Bendix brake valve question

[PuroCumminsPower]

I replaced the Bendix E8P brake valve on my 09 PROSTAR it would leak from where air comes out after you release brake. The new one is still leaking. I read that it can be caused by other parts putting pressure into brake valve. Anybody ever have this problem?

[Rawze]

(08-29-2016 )PuroCumminsPower Wrote:  I replaced the Bendix E8P brake valve on my 09 PROSTAR it would leak from where air comes out after you release brake. The new one is still leaking. I read that it can be caused by other parts putting pressure into brake valve. Anybody ever have this problem?

The parking brake chambers can leak air into the service brake lines and vice versa,... I would start there.

[Hammerhead]

(08-29-2016 )Rawze Wrote:  

(08-29-2016 )PuroCumminsPower Wrote:  I replaced the Bendix E8P brake valve on my 09 PROSTAR it would leak from where air comes out after you release brake. The new one is still leaking. I read that it can be caused by other parts putting pressure into brake valve. Anybody ever have this problem?

The parking brake chambers can leak air into the service brake lines and vice versa,... I would start there.

This was my first thought as well. With your wheels chocked to prevent the truck from rolling, release the parking brakes. With the truck shut off so it's quiet, crawl under the truck and listen for air movement. If you can't hear a small leak, one at a time remove the service line from each brake pot. You probably have one with an internal leak allowing air from the charged parking brake side into the service side, which escapes out of the released valve.

[the missing link]

One trick is to be very carfully take vice grips and pinch the lines on the brake pots with the brakes off. A flat bar pair of vies grips work very well

[Mr Hagg]

THE QR1 Valve is bad. It is located under fifth wheel. When you release your brakes there is a quick release valve in the rear that trips the air and not letting it come back to the front. You should have one that has 4 lines to it.

[Mr Hagg]

(08-29-2016 )Mr Hagg Wrote:  THE QR1 Valve is bad. It is located under fifth wheel. When you release your brakes there is a quick release valve in the rear that trips the air and not letting it come back to the front. You should have one that has 4 lines to it.

It should look like this

[PuroCumminsPower]

Thank you all for the input. I will check brake chambers and replace QR1 valve.

[PuroCumminsPower]

(08-29-2016 )Mr Hagg Wrote:  

(08-29-2016 )Mr Hagg Wrote:  THE QR1 Valve is bad. It is located under fifth wheel. When you release your brakes there is a quick release valve in the rear that trips the air and not letting it come back to the front. You should have one that has 4 lines to it.

It should look like this

Thank you for the information Mr Hagg, I see a valve directly under fifth wheel I will post a pic of it shortly and then there's a valve with 3 connections located near cat walk. Just want to be sure which is QR1, I will post a pic of both.

[PuroCumminsPower]

(08-29-2016 )Mr Hagg Wrote:  THE QR1 Valve is bad. It is located under fifth wheel. When you release your brakes there is a quick release valve in the rear that trips the air and not letting it come back to the front. You should have one that has 4 lines to it.

Here is valve directly under fifth wheel.