I need help guys. I can't figure this one out or where to begin. So, what I have noticed is that when I back into the drive way to put the boat up I will smell a burning smell. Well, I felt around and I noticed heat from the drivers rear wheel and the rim was much hotter than the rest. I also verified it will heat up with no boat behind me.

First I drove it to see if I felt or heard any dragging... not really. The thought was maybe I had a frozen caliper or a dragging parking brake.

So, on a hunch I adjusted the parkign brake out on that wheel, just to be sure... as I use it a lot with the boat. A las no change.

So, then I removed the caliper to check to make sure it was floating freely. It is, and I was able to use a C-clamp to depress the pistons to remove teh caliper. Nothing on the rotor or the pads looked odd.

I could rotate the hub by hand by the wheel studs... I mean not easily but I could as it had to turn the axle, ring gear, and driveshaft.

Finally, I put it all back together and jacked up the entire rear end and placed it on jack stands. Pumped the brakes back up, Dropped it in gear and let the wheels run at idle. Heard nothing odd, no rubbing or scrapping sounds. Dropped in on the ground drove it for about 5 miles and seend no odd heat. Nor did it seem to heat up much after a 7 mile trip to work this morning.

However, after work I drove to a marina to meet a buddy of mine to go out on his boat. When I pulled into the parking lot. I checked the weel and it was hot again, the again when I got home this evening. However I am no longer smelling the burning smell.

Oh and even with a deadblow hammer and PB blaster, I was unable to free the rotor/drum assembly from the hub. Any thoughts on what I should do about that?

The parkign brake cables are moving equally on both sides and the tension bar stays straight up and down when the brake is applied and released.

I guess my next thought is it could be and axle bearing, I mean the rear axle does get dipped in the water from time to time. But really, I dont hear any grinding.

Another point to note is that the day I first smelled this I felt a slight bumping up and down feeling on my way to the boat ramp. However I didn't think much of it on my way home because I didn't feel it anymore. Felt kind of like a tire out of blance but no shaking in the steering wheel.

 

I would think if you could smell something it would be a brake issue. Sticking caliper pins possibly. Maybe a bearing problem. Check the fluid level in the rear diff. Need a little more info on your truck. As far as the rotor being stuck. I tapped mine around the middle where the parking brake pads are with a small sledge. Loosened up enough to remove it.

 

Sorry, its a 2000 Model F-250 Diesel.

I thought the same thign about the smell, but didn't really see anything. Also, I was able to slide the caliper by hand on the pins... ofcourse this is after I dpepressed it with a C-Clamp.

 

I am guessing you are 4 wheel disk brakes, and it sounds like the rotor could be warped, easily done if they where hot when backed in the water to launch the boat. Try rotating the wheel without backing off the caliper, also compare the resistence to the opposite side. If there is no leaking fluid then it must be the pads you are smelling, could also be a corroded piston that is sticking, did you pull the rubber boot off and look at the piston it self?

 

I would also agree with sticking brake caliper. It wouldn't typically be the piston but the slide pins that are the issue. If you haven't, peel back the slide pin boots (they pop off one end easily) and check them for signs of corrosion. But it sounds like they are moving easily.

But another issue that can crop up on older vehicles is the flex hose can become constricted. Over time, brake fluid causes the hose to swell and restrict the flow of fluid. This can lead to dragging brakes as they don't fully release. The simple solution is to replace the brake flex hose. This is just the rubber section from the caliper to the hard lines on the frame.

Wheel bearing is possible, but the check for that is to jack it up and try to move the wheel up/down and side to side. Also spin the wheel and listen for any grinding noise with a stethoscope. Compare to the other side if you are unsure.

Good luck,

Dave

 

Yes 4 wheel disk. Rotor isn't warped... yet. Wheel rotated ok by hand before releasing the caliper. As easily as you would expect to turn the wheel in Neatural when having to turn the axle, ring gear and drive shaft.

Resistance seemed very similar.

Dave, we definately didn't get any play in the wheel. We were tapping it with a block of wood and a sledge and also a deadblow hammer... got nothing.

I guess, I know I am goign to have to replace somethign. I just want to make a good educated guess at it.

I did notice though, the pads had not worn on the surface very evenly.. *** the entire surface wasn't all shiny. But there was plenty of friction material left on both front and back pads. Also, I see no fluid leaking out of the rear axle anywhere and fluid level was checked and was ok within the last month.

 

It sounds like you checked it all real well, your only clues is the uneven shine on the pads, I would start there, iand replace the pads If it is the bearing the axle housing will be hotter on that side than opposite side. Just a thought have you checked the fluid level in the axle and does it smell burn't?

 

Idea : On that axle (Sterling 10.25) the rear axle bearings are lubbed by the gear oil.
If the gear oil is low you could have a hot hub area or bad bearing.
Also Long term Parking :If you allway's park with the Pass side down the driver bearing could be going dry.

 

I'd have a close look at those caliper slide pins again. I had to replace half of my caliper bracket due to the pins being rusted in. My caliper would hang up from time to time due to the bad pins.
JEV

 

Guys, thanks for all the great IDeas. You are ocming up with some stuff I didn't think to check.

As I said, I checked the fluid level within the last month, and it was good. However not since this issue started. I will start there this evening and see what the situation is. Make sure level is good, which it should be as I see no leaking anywhere on the axle, but I will check the smell of it as well.

I have not really checked the heat of the tubes. I figured it would be hot from heat transfer, thus hotter on one side.

As for long term parking. Its rare that I ever park this truck on an incline in any direction for very long.

I think what I am going to do next is when I get home from work, I am going to check the rear diff fluid and see if it can tell me anything. Then if all is well there, I am going to jack the rear end up again and let it run at idle speed and give it a good listen. As last time I had already depressed the piston and worked the slide pins before I ran it. This time, I know its generating heat and I will have touched nothing.

If all still seems to be normal. I am going to watch the caliper as my buddy pumps the brake and watch the fucntion of the caliper.

If all still seems well, I am probably going to take the caliper and carriage apart, clean the spring clips and put a slight amount of beaing lube in them. THen take the slid pins out and give them a good cleaning, a rub down with 1500 grit sand paper, and new grease and re-assemble.

Take it for about a 20 minute or so drive and then compare the heat.

I forgot to mention, this Truck only has 82,000miles on it.

Or I could by pass all that break work and just replace the caliper as was done by this guy from this thread. http://www.thedieselstop.com/forums/...-wheel-168644/

 

Don't use bearing grease on brakes!! Only use high-temp brake grease. They are usually silicone-based to take the heat. A small tube will last a lifetime and doesn't cost much.

(BTW I also use a dab of it spread around on the mating surfaces of the wheels and hubs to prevent them from corroding together. Helps avoid the stuck wheel problems you hear about from time to time on here. But don't get it on the stud threads.)

-Dave

 

Subscribing, as I have the same problem. 189K miles.....

 

Just an idea on greasing the slide pins, that has always caused me grief with dirt sticking and absorbing all the oil and I wound up with a bigger mess, but I travel lots of dusty gravel roads and lots of muddy trails in the fields. Never seize has been the best thing I have found for this application..good luck on your search, I like your plan of action.

 

Well, the fluid in the diff looked good. So I took the Caliper off and had my buddys (I was doing things alone the previous night) put gentle pressure on the brakes. One piston moved out, the other stayed where it was.

I assumed from this, the caliper must be bad. So, I replaced it, and all is now well.

 

Good deal!