clutch brake adjustment?

Discussion in 'Trucks [ Eighteen Wheelers ]' started by IUFAN87, Apr 15, 2011.

  1. IUFAN87

    IUFAN87 Light Load Member

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    Well, he's at Peterbilt in Nashville. Apparently the clutch is the self adjusting type. He said they wiped their finger inside the bell housing and came out with metal shavings. I know there is gonna be some but unsure what would be normal. They told him it is pretty well worn out and they are gonna replace the clutch, pressure plate, throw out bearing, flywheel, and clutch brake. They also told him it needs to have the trans fluid changed because of possible contamination from the clutch. I'm not buyin that. Sounds like B.S. to me. Maybe I'm wrong but I just don't see how the trans fluid could be cotaminated from the clutch "shavings". :biggrin_25512: Sounds to me like they're just tryin to sell more service. Supposedly gonna be $2600 for everything. Which doesnt sound out of line if they actually replace everything.Also told him they gotta charge an extra 2 hours labor cuz they have to move the air tanks to get the tranny out. That may be, idk.
     
    Last edited: Apr 16, 2011
  2. Mr. Haney

    Mr. Haney Road Train Member

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    The Eaton/Spicer Solo clutches are a pain in the arse. They require a special clutch fork also. The clutch can be changed to a standard Spicer Easy Pedal if he changes the clutch fork, but then he'll have to do regular clutch adjustments.

    Over the years I've learned a lot about clutches and how to properly adjust them. I'm willing to bet that 90% of the trucks with more than 500,000 miles on them have the clutch improperly adjusted.

    There is only one way to adjust a clutch

    The only way to adjust a clutch is to measure the spacing between the throw out bearing and the clutch brake. With the clutch brake against the front bearing cover..........you must have an air gap of 1/2" to no more than 9/16" between the brake and the throw out bearing. The clutch manufacturers like it to be at the 1/2" measurement.

    Now there is a second measurement........for toe play in the linkage.......but you do not use the toe play as your measurement. Each truck will be different depending on the truck builder and model of the truck........ do not adjust the linkage for a 2" toe play at the pedal

    Do not adjust the linkage for the clutch brake to work

    What do you adjust and measure then???????????

    You adjust the linkage to move the clutch fork to or from the throw out bearing. When you look up at the clutch fork there are two fingers that push the throw out bearing away from the engine towards the transmission..........you measure the air gap between these two pieces when the clutch is engaged

    The measurement is 1/8" between the clutch fork and throw out bearing.

    Now if the clutch brake doesn't work properly after the adjustment has been done in this manner..........you have a problem.

    The clutch fork and cross shafts can be worn. The flywheel could have been machined to thin at some point. The clutch linkage is worn and has too much play in it. The bushings in the bellhousing are worn.

    You can compensate for the flywheel being machined too much with thicker clutch brakes. The company's name that makes them is Illinois Auto Truck Company. They also make tools to measure the clutch adjustments, so you know that you set it properly without guessing at the measurements. Part numbers M-1748 and M-1749, you can buy both tools in a kit M-1750


    http://www.iatcoinc.com/eng/home.asp


    Once the clutch is set in this manner..........the toe play in the cab is what it is. You should never have to make an adjustment to the clutch linkage ever again. At each adjustment you will only adjust the distance between the throw out bearing and the clutch brake. When you replace a clutch at a later date............you will only have to adjust the distance between the bearing and clutch brake. If you need to use a thicker clutch brake, because of machining the flywheel to thin........then you use a thicker clutch brake, you don't adjust the linkage. If the linkage is worn.........you replace it, you don't adjust for worn linkage.

    If you follow these instructions in adjustment and don't abuse the clutch, you maybe surprised how long it lasts afterwards.
     
    Last edited: Apr 17, 2011
    picaso, IUFAN87, kwforage and 14 others Thank this.
  3. country29

    country29 Medium Load Member

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    yes they have to drop the air tanks on the ih to access the trans, should be 9-10hrs laber for the clutch r&r. metal shavings from the clutch in the fluid, BS. it may need to be changed, but not because of that. and are they turning the flywheel or replacing it? turning a flywheel will be 1hr in labor.
     
  4. black_dog106

    black_dog106 Road Train Member

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    Another post of great info by Mr. H...:biggrin_25514:
     
  5. SHC

    SHC Spoiled Rotten Brat O/O

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    I wish your shop was closer.....####!
     
