Hub/wheel are hot to the touch!

[sibanez]

A few days ago I noticed an odd smell from my driver-side front wheel . . having just taken the truck to the off-road park, I figured I must have smoke the rotor. Also, the wheel had more than normal brake dust on it so I stopped driving it and ordered two new rotors. I did notice that the entire wheel was hot, including the lug nuts, hub and the base of the axle. In addition, there was an odd smell coming from that side of the car.

Well, I installed new rotors today in the front and took her for a test drive. After three miles at roughly 45 mph, I stopped and felt the wheel. The hub on the driver-side front was warm, while the passenger side wasn

 

[kimboy]

How much break pad material do you have left? Are you sure it's not locked? You may want to relube the moving parts of the pad and make sure sand hasn't become caked on.

 

[khaug]

IMHO, not likely to be a wheel bearing: They generally get noisy before anything else happens.

My best guess: You have a brake caliper that isn't releasing the pads when you're off the brake pedal. Rebuild or replace it.

Good luck.

 

[sibanez]

How much break pad material do you have left? Are you sure it's not locked? You may want to relube the moving parts of the pad and make sure sand hasn't become caked on.

Both pads, inner and outer, have over 80 percent of the material left, measuring 11 mm. What parts would you lube, since the pads are pretty static, except for the two pins that hold them in place.

 

[sibanez]

IMHO, not likely to be a wheel bearing: They generally get noisy before anything else happens.

My best guess: You have a brake caliper that isn't releasing the pads when you're off the brake pedal. Rebuild or replace it.

Good luck.

Any way to check on this? I haven't had any odd sounds coming lately, but I did notice a lot of corrosion inside the pistons when I was replacing the rotors.

 

[EDGE]

This can't be a serious post, do you realize how much weight and force it takes to turn the tires and what is actually spinning, all those parts in the front wheel housing, including the hub, brakes etc... all heat up with normal driving, any off roading where you do slower driving with more brake usage will heat them up just as must.

Think of the body, when sleeping your cold but during the day when you do certain things you build up heat, same thing when driving, my hubs have gotten so hot it will burn the skin off your hands, it's normal.

 

[kimboy]

How much break pad material do you have left? Are you sure it's not locked? You may want to relube the moving parts of the pad and make sure sand hasn't become caked on.

 

[kimboy]

And definately blead your calipers. The rotor must have turned red from the heat and you might have exceded the maximum temp and boiled the brake fluid in the brake line.

 

[sibanez]

This can't be a serious post, do you realize how much weight and force it takes to turn the tires and what is actually spinning, all those parts in the front wheel housing, including the hub, brakes etc... all heat up with normal driving, any off roading where you do slower driving with more brake usage will heat them up just as must.

Think of the body, when sleeping your cold but during the day when you do certain things you build up heat, same thing when driving, my hubs have gotten so hot it will burn the skin off your hands, it's normal.

It's just the difference in heat that bothers me, why would one side be so much hotter than the other? I'm bleeding the lines and taking everything else apart one last time today.

 

[greasefingers]

I would think that both side should feel the same, as far as heat. Maybe a sticking caliper. Do both rotors look the same as far as shininess? Is one rainbow-colored?

When installing new rotors, one should clean them with a solvent like brake cleaner. This is because they come oiled so that they do not rust while being stored. You could have smelled this.

 

[bonedoctor]

I'd vote for the sticking caliper. It's not fully releasing the pads from the rotor. They're friction devices and it's functioning now like somebody riding the brakes. An amazing amount of heat from the friction can be generated. The smell, the big difference in heat (a sticking caliper will heat the wheel up so much that often you can't touch it--normally functioning brakes under normal use never do that) all point to the brakes. The extra amount of brake pad dust also makes sense. Wheel bearings get noisy. Sticking calipers (either the sliders or a sticky piston) do what you're describing. If it's sticking enough, it will pull the vehicle to the side of the sticking brakes. If the calipers are worn or thin enough, the tremendous heat will often warp the rotor and you'll get a pulsation in the brake pedal (and often a shimmy in the steering wheel) when braking, sometimes even the pulling to that side, too. I'm assuming you had to push the pistons back into the caliper a little to accommodate the new, thicker rotor. The pads are the same ones previously installed? Sometimes older calipers will act up when you do push the pistons back into the caliper to make enough room for the new thicker rotor and pads.

