Jump to content



T56 clutch issue


  • Please log in to reply
11 replies to this topic

#1 slowquest

slowquest

    Maybe someday, I'll be FastQuest

  • Members
  • PipPipPip
  • 2,502 posts
  • Gender:Male
  • Location:Cincinnati
  • Model:Conquest

Posted 14 November 2016 - 06:34 PM

I've got an LS1/T56 swap running, but having an issue with the clutch.  I'm using the stock starquest clutch master, and the stock 04 GTO T56 slave, connected with hard line and braided hose.  I removed the stock GM quick connect on the slave and am using a brake line flare adapter.

The issue is that the pedal will stick to the floor and not release.  I'm thinking it's a bleed issue, but have used every trick I know to no avail.

With engine running and pedal stuck on floor, I can shift trans to any gear and tires do NOT spin (car on stands)  I can pull pedal off floor, tires spin, push back to floor (sticks there) and tires stop spinning.  Can also spin tires by hand with engine off, trans in gear, clutch pedal on floor.

Any ideas?





#2 Funky Phil

Funky Phil

    Super Pooper

  • Members
  • PipPipPipPip
  • 6,418 posts
  • Gender:Male
  • Location:Hell's microwave TX
  • Interests:2 streaks of fire for 60ft when I leave.
  • Model:Conquest

Posted 15 November 2016 - 11:26 PM

Hyper extending the pressure plate maybe? Try taking out some travel.
10.95@122mph MoFuggin stickshift! https://m.youtube.co...h?v=8Q01UKt5q4U

Posted Image

#3 slowquest

slowquest

    Maybe someday, I'll be FastQuest

  • Members
  • PipPipPip
  • 2,502 posts
  • Gender:Male
  • Location:Cincinnati
  • Model:Conquest

Posted 16 November 2016 - 10:23 AM

I thought of that also, but doesn't seem like that's it.  If I push the pedal, say 3/4 of the way down, the clutch is not released fully.

#4 Funky Phil

Funky Phil

    Super Pooper

  • Members
  • PipPipPipPip
  • 6,418 posts
  • Gender:Male
  • Location:Hell's microwave TX
  • Interests:2 streaks of fire for 60ft when I leave.
  • Model:Conquest

Posted 16 November 2016 - 11:26 PM

Hydraulic system? Internal slave?
10.95@122mph MoFuggin stickshift! https://m.youtube.co...h?v=8Q01UKt5q4U

Posted Image

#5 slowquest

slowquest

    Maybe someday, I'll be FastQuest

  • Members
  • PipPipPip
  • 2,502 posts
  • Gender:Male
  • Location:Cincinnati
  • Model:Conquest

Posted 17 November 2016 - 07:18 AM

Yes to both.  Stock StarQuest master and stock 04 GTO slave.

#6 Walker

Walker

    Established Member

  • Members
  • PipPipPip
  • 911 posts
  • Gender:Male
  • Location:Ohio
  • Model:Starion

Posted 19 November 2016 - 11:52 AM

get it figured out?

#7 slowquest

slowquest

    Maybe someday, I'll be FastQuest

  • Members
  • PipPipPip
  • 2,502 posts
  • Gender:Male
  • Location:Cincinnati
  • Model:Conquest

Posted 19 November 2016 - 07:37 PM

Nope, but 99% convinced it's simply an air in the lines issue.  Just gotta figure out a good way to bleed it.

#8 Funky Phil

Funky Phil

    Super Pooper

  • Members
  • PipPipPipPip
  • 6,418 posts
  • Gender:Male
  • Location:Hell's microwave TX
  • Interests:2 streaks of fire for 60ft when I leave.
  • Model:Conquest

Posted 20 November 2016 - 05:38 PM

Someone made a speed bleeder for those
10.95@122mph MoFuggin stickshift! https://m.youtube.co...h?v=8Q01UKt5q4U

Posted Image

#9 Chad

Chad

    noob

  • Moderators
  • PipPipPipPip
  • 9,182 posts
  • Gender:Male
  • Location:Lincoln City Oregon
  • Interests:Starquest Fanatic
  • Model:Conquest

Posted 21 November 2016 - 11:38 PM

I haven't checked the geometry of the pedal asembly in a while, but I think past a point, the pedal return spring will do that.  It's a symptom of needing too much travel to get the job done.  I'd suspect the bore of the stock master doesn't match what the GM slave needs. you are making a lot of pressure but not moving enough volume.  The GM bores about 40% larger than the stock mitsu stuff.  Once the stock mitsu is maxed out travel wise, its only just starting to disengage the GM clutch.   Because you aren't loading up the pressure plate spring, it's not pushign back, and the pedal thumps down on the floor from overextending the return spring.

The stock bore is about 5/8", the GM is expecting something closer to 13/16".

#10 slowquest

slowquest

    Maybe someday, I'll be FastQuest

  • Members
  • PipPipPip
  • 2,502 posts
  • Gender:Male
  • Location:Cincinnati
  • Model:Conquest

Posted 22 November 2016 - 07:40 AM

Phil, I've got great access to the stock bleeder, getting great pressure out of it when bleeding.  I had thought about the speed bleeder setup, but hate spending that cash without a good chance of it being the fix.   Chad, I was hoping you'd chime in here.  I thought your adapter setup was using the stock master, but wasn't sure what slave.  From the little math and geometry I've done on this, the Conquest clutch pedal arm moves a further distance (stock) than the GTO pedal arm does, I was hoping that the extended stroke would make up for the smaller bore, but apparently that isn't working.  Guess it's time to start looking in to aftermarket masters....

Edited by slowquest, 22 November 2016 - 07:42 AM.


#11 Chad

Chad

    noob

  • Moderators
  • PipPipPipPip
  • 9,182 posts
  • Gender:Male
  • Location:Lincoln City Oregon
  • Interests:Starquest Fanatic
  • Model:Conquest

Posted 22 November 2016 - 10:24 AM

Ap racing makes a unit that is near stock  outside dimensions, but with a larger bore.  I bought one for r&d on an ls swap, but never completed that project.  My kits used a bracket to hold the stock slave on the lt1 clutch to avoid this issue, and works very well.  I'm 99% sure this bore ratio thing needs changed to get yours to work.

#12 SFBMX88

SFBMX88

    Established Member

  • Members
  • PipPipPip
  • 1,552 posts
  • Gender:Male
  • Location:SAN FRANCISCO
  • Interests:WE LIKE THE MOON!!!!!
  • Model:Conquest

Posted 16 October 2018 - 02:49 PM

Im little late, but this may help others down the road.  Some slave cylinders may require shimming.  Just another piece to the puzzle....

https://ls1tech.com/...-need-shim.html

Posted Image

Edited by SFBMX88, 18 October 2018 - 02:32 PM.





0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users