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Thread: Clutch fork pivot stud advice please

  1. #1
    Mark Eaton's Avatar
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    Clutch fork pivot stud advice please

    I have a TKO 600 and am installing a Forte hydraulic clutch. I have seen several threads where people had problems because their clutch fork pivot stud was either the wrong size or needed to be adjusted to a different length. It is still not clear to me how to determine if I have it correct. Here is my set up so far.







    What is the best way to determine if I need to adjust the length of the pivot stud?
    MK4 #9130 , complete kit, arrived 8/10/2017.
    DART SHP 347, EFI, TKO600, IRS
    http://thefactoryfiveforum.com/showt...n-Build-Thread

  2. #2
    Well Used Member boat737's Avatar
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    Make sure the pivot mount is threaded into the boss on the bell housing at least 5 threads or so. If it ends up threaded in only a few threads, then a longer pivot stud will probably be needed. I ended up having to buy a longer pivot stud because my clutch/pressure plate/pivot stud/clutch fork combination had the fork too far forward. (first picture) so a longer stud pushed the fork back to about where it should be. (second picture). On mine, it is darned near touching the rotating clutch package. (That is, don't back the stud out so far as to hit the clutch assembly. That's bad). Keep in mind that as the clutch disk wears, the fork will move back a tad, and take out slack in your slave push rod. So keep at least 1/2-3/4 inch or so clearance on the fork to the rear opening in the bell housing, as well as enough adjustment on your slave cylinder rod to put back in some slack on the fork some day.

    To me, the last picture of yours looks well within the ballpark.

    BTW, take care to mount the fork onto the throwout bearing properly. There is definitely a right way and a wrong way to mount it with the spring clip on the fork.
    Attached Images Attached Images
    Last edited by boat737; 06-04-2018 at 12:48 AM.
    If Brute Force doesn't work, you're not using enough of it.
    Bought a partially completed MK4. The Basic Stuff: MK4 Complete Kit #8439. The Extra Stuff: Wilwood's, 17" Halibrands, Stainless brake and fuel lines, Breeze cooling and Battery mount.
    The Old Fart Stuff: Heater, Seat Heaters, Footbox Fresh Air, Stereo, Keyless ignition, Power Steering, Hyd Clutch.
    The Young and Dumb Stuff: 427w Dart, TKO600, 3 link Moser M9/Ford 9", 3.5:1, Eaton TruTrac Posi

  3. #3
    Mark Eaton's Avatar
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    Thanks boat737,

    I guess what I am wondering is do I want the throwout bearing just touching the pressure plate at the end of the clutch fork travel? Or does it need to be pressing firmly against it? Because, correct me if I'm wrong, but if the thowout bearing doesn't reach the pressure plate it won't function properly and I won't be able to shift gears?
    MK4 #9130 , complete kit, arrived 8/10/2017.
    DART SHP 347, EFI, TKO600, IRS
    http://thefactoryfiveforum.com/showt...n-Build-Thread

  4. #4
    Well Used Member boat737's Avatar
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    Quote Originally Posted by Mark Eaton View Post
    Thanks boat737,

    I guess what I am wondering is do I want the throwout bearing just touching the pressure plate at the end of the clutch fork travel? Or does it need to be pressing firmly against it? Because, correct me if I'm wrong, but if the thowout bearing doesn't reach the pressure plate it won't function properly and I won't be able to shift gears?
    Not sure if I get the question or not... But...

    With the clutch pedal released, and the clutch disk engaged, you want a tiny bit of slack on the throw-out bearing. It should not be providing any pressure to the fingers on the clutch assembly all the time. It should have pressure against the fingers only when the clutch pedal is depressed. When you depress the clutch pedal, then the throwout bearing presses on the fingers in the clutch assembly and releases the clutch disk from the pressure plate/flywheel. I'm not sure exactly how much slack is needed or what the spec is on that, but it's not a lot. Keep in mind from what I said earlier, that as the clutch wears, the fingers on the assembly will move back just a bit, and take up the slack over time. It's just a tad though, not much.

