Bendix brake valve question

[Hammerhead]

(08-30-2016 )PuroCumminsPower Wrote:  

(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.

The pic in post #8 is the QR1 valve...

[Mr Hagg]

(08-30-2016 )PuroCumminsPower 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.

Here is valve directly under fifth wheel.

Valve under fifth wheel is a relay valve for your brakes them self. The QR valve is the first one it works your ebrakes. Get someone to release your brakes (MAKE SURE THE TRUCK IS BLOCKED UP SO IT DONT ROLL) and then pull it and see if air comes out there if not then there ya go. Replace it.. There are many diffrent ones that look just alike but the diffrence is in the piping of it the fittings on some are smaller or larger.

[PuroCumminsPower]

Thank you gentleman for the help.

[PuroCumminsPower]

Just updating the situation with this damn brake valve/ treadle valve. Its still leaking with parking brake on or off. Checked parking brake chamber no leaks. Checked service air line on chamber not leaking air. Can't find any other leaks. Also changed QR valve didn't make any difference. Any ideas?

[Pro Star Cummins]

Not sure ,but is there a small check Valve back by rear end housing
Along frame rail? I think there is a slinding part in there that gets stuck
In one position and allows air to bypass ,I had similar problem
Along time ago and that is what I found. Replaced brake treadle and
Quick release valve, but still same thing was driving me nuts till
I discovered that valve. Changed it out and that fixed the problem.
Google Bendix 2008 Pro Star Truck brake diagram .
Sorry I don't know how to load that address directly.

[Hedley]

http://www.meritorwabco.com/MeritorWABCO...tp9974.pdf

[PuroCumminsPower]

Thank you. I'll look into it.

[biscuits and gravy]

I don't know if you found the source of the leak yet. But if you haven't I can tell you I have had in the past my share also; with air leaks not in the normal places that temporarily drive me nuts trying to find them.

I would check to see if anybody replaced any parts before you started chasing the air leak. Maybe somebody else previously replaced something and reinstalled a couple of lines backwards.

I only mention this because I test drove my KW900 and liked it. It took a couple of days going back and forth to settle on a price with the seller. I went back and paid and picked it up.

Drove it home and the air gauges were indicating normal pressures at times and then at times it would only build to 70-80 pounds. Overnight it sat and leaked both tanks to zero.

Next day I chased after everything I could with soapy water and put on a new governor because I thought I had found the leak. I was wrong, I saw that there was a new drive axle load leveler valve on the truck earlier (but didn't soap it) that wasn't on it when I test drive it a few days earlier.

I called the seller and asked what was going on. He said it had a slow leak so he replaced it. I asked if he replaced anything else and he said no. I went back to the new load leveler valve and soaped it up and observed it exhausting a tiny leak. I wondered how this thing could be leaking if its brand new. Then I thought, what if the seller had the two air lines backwards. So I pulled the air lines and reversed them and the leak stopped. The air pressures then shot up and everything returned to normal.

Moving on from Krapworth and lets go to my Peteshit...

Chased my tail again with soapy bottle water spraying everything I thought might have an air leak. Short story, both tanks would leak over night to about 30-35 pounds. Discoverd my air blend door actuator was leaking air, then discovered after replacing it with a new one, that it leaked TOO. I then played with the master temperature controller and the air valve for the bilevel mode selector had a blown seal in it. I replaced that and it solved the mystery.

Moving onto one of my Interfucknationals....

Rinse and repeat again, no air leaks at the most common places so I peaked behind the dash to look and listen for air leaks and discoverd nothing. Went through my mental checklist and thought to myself I have not soaped up the air dryer. I then soaped it up and discovered that the flange mount bolts that circle the air dryer had several places around it leaking air through the bolt holes.i checked the bolts by trying to tighten them a little more and that didn't work.

I then removed the air dryer to inspect the inside. I discoverd that someone replaced the air dryer filter and reused all the o-ring gaskets. They didn't replace them and squirted a mess of silicone on top of them and bolted the air dryer back together. That silicone bandaid didn't work.

I replaced the entire air dryer with a newer updated air dryer and problem solved. I couldn't find replacement o ring sets because that model air dryer had become outdated. I believe the shop I paid to change the air dryer the previous 3 months or so before, discovered they couldn't get the o rings and just siliconed them. I don't know for sure, why they dropped the ball but they did. I always thought the o rings were automatically included with a filter.

Another thing that helps me chase air leaks is by blocking off one tank at a time and chasing the lines that are connected to that one tank to see each thing that tank supplies... while watching the air gauge for that tank. If that tank doesn't leak while I monitor the dash gauge for it. Then I've isolated the air leak to the other side.

I apologize in advance if my description above has wasted your time or confused you. Hopefully you've already found the leak before I posted this.

By the way, I have obscene names for all my trucks, but I still love'm. I think the trucks from International, KW & Pete that are about 5 years old and older are the better trucks out there.

[CFR__AND_SONS]

I'm having the exact same problem. I actually logged on to research this. I bought the new foot valve like PuroCumminPower did and got it replaced. Problem still there. They replaced the dash red and yellow valve and its still leaking. Just came back from the shop and they are looking at the whole air system. We'll see what or if they find something...