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Thread: What Caused this Clutch Disaster?

  1. #1
    Join Date
    Mar 2009
    Location
    Near Geelong, Vic.
    Posts
    455

    What Caused this Clutch Disaster?

    Today I began dismantling my gearbox. (Ser 2A 186 Holden)

    The "top hat" section thingy that pushes against the pressure plate via sliding thru a ball bearing has been demolished: 1st photo. There is a fine layer of swarf over the inside of the bell housing.

    This thing is presumably supposed to slide thru a ball bearing when pushed via the slave cylinder but it is siezed onto the inner race of the bearing & the bearing now moves in/out of its housing rather that the thingy sliding thru it!!

    When I unbolted the clutch actuating mechanism from the bell housing, the next 2 photos show what I found: the bolt & 2 thrust washers had fallen off the layshaft (? - sorry if that's wrong but this is my 1st time inside a GB!)

    The last photo show the pressure plate and there is a small spring visible that obviously belons elsewhere.

    I have a spare GB with a servicable clutch operating mechanism but I need to work out what happened.

    Now, there seems to be a lot of slop when I wriggle the end on the mainshaft. Is this normal? My only experience here is with air-cooled VW's. The early 36bhp ones were as tight as but the later ones had heaps of slop as they relied more on the spigot bearing in the flywheel\ than the early variants.

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    1961 Series 2A Holden 186
    1955 MGA
    1949 Citroen Big 6
    1950 Grey Fergie Tractor
    1987 BMW R100RS
    1962 Renault Dauphine Gordini (resto)
    1970 Peugeot 404 Utility (resto)
    "I love cooking with wine. Sometimes I put it in the food!"W.C. Fields

  2. #2
    Join Date
    Mar 2009
    Location
    Near Geelong, Vic.
    Posts
    455

    new photos

    1961 Series 2A Holden 186
    1955 MGA
    1949 Citroen Big 6
    1950 Grey Fergie Tractor
    1987 BMW R100RS
    1962 Renault Dauphine Gordini (resto)
    1970 Peugeot 404 Utility (resto)
    "I love cooking with wine. Sometimes I put it in the food!"W.C. Fields

  3. #3
    Join Date
    Aug 2006
    Location
    Melbourn(ish)
    Posts
    24,472
    chicken or the egg,,,

    did the spring come loose from the clutch and take out the throwout bearing
    OR
    did the throw out bearing let go and the resultant mess take out the clutch spring.

    my best guess without having it in my hands says that the pressure plate lost a spring and the uneven loading on the throwout bearing totaled it. For a II box this can be bad karma as the bearing dying can wind up throwing swarf backwards into the cover plate and into the box.
    Dave

    "In a Landrover the other vehicle is your crumple zone."

    For spelling call Rogets, for mechanicing call me.

    Fozzy, 2.25D SIII Ex DCA Ute
    TDI D1(its responded well to its lecture about poor performance)

    If you've benefited from one or more of my posts please remember, your taxes paid for my skill sets, I'm just trying to make sure you get your monies worth.
    If you think you're in front on the deal, pay it forwards.

  4. #4
    Join Date
    Mar 2009
    Location
    Near Geelong, Vic.
    Posts
    455
    Agreed Dave.

    But the pressure plate disintegrating is unlikely to SIEZE the throwout bearing? I mean the sleeve is as one with the bearing. The bearing moves in & out of the casing/housing instead of the the thrust doover sliding thru it!

    Can this be a result of poor alignment ie a low quality conversion?
    1961 Series 2A Holden 186
    1955 MGA
    1949 Citroen Big 6
    1950 Grey Fergie Tractor
    1987 BMW R100RS
    1962 Renault Dauphine Gordini (resto)
    1970 Peugeot 404 Utility (resto)
    "I love cooking with wine. Sometimes I put it in the food!"W.C. Fields

  5. #5
    Join Date
    Jul 2006
    Location
    East-South-East Girt-By-Sea
    Posts
    17,600
    What brand of adapter kit is it?

    I ask this because, some brands of kit have a reputation of being out of alignment in multiple planes and if so the pinion can bind on the throwout which will cause the type of damage you describe.

    Before doing anything with a replacement box, check the alignment with a dial indicator. See: BEFORE FITTING A HOLDEN ENGINE CHECK ALIGMENT FIRST

    You won't find me on: faceplant; Scipe; Infragam; LumpedIn; ShapCnat or Twitting. I'm just not that interesting.

  6. #6
    Join Date
    Aug 2006
    Location
    Melbourn(ish)
    Posts
    24,472
    Quote Originally Posted by geodon View Post
    Agreed Dave.

    But the pressure plate disintegrating is unlikely to SIEZE the throwout bearing? I mean the sleeve is as one with the bearing. The bearing moves in & out of the casing/housing instead of the the thrust doover sliding thru it!

    Can this be a result of poor alignment ie a low quality conversion?
    if the pressure plate is not putting even pressure on the throwout bearing it will cause uneven loading on the throwout. It may run that way for years because the throwout bearing isnt constantly in contact (and this only normally applies to radial bearings) and under load but eventually the uneven loading causes the casings to fatigue and let go.

    to check for misalignement simply check the condition of the spigot and the input shaft support wear there will indicate which way the alignment is out, if the spigot and support are ok then its most likely the throwout or clutch thats caused the problem.
    Dave

    "In a Landrover the other vehicle is your crumple zone."