    One more thing to check at this stage is the alignment of the bell housing vs. the crank/flywheel. The concentric tolerance for the TKO is very tight. If I remember right it's .005 inch., so make sure the bell housing is dead-nuts centered. From what I've seen (and my own) the Quick Time bell housings are pretty darned accurate.
    If Brute Force doesn't work, you're not using enough of it.
    Bought a partially completed MK4. The Basic Stuff: MK4 Complete Kit #8439. The Extra Stuff: Wilwood's, 17" Halibrands, Stainless brake and fuel lines, Breeze cooling and Battery mount.
    The Old Fart Stuff: Heater, Seat Heaters, Footbox Fresh Air, Stereo, Keyless ignition, Power Steering, Hyd Clutch.
    The Young and Dumb Stuff: 427w Dart, TKO600, 3 link Moser M9/Ford 9", 3.5:1, Eaton TruTrac Posi

  5. #5
    Mark Eaton's Avatar
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    Ok, I think I get it. I need to have this thing set so that as I depress the clutch pedal the throwout bearing will push against the fingers on the diaphragm and there needs to be enough travel so that over time as the fingers bend a little I can just depress the cutch a little further and still be able to release the clutch disk.

    Oh, and I'm good on the bell housing alignment.

    Thanks again.
    MK4 #9130 , complete kit, arrived 8/10/2017.
    DART SHP 347, EFI, TKO600, IRS
    http://thefactoryfiveforum.com/showt...n-Build-Thread

  6. #6
    edwardb's Avatar
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    Quote Originally Posted by Mark Eaton View Post
    Ok, I think I get it. I need to have this thing set so that as I depress the clutch pedal the throwout bearing will push against the fingers on the diaphragm and there needs to be enough travel so that over time as the fingers bend a little I can just depress the clutch a little further and still be able to release the clutch disk.
    Almost. The clutch changes adjustment because the material on the clutch friction disk wears. Much like brake lining or brake pads wear. Not because the pressure plate fingers bend over time. Very common in the life of a clutch to have to adjust it some. The first 1/4 to 1/2 inch of the clutch pedal movement should be pretty free. That will go away as the clutch wears, and needs to be adjusted back in. Otherwise you're putting too much pressure on the TOB, and it can wear out prematurely.
    Build 1: Mk3 Roadster #5125. Sold 11/08/2014.
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  7. #7
    Well Used Member boat737's Avatar
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    Quote Originally Posted by edwardb View Post
    Almost. The clutch changes adjustment because the material on the clutch friction disk wears. Much like brake lining or brake pads wear. Not because the pressure plate fingers bend over time. Very common in the life of a clutch to have to adjust it some. The first 1/4 to 1/2 inch of the clutch pedal movement should be pretty free. That will go away as the clutch wears, and needs to be adjusted back in. Otherwise you're putting too much pressure on the TOB, and it can wear out prematurely.
    Exactly.

    However, trying not to get into the weeds too much, but Paul, did you mean "the first 1/4 to 1/2 inch of the clutch FORK movement should be pretty free?" (not pedal?). That's what I was shooting for.
    If Brute Force doesn't work, you're not using enough of it.
    Bought a partially completed MK4. The Basic Stuff: MK4 Complete Kit #8439. The Extra Stuff: Wilwood's, 17" Halibrands, Stainless brake and fuel lines, Breeze cooling and Battery mount.
    The Old Fart Stuff: Heater, Seat Heaters, Footbox Fresh Air, Stereo, Keyless ignition, Power Steering, Hyd Clutch.
    The Young and Dumb Stuff: 427w Dart, TKO600, 3 link Moser M9/Ford 9", 3.5:1, Eaton TruTrac Posi

  8. #8
    edwardb's Avatar
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    Quote Originally Posted by boat737 View Post
    Exactly.

    However, trying not to get into the weeds too much, but Paul, did you mean "the first 1/4 to 1/2 inch of the clutch FORK movement should be pretty free?" (not pedal?). That's what I was shooting for.
    I did mean to say pedal, because in a traditional cable system you can feel (or not feel) the necessary free play there. But your point is a valid one. With a hydraulic setup, which is now pretty common, the fork movement would be the proper place to check and set the free play. Not nearly so obvious at the pedal, if at all. Best bet is probably to check at the fork in all cases as you suggest.

