Clutch Free Play Adjustment 1980 928 5 Spd.

[aluminum]

Hello Just how do you Adjust the free play in a 1980 928 US Model ?
The hydraulics work Just fine . Car is a 5 Speed manual and I have no Free play its tight all the way up and Clutch engages to soon as their is not enough free play.
I see Some photos on the net ? But am not sure if they are really for a 928 or not They don't look right ?

Thanks in advance if anyone knows what should be a simple adjustment

[JK McDonald]

Hey Aluminum, It looks like those photos are of a 911 set up. I think all the 5 speed 928 clutches were hydraulic but I could be wrong on the early ones. Some of the more experienced 928 owners will probably chime in to help with your adjustment. My 928's are both slush boxes.

Seeing those photos reminded me of a clutch cable adjustment problem on my 911 one time that drove me crazy. I changed out 2 new cables and was still grinding gears during every shift. It turned out that the pivot barrel on the very bottom of the clutch peddle had a spiral split in the metal. As the peddle was pressed the cable didn't begin to move for the 1st inch of application. Once the peddle was replaced - everything then worked like new - and luckily I didn't find any gear teeth in the drained transaxle oil......

Good Luck, Michael

[AirtekHVAC]

I don't know how to adjust the clutch, but there is no cable....all hydraulic.

[Mrmerlin]

the freeplay is adjusted under the dash at the top of the pedal assembly you want about 10MM of pedal travel before the pushrod starts moving the piston remove the rubber bellows if your not sure

[Pete R]

They are ALL hydraulic, the only adjustment is up on the pedal. I don't understand your problem, It engages too soon? engagement would be at the bottom of the stroke, free play would only make that worse. Disengages too easy? your clutch may be worn out

[aluminum]

Originally Posted by Mrmerlin

the freeplay is adjusted under the dash at the top of the pedal assembly you want about 10MM of pedal travel before the pushrod starts moving the piston remove the rubber bellows if your not sure

Thanks
I well try that > sounds like the right place to start and Hopefully the end of the Problem.

[aluminum]

Originally Posted by Pete R

They are ALL hydraulic, the only adjustment is up on the pedal. I don't understand your problem, It engages too soon? engagement would be at the bottom of the stroke, free play would only make that worse. Disengages too easy? your clutch may be worn out

Thanks Pete
The Problem is that I have no free play !!!! the Clutch works smooth however it has NO FREE PLAY at all and as such it engages to soon , or perhaps you might say to high up on the pedal movement with no free play .
Also with no free play if you floor the gas it slips a bit because it has no free play.
My understanding is that it is a new Clutch and it feels as such with good pressure
and very smooth clutch action .
Most all Standard Shift Cars I have have about a 1/4 inch of free play before you feel the Clutch pressure begin

[Pete R]

By engage your mean it starts to engage that clutch release action there by disengaging the clutch.
The end of the clutch rod at the pedal is threaded into the mount attached the pedal with a clip. I don't know if the rod turns, I undid the mount, rotated it and put it back. The other end is inside the master cylinder, I don't know if it's okay to turn it or not. It's real easy to figure it out once you see it.

[Opelotus]

IIRC the workshop manual procedure for adjusting the pedal pushrod says to:

-loosen lock nut (13mm wrench), remove retaining clip and slide pushrod off clutch pedal pin.
-adjust pushrod length so it can be easily slipped on and off the clutch pedal pin without moving the pedal or applying force to the master cylinder (basically so the pedal pin and the hole in the pushrod top adjuster are concentric when the bottom end is just resting in the master cylinder, and therefore no pre-load on the system while at rest)
-pre-load the pushrod ONE FULL TURN (8mm wrench, counter-clockwise if you are lying on your back, the goal is to make the pushrod longer by 1 turn) and tighten the lock nut + reinstall retaining clip.

That should result in just a little bit of freeplay. From what I have noticed it is less than your average 5spd car has, or at least it feels that way because of the resistance of the helper spring.

[aluminum]

Originally Posted by Pete R

By engage your mean it starts to engage that clutch release action there by disengaging the clutch.
The end of the clutch rod at the pedal is threaded into the mount attached the pedal with a clip. I don't know if the rod turns, I undid the mount, rotated it and put it back. The other end is inside the master cylinder, I don't know if it's okay to turn it or not. It's real easy to figure it out once you see it.

