Freightliner XCR 360 Chassis 2017
Rear Brakes dragging/locking up.
February 28, 2020, was the initial failure of the rear brakes.
The rear brakes would not release and smoke emitted from the rear wheels.
The coach was towed to Doggett Freightliner, El Paso, Texas.
This repair was under an extended warranty claim. See enclosed invoice.
Upon tear down and inspection, Doggett Freightliner determined to repair and replace the following components upon authorization under the warranty claim:
2 Rear brake Drums
2 rear S-Cams with bushings
Set of rear axle brake shoes.
Two rear air brake chambers
Replace two front rotors
Replace front brake pads
Replace all seals front and rear related to the brakes.
After Doggett ordered all parts, only rear brake drums, seals, and rear brake shoes were available. The other parts were on backorder for months. Early March 2020 with Covid lockdowns caused further unknown delays.
Service supervisor in Gaffney, SC, Freightliner, subsequently communicated with Doggett. Considering Covid and parts unavailability, it was decided it was unreasonable and impracticable nor safe for us to wait for parts and advised Doggett to leave the front brakes as is because he felt the bluing of the front rotors were normal wear on a motor home chassis.
Gaffney advised Doggett to free up frozen rear cams, replace two rear seals, two rear drums, and rear shoes for the right and left rear axle.
Freightliner advised me if this repair does not correct the rear brake failure the Freightliner would re-repair the brakes but now the coach is out of warranty. Great Lakes Freightliner will go to bat for me feeling the symptoms were repaired not the route cause.
While en route from Texas to Ohio, on or about March 15, 2020, I called Freightliner when I began hearing rear brake squeaking since leaving Doggett Freightliner on March 10, 2020. Gaffney Freightliner noted the issue and advised to have a local Ohio dealer inspect.
On June 15, 2020, Great Lakes Freightliner inspected the rear brakes. Great Lakes backed off the adjustors to remove the drums, inspect the shoes and drums. Great Lakes adjusted all rear brakes indicating no other work was required.
On June 17, 2021, Great Lakes Freightliner performed routine preventative maintenance and lubricated the rear brake cams which had several fittings on each cam.
On July 23, 2021, the same failure apparently re-occurred approximately eight miles from home while returning home (240-mile round trip). The initial sign felt like the brakes were dragging or engaged while ascending a small grade hill that occurred on two separate occasions within seconds apart. The indicator light for the tow braking system flickered on for a few seconds while accelerating. I pumped the brakes several times and the rear brakes appeared released. The towed vehicle was disconnected from the RV. The rear inner axle dual wheels were hot and my tire pressure monitor sensed excess heat buildup. I let the coach sit and let the brakes cool down. I drove approximately five miles to my home and twice experienced the same braking issues as described above;
My tire monitor indicated excessive heat on both inner dual wheels.
The tow brakes are activated by the air brakes on the coach. An indicator light was installed on the RV dash that is activated whenever the tow brakes are active. None of this circuit is connected to the coach and is powered by the towed vehicle.
I suspect that the rear brake air chambers are not releasing air pressure when the brake pedal is released, causing excessive heat that causes the s-cams to lose grease and the s-cams to bind. I believe the above brake incidents are interrelated.
What will cause this? Is there a valve below the brake pedal that is not releasing pressure, brake chambers, airlines?
What are your thoughts?