    Not to off topic too much, but I'm trying a Tilton hydraulic TOB on my Gen 3 Coupe build. Tilton advertises it as "self-adjusting." I'm thinking it's along the lines of a disk brake caliper that only retracts as much as needed as the pads wear. I'm going to be very interested to learn how well it works.
    Build 1: Mk3 Roadster #5125. Sold 11/08/2014.
    Build 2: Mk4 Roadster #7750. Sold 04/10/2017. #7750 Build Thread
    Build 3: Mk4 Roadster 20th Anniversary #8674. 03 of 20. 2015 crate Coyote, 2015 IRS. Legal 04/18/2017. #8674 Build Thread
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  9. #9
    Mark Eaton's Avatar
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    clutch fork and throw out bearing install

    Thanks to both of you for your input. I agree with Edwardb that those hydraulic throw out bearings are intriguing. In fact, I plan to use one on my next build!

    Here is where I am so far, I strapped the TKO to my floor jack and greased the bearing, fork and input shaft. BTW I found this youtube video

    helpful https://www.youtube.com/watch?v=OC4vRWQLGdk



    Here is a close up of it all lubed up and ready for penetration!! (or coupling ) Note the red arrow which is pointing to a ring which was in the box with no mention of its purpose. Thanks to Jazzman's thread I realized this needed to be installed with the tranny. Thanks Jazzman.



    The final product, Can someone tell me what the nob that the green arrow is pointing at is?



    I am planning to install and check the hydraulic clutch this weekend.
    Last edited by Mark Eaton; 06-05-2018 at 09:21 PM.
    MK4 #9130 , complete kit, arrived 8/10/2017.
    DART SHP 347, EFI, TKO600, IRS
    http://thefactoryfiveforum.com/showt...n-Build-Thread

  10. #10
    Mark Eaton's Avatar
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    One other thing, what are the torque specs to the bell housing? I'm guessing 42-50 ft-lb because they are 7/16" bolts but I have a bad tack record of over torquing and shearing bolts when I'm not careful...
    MK4 #9130 , complete kit, arrived 8/10/2017.
    DART SHP 347, EFI, TKO600, IRS
    http://thefactoryfiveforum.com/showt...n-Build-Thread

  11. #11
    edwardb's Avatar
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    The part you're pointing to on the TKO is a vent. It's there to relieve any internal pressure inside the trans during operation and help prevent pressure from pushing fluid out where it shouldn't. Normally will be dry. Same thing on an 8.8 solid axle, IRS diff's, etc. for the same reason.

    IMO, that's an excessive amount of grease you've got there. No problem with a film layer, but that much, especially on stuff that spins, can sling up into the clutch and be a problem. I watched the YouTube and especially didn't like how much he was putting on the TOB. The pivot, OK. But the rest was excessive.

    Lakewood/QuickTime instructions are to torque the bolts equally to 35-45 ft./lbs.
    Build 1: Mk3 Roadster #5125. Sold 11/08/2014.
    Build 2: Mk4 Roadster #7750. Sold 04/10/2017. #7750 Build Thread
    Build 3: Mk4 Roadster 20th Anniversary #8674. 03 of 20. 2015 crate Coyote, 2015 IRS. Legal 04/18/2017. #8674 Build Thread
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  12. #12
    Mark Eaton's Avatar
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    Thanks Paul, I guess I'd better wipe some of that grease off.
    MK4 #9130 , complete kit, arrived 8/10/2017.
    DART SHP 347, EFI, TKO600, IRS
    http://thefactoryfiveforum.com/showt...n-Build-Thread

  13. #13
    Well Used Member boat737's Avatar
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    Yep, that's a ton of grease. Paul is right on on that.

    As for the alignment ring in the bell housing, mine came with two, for different transmissions. I can't remember which one is which (a gold one and a silver one) but one is for the TKO, and the other for something else, maybe a T56, I can't remember. if you have two rings, make sure it is a snug fit in on the trans as well.
    Last edited by boat737; 06-05-2018 at 10:15 PM.
    If Brute Force doesn't work, you're not using enough of it.
    Bought a partially completed MK4. The Basic Stuff: MK4 Complete Kit #8439. The Extra Stuff: Wilwood's, 17" Halibrands, Stainless brake and fuel lines, Breeze cooling and Battery mount.
    The Old Fart Stuff: Heater, Seat Heaters, Footbox Fresh Air, Stereo, Keyless ignition, Power Steering, Hyd Clutch.
    The Young and Dumb Stuff: 427w Dart, TKO600, 3 link Moser M9/Ford 9", 3.5:1, Eaton TruTrac Posi

  14. #14
    Mark Eaton's Avatar
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    So, I backed the transmission and clutch fork/thowout bearing back out and wiped all that grease off, or at least most of it. I know, the photo is overkill but I can't help myself. Plus, I have a system all rigged up to do it myself. Kind of fun!