Thanks again Pete
I just adjusted the Pedal Rod ( under the dash ) and YES the Pedal Rod does turn after loosing the lock nut > so you don't need to pull the Clip
Its midnight here in Las Vegas and Very HOT like 108 Degrees so late is a good time to work .
I just adjusted it so the pedal had about 1/4 inch free play by feel and locked it down . The Road Test . No longer does the Clutch start to slip as the power come on as and the revs come on . Clutch does not slip at all now under any conditions . Free play feels fine however perhaps it could be slightly less and still work fine.
No doubt the throw out bearing was turning all the time before the adjustment ! another good reason for the proper adjustment .
The clutch works smooth and with no shimmy as before but now with no slip under Hi RPM Load .
I have replaced many clutches in my life and know that as the Clutch "DISK" wears down the free play increases and most likely one would have to adjust the other way to reduce Free play . As I have not driven this car many Miles I suspect the Pedal Rod was not ever adjusted properly after the clutch was replaced .

[aluminum]

Originally Posted by Opelotus

IIRC the workshop manual procedure for adjusting the pedal pushrod says to:

-loosen lock nut (13mm wrench), remove retaining clip and slide pushrod off clutch pedal pin.
-adjust pushrod length so it can be easily slipped on and off the clutch pedal pin without moving the pedal or applying force to the master cylinder (basically so the pedal pin and the hole in the pushrod top adjuster are concentric when the bottom end is just resting in the master cylinder, and therefore no pre-load on the system while at rest)
-pre-load the pushrod ONE FULL TURN (8mm wrench, counter-clockwise if you are lying on your back, the goal is to make the pushrod longer by 1 turn) and tighten the lock nut + reinstall retaining clip.

That should result in just a little bit of freeplay. From what I have noticed it is less than your average 5spd car has, or at least it feels that way because of the resistance of the helper spring.

Thanks Much
This sounds like the correct procedure however I recommend just a bit more free play then that . just a tad < Reason being on these old cars things wear like the motor mounts and such but the linkage stays solid ( under the dash ) so having free play may very a bit sometimes. This I have found to be true on many different car's . to save the throw out bearing free play is certainly a must have .

[Mrmerlin]

glad you got it sorted out a few things to keep in mind on the 928 clutch system

The throw out bearing will be spinning at engine speed and it will spin whenever the the engine is turning. In other words the TOB spins full time.

The clutch is self adjusting IOW once the discs wear down the slack is removed due to the slave cylinder and the spring placed inside it.

Caveat the push rod must first be properly adjusted to allow feeplay so the piston returns to its stop.

The 928 clutch operates backwards from most other clutch designs IOW the release arm pulls the clutch to the rear of the car to release the disc.

The release arm must have a good bushing it it or clutch performance will be compromised

Replace the pin and clevis at the top of the pedal for the clutch to work as it should these parts get overlooked and are a wear item

[aluminum]

Re Mrmerlin
" The throw out bearing will be spinning at engine speed and it will spin whenever the the engine is turning. In other words the TOB spins full time. "
No Kidding ? I did not know that ? well live and learn , I have never heard of a throw out bearing that spins full time as the motor runs wow
Anyway it seems to work now that I have free Play .
Do You Happen by chance to have a link to this information ? I would love to read about this Spinning all the time Throwout bearing information on a 928 I can't find it on the net and don't have a manual . Perhaps that info is in the manual .

[Mrmerlin]

the TOB is fastened to the PP fingers with the hardened collar and is kept under pressure from the spring inside the slave cylinder and the thin anti rattle spring on the opposite side of the fingers,
this loads the TOB collar onto the PP fingers.

Thus the TOB will spin with the PP ,the PP is bolted to the flywheel, the flywheel is bolted to the crank

[SharkRat]

Hey, I couldn't resist bumping this old thread. Doesn't one full turn of "preload" mean the opposite? Make the rod shorter? To me that seems to more accurately fit the definition of "preload". It's a load that's applied in advance of the load that you apply with your foot. Making the rod longer creates more free play, so that seems like the opposite of "preload". Of course, they could be talking about the pressure plate load. Wish the WSM was more clear here.

Edit: actually that's backwards. Making the rod shorter creates more free play. Was just tinkering with mine. But that still seems like the opposite of "preload" to me.