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Wayne
Wayne, Journeyman
Category: Medium and Heavy Trucks
Satisfied Customers: 9820
Experience:  worked on, Gmc, Macks, Freight liner,Mercedes Benz,,Ford, sterling
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If it this 2007 Columbia When there is a brake application

Customer Question

If it this 2007 Columbia
When there is a brake application
With the trailer
Sometimes the trailer brakes stays on
Without trailer too sometimes the brake light stays on
I checked the drake switch air line there is minor air in it which trigger the tractor protection valve and brake light
Changes all valves in system
Plz help
Something is not completely dumping air
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Wayne replied 1 year ago.

Hi I'm Wayne

I will help you with this

What valves did you replace

Let me know ,Please

Customer: replied 1 year ago.
Tractor protection, dash valve, foot valve
Customer: replied 1 year ago.
When I apply brake and release it
Very minor like 5-10 psi air remain on trailer side airlines which trigger it
Expert:  Wayne replied 1 year ago.

Thank you for that

If this is doing it on the trailer, slow release it is 2 things

1st The QR valve for the trailer

or the mulit fuction valve on the trailer

I would replace the QR valve 1st $17.00

I hope this helped you

Hi if this helped you

Please rate my answer 3 or more stars

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Not Poor/Bad service

Wayne

Customer: replied 1 year ago.
Customer change trailers daily
It's cant be wrong in all trailers
Expert:  Wayne replied 1 year ago.

Hi Thank you for that

Sorry about the delay

You did not mention it was all different Trailers

You need to give all info that you have, as I am not there ,

seeing it,

if they are dragging , not releasing all the way, replace the QR valve on the tractor

It is located on the back of frame , 2 lines go to it

Hi if this helped you

Please rate my answer 3 or more stars

If you need more info, use request button

Not Poor/Bad service

Wayne

Customer: replied 1 year ago.
ok here is the detailed
when bobtail- on brake application truck application fine but sometimes brake lights stays on but truck brakes are released
and as u know there are 4 lines on tractor prot. valve
1) from dash valve red one
2) 1/4 line for brake switch
3)brake control (primary) from foot valve
4) brake control (secondary) from foot valve
when lights stay on there is a very little pressure that stays in line (2) , (3) ,(4)
which trigger the lights
tractor brakes are ok.
when trailer hooked up same thing but this time trailer brakes remain applied, dragged but truck ok
same way if i un hook any one of 3 lines it releases
Expert:  Wayne replied 1 year ago.

Hi Thank you for that

You gave a good explanation, of Issue, Good Job,

Ok looking at what valve you replaced

I would like yo u to do something

break loose air line at the multi-function valve of tractor

that is the one that has brake/paring valve combo

let me know

Customer: replied 1 year ago.
I didn't understand what u said
Expert:  Wayne replied 1 year ago.

HI

With the tractor not on trailer

back on the frame rail , you have vale/vales that go to the brake chamber,

loosen that line and see if air leaks out ,and release the brakes

Customer: replied 1 year ago.
That Valve is ok
Checked it
Expert:  Wayne replied 1 year ago.

Thank you for that

now got to each Brake canister , and loosen line

on the service side,brakes set, then parking brake set

you should not see or hear any air

Ps , I go off for the night, will , continue in the morning

Wayne

Customer: replied 1 year ago.
Truck is out on road now
Could there be problem with truck canister as I see no back pressure at tractor delivery side of foot valve
Expert:  Wayne replied 1 year ago.

Morning

Thank you for that

Yes the brake chamber , that is why i mentioned to

loosen the lines and se if you get air,

you have a brake canister internal leak

I hope this helped you

Hi if this helped you

Please rate my answer 3 or more stars

If you need more info, use request button

Not Poor/Bad service

Wayne

Expert:  Wayne replied 1 year ago.

Hi

Just following up with you

did my answer help you

let me know ,Please

Wayne