G50 clutch makes grinding noise when pedal floored ALL the way down

[r-mm]

About 9k miles ago I replaced my g50 clutch with a new sachs spring centered unit, did all the recommended cross arm updates and it has shifted like a dream since. I Did not touch the master or slave, did not bleed. In normal operation it is fine. If i really floor the clutch, as in push it all the way down then reeeealy keep pushing i get a rang-rang-rang-rang metallic interference noise you might expect was caused by a rotating part hitting a static part.

You might say, well don't push it down so hard. Fair but I'm wondering what the noise might portend. So far as i know there is no adjustment to be had with the hydraulic clutch?

Ideas?

[livetopedal]

Has your car had the cross shaft bearing update? My G50 made the same sound due to bad bearings and a worn release fork.

[livetopedal]

Oops. Hit reply too quickly.... I see you did the updates.

[john walker's workshop]

Fork touching the edge of the pressure plate is my guess.

[r-mm]

John I presume that would be the slave cylinder end of the fork hitting the PP?

What would be a cause/remedy or just let it be?

[john walker's workshop]

Never had that problem. Yet. Is your floor board damaged?

[ganun]

IIRC the clutch pushrod has a length adjustment spec of 150mm ( but hopefully someone gives the exact number) THEN the travel also has a spec that is adjusted by the metal cross piece bolted to the floorboard.

[ganun]

Or something like that....��

[Lyle O]

Had the same issue when I replaced my clutch recently. You need to lengthen the pushrod at the pedal cluster, and adjust the pedal stop, so as to decrease the total throw. It doesn't take much, but it will solve the problem.

[3literpwr]

My '87 did this and it turned out to be a broken finger on my pressure plate. Seeing as yours is only 9k miles old, this may not be the issue.

[Quicksilver]

A few posts have alluded to the pedal stop/metal cross piece/floorboard but to be more direct:
There is a pedal stop designed to limit the pedal travel and it is there for a reason. There isn't a reason to go much past full release and as John Walker pointed out you can press it till the fork hits the pressure plate.

You should adjust the pedal stop so you get full release plus some extra so the clutch will still work if it picks up some air in the line or normal wear.

[JOHN21BLACK]

I had same issue. Grinding noise. Thought I put TB in wrong. Turned out to be pedal was being pushed to far down.Turned out to be that I didn't have floor board in when I did clutch adjustment. Readjusted and grinding noise stopped.

[r-mm]

Thanks all i pulled the carpet last night and see the stop. Bentley is not particularly good at letting you know how much stuff needs to come off for any given operation. So, any tips?

[r-mm]

Guys - haven't got the chance to address this yet, but on a highway drive today I noticed that the clutch seemed to be slipping above 5,000 RPM. She pulls hard to ~4900 then surges up to ~6000 unusually quickly as though she's on boost. Could this be from a poorly adjusted clutch not fully engaging? The original problem I posted about seems to be getting somewhat worse.

[Marc Bixen]

I'm assuming a 3.2 Carrera 87-89? Is it possible someone resurfaced the flywheel? Porsche says it's a no,no. The slipping over 5,000 can be caused by an improper step from the pp mounting surface to the friction surface. The same thing happens with 356 flywheels. If the flywheel was surfaced, throw it away and start over.

[r-mm]

My hunch is that the car was on its first rubber clutch when i opened it up 10k ago. I did not resurface the flywheel, just cleaned it and reassembled w a sachs spring center clutch kit.