attn Racer

Discussion in 'Truck Maintenance and Repair' started by boone315, Sep 17, 2010.

  1. boone315

    boone315 SPACE TRUCKING

  2. boone315

    boone315 SPACE TRUCKING

    And some of the throw out assembly View attachment 2476 Not a very good picture but if you think I can get to it by taking that off, I should be able to replace the clutch brake myself, but I don't want to start taking things off and find out I am getting in over my head, also, should I be concerned with the rust I see in these pics, did not notice it before?
    View attachment 2476
  3. Racer X 69

    Racer X 69 Member

    I'll cover the last concern first. No, you don't need to be concerned about the rust. Rusty buildup is cause by the wearing of the clutch friction material and the flywheel and pressure plate. The bits of metal collect and then moisture in the air cause the rusty appearance. Also, none of the parts are painted or otherwise protected from corrosion, so they all get a nice "protective layer" of rust on them.

    As far as getting better access to replace the clutch brake, it looks like you can take the clutch release assembly off and get a fairly clear access into the housing. It looks like there is just 4 bolts holding the assembly to the housing, don't try to disassemble the clutch release mechanism. This setup is different than the Eaton type I have worked on but I think as long as you don't disconnect the hydraulic line you should be good to go. See if you can take some better pictures of the inside, and how everything goes together inside there (so you have an idea how it all goes together when it is time to put it all back), and then make sure you get it all back together the way it was.

    Good luck.

    One thing I think that a lot of drivers do not know is that when they are using the clutch, they do not need to depress it all the way to the floor, unless they have come to a stop and need to get the tranny back into gear. That is what the clutch brake is for, that and when just starting out after having been stopped.

    When the truck is moving the clutch does not need to be pushed all the way to the floor, going about halfway is all that is needed to disengage the clutch, if a driver uses the clutch at all when shifting up or down. What happens when the clutch is depressed all the way down while the truck is going down the road is that the release arm moves the throwout bearing up against the clutch brake causing unnecessary wear to it.

    I don't think this is taught to new drivers. I was never taught this, and for many years pushed the clutch all the way down when shifting, just like in a car or pickup. Then I started working on big trucks, and had to replace a clutch brake that could mot be done without pulling the tranny. And that was when an older mechanic gave me the heads up about what a clutch brake is, what it does and how you can screw them up.

    There was another guy on here who has a transmission business, I am surprised he has not weighed in on this.

    This guy: View Profile: JM Transmissions - Truckers Forum
  4. boone315

    boone315 SPACE TRUCKING

    Thanks,,you have been very helpful,, I know about depressing the clutch, rarely use it unless at a stop, the brake was already wore out when I bought the thing, I just don't like having to have to grind the gears when putting it in first or reverse,
  5. Racer X 69

    Racer X 69 Member

    Yep, many drivers do know about the proper use of the clutch in a truck and how it differs from a clutch in a car or pickup, but I don't think that little detail is taught to new drivers. I drove big trucks for many years before someone clued me in. Yours is most likely worn out from misuse by an uninformed driver before you got the truck.

    Let me know how this all works out.
  6. boone315

    boone315 SPACE TRUCKING

    Now my clutch fan is staying on, had it happen a couple times before in other trucks, might be the solenoid, if I can find it, there is something under the truck with about four lines coming out of it, I don't know if that is it or not, got the number for the volvo tech dept. they are supposed to be sending me some info.
  7. Racer X 69

    Racer X 69 Member

    The fan clutch staying on could be for a number of different reasons.

    The solenoid could be malfunctioning, the valve that supplies the air could be stuck, the temp sensor that tells the system when to come on and go off could be going legs up.
  8. boone315

    boone315 SPACE TRUCKING

    I did not know about the temp sensor, the sensor on my exhaust(right behind the turbo) is malfunctioning, would that be the one you are talking about or the water temp sensor( gauge appears to be working fine)
  9. Racer X 69

    Racer X 69 Member

    It would be a coolant temp sensor, but they don't use the same one that sends the signal to the gauge. Most electronic engine management systems use dedicated sensors ans sending units for all the data that the ECM needs to decide what the engine needs to run properly, and then gauges are separate from that system.

    The sensor behind the turbo in the exhaust pipe should be for the EGT, or pyrometer.

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