Trailer backfeeding at Tractor protection valve when applying service brakes.

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Rideandrepair, Dec 22, 2023.

  1. 201

    201 Road Train Member

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    Perhaps Santa has a nice company job for you? Write it up, see you Tuesday. I certainly don't mean to admonish you, you seem to be the most prolific when it comes to truck problems,,nothing unusual, mind you, just got to be getting old. Cold weather, maybe, something froze? Good luck, pal, have a safe holidays.
     
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  3. Judge

    Judge Road Train Member

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    pretty easy fix.
     
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  4. Rideandrepair

    Rideandrepair Road Train Member

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    This is a Company Truck. Mines parked. Been volunteering for weekend work. The Owners been finding extra work for me. 4 weeks on the job so far. Looking for ways to get more hours. Cut the repair shop out of things a bit. Save the Owner some money at the same time. Win Win. Worked. Last Sunday. I’m working 4 hrs this Sunday on Christmas Eve. Appointment at Sam's Club. Might as well, it all adds up. All in all I’m still working less than when I ran my Truck. In the process of getting rid of all the things that went along with it. IFTA filing one more time. That’s the plan for now anyways. Unless someone offers me $1000 per day short run home every night. Then I’ll be back at it. 3 Trucks 3.5m+ miles over 27 years. I’ve finally had enough. If I find something else I like besides Trucking, I’ll give it a try. Right now, just trying to use what I’ve learned mainly by default over the years. Truckings not like most jobs that you can simply become the Supervisor when you’re old and wore out. So I’m trying to improvise. Lol. Need about $300 more per week. No Uber or Door Dash!! Ughhh!!
     
    Last edited: Dec 23, 2023
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  5. Big Road Skateboard

    Big Road Skateboard Road Train Member

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    Hope this keeps workin out for ya, sounds like a decent gig
     
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  6. Rideandrepair

    Rideandrepair Road Train Member

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    Update. Never did change the QR valve. Had 10 days off work. Been working this week. Today after I dropped my Trailer, it started leaking again. Been meaning to pick one up and at least have it onboard. Luckily it held out all week. Picked up a brand new Bendix today for $27, get some extra OT for swapping it out. Trying to catch problems before they get worse. Meanwhile a so called Trailer Tech couldn’t find an obviously leaking brake chamber on another Trailer. I called and explained which one and that it’s the service side thats leaking. Said he had no way to test it. Usually just puts air to the parking brake only. Didn’t know how to check the service side. Dummy also tried to tell us DOT will put you OOS for a hole in the roof, Lol. He patched the roof, did an annual DOT Inspection, brand new sticker. Chambers still leaking, didn’t see a rusted light cover. It literally came off in my hand. Accident waiting to happen. This is a Major Trailer Dealers Mechanic. Unbelievable. That’s the 2nd Trailer I shut down for service side brake chamber leak. I’m going to cut these repair services out as much as possible. Do every little repair I find for extra hours on the clock. Owner saves money, I make extra money. We all stay out of trouble.
     
    Last edited: Jan 5, 2024
  7. Big Road Skateboard

    Big Road Skateboard Road Train Member

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    Sounds like a good deal for ya. Also sounds like the dealers guy is like most "mechanics" i come across.
     
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  8. Rideandrepair

    Rideandrepair Road Train Member

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    Update!! Changed the QR valve. Still leaking. Only when bobtail, and applying the foot brake. Definitely leaking from the TPV. It’s weird, I could have sworn it was leaking from the QR valve with the trailer hooked, while applying the trolly brake, holding it with a bungee cord. Oh well, so far my mechanical Creds aren’t looking very good. Lol. New QR valves a good idea anyway if changing the TPV. This Truck has QR valves on both park and service sides of TPV. I looked at my old Truck. Only QR valve on service side. None on park side. I wonder why?
     
  9. terryt

    terryt Heavy Load Member

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    It a bad brake chamber been doing this for years it back feeding you wont hear the leak.
     
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  10. Hammer166

    Hammer166 Crusty Information Officer

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    Not in his case... It's only with the service brake applied. The case you're talking about is when it back feeds through the service from the park. And it's really fun to find the first time you run across it!
     
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  11. Rideandrepair

    Rideandrepair Road Train Member

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    It’s definitely the Tractor Protection Valve. I still don’t understand why it was leaking from the QR valve. I’m pretty sure it was leaking with the Trailer lines hooked up. Maybe the bad QR valve caused the TPV to go bad? I don’t know. Now it’s fine unless Bobtailing. Hit the brakes Bobtail and air comes out of the blue glad hand. First time I’ve ever had a bad TPV.
     
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