Hayter Harrier drive problem.

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  • April 30, 2015 at 6:32 am #12790
    joegrgraham
    Participant

    Morning all,

    A question for the mower mechanics. I have a Hayter Harrier 56 that struggles to pull itself along. The slightest resistance and the roller starts spinning, I can hold it back with one finger!. Any ideas where to look? Nothing is dragging on the ground, the belt is new and everything is greased as it should be. One thing I have noticed is that only one half of the roller is powered, is this correct?.
    Thanks, Joe.

    April 30, 2015 at 6:54 am #12791
    charlie
    Keymaster

    Sounds like ratchet mechanism in roller may be at fault.

    April 30, 2015 at 7:22 am #12794
    joegrgraham
    Participant

    The drive mechanism itself appears to be working, it is impossible to stop the roller turning whilst drive is engaged. The problem is with excessive ‘wheelspin’. I thought it may have been due to the level of wear in the rollers, so I have just replaced them, but found no improvement.
    Whilst inside the roller assembly, on the main shaft are two sprockets, the owners book calls them ‘roller freewheel’, it appears that it is these that transmit the drive from the shaft to the roller. I noticed that one is fixed to the shaft and one is not, hence the drive to only one half of the roller assembly. Is this correct?

    Joe.

    April 30, 2015 at 9:24 pm #12808
    stuart
    Participant

    Those freewheels act like a differential to make turning easier.If you lift the rear of the mower up using the handles (so the rollers are off the ground) put your foot against one roller half then engage the drive lever……..you should find that the other roller half turns and visa versa.
    Only use genuine Hayter belts and check the cable adjustment.Also check the PTO pulley on the LH side as they do wear.

    April 30, 2015 at 10:20 pm #12810
    wristpin
    Participant

    The free wheel units screw to a hub which is solid with the roller shaft. They can each spin freely in one direction only and should lock in the opposite direction ie with the engine off and the drive engaged you should be able to push the machine forward but not pull it back. If both rollers can be locked with the above test I would suggest that your problem is roller slip on the ground and not a mechanical issue.
    From memory the free wheel units have a small arrow etched into them to denote the direction of drive. Again, from memory I think that it is possible to assemble the ratchet units to the shaft the wrong way round resulting in no drive being transmitted to that roller.
    The attached scan shows the general layout.

    Attachments:
    1. Hayter-Harrier-48-pts-diag0001.pdf
    May 1, 2015 at 7:36 am #12814
    joegrgraham
    Participant

    Thank you Gents,

    Wristpin, pushing/pulling the mower with engine stopped and drive engaged resulted in only one roller half constantly locked, regardless of direction of travel.

    And Stuart, one roller was impossible to stop, the other one never gets any drive.

    So I think ’tis cream-crackered!. It appears that one freewheel has seized up and the other has broken loose. Does this sound about right to you?.

    Joe.

    May 1, 2015 at 4:38 pm #12820
    wristpin
    Participant

    Quite possibly but depending upon how much you value the machine not a disaster and not a difficult job to do. Worst scenario is that the roller shaft drive sprocket is well and truly seized on the shaft and it has to come off to get the roller out of its carrier. Put a puller on it and it turns inside out, warm it up too much with the gas axe and you melt the plastic bearing carrier behind it. Carrier is cheaper than the sprocket but in a commercial situation if the sprocket didn’t yield so some gentle persuasion we would probably cut it off !
    Try a bit of heat on the sprocket, careful use of the puller and some plus gas releasing fluid and with a bit of luck it will draw off.

    May 1, 2015 at 7:27 pm #12821
    joegrgraham
    Participant

    The whole assembly came apart almost disappointingly easily!
    The whole freewheel assembly is a big rusty mess, so i’ve left it to soak for the weekend, then next week I’ll try and pull it apart and see whats what.
    Thanks for the help Gents.

    May 5, 2015 at 7:48 pm #12936
    joegrgraham
    Participant

    Any tips on removing the free wheel units from the shaft (lock nut is off), or is it a case of heat and beat?

    May 5, 2015 at 8:52 pm #12937
    stuart
    Participant

    The only way to get them of when they are seized / rusted on the threaded shaft is to use a pin punch and a hammer.Naturally this destroys them but as you are fitting new ones is does not matter.

    May 5, 2015 at 9:32 pm #12939
    wristpin
    Participant

    Sometimes easier to weld them solid and then grip with 30″ Stillsons!

    May 16, 2015 at 6:34 pm #13090
    joegrgraham
    Participant

    Just a quick update,

    Replaced the freewheel units, shaft and the bushings and its like I’ve got a new mower.

    Thanks everyone for your input and advice.

    Joe.

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