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Slow clutch pedal return

Discussion in 'Bay Tech Clinic' started by Stormin12345, Aug 13, 2021.

  1. Stormin12345

    Stormin12345 Member

    Messages:
    75
    Location:
    Sydney
    ADBFD16A-0A2D-48EB-B457-729F53DBA5CE.jpeg 846327A2-C7C8-4506-973A-716459270E59.jpeg E41CD5A6-11DE-4B79-9EF3-C438B98ABA66.jpeg 2499D51A-89D1-4EDA-AEA1-4E702888683D.jpeg 99B8B119-BE2B-4622-BABE-B546C1889D24.jpeg FADFD639-305E-4E2C-8F4C-795907C314A2.jpeg 0C365931-CBCD-4C9B-BF43-7A0D18AE1001.jpeg 6BC4453A-ADE3-4A78-84ED-ACED647B9AC4.jpeg 691480D4-D89C-449B-999B-4482C5699883.jpeg CB49AA9C-71F2-4248-BA2B-F9DDF704021C.jpeg 0C365931-CBCD-4C9B-BF43-7A0D18AE1001.jpeg So I went out and tried to drive the bus a little further yesterday only to find that when accelerating up the hill that is my driveway it felt like the clutch was slipping. So its clearly not right, so I bit the bullet and pulled the motor out, especially mindful of T1 Terrys thoughts that it might be not well aligned. The good news is that the pressure plate seems straight (and no gaps when the clutch plate sits on it)...in fact everything looks to my uneducated eye like it should aside from the amount the clutch arm/release bearing is wound on. So the bad news is I have no idea what is wrong now! I have attached some pictures would love any ideas that people have!
     
  2. rstucke

    rstucke Well-Known Member

    Messages:
    1,946
    Location:
    Wamberal NSW AUS
    do you still have the original pressure plate

    Put both on a flat surface, See if the covers are at the same height

    Put both on concrete stand on the fingers with the heel of your foot, do they feel like they have the same tension.
     
    Wiz likes this.
  3. rstucke

    rstucke Well-Known Member

    Messages:
    1,946
    Location:
    Wamberal NSW AUS
    measure the distance of the friction surface of the flywheel to the step where the cover (of the pressure plate ) bolts to as accurately as you can.
    I have a spare flywheel that I can measure in the morning.
     
    Wiz likes this.
  4. Stormin12345

    Stormin12345 Member

    Messages:
    75
    Location:
    Sydney
    Thanks @rstucke, I kept the old one, the pressure plate and clutch are the same size (even same brand - LUK) and when I put my heel on them as you suggest feel similar. I wonder if you are onto something with the flywheel - I measured mine with my verniers and reckon it’s 22.56mm would love to know what yours is - many thanks in advance!
     
  5. rstucke

    rstucke Well-Known Member

    Messages:
    1,946
    Location:
    Wamberal NSW AUS
    get back to you tomorrow mid morning (it's in my workshop)
     
  6. rstucke

    rstucke Well-Known Member

    Messages:
    1,946
    Location:
    Wamberal NSW AUS
    looks like the flywheel is your problem
    I measured mine and found a couple of problems with yours but this is only gospel for a 228mm clutch plate and 2ltr flywheel (I notice you have the 002 box).
    I measured the depth on the 2 flywheels I have at 25mm
    also the area that the pressure plate bolts is raised above the ring gear (see pic) yours is below
    This causes 2 problems, too much diaphragm spring deflection (tends to turn inside out and looses most of the clamping force, and the throwout bearing moves further towards the fingers to get the correct freeplay causing the adjustment to run out (like you show in the pictures).

    Now if it is an earlier flywheeI with a smaller clutch plate and the flywheel is the same as yours (don't know, I don't have one to check) then you have the wrong clutch kit

    A check you can perform either way
    put the clutch plate on the flywheel place the pressure plate on top without bolts give it a tap to settle it onto the locating pins
    the gap between the cover (where the bolt goes through) and the surface it bolts to should be 4 to 5 mm. This is how the diaphragm creates the clamping pressure on the clutch plate. Too little and the clutch slips, too much and the diaphragm starts to turn inside-out and the clutch slips

    Because yours is recessed it's going to be hard to measure.
    put the pressure plate bolts in finger tight take a measurement at the top of one of the bolts, tighten all the bolts, take another measurement
    The difference should be 4 to 5mm.

    1.jpg 2.jpg
     
    David H, oldman, Wayne murray and 2 others like this.
  7. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,771
    Location:
    Mannum South Australia
    I doubt if it's the pressure plate fingers going over centre, you can hear the fingers hitting the damper springs in the clutch plate when that happens.
    Check the thickness of the cast steel section of the pressure plate, the one in the photo looks rather thin, but it might just be the angle the photo was taken, but it will be obvious compared to the pressure plate you removed.
    Ff it is a reconditioned kit and that part has been excessively machined, the whole distance between the compressed and uncompressed pressure plate will be wrong resulting in not enough pressure being applied to the clutch plate to clamp it to the flywheel. Unlike truck pressure plates, the height can not be adjusted to compensate so the clamping pressure is maintained.

