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Disk brake replacement problem Massey Ferguson 65 1959

Discussion in 'Massey Harris-Ferguson' started by daturley, Sep 4, 2012.

  1. daturley

    daturley New Member

    6
    Mar 3, 2011
    Got a situation with a MF 65. On the upswing with a complete rebuild getting to the axle tubes and the brakes.

    Soon after getting the axle tube with brake assembly inside bolted up to the rear end we noticed that the disks are tight. This has the nasty impact of not allowing the disks to move and accommodate the half shaft insertion.

    When we first loaded the brake actuator we noticed it was fairly tight fitting into the casting. The tightness didn't offer much resistance and just seemed like something you might encounter with new parts.

    The actuators appear to be more or less symmetrical in design aside from the lever attachment points. We checked both orientations and both seemed to fit the same.

    Both actuators and both axle tubes fit the same.

    I noticed after we installed the tube I could see a hint of the ball bearings which tells me the actuators are open by about 1/16" of an inch. I didn't notice this prior to install so I don't know if this the "start" position or if they are opened up.

    What do I do? If I didn't know any better I would say I needed to mill metal off the new actuators but that makes no sense on new parts.

    Anybody have insight about this problem?
     
  2. daturley

    daturley New Member

    6
    Mar 3, 2011
    Ok, gents. Figured out the problem. The new actuators do indeed need "adjustment" before installing. Hopefully, this info will save others from the same "uh oh" moment. Although the actuators will fit into the casting they MUST not fit in any form snug. Especially with new brake discs! Basically, if they touch casting and require even the slightest of pushing to install.. stop... shave off some material and check the fit again. End grinder is a fine tool for the adjustment.

    See the pictures and the captions below.

    Looking closely at the top down picture you can see the original actuator has slightly wider opening/skinner casting boss where the bolt is.

    Although difficult to see in the side view, there is a marker on the red painted new actuator is the amount of material that needs to be removed. Roughly 1/8" of material is enough to cause the actuator to "engage" as if the brake is applied.

    Lastly, here is the "adjusted" actuator back into the axle tube housing. Before removing the extra material the actuator fit snug and actually pinched the pull clevis just enough to lock the brake. After the adjustment the actuator was able to float ever so slightly allowing it to fully retract.
     

    Attached Files:


  3. shona13

    shona13 Member

    190
    Aug 12, 2011
    G,Day daturley .
    Tell me you are not trying to assemble the brake assembly without the final drive and planetary unit installed first!!!!
    To fit the brake expander unit put the adjusting rod through the hole then pull a little bit on the rod this will reduce the distance between the STOPS,if you grind the end stops on the expander and make the assembly loose when assembled and the brakes applied you will get a clunk and possibly a shudder when the expander makes contact with the brake discs , Do not remove anything from the expanders.
    To assemble ,the planetary and drive shaft MUST BE INSTALLED into the trumpet housing first,then the brakes over the drive shaft.
    regards .
    Hutch.
     
  4. daturley

    daturley New Member

    6
    Mar 3, 2011
    Hutch,
    I know what you are saying. However, there was -->**CLEARLY**<-- an interference problem between the expander casting and the trumpet housing casting. The trumpet housing casting faces are slightly thicker toward the interior of the bell. This has the effect of pinching the expander ***CAUSING*** it open up when inserted into the proper location.

    Upon close inspection of the ORIGINAL parts one can easily see that the new part machined faces are about 1/8" thicker. The original engineers knew what they were doing. Replacement part manufacturers tend to fall into the "just enough" category. Modifying the replacement part to match the factory original is the correct course of action.

    Pulling the brake expander as you suggest is exactly the opposite of the solution required to make this work. Making the actuator expand in ANY way caused the overall brake width to be too wide. Doing so and installing that way will result in locked up brakes first and then attempting to drive like that will result in burned brakes.

    Regards,
    Dwayne
     
  5. shona13

    shona13 Member

    190
    Aug 12, 2011
    G,Day daturley .
    I now understand what you mean ,You are reducing the "Thickness "of the expander !!
    To deglaze the axle housing where the brake discs contact I use a 5 inch angle grinder with one of those Flapper discs it is made up with layers/strips of emery cloth the best things I ever bought ,with a bit of practice you can do anything with them ,grinding ,they will remove three times as much as an ordinary grinding disc down to even Polishing ,as i said with a bit of practice,try one.

    Did you change the shaft seals and housing gasket?
    Regards .
    Hutch.
     
  6. fasteddie

    fasteddie New Member

    1
    Mar 6, 2013
    ed folk , can you change the brake pull /adjuster rod with out taking the rear apart? I only have a broken rod , the brakes did work before the rod broke e mail fatseddie17960@hotmail.com