    I had sent a photo of the clutch fork installed to Mike Forte and he said my pivot bolt looked "perfect" so I installed the slave cylinder. I initially trimmed 5/8" from the push rod, then another 3/8" and here is where I am now.





    In this position there is a little over 1/8" play before the throwout bearing comes into contact with the pressure plate fingers. I am planning to hook this up the the wildwood MC and check the clutch action while someone turns a slip yoke to make sure it seems to be working properly. It looks to me like the clutch fork is a little far forward facing. I invite opinions...
    MK4 #9130 , complete kit, arrived 8/10/2017.
    DART SHP 347, EFI, TKO600, IRS
    http://thefactoryfiveforum.com/showt...n-Build-Thread

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    edwardb's Avatar
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    Making good progress. Your setup will probably work OK like that. But I'd recommend the fork a little further back as you suggested. This is the time to get it right. Gets a lot harder later. FWIW, this was my #8674 setup right before it went into the chassis. Approaching 2,500 miles now and working great.

    BTW, I see you have the SFI version of the QuickTime bell housing. Have you had it in the chassis yet? It's a tight fit with possible interference and it will hang below the chassis rails quite a bit. Just something to watch for. Even the non-SFI version I have pictured here required a slight trim on the bottom to not hang below the rails.

    Last edited by edwardb; 06-09-2018 at 06:01 AM.
    Build 1: Mk3 Roadster #5125. Sold 11/08/2014.
    Build 2: Mk4 Roadster #7750. Sold 04/10/2017. #7750 Build Thread
    Build 3: Mk4 Roadster 20th Anniversary #8674. 03 of 20. 2015 crate Coyote, 2015 IRS. Legal 04/18/2017. #8674 Build Thread
    Build 4: Gen 3 Type 65 Coupe #59. Delivered 12/2/2017. #59 Coupe Build Thread

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    Mark Eaton's Avatar
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    Thanks Paul, I am going to test it the way you outlined in 8673 build.

    I have had the engine in the chassis twice now but I didn't look carefully at the bell housing hanging below the 4" rails. The idea of just cutting the bottom off of it makes me a little nervous. I mean, how much can I actually remove with out damaging it?
    MK4 #9130 , complete kit, arrived 8/10/2017.
    DART SHP 347, EFI, TKO600, IRS
    http://thefactoryfiveforum.com/showt...n-Build-Thread

  17. #17
    edwardb's Avatar
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    Quote Originally Posted by Mark Eaton View Post
    I have had the engine in the chassis twice now but I didn't look carefully at the bell housing hanging below the 4" rails. The idea of just cutting the bottom off of it makes me a little nervous. I mean, how much can I actually remove with out damaging it?
    I can't provide hard data or a technical response. Only my opinions FWIW. (1) A "reasonable" amount trimmed from the bottom that doesn't create an opening between the bell housing and the block plate (it doesn't) shouldn't hurt anything, (2) Letting it hang below the 4-inch tubes and taking a hit there is likely to do very serious damage to some expensive parts. I wouldn't recommend taking that risk. (3) The SFI version trimmed in that manner will be very similar to the non-SFI version that doesn't have a bolted ring all the way around. So I'm confident it's still very robust. Perhaps it would be deemed no longer SFI compliant if really inspected and that's important to you. For me, that's not an issue.
    Build 1: Mk3 Roadster #5125. Sold 11/08/2014.
    Build 2: Mk4 Roadster #7750. Sold 04/10/2017. #7750 Build Thread
    Build 3: Mk4 Roadster 20th Anniversary #8674. 03 of 20. 2015 crate Coyote, 2015 IRS. Legal 04/18/2017. #8674 Build Thread
    Build 4: Gen 3 Type 65 Coupe #59. Delivered 12/2/2017. #59 Coupe Build Thread

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    Quote Originally Posted by boat737 View Post
    With the clutch pedal released, and the clutch disk engaged, you want a tiny bit of slack on the throw-out bearing.
    That may not be true. It depends on the throw out bearing you used. IMO, the best bearing comes from Ford. Aftermarket bearings don't seem to be strong enough, or last nearly as long. When you hold two bearings, like Ram and Ford, you can feel and see the difference.

