Would brakes seize because engine was hot?

joanfenn · June 21, 2014, 08:41 PM

Bringing the MH out to its summer home the brakes seized. Pulled over to the side of road then noticed that the fans werent running. Could the motor heating up cause the brakes to heat up and seize? Hot wired the fans and by then the brakes released so continued on to the farm. Will be fixing the fans but what would cause the brakes to overheat? There is lots of brake fluid in the system maybe too much??

Oz · June 21, 2014, 09:30 PM

I had something similar happen on the turnpike. Ambient temp was 103Â° so the temp at road level must've been a bit higher. All of a sudden, the RV started slowing down. I thought it was the motor but when I gave it gas, the rpm increased but I could tell it was fighting something and it definitely felt as if something was actually slowing down the rig. Pulled over and then the RV wouldn't budge.

After calling road service and waiting an hour and a half, I decided to try to move the RV to a safer spot. Engine fired right up and no problem moving backward or forward.

Never had the problem before and never had it after. I'm not sure if it was in the eBook "Rx for RV Performance" (available in the club store), in the section on common problems and repairs, but apparently the brake pistons can get so hot that they expand just enough to lock everything up. Once they cool, it's okay.

Just a thought.

joanfenn · June 21, 2014, 09:42 PM

Exactly. The brakes did release and a storm front was moving in so temp got cooler and didn't happen again,by then the engine fans were running also. I am just thinking that it was coincidence that the fan not working would cause the brake to seize. Thinking that there is a relay for the fans that will have to be checked also.

DaveVA78Chieftain · June 21, 2014, 10:57 PM

Disk brake calipers perform a clamping action on the rotor. Rust can build up on the caliper piston surface and/or the caliper sliding mounting bolts from sitting all winter. When bringing the rig out in the spring and start using the brakes, the caliper can bind up resulting in the brakes seizing. When the brakes seize a lot of heat is generated into the hub assembly. When you pulled over, the cooling process may have broken the binding loose allowing the caliper to return to it's normal at rest position.

Chevy caliper rides on the mounting bolts. Dodge M-Series rides on a metal to metal rail surface. Either can rust up resulting in seized brakes. Had it happen to me last year when I initially brought the rig back to life in the spring. On the initial trip in the spring you should drive the rig about 5 miles then pull over and stop. Get out and feel the heat in all 4 hubs. They should all be the same. If one is hotter then the others then either the brakes are not releasing or a bearing is freezing up.

Dave

Oz · June 21, 2014, 11:05 PM

A good way to avoid that... When I would periodically start the RV in winter, I would put it in drive and move it a few feet forward, then reverse. I'd do that a couple times each way. Should at least keep things from getting rust locked.

M & J · June 21, 2014, 11:09 PM

And keeps bias ply tires from flat spotting.

joanfenn · June 21, 2014, 11:11 PM

We do start it monthly in the winter, to keep things lubed. The brakes seized about 30 miles from home. Actually pretty close to where the truck broke down two weeks ago. Maybe we should stay off that road

TerryH · June 22, 2014, 01:23 AM

Quote from: Oz on June 21, 2014, 11:05 PM
A good way to avoid that... When I would periodically start the RV in winter, I would put it in drive and move it a few feet forward, then reverse. I'd do that a couple times each way. Should at least keep things from getting rust locked.

Quote from: oldrockandroller on June 21, 2014, 11:09 PM
And keeps bias ply tires from flat spotting.

and putting it in gear is very friendly to the tranny seals and pump.

legomybago · June 23, 2014, 11:56 AM

its good practice to pump them brakes often when the rigs set too....

GONMAD · June 23, 2014, 03:00 PM

Hello Folks, I have been through this a couple times. If your pads are worn more than halfway the pucks can cock in the bore & cause a lockup when hot. The ford stuff is the worst for this problem. Inspect the pads & do not think everything is OK because the pads are 1/2". These RV pads are a lot thicker than an auto & look fine. See how much thicker NEW pads are than the old ones to be sure. My brother had his power boost setup rebuilt & NOTHING changed until we installed new brake pads all around & no more problems with them locking up & actually bringing his rig to a full stop without even touching the pedal. Sometimes the excessive heat will boil the fluid in the lines & do the same thing. If you have headers this IS a problem. In this area I cover all the lines around the exhaust, whether stock or modified with flashing material & mechanics wire as tie wraps will melt. It's also a real good idea to buy a starter heat wrap & shield the starter from this overheat condition. This heat around the starter significantly reduces the bushing life of the starter & is a real pain to change on the side of the road!! I build very fast cars & I use an axiom that stated " If you can't stop it... Don't start it" I generally begin with the braking system first & then the rest. I hope any of this helps someone in the future. Have a good day all GONMAD