Question about clutch slave rod, master/slave assembly, and swapped transmission

Discussion in '40- & 55-Series Tech' started by Scytale, Apr 16, 2018.

  1. Scytale

    Scytale

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    Hi all:

    I own a '73 (10/72) FJ40. A previous owner swapped the 3-speed (J30?) for the 4-speed (H42?) (working on correct code lingo for the 40-series - bear with me). Only information I got about the 4-speed is that it "came from a newer FJ40", so I am not sure which generation of the 4-speed I have. When it was purchased and before I picked it up, repairs were made to the clutch plate (which I was told was worn to nearly to the point of no-operation).

    Been problem-free since those repairs (in another city) for most of six months. However, I was driving about last weekend when the clutch suddenly stopped disengaging. Clutch will go to the floor and return without providing any resistance. Can shift gears when the vehicle is off, but not when the vehicle is running. The vehicle will start and drive around in whatever gear it happens to be in when the vehicle is started.

    Surveying the components, the clutch master cylinder looks like this:

    [​IMG]

    Hose does not appear to be cracked or leak, and it is not disconnected. Fluid levels are as you see.

    The clutch slave cylinder looks like this:

    [​IMG]

    Currently focused on the clutch slave rod, which does not appear to align with the clutch slave cylinder when the clutch pedal is depressed.

    Questions:

    1) From the photo and description, does it seem like the clutch slave rod is shot? Or is the clutch slave assembly shot?

    2) If it is the clutch slave rod, could I replace without replacing the whole clutch slave cylinder?

    3) If the clutch slave cylinder seems to be done for (or should be replaced anyway, which would likely be done in tandem with the master cylinder), what would be the suggested replacement?

    a) A set based on the vintage of the vehicle, so one for a '73 (10/72) FJ40?

    b) A set based on the swapped-in 4-speed transmission, if the type of transmission makes a difference?

    c) An upgrade kit to upgrade from pre-8/74 to post-8/74 from SOR or CCOT?

    I would appreciate any help - thanks for your time!
     
  2. LAMBCRUSHER

    LAMBCRUSHER

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    check that the fork is still being supported by the ball inside the bell housing... seems like a bunch of air or no fluid in the system, but that slave rod to fork line looks flummoxed to me...
     
  3. Cruiserdrew

    Cruiserdrew On the way there SILVER Star

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    Looks like the wrong slave mount to me. Almost like they tried to cobble it together with the 3 speed mounting ears.

    But it does sound like the slave is likely toast anyway and since they both look old, replace them. They are not that expensive.

    Open the inspection cover and look carefully at the fork and the pivot.
     
  4. RWBeringer4x4

    RWBeringer4x4 Mechanically Challenged SILVER Star

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    You definitely have a 4-speed fork. By the look of the slave misalignment, it's possible that the rod is binding on the slave cylinder's wall and not traveling with the piston, causing the fork to bind. That return spring probably isn't doing much good either - its purpose is to pull the throw out bearing off the pressure plate so it isn't riding constantly on the pressure plate fingers. If the bearing is bound up from riding the fingers, or if the fork can't retract enough to disengage, this could also be your problem.

    You're also missing a lot of fluid. I can also see the "groove" the slave boot is supposed to ride in, sitting way in front of the slave's boot. It could also have pushed out so far that it puked some fluid and sucked in air. I'm not 100% sure on whether this would be a problem (probably not), but I thought when they went to the 4 speed, they moved the fork to the passenger side.

    Long story short - the issue is definitely at least partially (maybe entirely) to do with your slave. You'll need to figure out a way to mount it in-line with your fork that allows the return spring to move freely and not bind on the motor mount.

    It looks like you have plenty of room to remove some meat from the rear bolt "spacer" on that mount, or just build a new bracket to move the whole thing inboard toward the bellhousing - unless, of course, that is also your motor mount, in which case I won't advocate grinding to fit.
     
    Last edited: Apr 17, 2018
    thebigredrocker likes this.
  5. Downey

    Downey

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    Scytale, on the Downey aluminum 4 speed bellhousing adapters we used a slave cylinder mounting bracket that was adjustable so that it could point the slave cylinder directly at the end of the shift fork, push rod not on an angle, push rod 180 degrees with the slave cylinder. You might be able to make something like this with a piece of angle iron???
     
  6. FJ40Jim

    FJ40Jim The Cruiser Whisperer SILVER Star

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    That's the early slave mount, but the cast iron late release fork. Not sure of compatibility there. The correct stamped steel release fork may line up better with the slave.

    Also noteworthy: The upper engine mount puck is upside-down.
     
    VTX78FJ40 likes this.
  7. Scytale

    Scytale

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    Appreciate the information and the suggestions about possible repairs - thanks, everyone!
     
  8. 65swb45

    65swb45 Elder Statesman Supporting Vendor

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    The slave pushrod is obviously broken. The nut that locks the adjuster is not in the same plane as the adjuster. This is a common problem when the early pushrod adjuster gets ‘captured’ inside the hole of the later model fork.

    Get a late model pushrod and adjuster before you do anything else.
     
    LAMBCRUSHER likes this.
  9. Coolerman

    Coolerman SILVER Star

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    I did the 4 speed swap and used the stamped arm as FJ40Jim suggested. Here is a pic showing the proper alignment of the rod/slave cylinder and clutch arm using the same mounting bracket your truck has. Also shows the correct position for the engine mount puck.
    This was during mock-up, so yes, several things are missing!

    IMG_1484W.jpg
     
    FJ40Jim likes this.
  10. Scytale

    Scytale

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    Appreciate the suggestion, 65swb45, about the correct pushrod - thanks!
     
  11. Scytale

    Scytale

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    Thanks for the photo, Coolerman - it clears quite a bit up for me, including a previously unmentioned issue about the reverse lights (the reverse lights and the switch controlling them had been removed from the vehicle prior to purchase).
     
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