Hydraulic Clutch Conversion, chime in here....

Discussion in 'U-shift em' started by moleary, May 3, 2015.

  1. moleary

    moleary GOD Bless America

    Are you pleased with the clutch conversion?
  2. sriley531

    sriley531 M.M.O.G.

    Went for about a 5 mile shakedown cruise yesterday so finally got to upshift/downshift/the gammut and see how she did. Overall the function is there, BUT it is short and pretty heavy. It is perfectly drivable as is as long as you are good with a manual (not for a novice) and have a fairly strong left leg, and is staying in its current state for the short term. But I am going to come up with a way to move the heim joint closer to the pivot point of the pedal to increase throw/decrease weight.

    Overall, the setup works, is silky smooth, and I can't complain too much function-wise. I think once I move the pivot point, my answer will be absolutely pleased (with the 1 caveat that the install takes a bit of creativity).
  3. moleary

    moleary GOD Bless America

    I decided to piece together the hydraulic conversion instead of a kit and will fab the firewall mounting bracket & reinforcing back plate. I plan to model it after the American Powertrain (AP)adjustable piece in their kit. The set up is using the following items listed below and ends up costing a bit more than the American Powertrain kit but that is because I decided to not have any rubber hose and go all AN lines and the billet remote hydraulic fluid reservoir. All in $606 and I still have to fab the firewall mounting piece. The AP kit from Summit is $580 for comparison.

    Wilwood Master Cylinder WIL-260-6089 http://www.summitracing.com/parts/wil-260-6089

    Wilwood Remote billet reservoir kit http://www.summitracing.com/parts/wil-260-12697

    3/8" x -3AN Fitting for reservoir to adapt to -3AN stainless braided line between master and the reservoir

    3/8"-24 UNF x -4AN fitting to adapt master for -4AN line from master cylinder to TO bearing -4 leader http://www.summitracing.com/parts/RUS-640301

    7/16"-20 UNF x -3AN fitting to adapt master cyllinder to -3AN line to reservoir http://www.summitracing.com/parts/RUS-641321

    6' of -4AN Female x female line between master and TO bearing lead http://www.summitracing.com/parts/RUS-658340

    -4AN Male x Male adapter to connect TO bearing lead line to master line http://www.summitracing.com/parts/EAR-981504ERL

    Hydraulic Throwout Bearing http://www.summitracing.com/parts/mcl-1300-1

    Parts should be here today for some weekend work.

    I returned the Centerforce clutch kit & TO bearing and will be using the Zoom Perfection I took out as it is still essentially new with only 500 miles on it max.

    The new "old' 455 engine I pulled last Saturday and prepped the new "new" 462 engine to put in after the clutch conversion.

    Stay tuned
    Last edited: May 22, 2015
  4. moleary

    moleary GOD Bless America

    All the parts are here and I plan to start the fab of the firewall mounting assembly as time allows today. Updates to follow.
  5. sriley531

    sriley531 M.M.O.G.

    Keep us updated Mark! Sounds pretty comparable (other than the billet reservoir, that's a cool upgrade!). I'm about 50 miles in now and have to say, other than the pedal being a bit heavy, I'm absolutely pleased with the function. Even the weight of the clutch pedal isn't unbearable. I can say without a doubt I'm 100% pleased I decided to do it. Once i move the pivot point up a hair, it'll be the cats meow!
  6. moleary

    moleary GOD Bless America

    Not doing much this weekend other than golfing, eating and drinking with wifey.

    Did spend about one hour this morning before heading out to play for the day and have the Cardboard prototype master cylinder mount fashioned up. Tested and ready to produce Tomorrow.

    Material will be 3/16" plate Steel.

    On Friday I spent a couple hours on it. With the dial indicator I checked alignment of bellhousing which was in spec as is, out .003". FYI the Robbmc Offset dowell pins are nice.

    I also removed the front seat, clutch pedal rod, gathered tools and made the outside mounting plate using the boot retainer as the template.

    I'll gather the 1/4" and 5/16" hardware bolts and nylox nuts today when out and about.

    Monday plan is to complete the master mount, install it and the reservoir, install the TO bearing and lines onto the trans, pop a new pilot bushing into the new mill, install clutch and trans so its ready to drop in next weekend.

    Stay tuned.

    Attached Files:

  7. moleary

    moleary GOD Bless America

    Time to work on the clutch conversion has been intermitent and interrupted by other chores and fun stuff, but I did make some headway this weekend; here is the update:

    As planned I fabricated the adjustable firewall mount for the master cylinder modeled after the American Powertrain piece. The outside firewall mount plate and inside backing reinforcing plate mimic the shape and mounting thru holes of the factory boot retainer so utilizing longer 1/4" coarse thread screws to mount the master from the outside extend inside and use the three nuts welded to the firewall plate. Three additional 1/4" nuts on the inside secured to the extended screws mount the inside reinforcing plate to sandwich the firewall opening and make for a clean and very rigid install. I hope this is enough to prevent tearing of the firewall over time of repeated pedal pressure.

    Mounted the master and set up the pedal push rod. There is 2" of stroke and pedal travel ratio appears to be spot on 5:1 ratio.