    T1 Terry
     
  8. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,771
    Location:
    Mannum South Australia
    Looking at the first photo with the pressure plate bolted down, those fingers don't look even close to flat, they don't look much different to the height when the pressure plate is removed a few photos further down.
    If it isn't the thickness of the cast section of the pressure plate, then the problen is the face where the pressure plate bolts on is not machined deep enough

    T1 Terry
     
    oldman likes this.
  9. Wayne murray

    Wayne murray Well-Known Member

    Messages:
    4,740
    Location:
    Seven hills
    My human encyclopedia can't remember which books states what tolerance should be, between the mounting face of the clutch to the surface of the pressure plate contacts with.
    He can remember that it is 816 to 840 thou or 20.4 to 21 mm. Measured the 1600 fly wheel sitting in the garage it is 20.9 mm. It has a step down like yours.
    Not sure what it would be for a 2l fly wheel.
    You gearbox number looks like CE which is a 1600 1700 gearbox
    Don't know if this info is any good or use for you.
     
    oldman likes this.
  10. oldman

    oldman Super Moderator Staff Member

    Messages:
    10,983
    Location:
    Avalon Beach NSW
    This is the type of experience that leaves the VW fraternity when older fellas retire….
    Nice that you have it on tap, Wayne :cool:
    Cheers,
    Mark
     
    Wayne murray likes this.
  11. Wayne murray

    Wayne murray Well-Known Member

    Messages:
    4,740
    Location:
    Seven hills
    I've got a good memory but for figures like that ,haven't mastered retaining them.:oops:
     
    oldman likes this.
  12. Stormin12345

    Stormin12345 Member

    Messages:
    75
    Location:
    Sydney
    Fantastic, thank you all it sounds like we are onto something. I will get out there in the morning to try your test @rstucke. My gearbox is a CE, my motor is an AP 1800 motor. Original motor, retrofitted gearbox in the distant past by a PO. But from what you are saying @Wayne murray it looks like I have a 1600 flywheel to match the gearbox (which would make sense)? It has a 215mm clutch. Its a brand new clutch kit, sold to me by own of our well known kombi parts suppliers so hopefully the right one but perhaps not. @T1 Terry your point about the fingers being ‘flat’ I will also look at tomorrow, I don’t have much point of reference however. All said if this is a 1600 flywheel, and it should be between 20.4 to 21 mm cit sounds like 22.5mm is too much, and sounds like the flywheel surface was machined without the surface the plate mounts to being the same amount. I will go and do some measurements in the morning.
     
    tintop, Wayne murray and rstucke like this.
  13. Wiz

    Wiz Well-Known Member

    Messages:
    563
    Location:
    Near Ballarat
    What diameter was the original clutch you took out?
    210mm or 215mm?
    <edit>
    The 74 microbus had a 210mm clutch from PO, I am replacing with a 215mm when engine goes back in.
    Watching with interest hoping I don't end up with similar problem to you.
    PR
     
    Last edited: Sep 13, 2021
  14. Wayne murray

    Wayne murray Well-Known Member

    Messages:
    4,740
    Location:
    Seven hills
    Clutch for a 1600 motor and gearbox should be 200mm, You wouldn't have a 1600 flywheel they are mounted with a single gland nut in the middle not mutable bolts like what you have.
    You can have a 215mm clutch with what you have.
    Does the pressure plate you have sit inside the step section all the way around, where it bolts to your fly wheel?
     
    tintop likes this.
  15. Stormin12345

    Stormin12345 Member

    Messages:
    75
    Location:
    Sydney
    I took out a 215mm, this one seems the same
     
  16. Stormin12345

    Stormin12345 Member

    Messages:
    75
    Location:
    Sydney
    0118DE70-DEA5-4A13-94B6-88BE3AC569E8.jpeg
    Yes I thought after I wrote that it was incorrect, not that I have ever worked on 1600 but know they are different from when I was buying seals shims etc. The pressure plate is flush with step section where it bolts to the flywheel, the bits between the bolts slightly proud if this pic is what you mean?
     
  17. Wiz

    Wiz Well-Known Member

    Messages:
    563
    Location:
    Near Ballarat
    My gearbox is stamped CA089, engine is AP.
    Am I likely to experience the same problems as @Stormin12345?
    The clutch plate that I removed is marked 1861441234 and the pressure plate TYP M 210.
    Replacement is Exedy VWK-6043 (VWD8227 215mm clutch plate, VWK-6043 pressure plate and BRG2126 throwout bearing).
    Apologies if I'm hijacking the thread but I could be heading for the same problem/solution as OP.
    PR
     
  18. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,771
    Location:
    Mannum South Australia
    The wear marks from the new clutch show the friction surface area of the clutch plate match the machined area of the flywheel, so that part is correct.
    Try sitting the new clutch plate and old pressure plate on the flywheel. Without bolting it down, measure the distance from the pressure plate cover to the recess machined in the flywheel, you can use the pin end of your vernier through a bolt hole to the surface of the pressure plate as you are only looking for a comparison. Now do the same with the new pressure plate, is the measurement the same? This should at least rule out the cast plate thickness being an issue.
     
  19. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,771
    Location:
    Mannum South Australia
  20. Wiz

    Wiz Well-Known Member

    Messages:
    563
    Location:
    Near Ballarat
    Thanks T1 Terry, I'll measure mine when CoVID-19 allows.
    PR
     

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