My Parking Brake Will Not Release

[sealevel_ram]

My Ultimate Freedom with a Cummins ISL 400 and Allison transmission will not let me release the parking brake. I push it in to release, and it just pops back out.

I have noticed that it has been doing this a few times lately but always eventually released. Not so now, at least not yet. Air pumps up fine, and yes, I am holding my foot on the brake.

Any advice would be much appreciated.
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[sealevel_ram]

gbopp wrote:

sdianel wrote:
http://rainbowrv.com/rv-talk/air-parking-brake.html

Clicky

Any idea where this is located on a Spartan chassis? Is there just one, or are they at every wheel?

Thanks.

[Gasman_2]

100 psi should release the brakes. Do you have 100 psi on the front and rear both ?

[sealevel_ram]

rcmiller32 wrote:
100 psi sounds a little low for your max air pressure. should be in the 120 to 130 range. can take 90-100 psi just to compress the parking brake spring. sounds like the governor is bad.

I should have said it goes OVER 100 psi. I will look and see how much over and try to adjust if necessary.
I did have a repair done on my air system a couple of months ago. Maybe they messed up the max pressure setting.

[John_S_]

I would try turning the governor up till you hit 120. If it will not go up then you will need a new one. Cheap part but make sure you find one that comes on at 90 psi instead of 70. I know in my FT we need more air for the suspension.

[rcmiller32]

100 psi sounds a little low for your max air pressure. should be in the 120 to 130 range. can take 90-100 psi just to compress the parking brake spring. sounds like the governor is bad.

[gbopp]

sdianel wrote:
http://rainbowrv.com/rv-talk/air-parking-brake.html

Clicky

[sealevel_ram]

sdianel wrote:
http://rainbowrv.com/rv-talk/air-parking-brake.html

Thanks for the link. It explains how it works. Must be a leak somewhere and the spring is not compressed so the brake stays set.
I would like to know if anyone else has replaced or worked on this.

[sealevel_ram]

happy-2 wrote:
Can you pump the brake peddle till the compressor comes on and see how high the pressure goes?

Pressure goes up OK, to 100 psi.

[happy-2]

Can you pump the brake peddle till the compressor comes on and see how high the pressure goes?

[happy-2]

whats your air gauge read?

[sdianel_-acct_c]

http://rainbowrv.com/rv-talk/air-parking-brake.html