07-14-2021, 01:41 PM
Something occurred to me late in the diagnostic procedure for a really hot brake incident, that I thought I would pass on. It sounds SO......simple, but in the heat (no puns) of the moment, it didn’t occur to me initially. If you suspect a dragging brake, jack the wheel up and turn by hand. Duh huh.
Here is what happened. Over the winter I did all the brakes, including new rotors on the front. I am pretty conscientious about using the jakes to hold the speed on a grade somewhat below the speed limit because that prevents the emergency braking system that sits in the passenger seat from activating.
But just for grins on a long grade in Montana, I decided to see what slowing the coach down a long grade without the jakes would be like. So, I used the brakes a good bit. When we hit the bottom I smelled the characteristic hot brake smell. OK, no biggie I thought. But it continued for over ten miles until I could find a safe place to pull off. The left front brake was wisping smoke. And as I watched the wisp grew. To be safe, and not burn the coach to the ground, I gave it a shot from the fire extinguisher. Smoke went away. I cribbed the front, and crawled under. The caliper moved a bit when coerced by a long screwdriver. I wasn’t quite sure what was happening. The navigator said there is a truck pull off in two miles, so I decided to limp there for further detective work. We made it, and the brake was not smoking upon arrival nor was there any smell. I pulled the caliper pins with the 14mm hex tool, and both were slick, lubed, and showed no signs of seizing. They came out by hand. But I still was not sure if I had a problem or not. Then the bone simple idea hit me. Jack it up, and turn by hand. OK, no resistance from the brakes at all.
We have driven about 700 miles since then with plenty of brake application. I have checked the rotors with the IR gun at each rest stop and they read within a few degrees of one another which give me confidence that the problem was transient, although I will keep a close eye on it.
Two things to note. One, the temp sensors in my TPMS did NOT show any difference from side to side while driving. However once stopped, the temp sensor showed a 50 degree increase on the sticking side after we sat on the side of the road for 20 minutes. I suppose it took some time for the heat to transfer from the disc to the wheel, through the stem, to the transmitter. Second, there was NO pull when taking hands off the wheel to indicate a stuck caliper on one side. There is also no pull when hard braking.
I don’t know what happened and I wish I did. My speculation is that this was the first time the new brake pads had seen significant heat, and something came out of the brake pad and lodged itself against the rotor. I won’t be able to prove that until I take the tire off and pull the pads. Unless I have another issue, I won’t do that until I get home.
Here is what happened. Over the winter I did all the brakes, including new rotors on the front. I am pretty conscientious about using the jakes to hold the speed on a grade somewhat below the speed limit because that prevents the emergency braking system that sits in the passenger seat from activating.
But just for grins on a long grade in Montana, I decided to see what slowing the coach down a long grade without the jakes would be like. So, I used the brakes a good bit. When we hit the bottom I smelled the characteristic hot brake smell. OK, no biggie I thought. But it continued for over ten miles until I could find a safe place to pull off. The left front brake was wisping smoke. And as I watched the wisp grew. To be safe, and not burn the coach to the ground, I gave it a shot from the fire extinguisher. Smoke went away. I cribbed the front, and crawled under. The caliper moved a bit when coerced by a long screwdriver. I wasn’t quite sure what was happening. The navigator said there is a truck pull off in two miles, so I decided to limp there for further detective work. We made it, and the brake was not smoking upon arrival nor was there any smell. I pulled the caliper pins with the 14mm hex tool, and both were slick, lubed, and showed no signs of seizing. They came out by hand. But I still was not sure if I had a problem or not. Then the bone simple idea hit me. Jack it up, and turn by hand. OK, no resistance from the brakes at all.
We have driven about 700 miles since then with plenty of brake application. I have checked the rotors with the IR gun at each rest stop and they read within a few degrees of one another which give me confidence that the problem was transient, although I will keep a close eye on it.
Two things to note. One, the temp sensors in my TPMS did NOT show any difference from side to side while driving. However once stopped, the temp sensor showed a 50 degree increase on the sticking side after we sat on the side of the road for 20 minutes. I suppose it took some time for the heat to transfer from the disc to the wheel, through the stem, to the transmitter. Second, there was NO pull when taking hands off the wheel to indicate a stuck caliper on one side. There is also no pull when hard braking.
I don’t know what happened and I wish I did. My speculation is that this was the first time the new brake pads had seen significant heat, and something came out of the brake pad and lodged itself against the rotor. I won’t be able to prove that until I take the tire off and pull the pads. Unless I have another issue, I won’t do that until I get home.
Richard and Rhonda Entrekin
99 Newell, 512
Maverick Hybrid Toad
Inverness, FL (when we're home
)
w KTM 300, and MTB in the back