  6. JohnP3

    JohnP3 Road Train Member

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    Well somebody has to set the clutch linkage some time, or they would not make it adjustable. I worked at a dealership and can imagine the look I would have gotten if I told then I wanted to remove the transmission to try a different clutch brake. Or cut out the new brake to put in a different brand of two piece.
    I set the clutch brake for full on with about 1inch pedal from the floor, then I set the gap to 1/2 inch that gives you about 1 1/2 inches free play on the pedal in a Freightliner. a KW you can give it a little more gap closer to the 9/16.
    Once the linkage is adjusted and you grease the cross shafts, that should not need adjustment for a long time. some units from new need the linkage adjusted with the first internal setting to compensate for initial wear.
    Drivers that want to leave there foot on the clutch pedal can be cured of that habit, by removing the pedal cover drilling a 1/2 inch hole in the pedal and putting a 1/2 inch bolt with about 1/2 inch of thread threw the nut sticking up. It is no problem to push the pedal down, but if you leave your foot there it will give you a learning experience.
    Just a thought!
     
  7. Mr. Haney

    Mr. Haney Road Train Member

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    I don't mean to be a hardnose about this, but if you read the Service Bulletin from Eaton labeled Eaton Clutch Performance Evaluation and Set-up

    http://www.roadranger.com/Roadrange...s/index.htm?&pt=OW_GL_RR&target=1162919212185

    The measurements are clearly written as I've previously stated.

    Yes, it states that if you don't have enough clutch brake contact(squeeze) to adjust the linkage.........but if you adjust the linkage you change the measurement between the clutch fork fingers and the throw out bearing. So you are compensating for either a poorly designed linkage system from the OEM manufacturer or.......... you have worn linkage........ a flywheel that's been machined to thin .......worn clutch cross shafts and bushings........a worn clutch fork.

    The truck manufacturer should have built the truck to meet Eaton's measurements specs and have the pedal within the 1/2" to 1" measurement from the floor while contacting the clutch brake. If you need to adjust the linkage to keep the clutch brake functional and in this area from the floor...........something has worn and needs to be addressed,............but nobody wants to pay for the additional work needed to correct the problems, when it takes fifteen minutes to re-adjust the linkage to hide the problem

    If you adjust the external linkage adjustment to be 1/8" between the fork and throw out bearing, you'll find that the clutch is easier to push in.......the fingers have more leverage at this measurement. You will also notice that the clutch is much easier to modulate how it engages........it will be a smoother engagement instead of trying to grab as you let the pedal up from the floor.

    With the years of driving a truck in an urban environment with a 5500 Lbs plate load and now a 6200 lb plate load..........you want as much leverage as possible to push the clutch in and be able to release it as smooth as possible..........I have taken great notice of the effort it takes to do this with a clutch the least bit out of adjustment. If the toe play at the pedal changes by a 3/8" or more from clutch wear..........I notice the difference in both the engagement smoothness and how much harder the pedal is to depress. I haven't made an external adjustment to my linkage in 8 years, 620K miles and 5 clutches.........I know, how does someone go through that many clutches in such short amount of time? Horsepower is heck on em'

    I have had to replace linkage parts for wear though, but the adjustment rod hasn't been changed in so long that I'm afraid the helm joints are frozen in the rod.

    [​IMG]
    [​IMG]
     
  8. superhauler

    superhauler Super Crusty

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    i was taught by my daddy long time ago if i messed with the linkage my butt would hurt where his foot was imbedded. :biggrin_25524:
     
  9. JohnP3

    JohnP3 Road Train Member

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    The adjustment of the linkage sets the preliminary measurement, the yoke and the clutch brake sandwich the pieces with the bearing cover plate on the transmission. The reasons to adjust the linkage are cross shaft bushings and shaft wear, linkage wear, yoke wear, and clutch brake wear.
    As long as you grease the unit you will not have to adjust it very often but that is the base adjustment, to the clutch adjustment. If the flywheel is thinner, then you would have to adjust the ring to compensate. You can not adjust linkage to compensate for flywheel wear, or machining.
     
  10. Mr. Haney

    Mr. Haney Road Train Member

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    There is no preliminary measurements........it's either on the measurements or not. Next time the RoadRanger rep comes into the shop.......ask him about these questions you have concerning my posts