Brake pedal valve

[Coco620]

Hello,
It’s been a while since I logged on hope everyone is well.
After noticing my braking power being weak, and truck would start moving at a traffic light with my foot on the pedal, I discovered a small air leak coming from that valve,I changed it, (wishing I never had to fo that again lol) braking power still weak and valve started leaking sir now worse than before. If anyone has experienced this please share. Kenworth w9.
Thanks in advance

[Coco620]

Ps. If I lightly touch trolley brake it has incredible braking power just not with the pedal

[Chamberpains]

Sounds like your brakes are way out of adjustment on the truck or you have a couple bad brake chambers bad. Have someone push the brake pedal while you crawl around listening to the brake chambers. They can leak internally and be hard to hear from up in the cab. I've had this happen a few times.

[Coco620]

(09-16-2018 )Chamberpains Wrote:  Sounds like your brakes are way out of adjustment on the truck or you have a couple bad brake chambers bad. Have someone push the brake pedal while you crawl around listening to the brake chambers. They can leak internally and be hard to hear from up in the cab. I've had this happen a few times.

I appreciate it! Yes I checked adjustments, & checked every brake can individually w someone up in the cab even with the engine off , everything seems fine except that valve leaks out fast ; Is it possible I the new valve went bad in two days ?

[snailexpress]

Is valve leaking from exhaust port or where?

[Chamberpains]

Which valve is it thats leaking?

[snailexpress]

I guess treadle valve.

[Chamberpains]

That's what I was guessing because its the hardest 1 to replace.
Hopefully you took a picture of the line positions before you did the job and marked which line went where as you took them off. They are incredibly easy to mix up when you work in that tight of an area.

Also check your relay valves aren't shot or gummed up. One should be just in front or under the front of your 5th wheel.
It should look something like this though not exactly.
   

[dhirocz]

How does it act bobtail vs with a trailer?

Air pressure with the foot brake applied lower when this happens?

You could have a bad chamber backfeeding out the exhaust. For me, it only did it when I was bobtail...my tractor protection valve was at fault.

I also noticed when I started replacing valves the other ones in the circuit started acting up...I said the hell with it and replaced them all.

Also, you aren't using aftermarket valves, are you?