Rotor very hot after 30 minute drive

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BigMF

BigMF

Joined
Feb 11, 2020
Threads
32
Messages
519
Location
Franklin, TN
All, went for a short drive this AM and when I got out I noticed a “hot” smell coming from left rear wheel area. The wheel itself was hot enough to burn. I sprayed a bit of water on the rotor and it immediately steamed off. Any thoughts or suggestions on what it might be and how to resolve?

FYI, brake fluid is normal capacity.

 
Was a brake job or any brake related adjustments done recently. Need more info. Lift the tire off the ground and turn the wheel by hand. Feel any resistance? Is the other sides wheel cooler and less resistance? Is your parking brake handle down all the way?
 
ceylonfj40nut said:
Was a brake job or any brake related adjustments done recently. Need more info.
Click to expand...

Not really. I did flush front front brakes a few weeks ago. Long story on why rear didn’t get flushed yet.
 
Sounds like a frozen caliper. Either the slide pins are frozen or the brake piston is frozen.
If both of those are ok, then check the parking brake.
 
gumbyfj40 said:
Sounds like a frozen caliper. Either the slide pins are frozen or the brake piston is frozen.
If both of those are ok, then check the parking brake.
Click to expand...

Thanks. My problem right now is that I’m 30 min from home. 🤔
 
Let it cool down. Go slow on the way home. Stop and let it cool if you need to. Plan on replacing the rotors (as well as resolving whatever is dragging).
 
Get it towed home or limp home at low speed of you can. Your call. If ya have AAA or Hagerty you will get a free tow. I guess you need to share your “long story”.
 
Wondering if a bad wheel bearing would cause the hub/rotor to heat up too.
 
One side or both ? Probably a frozen caliper if one one side. Tow it, do not drive it. You could melt the tire to the wheel. That happened when my daughter lent her horse trailer to a friend and the brake controller was out of adjustment. A half hour away is way too long to drive it.
 
Probably a frozen caliper. Let it cool down, then drive home. Pull over 1/2 way and check the wheel. Let it cool down if necessary.
 
If you made it 30 out, you'll make it 30 back, with cooing stop halfway. Don't spray cold water on it when it's cooking.

Edit: And, BTW, no one is allowed to say "long story" on here without eventually providing details........
 
Hey guys, thanks for all the tips. I made it home with a few stops on the way.

The long story is not REAL long but I was on my phone and wanted to get the request for help quickly. Basically, a few weeks ago I was flushing the brakes for the first time. I was following the TSM and completed the front with no problems. However, when I got to the back right wheel, I couldn't get any fluid to come out of the bleeder, even after several complete turns. Assuming it was clogged, I just screwed it back in and did NOT move to the left side, which is the problem wheel this AM. I ordered and received some new bleeder plugs but have not had the chance to replace them.

Right now, I've got it up on a jack stand with the wheel off and a fan blowing on it to try and cool it down some while I eat my banana bread and coffee. Also, gives me some time to do some research. If you look at my activity on here you'll see that I'm pretty new to the repair scene but have been able to replace my own spark plugs, including replacing the leaking o-rings and valve cover gaskets, all the fluids (except finishing the brakes obviously), etc. So, all in all, I'm very handy and a quick learner but this is new territory for me. I'm willing to try and tackle this project but usually have more time to research and plan.

Based on the fact that this is obviously a critical system and doing it wrong can be fatal, I'm thinking I'll probably have a shop look at it unless you guys feel like it should be easy to diagnose the issue first and go from there.

Thanks again for all the quick responses!!
 
When my daughters horse trailer, see above, fried the brakes it also melted the grease in the wheel bearing. Have your guy check that while he is in there.
 
Weedhopper said:
When my daughters horse trailer, see above, fried the brakes it also melted the grease in the wheel bearing. Have your guy check that while he is in there.
Click to expand...
Important consideration and smart to think about, but I don't believe grease on the 200 sealed rear wheel bearings can be checked. Oops, I mean what @KLF said.........
 
Last edited:
This sounds like a common caliper issue, as mentioned. Either sticky slide pins or a stuck piston. Easy repair, and will give you a chance to swap the bleeders at the same time.

Rear wheel bearings don't have grease in the 200 series. And it is a MAJOR job to pull it out to inspect. If the paint isn't baked off the backing plate and you don't smell anything besides cooked pads, I wouldn't bother.
 