I had a BMW 535i that liked to do this. The caliper design slid on these large pins that would get sticky (needed occasional grease) or the pistons in the caliper would get sticky and they pushed out of the caliper as the pads/rotor wore. A piston should be able to extend and retract in the caliper and they'd stick in the extended postion keeping the pads in heavy contact with the rotor. I had to rebuild the calipers ocassionally to keep them working--push pads against the rotor when braking, and releasing slightly when your foot is taken off the brake pedal and releasing the pads from the rotor.

Somebody pointed out looking at the new rotor. It should be shiny silver color, not a blue or rainbow color which are signs of overheating.

Another person mentioned bleeding the calipers/brake system. Brake fluid boils at a very high temp--that's why it's used. But get a little water in the system (brake fluid is hydroscopic, i.e., picks up water )and then heat that's normally not a problem with clean, moisture-free fluid can cause a total loss of brakes. Here's why...fluids are incompressible and that's a property that we exploit with hydraulic systems. Force applied in the liquid is transmitted throughout the liquid. But get a little moisture in the brake fluid and get it hot enough and the moisture boils at 212 degrees at atmospheric pressure, a little higher in the brake system since there's pressure being applied (and the moisture boils when its vapor pressure exceeds the pressure being applied). Now you've got water vapor which is easily compressible and the force applied in the master cylinder doesn't get transmitted through the fluid column to work the caliper because there's some compressible water vapor in the system--no brakes!

 

[Light_Mania]

Driving 3 miles at 45 mph shouldn't result in any discernible heat buildup in the tire/wheel/wheel carrier assembly. I'd vote for a sticking caliper too. It wouldn't have to be dragging very much to put a lot of heat into the assembly. Sounds like you may need a caliper rebuild.

 

[boston_kevin]

It's just the difference in heat that bothers me, why would one side be so much hotter than the other? I'm bleeding the lines and taking everything else apart one last time today.

Also remember, you have more weight on the driver's side (unless you always have a passenger). You may have a sticky piston (these are 4 piston calipers I believe) which could create more force on once end or the other.. Since this is a new thing (you have had the lift and tires for over 10k miles), it is more indicative that this may be a long term effect of the increased weight from the lift/tires combination.

 

[Koz]

Lift the front of the vehicle and spin each wheel and see if there is the same resistance to spin and how long it spins. You can take the wheels off and have someone press the brakes while you look at the distance between the pads and rotors on both sides to see if the pads are releasing equally.

Koz

 

[Bossman]

Hey sibanez,

I had the exact same symptoms that you described ... I first noticed the odd burnt smell coming from my left front wheel. Upon visual inspection, there was significantly more brake dust on that rim than the right front rim.

Having just had a complete brake service done only a few months back, my bet was on a seized piston in the brake caliper. Sure enough, that was it.

So I had the caliper replaced with a remanufactured unit. No point trying to mess around with a caliper rebuild - as who knows how badly scored the piston(s) might be.

 

[ellmer]

I had the same happen a few years back on my Wrangler. I had just swapped wheels and tires and by the time I got home, the wheels were very hot. Took it to a tire shop to get the wheels balanced and the heat went away. Turns out, with aluminum wheels, torque on the lug nuts is critical or you can warp the wheel/rotor set up. This explains hot but not red hot. Could be either this or the stuck caliper.

 

[sibanez]

I see you are in Canada so I'm guessing they use salt on the roads too. I believe that is the cause of these issues; it's just brutal on the pistons. I have a 2005 Tacoma now and had to redo the rear drums because of all the rust.

Hey sibanez,

I had the exact same symptoms that you described ... I first noticed the odd burnt smell coming from my left front wheel. Upon visual inspection, there was significantly more brake dust on that rim than the right front rim.

Having just had a complete brake service done only a few months back, my bet was on a seized piston in the brake caliper. Sure enough, that was it.

So I had the caliper replaced with a remanufactured unit. No point trying to mess around with a caliper rebuild - as who knows how badly scored the piston(s) might be.

 

[Trdsupranick]

probably stuck piston in the caliper....mine did the same thing...i did researching when i had the problem and our oem calipers are notorious of seizing

 

[Bossman]

Hey sibanez,

Tons of salt used in the winter on our snowy/icy roads up here. No doubt that this has an adverse affect on those exposed pistons/calipers.

I try my best to give my T4R a quick rinse at one of those self-wash places (especially the undercarriage) at least every 2 weeks in the winter.

I see you are in Canada so I'm guessing they use salt on the roads too. I believe that is the cause of these issues; it's just brutal on the pistons. I have a 2005 Tacoma now and had to redo the rear drums because of all the rust.