How hot should brake drums run?
 

99 F150 Lariat 4x4.

This has rear brake drums and I'm wondering how hot is normal for average driving conditions. Just had the rear brakes totally rebuilt complete with drums and I think they were adjusted using the standard rule of thumb (tight enough to drag very sightly). But this was cold parts and I find the drum surface temps at 325 to 350 degf after driving maybe 10 miles at speeds under 60 mph and only a few stops. At the same time the front rotors are ~ 130.

Did you replace the wheel cylinders? Brake hoses?

That is WAY too hot, rear drums should be almost ambient temperature because the fronts do 80% of the work.

They are dragging, they are either adjusted way too tight or you have a hydraulic issue or the parking brake cable may be too tight.

^^What he said^^!!

Back off the star adjusters a couple clicks and see how things work. If they're still warm, back them off some more.

- Jack

Agreed
 

I felt that 300+ was way to hot too. Going on a lift today for another check and back off on the adjusters maybe 3 clicks. Parking brake isn't an issue and I doubt it's in the hydraulics. Wheel cylinders were replaced and I think the right rear wheel cylinder was the original issue. We'll see.

For anyone interested... according to Ford, the drums on my truck can normally run between 220 and 250 degf under normal driving conditions. Heavy braking may produce temperatures up to 300 or more. Now that both the rear brakes have been adjusted and 'tweaked' I'm now getting temps around 220 on both sides under normal breaking.

Excellent!