Braking Issues

Discussion in 'Trucks [ Eighteen Wheelers ]' started by MX127, Dec 24, 2019.

  1. Ridgeline

    Ridgeline Road Train Member

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    Did you replace the cans with the wrong stroke?
     
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  3. BoxCarKidd

    BoxCarKidd Road Train Member

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    What valves are on your truck that control air to the chambers. R12, R14, BPR 1, other? I suspect a problem with the drive axle brake proportioning system. Are you reading your 4-15 PSI from a brake application gauge on the dash. Testing first is usually better than swapping parts.
     
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  4. baha

    baha Road Train Member

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    Merry X/mas or happy hol/days, because you may have the old stile brake drums on the 99 yr. some one may have put the new hub centered stile drums on it or other way around, old stile drums on hub centered axles, you can jack up the rear axle and back off adj. then spin wheels and look for hot spots spread out on drum where shoes are only hitting on a few spots
     
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  5. BoxCarKidd

    BoxCarKidd Road Train Member

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    Sometimes you can look inside the holes in the rims and see the drum. If it is the wrong one hole in the drum maybe to large for the hub and offset to one side.
     
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  6. AModelCat

    AModelCat Road Train Member

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    Instead of the pick-a-part-and-pray method, why not buy a pressure gauge and plumb it in a few different places and find out what exactly the system is doing?
     
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  7. rolls canardly

    rolls canardly Road Train Member

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    What AModelCat said.
    Confirm readings on any suspect locations.
    Go to last place you, or someone, worked on unit
    and see if numbers on newly changed part correspond with #'s on rest of truck.
    There is a wealth of information just in this thread - to be able to get a handle on it.

    Please Let everyone know what you find.
    Merry Christmas!!
     
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  8. MX127

    MX127 Bobtail Member

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    Yes, application reading for psi is coming directly from brake gauge. Truck has R12 mounted on cross member directly under the 5th.
     
  9. MX127

    MX127 Bobtail Member

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    Copy, and thank you all. That will be something to look into, I'll have to see if I can locate pneumatic diagnostic test equipment for purchase.
     
  10. MX127

    MX127 Bobtail Member

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    Full agreement with everything you said, and yes, today's autonomous vehicles/trucks are dangerously scary. I had a rental from Penskee for about a month. The truck has the cruise monitor system (CMS or CMS), I can't recall complete the definition, but that thing would brake check out of no where autonomously. Rain, ice, or snow, it's not bias of road conditions or traffic in front or behind, it hammers down. Whether a driver nearly missing their exit, cuts off the truck or approaching bridges and underpasses, the instrument panel flashes red "out of no where", blinking "eminent collision!" sounding like a smoke alarm just went off! Scared the living life out of me. Also did this several times passing in a wide open lane, not to forget, it paces you with the slowest vehicle on the road, so much for cruising these days, the terminator is finally here, say no to A.I. :(
     
  11. MX127

    MX127 Bobtail Member

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    You know, I was wondering if they were the wrong drums, here is why. When I adjust the brakes, the top shoes are always the most out of adjustment, like not even close. Therefore, as the slacks are rotated the bottom shoes hit the drums first, rather then simultaneously top and bottom. I then follow with an additional fraction of rotation 1/4 or 1/2 drawing the top to the drums.

    I found that unusual but the fact all drums, shoes and hardware on this unit came worn out, I have nothing to compare with.

    You gave rise so something I'll need check into.

    Thanks for the reply to all!

    Merry Christmas :)
     
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