BigMF said:
Hey guys, thanks for all the tips. I made it home with a few stops on the way.

The long story is not REAL long but I was on my phone and wanted to get the request for help quickly. Basically, a few weeks ago I was flushing the brakes for the first time. I was following the TSM and completed the front with no problems. However, when I got to the back right wheel, I couldn't get any fluid to come out of the bleeder, even after several complete turns. Assuming it was clogged, I just screwed it back in and did NOT move to the left side, which is the problem wheel this AM. I ordered and received some new bleeder plugs but have not had the chance to replace them.

Right now, I've got it up on a jack stand with the wheel off and a fan blowing on it to try and cool it down some while I eat my banana bread and coffee. Also, gives me some time to do some research. If you look at my activity on here you'll see that I'm pretty new to the repair scene but have been able to replace my own spark plugs, including replacing the leaking o-rings and valve cover gaskets, all the fluids (except finishing the brakes obviously), etc. So, all in all, I'm very handy and a quick learner but this is new territory for me. I'm willing to try and tackle this project but usually have more time to research and plan.

Based on the fact that this is obviously a critical system and doing it wrong can be fatal, I'm thinking I'll probably have a shop look at it unless you guys feel like it should be easy to diagnose the issue first and go from there.

Thanks again for all the quick responses!!
Click to expand...
Diagnosis will likely mean removal of the rear brake pads, which is a relatively easy DIY job. You'll know from doing that if you have a stuck piston in the caliper, or a stuck caliper pin. If those are ok, you'll need to dig a bit deeper and pull the rotor to check the parking brake shoes. After diagnosis, you can decide if you want to tackle replacement of parts, etc. Or, just take it a shop and have them look it over. Overall, the mechanical parts of the brake system are not complex.
 
All good info here. Summarizing, it can be a number of things.

1) Brakes
- stuck pistons
- stuck slide pins
2) Parking brake
3) Wheel bearing

or a combination there of.

Having just done complete maintenance on my rear axles including the rear wheel bearings, they cannot be visually inspected. They are deep in the hub fixture. Better than visual anyways, is testing for play, noise, and smoothness.

As you touched the brakes recently, that would be the most likely suspect. Even though you didn't touch the left rear, the braking system is intertwined. My suspicion is that you got air in the lines, that migrated up to the master cylinder, and now impacts the left rear. Our master cylinders are electric assisted and self priming. I'd wager it's air that's heating up in the left hand circuit, causing continued line pressure after brake release, causing the brake piston to ride the rotor. As the system heats up further, expanding gas further increases brake line pressure.

When you tried to bleed the rear, was your car on (but motor off)? Can't bleed it without the system on.

Could be anything quarterbacking from here. Good luck.
 
TeCKis300 said:
As you touched the brakes recently, that would be the most likely suspect. Even though you didn't touch the left rear, the braking system is intertwined. My suspicion is that you got air in the lines, that migrated up to the master cylinder, and now impacts the left rear. Our master cylinders are electric assisted and self priming. I'd wager it's air that's heating up in the left hand circuit, causing continued line pressure after brake release, causing the brake piston to ride the rotor. As the system heats up further, expanding gas further increases brake line pressure.

When you tried to bleed the rear, was your car on (but motor off)? Can't bleed it without the system on.
Click to expand...

I was VERY careful when bleeding and kept a close eye on the tube to make sure air didn't make it back in but that is no guarantee of course. I did have the engine running when my teenaged daughter was doing the honors of pushing the brake pedal down while I was under the truck to monitor and close the valve as necessary.

At this point, I think I'll start taking things apart and diagnose section by section until I get to the parking brake. Perhaps it'll be obvious once I get in there. Fortunately, the only other thing on my schedule was changing the oil on my wife's Highlander today. Even more fortunately, it happened today and not a week from today when we would have been on an 8-hour drive and probably wouldn't have noticed it until someone drove by saying my tire was on fire.

I'll let you guys know what I find and will probably be updating as I go.
 
Curious why the other side didn't bleed as you did have the system on. I just bleed my brakes again last night and it only take opening the nipple like 30 degrees.

Still probable air got in. Air can get into the bleed nipple around the outside threads if you open it up several turns.
 
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