Hi. I need help on this one. Parking Brake running hot after dealer service. Three visits and they're still running hot (up to +125℃ on the rotor hub where the parking brake drum is).

Car is W211: 2008 E350 4Matic sedan, sports suspension in case that matters.

Had the rear brakes done (new pads and rotors) on a Friday about 2 weeks ago. While it was apart, also had a 'parking brake kit' installed, includes new parking brake shoes of course.

Picked it up late Friday, didn't drive much over weekend. By Monday, I'd figured out that the rear brakes were dragging. Using laser pointer guided IR Thermometer, found peak temperature was on the drum part of hub. Peak reading almost +200℃. Disc surface cooler. So parking brake dragging.

Got booked in 2nd visit for the next Friday, a full week of dragging brake and poor fuel economy. Tried to be gentle and slow while driving.

On this 2nd visit, dealer tech adjusted parking brake. Said it was now in spec.

Try again. Improved. Drag a bit less noticeable. Still +150℃ readings on rear hubs, the drum part of rotors.

Back in again today, Tuesday. 3rd visit. Tech took everything apart, parking brake shoes reported to be in good condition (but I didn't see them). Further very careful adjustments. Double checked.

But still getting +125℃ on hubs. Still gentle signs of dragging, but milder.

For comparison, front brakes measure only slightly above ambient. This issue has nothing to do with heavy braking. Rear discs are also not very hot, except nearest hub. Doesn't seem to be related to calipers, pads, discs.

Is it as simple as the adjustments being done incorrectly, three visits in a row?

Brooklands manual mentions a parking brake compensation device under rear seat, not sure if it applies to my car. I didn't see them anywhere near the rear seat. I assume they didn't touch that system.

Any advice welcomed. Thank you!!

 

Just to add, I'm assuming it's abnormal that the parking brake hubs should be +125℃ (over 250℉).

That's hot enough to feel the radiant heat. Too hot to touch.

I don't recall it being like that before.

 

Drive to work this morning.
Left rear hub, +105 °C (= 220 °F).
Right rear hub, +160 °C (= 320 °F).

The hot spots are on the parking brake drum (hub) part of the rear discs (rotors).

Is this as simple as the adjustments being too tight?

Any tricky process that's being missed?

Any other things to check?

Thanks for any advice.

 

bring it to a different dealer or check some youtube vids on how to adjust the parking brakes with a small flathead screw driver

 

https://www.google.com/search?client...ke+adjustment+

 

Although there are no other dealers within 100 miles, I believe that you are otherwise correct.
It's time to open up the adjustment and confirm that the adjustment is the basic root cause. As simple as that.
Even if the adjustment is overly loose so that the foot Parking Brake pedal reaches the floor, it'd be a good test step anyway.

If it's not that, then the parts installed might be out of spec, or somehow installed incorrectly. Less likely possibilities.

Thank you!!

PS: I looked under the rear seat and there's no access to the parking brake lever thingy from there on this car. No access panel.

 

Im experiencing the same issue on my passenger rear. I initially thought it was my caliper so I got a new one. Still the same problem. After doing my own research. I found out that my parking shoes were the problem. After adjusting the problem still persists.