    Ford designs their bearings to rest on the fingers at all times. Not enough to pre-load the bearing or clutch, but enough pressure to keep the two parts in contact with each other at all times. They did this to decrease noise and chatter.
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  19. #19
    Mark Eaton's Avatar
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    Cutch Testing

    I threw the wheels on the chassis and wheeled it next to the drivetrain and hooked up the clutch system, bled it with my power bleeder from CNC. I have an extra slip yoke because in my original shipment FFR sent the wrong drive shaft, they replaced it and didn't want me to send the first one back. So I put it in the output shaft and my 12yo cranked it while I tried the clutch. It works great!! I checked it in first and second gear. Seems to catch at a comfortable spot for driving. I adjusted the pushrod a little bit. Overall I'm very happy, especially after the demoralizing day I had yesterday trying to bleed my brakes...



    MK4 #9130 , complete kit, arrived 8/10/2017.
    DART SHP 347, EFI, TKO600, IRS
    http://thefactoryfiveforum.com/showt...n-Build-Thread

  20. #20
    Mark Eaton's Avatar
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    Quote Originally Posted by edwardb View Post
    I can't provide hard data or a technical response. Only my opinions FWIW. (1) A "reasonable" amount trimmed from the bottom that doesn't create an opening between the bell housing and the block plate (it doesn't) shouldn't hurt anything, (2) Letting it hang below the 4-inch tubes and taking a hit there is likely to do very serious damage to some expensive parts. I wouldn't recommend taking that risk. (3) The SFI version trimmed in that manner will be very similar to the non-SFI version that doesn't have a bolted ring all the way around. So I'm confident it's still very robust. Perhaps it would be deemed no longer SFI compliant if really inspected and that's important to you. For me, that's not an issue.
    Thanks Paul,

    I am definitely going to trim off any part of the bell housing that is hanging below the chassis after my final engine install. I remember reading somebody's thread where they did have their bellhousing hit something because it was hanging too low.
    MK4 #9130 , complete kit, arrived 8/10/2017.
    DART SHP 347, EFI, TKO600, IRS
    http://thefactoryfiveforum.com/showt...n-Build-Thread

  21. #21
    Mark Eaton's Avatar
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    Quote Originally Posted by Bob Cowan View Post
    That may not be true. It depends on the throw out bearing you used. IMO, the best bearing comes from Ford. Aftermarket bearings don't seem to be strong enough, or last nearly as long. When you hold two bearings, like Ram and Ford, you can feel and see the difference.

    Ford designs their bearings to rest on the fingers at all times. Not enough to pre-load the bearing or clutch, but enough pressure to keep the two parts in contact with each other at all times. They did this to decrease noise and chatter.

    Not sure which throwout bearing I have, which ever one Forte sent me. It looks pretty sturdy, I sure hope it doesn't wear out replacing it would be tricky.
    MK4 #9130 , complete kit, arrived 8/10/2017.
    DART SHP 347, EFI, TKO600, IRS
    http://thefactoryfiveforum.com/showt...n-Build-Thread

  22. #22
    Senior Member Fixit's Avatar
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    No kidding on the "hanging below the frame" on anything...
    I think it was 2 or 3 years ago at the Car Craft Summer Nationals (MN Fairgrounds) a guy in a wicked early Nova was zipping in on opening day (before the show was open to the public) and caught a sewer cover.
    The roads were being resurfaced, and the thing was sticking up about 3"... you know how that is when they grind down the asphalt?

    He smacked this thing at about 30mph. He was running an automatic - the impact shattered the bellhousing which then caused a chain reaction with the converter, front pump, and the rest of the gearbox. BIG puddle of cherry-juice and lotsa parts on the road.
    John D. - Minneapolis 'Burbs

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