murray928

Please help. What should be the torque on the six bolts/screws which tighten the flex-plate. I can only determine that the bolts/screws which tighten the flex plate clamp are 62ft.lb according to one of Greg's posts "It also appears that the 8mm headed cap screw that tightens the flexplate clamp is rounded out. You will need a new one. 931 421 240 00 is the part number. 62 ft.lbs. is the torque."
So what about the six that tighten the flex plate ? Please !!

Black Sea RD

Believe them to be at 33 ft. lbs. each. Be sure to use a good torque wrench since you can damage the flywheel threads if you go to a higher setting, BTDT.

Not easily found in the WSMs or even the small 928 spec book. They are in the WSMs, but you really need to search.

The actual ft. lbs. for that front clamp bolt is 59 ft. lbs. by the WSMs, but most go to a 10% higher torque due to an old post from a 928 owner whose mechanics were asking for help with the drive shaft movement at the front clamp from the Porsche factory. The factory mechanics advised to change out the front flexplate/clamp with a new one and clamp it to a 10% higher rating to try to control the movement. This then digressed to just clamping the bolt to a higher ft. lb. rating since changing the front flexplate/clamp with a new one is not feasible for most owners.

HTH,

namasgt

30 ft lb or 42 NM

Black Sea RD

namasgt, where did you find that info?

murray928

Attaching a pdf of what I found in WSM

I'm getting confused. Can someone advise please.

Also from previous forum posts on same subject.


Originally Posted by Constantine
33 ft lbs. for the six front flex plate to flywheel bolts. No lock washers from memory and a check of the PET diagrams. One must be careful to not exceed this ft lb. torque setting since you will strip the threads in the aluminum flywheel.
TDT.Cheers,
Flywheel is steel.

These bolts are grade 12.9. 33 ft lbs is the correct number.
__________________
greg brown

928TransmissionTorques.pdf

Black Sea RD

Murray,

Where are you confused?

Previous posts above seem to support 33 ft lbs. for those bolts.

This is in the WSMs, but is buried in the automatic driveline section.

murray928

Constantine, Thanks, but did you not look at the pdf of the workshop manual which I attached to my last post ?
That is why I am confused !!

You need to open the pdf .

murray928

928TransmissionTorques (1).pdf

Black Sea RD

Hi Murray,

I see what you mean and this happened to me too.

The bolts you need are not there.

I don't have the WSMs with me since they are in storage due to our move.

The bolts are also not shown in the diagram above. The diagram is for a very early torque tube as evidenced by the rear coupler.

The bolts are mentioned in the WSMs, but are buried in the text from memory.

Best I can do at this time.

namasgt

I got them from the red manuals. The torque values are for the rear plate to the converter, which to me are the same bolts used to mount the front plate to the flywheel.
Its not obvious in the wsm diagram. It only shows one bolt next to the access hole on the cover housing for the converter.

Its the same bolt front and back, correct me if I'm wrong.

Black Sea RD

Hi namasgt,

I was sent the small tech book PDF from Murray928 and looked up the rear bolts which you called out. The torque specs call for these bolts to be set at 46 NM which resolves to 33.92786 ft. lbs., which is close to what I initially posted at 33 ft. lbs. for the bolts at the front flex plate.

Wish I had access to the WSMs to be extra sure since I remember having to hunt for this information initially. I can't remember if this is the information I finally settled on for the front flex pate bolts or if I also found this information in the WSMs somewhere too.

Cheers,

namasgt

Yes, I just looked at the digital copy, volume_3 page 32-102 and 32-103 shows the bolt and torque value. #1 torque to 46 Nm (34 ftlb).
That bolt is shown again on the same manual page 37-136 and the same torque value on 37-137.

On my red manual Transmission volume III, page 32-102 and 32-103 shows the same exact diagram and the torque value is called out 42 Nm (30 ftlb).
37-136 and 37-138 shows 42 Nm (30 ftlb), same diagram.

Looks like they changed the value on the grey manuals (which is what I think the digital copy is from).

Obviously I would use the later torque values, 46 Nm (34 ftlb).

Cheers,

murray928

I'm really grateful to Constantine and Namasgt for taking the trouble to research further into my problem with the correct torque spec for these bolts. I'm happy at last to go with the 46Nm.