KeeferSC

I just picked up a 2006 Cobalt SC with a "newer" clutch. It felt great when I bought it but 3 weeks in it started slipping. All OEM GM parts and it looks worn enough and rusty enough to be original. 120k miles so it's definitely over due. I replaced everything with OEM parts straight from the dealer. New clutch disc, pressure plate, flywheel, slave/TOB combo and even did a rear main seal while I was in there. I bled the new clutch the old fashioned way with the pump and bleed method. Took a while but I got good pressure and it felt nice. Got it all back together and took it for a ride. Made it about a mile and the pedal went soft. Bled it again until I was sure I got no air, all clean fluid. Drove it again, got soft, bled again. Felt great, drove it and everything felt good. I took it to work today and I noticed the pedal would only return about 3/4 of the way after a couple shifts. If I pull it up it has perfect pressure but then once I use it 3-4 times it doesn't return again. I came out of work and the pedal was soft. Pump it once and it has pressure again. I got home and noticed the fluid was a tiny bit lower than I remember. I laid under the car and had my sister pump the pedal 50-60 times and I can't see any fluid leaking anywhere and it never got soft. Held pressure the whole time but I figured I'd bleed it again just in case. Still clean fluid and no bubbles. Took it for a ride and it does the same thing still.

Does anyone have any idea what this could be? Im suspecting a possible small leak in the slave or maybe where the line threads into the slave but it seems weird that it would hold perfect pressure until I start driving it. Could there possibly still be air in the slave cylinder and it's slowly coming up? I know these cars suck to bleed but I've never had to bleed a clutch this much to get it to hold pressure. I'm hoping there's a solution before I have to drop the trans again. And yes it held perfect pressure before I changed the clutch so I don't think it would be the master cylinder.

Thank you for any help and sorry for the long post, just trying to give a good description of this weird issue.

dmstk8d1

Something of this nature may help that problem. Somewhere I read that LSJs can experience issues with pressure bleeding off.

Ecotec Parts Throw Out Bearing Spacer

63 Nova SS

iTrader: (3)

So it engages fine for a little bit then won't hold pressure? And leaks at all around/under the trans? Are you losing fluid? Is the little rubber seal still in the clutch pipe? Are you sure the little retainer is in the distribution block and it's holding tight to the clutch pipe?

KeeferSC

Thanks for the help guys. It was losing a little bit of fluid and I couldn't see a leak because the fluid was slowly dripping into the trans through the clutch pipe retainer. The rubber o ring where the quick connect block clips onto the pipe wasn't seated correctly. A few days ago I found an old post from 09CobaltSS1 on here and he posted this picture. You can feel the o ring click into place when it's on right. I've had it back together for a few days and it feels perfect.

ItalianJoe1

iTrader: (10)

Glad you found it, I was gonna say from your description it sounds like you had to have a leak somewhere. Or an internal master cyl failure.

63 Nova SS

iTrader: (3)

Nice! I was wondering if that joint was giving you the issue.