379, exhaust question, are the flexible Y pipe hangers needed?

Discussion in 'Peterbilt Forum' started by Mr. Cob, Apr 30, 2021.

  1. Mr. Cob

    Mr. Cob Light Load Member

    Howdy All,

    That yeller kitty under the Hood, was snarling rather then purring so I figured it was time to replace some parts on the exhaust system. This is what I found.
    [​IMG]

    While taking everything apart I noticed that the 2 flexible hangers that mount to the truck frame and then to the Y pipe were also rusted away where they clamp around the Y pipe. These 2 mounts even when the cab was fully aired up NEVER supported any weight they had quite a bit of flex in them. I might add these flexible mounts cost 250 bucks EACH, as they don't support any weight, are they really needed?

    Thanks for any advise you can give.

    Dave
     
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  3. SmallPackage

    SmallPackage Road Train Member

    2,455
    6,708
    Dec 20, 2019
    Marion Texas
    0
    They take the stress and vibration off of the aluminum cab. Pete started using them mounted to the frame 50 plus years ago on the aluminum cabs because the brackets would pull out. The old steel cabs held the bolts better. It doesn’t seem like a lot of hanging weight but bouncing down the road it constantly tugs on things.
     
    Mr. Cob Thanks this.
  4. Mr. Cob

    Mr. Cob Light Load Member

    Howdy SmallPackage,
    Thanks for your reply, your answer to my question kinda confirms my thoughts, it's more of a vibration dampner then a weight support system. I know it's a Pete, but to say that the price of these flexible mounts took me by surprise is a gross understatement, oh well class comes a price I guess.
    Dave
     
  5. SmallPackage

    SmallPackage Road Train Member

    2,455
    6,708
    Dec 20, 2019
    Marion Texas
    0
    I was gonna mention the Dirks but @062 is on the ball.

    You can also build your own out of steel, stainless steel bolts, and thick cord impregnated mudflap rubber.
     
    AModelCat and Mr. Cob Thank this.
  6. SmallPackage

    SmallPackage Road Train Member

    2,455
    6,708
    Dec 20, 2019
    Marion Texas
    0
    AFFB502F-A518-4BE4-A8D3-6200CE7595A5.jpeg
    My old lady isn’t air ride cab so they don’t need to be flexable. The flex pipe is good enough. These home made ones were built for it years ago. They are 3” wide 1/8” thick. They support everything just fine. The originals were aluminum and cracked beyond repair decades ago.
     
    Mr. Cob Thanks this.
  7. Mr. Cob

    Mr. Cob Light Load Member

    Howdy SmallPackage,

    On my truck there is an 18" long section of stainless steel flex-pipe in-between the Y pipe and the elbow that goes up to the stacks. I thought about just using solid hangers much like what is in your photo to support the Y pipe, but if the Y pipe were solid mounted that would put a sever strain on the flex-pipe between the Y pipe and the stacks because of the air mounted cab, I am sure it wouldn't take long for the stress to break the flex-pipe coupling. So I will just repair everything and put it back stock, the amount of miles "I" am going to be putting on this truck ( about 15-20K per year ) I could probably get by not replacing these mounts and just let everything hang from the stacks but I don't roll that way.

    Dave
     
    SmallPackage Thanks this.
  8. Don379

    Don379 Medium Load Member

    383
    585
    Jan 7, 2021
    0
    no no no no no. yes you need those flex hangers!. They move just enough when air is in the cab air springs and when there is none. And when the cab is bouncing up and down on the highway with the air springs. Drop the air out of the bags and then air up. Watch how much those flex hangers extend up and then down. Something has to give. Your stacks are mounted to the cab. Those flex pipes cant take that! there isnt enough flex pipe. Take it with a grain of salt from a 379 owner. They were designed for a reason
     
    Mr. Cob Thanks this.
  9. Mr. Cob

    Mr. Cob Light Load Member

    Howdy Don379,

    I know what your talking about as I have seen the flex your talking about as the tanks lose air over a couple of days when parked. And on some of the great roads we have in this country that cab is bobbing up and down like a 70's porn star doing ole Johnny Homes ( yeah I am that OLD to remember such things ) Like I was saying for the amount of miles that I put on the truck I could probably get by leaving the flexible mounts out but I hate abusing equipment and would never do such a thing but #### Pete, is sure proud of those chicom made buggers.

    Dave
     
  10. Don379

    Don379 Medium Load Member

    383
    585
    Jan 7, 2021
    0
    ha yeah i remeber homes.
    change them when time and money allows ole buddy
     
    Mr. Cob Thanks this.
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  • Draft saved Draft deleted