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'00 RS / V5 STI
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583 Posts
Discussion Starter #1
Hey,
I'm wrapping up a 6-speed swap with a 2004 STI transmission but am having issues with the clutch not disengaging.

I'm using (30620AA151 - 2006 STI) as the slave, but I'm wondering now if I should be running (30620AA0908A - 2004 STI) instead. Specifically, I'm wondering if 30620AA0908A is longer than 30620AA151, resulting in more travel of the release lever.

Has anyone held both side-by-side and seen a difference? Image searching is not conclusive.

Thanks,
-TC
 

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'00 RS / V5 STI
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583 Posts
Discussion Starter #2
Disregard the above post - I can’t edit it now.

I installed a late 2004 USDM STI trans into my GC, and have verified the following part numbers as being correct: clutch, flywheel, pressure plate, throw out bearing, pilot bearing, slave cylinder, starter, and clutch fork. All are for a 2004 Subaru STI, all brand new. I’ve also bled the clutch using a c-clamp and blocking the piston with it elevated above the master cylinder - it’s bled correctly.

With the car in the air I can start it in neutral, but have to force it into first where the wheels will turn. The friction disk doesn’t fully disengage - speed increases with revs even with the clutch on the floor. After popping off the rubber cover over the fork, I’ve watched it do it’s job. I’ve also looked at pictures that show the friction disk being installed correctly.

Put another way - clutch on the floor, car in first and in the air - step on the brakes and the motor will stall out.

My best thought is that the friction disk isn’t able or willing to slide on the input shaft of the transmission, though I think I tested that before installing it all. Other than that, I can’t for the life of me figure this one out. I’ve replaced clutches/transmissions 6 times (all 5 speeds before) which never had this kind of a hiccup.

Any thoughts?

-TC
 

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2001 SRP 2.5RS/RA/SOHC Monster
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2,795 Posts
I've had to bench bleed every new master/slave combo I've ever done.
 

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'00 RS / V5 STI
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583 Posts
Discussion Starter #4
I only changed out the slave and I used the Subaru-method to bleed it - lock the slave cylinder piston all the way back and lift it to the highest point while bleeding. There’s no more air to get out.

The master cylinder was working fine with the 5 speed, and it never ran dry while bleeding.

-TC
 

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2000 RS Coupe
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146 Posts
Had a similar problem after a Fozzy EJ253 engine rebuild. All clutch components replaced (clutch, pressure plate assembly,flywheel). After extensive bleeding and recheck of entire system I bit the bullet and removed the engine. Despite careful merging of the tranny and engine block, by this I mean not stupidly clamping the engine and tranny using tranny/block bolts to tighten the two mating surfaces together, it turns out a few of the input shaft splines got bunged during the install and were not allowing complete pressure plate engagement/disengagement. After deburring the splines and taking a little more care with alignment, clutch ended up working flawlessly. The thing that really sucked was that i took care when mating surfaces and by all outward appearances, everything was assembly correctly, system was properly bled, clutch fork and pivot system was free of abnormality and functioning correctly, etc...Stupid, unforseen error gave me a lot of grief.
 

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'00 RS / V5 STI
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583 Posts
Discussion Starter #6
Thanks Demon, I think this is likely the answer. I plan to (begrudgingly) drop the trans out again this weekend to check it all.

In the mean time, I may poke a mini bendable camera into the clutch fork cover and check to see if the friction disk is backwards for some silly reason, or for anything else off (TOB being disconnected sorta deal). But, I'm assuming that the issue lies on the input shaft and that friction disk being able to slide on it.

-TC
 

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2000 RS Coupe
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146 Posts
I'm almost embarrassed to admit to such an asshole and time consuming mistake but if it helps anyone in a similar situation...I'll gladly own it. I also went in the clutch fork boot opening with a camera...to no avail. Good luck!
 
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