Cold weather things: Park Brake

[Primussucks]

Hi everyone.

Question. I recently had my truck up in Colorado and the temps dipped down to 15 overnight. Aside from a long start (I haven't re-connected my ether and didn't have block heater), something I wanted to ask about.

After I let the truck warm up and we were about to head out, I disengaged the park brake and it sounded like a slow/weak venting.. more like a slow release then the normal big puff of air. The Park Brake light remained illuminated, even though the brakes released. I was able to drive (forward and reverse) with the light on, with no resistance. I stopped and let it idle a bit longer and the light eventually turned off.

When I drove to my destination, about an hour away, stopped and engaged the Park Brake, again a small air whisper. The brake never engaged. I ended up chalking the truck against a curb... with the Park Valve engaged. After about 10 minutes the Park Brake eventually engaged and the light on the dash illuminated.

I did not investigate if there was any water in the system. My dryer (current Haldex version) has been serviced, desiccant cartridge changed, recently.

I did not empty the tanks over night during the cold.

Do I need to do something to protect/insulate the Park Valves? I haven't read about anyone running into this before, is it common?

What are the best practices here?

Thanks

 

[Ronmar]

Is your front red gladhand capped/frozen? That could keep your brakes from disengaging. Is your system free of moisture. Water in the system will keep things like 2way check-valves from doing their job properly…

the park/emer lights are controlled by a 66PSI pressure switch behind the grill. This switch senses the air being sent from the park control valve down to the anti-compound valve. Should be no real woosh when you release the park brakes as you are sending park air to release them. but that light should go out immediately if air is flowing properly. The woosh should come when y0u set the brakes by releasing park air…

 

[GeneralDisorder]

Have you replaced all the check valves in the system? The one behind the front glad hand, the one's behind the driver's step curtain, and the one's at the back of the air tranks?

I had to swap out my park/emergency control knob assembly due to leaking from the shafts. There's a sintered bronze discharge filter screwed into it that needs to be clear to release the park air.

 

[Primussucks]

I have not replaced any check valves.
The front glad hand is capped (with the vent), hasn’t been touched.

the rear glad hands have been deleted and the ports on the valves plugged.

Has never been an issue, except for that cold morning.

hmm.

 

[GeneralDisorder]

Check the vent on the front glad hand. That has to be open or the system will not release. Maybe moisture in there temporarily blocked it with ice.

Definitely just change all the check valves. They get rusty and the springs can break from rust.

 

[Ronmar]

Yea the fact the brakes released means you sent at east 60PSI of park air to do so, perhaps the cold stiffened up that switch mechanism delaying the dash light turnoff. But releasing park air should have vented vigorously from in front of the radiator and the anti-compound relay(top air relay) in the back. If it vented by the radiator or in the center dash, it sounds like that front glad hand ckt is an issue

If it didnt vent in front thats something with the park control valve or the vent. On older trucks the front park vent is tied to the pedal vent to a floor port up in front of the radiator…

 

[GeneralDisorder]

On the later trucks like his, the parking brake vents right at the hand control. It's not tied to the port behind the radiator.

 

[Ronmar]

yep, have no idea what year/model we are talking about same applies though, set brakes air should vent in dash which causes the air at the rear relay to vent. no front vent, issue is at the park control. vents at front, but not at the rear issue is with the unvented red front glad hand or at the rear top relay/anti-compound valve

 

[GeneralDisorder]

Ah yeah. Not sure just mentioning it in case.

 

[Primussucks]

Thanks as always guys...
(my model year is in my sig ). 2007 A1R

I'm not with the truck now, but reading here, I suspect it was the front glad hand vent that was frozen.

I'm not 100% certain I'm going to keep the fronts, the only reason I can think of is for a tow... They need to either be deleted or moved to make room for a winch anyway.

I've watched your 'delete' video Ron.. Maybe thats what I'll just do when I get the truck back.