Air brake not wanting to release, what gives? - Printable Version

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+--- Thread: Air brake not wanting to release, what gives? (/showthread.php?tid=6390)

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Air brake not wanting to release, what gives? - rundlc - 10-18-2021

Morning all, I've had a few instances where my emergency brake didn't want to release. 

Any ideas what would cause that?
Thought I'd ask here first before calling newell service. I'm home now but don't like what I'm seeing with it.

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RE: Air brake not wanting to release, what gives? - pairodice - 10-18-2021

You might check that the little nut on the back of the brake knob is tight.

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RE: Air brake not wanting to release, what gives? - Richard - 10-18-2021

Could be a few things.

One it takes at least 60 psi to release the brakes. Check your air pressure.
Two, the mount for the release knob could be loose as Adrian said, meaning you are not actually pushing it in as far as you think.
Three, you could have an air leak somewhere in the path between the knob and the brakes.
Four, sometimes the shoes stick. A rap with a mallet is in order.

So, do you hear the typical air whoosh when you press the release knob?

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RE: Air brake not wanting to release, what gives? - rundlc - 10-18-2021

Richard I am hearing a air release and then the knob will pop right back out. Normally I apply the brake before trying to release it. Maybe I should not do that.
Thanks for the tips I'm going to check some of those items when i get in.

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RE: Air brake not wanting to release, what gives? - Richard - 10-18-2021

If the knob pops out, then it is sensing the supply air is less than 60. The knob popping out is the built in safety feature that activates the spring load park brake because your brake supply is below 60.

What is your air pressure when you are releasing the brake?

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RE: Air brake not wanting to release, what gives? - DK on the road - 10-18-2021

Check out this You Tube video on air systems and brakes.

https://www.youtube.com/watch?v=rMZwffPGAiQ

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RE: Air brake not wanting to release, what gives? - rundlc - 10-19-2021

As a school bus driver, I do the pretrip every day at work LOL,LOL From now on Ill pay attention to the air pressure. I don't have those issues on my bus

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RE: Air brake not wanting to release, what gives? - kaptain - 03-30-2023

(10-18-2021, 04:51 AM)rundlc Wrote:  Morning all, I've had a few instances where my emergency brake didn't want to release. 

Any ideas what would cause that?
Thought I'd ask here first before calling newell service. I'm home now but don't like what I'm seeing with it.

I wonder if you were able to pippoint the root cause of the symptoms, and be able to fix it?
If you replaced the parking brake release valve, please share the valve maker and model/part number.
Thanks

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RE: Air brake not wanting to release, what gives? - Richard - 03-31-2023

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