A Co-worker Of Mine Has A 99 Z28 That Will Not Shift Above 4000 Rpm's. We Have Replaced The Master And The Slave Cylinders And It Has A New Centerforce Duel Friction Clutch. Need Advise.

 

This post should be here: Drivetrain

I bet it's not fully disengaging. Did you replace the master with an adjustable or stock piece?

I don't like the centerforce dual personally. They use weights that apply more clamping force as the motor spins faster - great for clutch grip...harsh on hydraulics. Ideally, you want it to grab more at the top of the clutch pedal's travel and not right off of the floor (mine did this w/ the stock master). The extra pedal travel should theoretically pump more fluid into the slave and hopefully apply enough force to fully disengage the clutch.

 

Did you bleed the master really well?? I've read that it can take a long time to get it bled 100%. Heck, even mine isn't quite right I don't think!! Also, you might consider doing the "drill mod" ..... I'll be performing this to my car over the winter. Sorry I don't have any quick links to it, but do a search ... it's a common mod to the T56 hydraulics. Apparently it really helps high speed / high RPM shifts . FWIW, I've got a Centerforce Dual-friction in my car, and I've not had any problem shifting at ~6000 RPM, at the track or on the street .

 

If you didn't shim the slave with the new clutch it might not be disengaging for that reason, BUT the problem is probably the clutch is not bled properly. Keep trying to bleed the clutch, and when you think you're finished put a mighty vac on it.

Oh, and you're killing your synchro's like that.

Ben T.

 

I Believe The Master Is Stock But Im Not 100% Sure (not My Car). It Was Bled With A Mighty Vac. Thanks Fo All The Input I Will Pass It Along

 

SsmoknLT1, please turn off caps lock.