    Next was setting up the Mcleod 1300-1 TO bearing. After unbolting the outer bearing collar I gained access to the bearing retainer oil slinger nut. This needs to be resized from 1.98" to 1.80" per Mcleod spec. I marked the excess material with sharpie and went at it with 80 grit on the belt sander measuring constantly, then reinstalled it using some loctite. I opted aginst purchasing the Muncie Wrench for $45, and just made a crude "wrench" for that nut which is ~ 1-5/8" opening using the 3/16" plate stock. (Note that it is reverse thread). Using some new allen head bolts about 1/4" longer than bolts removed for the collar, a little ATV silicon and the gasket, the TO Bearing is installed and ready to go. Once installed I put some rubber shields on the -4 lines as added protection inside the bell housing.


    Last chore yesterday was to install new oilite pilot bushing, assemble clutch and bell housing and measure for proper clearance between TO bearing and clutch fingers. Per Mcleod spec looking for min = 0.1" max = .250". I measured 0.136" which is good to go.

    The AN lines are plumbed from the master to the remote reservoir and to the awaiting trans. Next step next Sunday will be to complete the long block assembly, install trans and drop it back into the awaiting engine bay.
  8. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    Learn from my mistake- Weld a brace on the pedal before you bend it!
  9. moleary

    moleary GOD Bless America

    please post some more details and photos for the lessons learned:idea2::TU:
  10. moleary

    moleary GOD Bless America

    Did you have a chance to get some pics of pedal brace mod before I get this all together? Please post pics here
  11. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    Sorry Mark I don't have pics and the car is not accessible at this time. All you have to do is reinforce the bracket to the pedal. I also welded the bracket all the way around the pedal. Looks like the factory just used some spot welds. Its a pretty easy job.
  12. moleary

    moleary GOD Bless America

    The set up seems to be working flawlessly after a couple modifications.

    The first test was showing that the 5/16" threaded rod was flexing under pedal pressure. I could not find Grade 8 in 5/16" so I switched from a 5/16" threaded rod to 3/8" which is much stronger and doesnt flex under pressure and by the make up, there isn't but a few inches of threaded rod in the set up. I used the 3/8 heim joint with a long exhaust stud which is 24 thread into the heim and 16 tpi on the other side. A 3/8" 16 rod coupler threaded onto that end and a short piece of 3/8" threaded rod to a 3/16" : 5/16" threaded rod reducer I welded together to thread to the Wildood master . The reducer is available to purchase biut not in stock at many stores FYI either order ahead of time or make your own if you have the means to. I suggest using as little threaded rod as possible and this set up does just that and allows for plenty of adjustment.

    I also removed the clutch pedal to straighten out the rod tab as prior manual clutch geometry issues resulted in bending it. I then welded solid beads on all sides where the rod tab mates to the pedal arm and reinstalled that.

    After a nice long test drive it proved so far to be working perfectly and I can drive with confidence.:TU:

    The photo makes it appear the hitch pin is rubbing the brake light switch but in reality there is over 1/2" of clearance; nothing rubs or interferes with each other so it is a success!

    Last edited: Mar 12, 2017
  13. Marv Marksberry

    Marv Marksberry Well-Known Member

    I would like to say thanks to everyone who contributed to this thread for all the valuable information (and part numbers) that have been provided. It has saved me a lot of time and made my 70 GS 4-speed project more enjoyable.

  14. moleary

    moleary GOD Bless America

  15. 68Rivi_In_Cali

    68Rivi_In_Cali Well-Known Member

    This thread should be a Sticky for the guys attempting to convert to hydraulic clutch.

    What do you guys think? I was going to spring for the American Powertrain kit but it looks like I have to still make a mounting plate.

    I was thinking I could use my automatic column plate and waterjet something using that plate.

    I found a clutch pedal kit from a chevelle that might work as well. Maybe it has the correct angle already built into the master cylinder so I won't have to make a bracket to hold it.

    The hydraulic bearing is from Speedway motors and it has good reviews. I would just be missing the hydraulic hose lines.

    What do you guys think?

    SmartSelect_20200104-145513_Chrome.jpg SmartSelect_20200104-145313_Chrome.jpg
  16. moleary

    moleary GOD Bless America

    3692A0E8-52FD-4BDD-94B0-0275313275D4.jpeg A4D4E4EE-D86C-4146-A8C9-45B64AC997FF.jpeg 91FFEDA4-2524-4FEA-93CD-491B7F859773.jpeg When I was taking on the conversion, it didn’t pencil out to buy a kit since the kit wasn’t tailored to a Skylark/GS subtleties.

    I piece it together and fabbed the parts and still flawless performance.

    When I swapped to newer M23 I had to change hydraulic throw out bearing from the McCleoud to American but the hydraulic pedal and mechanical rods and are still as I built originally.
    68Rivi_In_Cali likes this.
  17. 68Rivi_In_Cali

    68Rivi_In_Cali Well-Known Member

    I am also going to be taking a stab at it.

    I ended up purchasing the following items from Speedway Motors.

    I have threaded Rod & nuts and bolts already.

    Only thing left is to create the mounting bracket which seems to be an easy task. I will keep you guys updated.

    I will post the part #'s in case someone wants to build their own kit.

    Screen Shot 2020-01-04 at 11.55.11 PM.png
    Screen Shot 2020-01-04 at 11.55.21 PM.png
  18. josehf34

    josehf34 Well-Known Member

  19. moleary

    moleary GOD Bless America

    68Rivi_In_Cali likes this.
  20. moleary

    moleary GOD Bless America

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