Stemco Bearing Setup Procedure

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by sirrepairsalot, May 27, 2023.

  1. sirrepairsalot

    sirrepairsalot Bobtail Member

    Aug 9, 2018
    I am wondering if any of you that ever do this procedure, found that the bearings were kind of loose after doing the procedure.. I wasn't convinced that is all that is needed, so I always snug it somewhat after doing these settings.
    Rideandrepair Thanks this.
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

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

  3. AModelCat

    AModelCat Road Train Member

    Jul 7, 2015
    Did you verify the play with a dial indicator?
    jamespmack, Catmando and Rideandrepair Thank this.
  4. Rideandrepair

    Rideandrepair Road Train Member

    Aug 8, 2015
    Yes, I have. You have to be careful when using a 2 nut system. The problem is when torquing the outer nut, the tiny amount of slack or slop in the inner nuts threads get snugged up. Especially I’m guessing with older parts. I had my steers done a few years back. I didn’t like the way the mechanic did them. I re did them a couple years later. Good thing, they were obviously too tight. Bearings were starting to fail. I replaced everything and snugged them by hand, basically 1/8 turn tighter than spec. Had a wheel seal go bad a couple years later, last summer. Found the new bearings were darkened, obviously too tight. Replaced everything again. This time, followed the spec to a T. Double checked with a dial indicator. Also did new bearings, races, seals on drives. Same thing. Dial indicator showed 2 were loose. Tiny amount makes a big difference on the indicator. What happens is when tightening the outer nut, the inner nut gets tightened also, due to slack or slop in the threads. A dial indicator is a must. The procedure is designed to prevent over tightening. It’s not an exact science. Too loose will cause early seal failure, maybe cause bearings to show wear on the outside. Too tight will burn up quick. The procedure leans on the looser side, usually taken up by torquing the outer nut. If for instance the inner nut threads are sloppy, the end result would tighter than desired spec. once the outer is torqued. The only way to know is by using a dial indicator. Steers are particularly sensitive. It’s hard to get them right without a dial indicator. Helps to know what thread per inch the spindle is, the back off procedure is different for each. New nuts, especially inner one, isn’t a bad idea. Especially if you’re having a hard time getting it right. Dial indicator tells you the final result.
  5. blairandgretchen

    blairandgretchen Road Train Member

    Dec 9, 2011
    South west Missouri
    Not a mechanic.

    Had Stemco installed, went to Chad at KC , he had me have the procedure redone by the shop next door to his specs - before alignment.

    I trust him to know what he’s doing, and haven’t had any problems, long story short -

    There seems to be a difference between Stemco specs and real world situations.
    loudtom and Rideandrepair Thank this.
  6. Big Road Skateboard

    Big Road Skateboard Road Train Member

    May 2, 2021
    So, IMO following most adjustment methods leave bearings too loose.

    I've adjusted bearings the same way since 95, and I've found less tire issues than those adjusting with any "method".

    Most mechanics would say my adjustments were too tight.

    The Dr Preload tool is the only one I know of that actually measures preload
  7. AModelCat

    AModelCat Road Train Member

    Jul 7, 2015
    I've never had an issue with tighten to set the bearings, back off, then tighten the nut until the end play was at the tight end of spec.

    MRMTRANS Light Load Member

    Apr 28, 2015
    I wrote these torqing specs down 10 years ago listening to Mike Becket at MD Alignment. Never had a problem. 25 ft-lb is for the inner nut when the hub is bare; 35 when the steer tire is mounted; 75 when duals are mounted; & 60 when wide single is on. If course torque the outer nut as much as you can (300ft-lb).

    Attached Files:

  9. Cattleman84

    Cattleman84 Road Train Member

    Nov 1, 2017
    The Sticks, Idaho
    Ive always set wheel bearing by feel and never had a problem.

    I set the bearing and seal with only the drum on, and i tighten it as tight as I can with a breaker bar. Then I bolt a wheel and tire on, back off the spindle nut 1 turn, get the tire spinning and snug the spindle nut until I feel heavy resistance when spinning the tire. I then back off 1/2 turn, retighten until I just feel slight resistance while spinning the tire. Snug the outer nut to a heavy snug feel and lock it down with whatever locking device is required (cotter pin, bent over tab... Depending on specific design.) Never had any issues doing it this way.
    Rideandrepair, AModelCat and lester Thank this.
  10. jamespmack

    jamespmack Road Train Member

    Mar 25, 2014

    I don't care about brand. .001-.005 acceptable by TMC guidelines. I shoot for .003 or less. You have to take a educated guess on th 2 nuts system. Recheck after final torque. If it's to tight, redo it. It can get annoying. But part of the job.

    You can run and old bearing alittle tight. And a new bearing alittle loose. But never opposite.

    I have seen the Dr. Preload tool? Never used it. Can't afford it. A tapered roller bearing will handle preload. Problem for decades, we didn't have a way to measure it. So I hear we do.

    Sneek up on .000-.003 you will have great tire wear. Like anything else, needs checked often. I check mine 2 times a year, and any time you jack one up. If you can feel movement with brakes released, it's loose.

    Hope this helps everyone.
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

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

  • Draft saved Draft deleted