH lane, slamming on their brakes and turn signal and turning into their destination, coming to a damn near dead stop just in front of you on a 50 mph street. Some days I've had that happen close to 10 times just in the half-mile between two lights, to the point I'm ready to commit road rage.

Being in a vehicle that weighs 4300 lbs curb doesn't help matters.

Was already planning on doing the flush prior to all of this, along with the yearly inspection. I'm also planning on my friend's slotted rotor upgrade sooner rather than later.

If it has any bearing - this beast has ceramic pads stock from the factory.

JohnM. · #13 04-14-2010, 12:27 AM

If the bluing is due to heat you should be able to smell the hotness in the brakes once you get out of the car after driving. Otherwise, it could just be funky rotor material like you said. But if they really are getting up to extreme temperatures regularly, that can lead to cracks in the disc if left unchecked. At least rule out the heat factor so you can have peace of mind and not a disaster the next time someone cuts you off.

soothappens · #14 04-14-2010, 09:18 AM

Quote:

Originally Posted by retmil46

That was basically the mechanics take on it - type of metal, asking if I was in the habit of riding the brakes, etc. With the drivers in SA, unplanned swift stops are the order of the day - as I mentioned, people down here are in the habit of just zooming along in the middle lane, then at the last second cutting over in front of you in the RH lane, slamming on their brakes and turn signal and turning into their destination, coming to a damn near dead stop just in front of you on a 50 mph street. Some days I've had that happen close to 10 times just in the half-mile between two lights, to the point I'm ready to commit road rage.

Being in a vehicle that weighs 4300 lbs curb doesn't help matters.

Was already planning on doing the flush prior to all of this, along with the yearly inspection. I'm also planning on my friend's slotted rotor upgrade sooner rather than later.

If it has any bearing - this beast has ceramic pads stock from the factory.

Try navigating the same streets in a 26,000 LB service truck !

My rotors are rainbow with heat cracks !!!

I was kind of joking about the San Antonio thing ................ Kind of.....

DieselPaul · #15 04-14-2010, 09:26 AM

Bad hoses can cause temporary hanging brakes. They become one way valves, brakes will work but the collapsed rubber in the hose won't let the fluid back out of the caliper immediately, eventually it does escape and the brake releases. Do this,

Jack the car up and put it on a stand. Remove the wheel. With it running turn the rotor and have someone stab the brakes. It should stop obviously. Then have them release the brakes, it should free up pretty soon, if it takes any notable amount of time, you need hoses. This happened to my fiero. Braided Stainless lines fixed that issue.