    For spelling call Rogets, for mechanicing call me.

    Fozzy, 2.25D SIII Ex DCA Ute
    TDI D1(its responded well to its lecture about poor performance)

    If you've benefited from one or more of my posts please remember, your taxes paid for my skill sets, I'm just trying to make sure you get your monies worth.
    If you think you're in front on the deal, pay it forwards.

  7. #7
    Join Date
    Mar 2009
    Location
    Near Geelong, Vic.
    Posts
    455

    Oh Dear!!

    Amazing what you find when things get cleaned!

    Here is the adaptor plate. 1st photo. Un-branded. Is that normal? The only other converted vehicle I've had was a 1963 J3 Bedford with a thumping 265 Hemi. Great conversion. By Haddon, from memory. The name was embossed on all the non-std bits.

    The next 2 show the back of the Holden block. It's on a stand & the shim is still in place but it seems to have only 2 locating dowels: one under the starter mtr mount & one opposite. There seems to be a non-threaded hole at the top between the two engine stand top mounts. Is this meant to be another dowel? There is no corresponding hole for it in the plate. I find it hard to believe that 2 dowels are enough to locate the GB?

    The next two photos show that the plate has split along the welding line.

    That's a quarter inch whit bolt for reference & I can see daylight thru the crack. It's about 15 thou.

    But to reiterate Dave's point:

    Did the split cause misalignment or vice versa?

    I guess the 1st step is to squeeze the plate back together & weld it. Then it will need to be refaced on both sides to make sure it's true. Can I assume the back of the block is OK? Otherwise I have to strip it & get it faced as well. The only problem I have with that is I may be throwing good money at something bad. I may source a new plate? Castlemaine Rod Shop used to SELL adaptor plates eg Toyota Celica 5-speed gearboxes to MGB's. They may have patterns etc to do one from scratch.

    Then the all important dial-indicator alignment.

    BTW most of the slop in the mainshaft is at the bearing.

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    Last edited by geodon; 29th December 2011 at 07:22 AM. Reason: more info
    1961 Series 2A Holden 186
    1955 MGA
    1949 Citroen Big 6
    1950 Grey Fergie Tractor
    1987 BMW R100RS
    1962 Renault Dauphine Gordini (resto)
    1970 Peugeot 404 Utility (resto)
    "I love cooking with wine. Sometimes I put it in the food!"W.C. Fields

  8. #8
    Join Date
    Mar 2009
    Location
    Near Geelong, Vic.
    Posts
    455

    Cowabunga!

    Land Rover

    GEEEEZE!

    The kit ain't cheap, is it?

    I'll price a new adaptor & we'll see where it goes!
    1961 Series 2A Holden 186
    1955 MGA
    1949 Citroen Big 6
    1950 Grey Fergie Tractor
    1987 BMW R100RS
    1962 Renault Dauphine Gordini (resto)
    1970 Peugeot 404 Utility (resto)
    "I love cooking with wine. Sometimes I put it in the food!"W.C. Fields

  9. #9
    Join Date
    Aug 2006
    Location
    Melbourn(ish)
    Posts
    24,472
    so long as you're not in a hurry, I have a holden 6 adaptor plate sitting in a pile somewhere and I have another that comes with a completish holden 6.
    Dave

    "In a Landrover the other vehicle is your crumple zone."

    For spelling call Rogets, for mechanicing call me.

    Fozzy, 2.25D SIII Ex DCA Ute
    TDI D1(its responded well to its lecture about poor performance)

    If you've benefited from one or more of my posts please remember, your taxes paid for my skill sets, I'm just trying to make sure you get your monies worth.
    If you think you're in front on the deal, pay it forwards.

  10. #10
    Join Date
    Mar 2009
    Location
    Near Geelong, Vic.
    Posts
    455

    Wait a minute!!

    What I thought was a siezed clutch mechanism bearing is nothing of the sort!

    It's the status quo!

    The two prongs forming the clutch throwout fork push on the outside race of the bearing. The whole bearing's MEAN'T to slide in & out. Wierd! If that's the way it works, one would expect to see a brass bush or something rather than a whole bearing race sliding in/out of an aluminium casting! Does this have a history of wearing? From my VW days I remember that early engines had camshafts that ran directly in the alloy crankcase and after a prodigious mileage a line bore & shell bearings were necessary.

    Still, it swims in oil so I suppose it's OK.

    SO! IMHO this could be what happened:

    1.The adaptor plate split down one side.
    2. The gearbox pulled away from the engine on that side.
    3. The other side of the clutch thrust plate then took the the brunt of the thrust causing its demise & stuffing the 1st bearing ( at least) in the gearbox.
    Attached Images Attached Images
    1961 Series 2A Holden 186
    1955 MGA
    1949 Citroen Big 6
    1950 Grey Fergie Tractor
    1987 BMW R100RS
    1962 Renault Dauphine Gordini (resto)
    1970 Peugeot 404 Utility (resto)
    "I love cooking with wine. Sometimes I put it in the food!"W.C. Fields

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