Moly grease slack adjusters

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by redgod7, Mar 30, 2020.

  1. redgod7

    redgod7 Light Load Member

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    May 18, 2013
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    Hey guys. I hope everyone is staying safe out there.
    I'm shut down getting some work done on the truck while things cool down.
    I was putting brake chambers on and after scraping all the grease and grime I noticed a problem with the slacks. They're M1D which I think are like the AA1s. The so called mechanic who worked on it last didn't set them properly with the control arm pointing in the groove and also overtightened the little bracket nut and bent the #### out of the control arm. They seemed to be adjusting properly but now I don't trust them so I bought new slacks as well.
    I am wondering how many use moly grease on the slacks? I have been using 3% moly grease on everything including slacks and u joints with no issues. Haldex however does not recommend moly. They say it might not allow it to self adjust.
    What are your thoughts?
     
  2. Shawn2130

    Shawn2130 Medium Load Member

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    I have used moly grease personally as well but for slacks, I think they’re too thick when it gets cold out.

    In the winter, I’ve had to place the grease gun on a warm surface to warm it up to be able to pump it.

    Even when I’m able to pump it, it’s harder than normal grease.
     
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  3. Snailexpress

    Snailexpress Road Train Member

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    Not sure it's for all slack adjusters but Gunite manual says NO MOLY grease
     
  4. Cali kid

    Cali kid Road Train Member

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    Don't pop moly driver that stuff is the devil!
     
  5. redgod7

    redgod7 Light Load Member

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    Yea haldex says the same thing. Something about the clutches inside and not enough friction to kick the self adjuster.
     
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  6. redgod7

    redgod7 Light Load Member

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    Detroit, MI
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    Lmao
     
  7. BoxCarKidd

    BoxCarKidd Road Train Member

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    In about 1985 A company sent me to a week long Rockwell class. I asked the man directly. So you are telling me that we should keep a hand grease gun with a lighter grease just for the automatic slack adjusters? YES!
    Do not consider heaver grease a problem in the south.
    I know that is a different brand from a different time but do they all not work about the same? Not so sure about white grease in some cases. I like JD corn head grease better for stuff like that. Not selling a brand but it is a good product for the application. You can look it up online and buy it in many brands.
     
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  8. redgod7

    redgod7 Light Load Member

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    May 18, 2013
    Detroit, MI
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    I found another thread discussing grease. I guess a polyurea grease is preferred for slack adjusters. I've been using a 3% moly grease on everything. Maybe I'll just stick with it. I'm trying to avoid having multiple greases/guns.
     
  9. HoneyBadger67

    HoneyBadger67 Road Train Member

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    Do not use polyurea grease in your slack adjusters. Polyurea is only for high shear environments, (think automotive wheel bearings), low shear turns the grease to water.

    Do not use molybdenum in your slack adjusters. Moly is for shock load applications.

    I know these things because I used to work in a chemical factory (10 long years) that specialized in lubricating products.

    Use a 1 or 0 grade grease kinda like @BoxCarKidd mentioned. 2 gets too stiff in colder climates and 00 is too runny. It's definitely a PitA to carry multiple grades and guns but probably more so to put the wrong stuff into the wrong zerk.
     
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  10. Ribeye

    Ribeye Light Load Member

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    Jan 4, 2012
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    Grease is relatively cheap, why scrimp. Use red, blue or the green stuff for everything. Moly is not waterproof either, more prone to washout, dropout temp is lower too. I only use moly on fifth wheel plate if no other option.
     
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