Transmission weirdness - Groove in clutch fork

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Sean M Rooks
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Transmission weirdness - Groove in clutch fork

#1 Post by Sean M Rooks »

Hello gents.

I've decided to pull the motor in my '64 C coupe to identify the source of an oil leak (I think it might be the seal behind the flywheel) and generally clean it up and fix some of the inaccuracies and weird things the PO did. First time doing that but it went well.

Upon getting the motor out, I took a look at the flywheel and the bellhousing and noticed some unusual wear I'm hoping you can help me diagnose. The fork that holds the throwout bearing has a circular groove worn into the arms. See below:

Image

It looks like it might have come from the raised lip on the pressure plate around the diaphragm springs:

Image

So i'm hoping you knowledgeable folks can help me with the following questions:

1) What could cause the wear on the clutch fork?
2) Is the pressure plate permanently damaged and need to be replaced? Should I do the clutch and flywheel too?
3) What are the drill marks on the pressure plate? Is that from balancing the flywheel, clutch, and PP before install?

Apologies for the questions - I'm not super savvy on engine stuff but trying to learn.

Here's a photo of the bottom of my trans for help in diagnosis. It doesn't appear original to the car (maybe a '59 741 based on Vic's numbers?)

Image

Thanks!

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Jacques Lefriant
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Re: Transmission weirdness - Groove in clutch fork

#2 Post by Jacques Lefriant »

your fork may have been installed backwards the thicker part pushes the to bearing. also the 180 clutch uses a tall to brg with the 741 part no not the 901 shorter.
j
 

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Thomas Sottile
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Re: Transmission weirdness - Groove in clutch fork

#3 Post by Thomas Sottile »

The C should come with a 200mm clutch.

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Vic Skirmants
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Re: Transmission weirdness - Groove in clutch fork

#4 Post by Vic Skirmants »

Jacques Lefriant wrote:your fork may have been installed backwards the thicker part pushes the to bearing.
j
Also; if the clutch pedal stop is permitting over-extending of the bearing, the fork will contact the pressure plate. No harm done to the plate; the holes are from balancing; a little excessive, in my opinion.

Jay Darlington
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Re: Transmission weirdness - Groove in clutch fork

#5 Post by Jay Darlington »

Also if you remove the pressure plate see the punch marks about 1:00 in your picture. be sure to line them up when you install.
Jay D.
jay darlington

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Sean M Rooks
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Re: Transmission weirdness - Groove in clutch fork

#6 Post by Sean M Rooks »

Thank you everyone!

So I think I may replace the clutch fork and do a new clutch adjustment when the motor goes back in. Bothers me thinking there's a damaged part in there. Can I assume that the removal procedure is to knock out the roll pins to remove the rod from the fork?

Looks like I'll be removing the clutch and flywheel to get to the case behind the flywheel and see what's leaking. Can I reuse the bolts?

Thanks for the tip on the alignment jay - I wondered what those marks were for!

-Sean

Dick Weiss
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Re: Transmission weirdness - Groove in clutch fork

#7 Post by Dick Weiss »

The printed number on the P/plate indicates it's a 200mm.
I agree; All the 'spot drillings is excessive, but the disc needn't be included during a balance job.

Dick

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Sean M Rooks
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Re: Transmission weirdness - Groove in clutch fork

#8 Post by Sean M Rooks »

Dick Weiss wrote:The printed number on the P/plate indicates it's a 200mm.
I agree; All the 'spot drillings is excessive, but the disc needn't be included during a balance job.

Dick
So should I look at a new pressure plate? what should I look for in terms of wear when I pull everything apart?

So I understand, you just get the flywheel and pp balanced and not the clutch disc? What could the excessive drilling indicate?

E Rutherford
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Re: Transmission weirdness - Groove in clutch fork

#9 Post by E Rutherford »

Now that the system is ALMOST all a part, finish taking the rest a part.

Take the clutch return spring off, so that there is no pressure on the cross arm shaft. Check for sloppy bushings, any play - Replace.
Clean your T/O bearing, inspect and repack.
Inspect your PP, if those "fingers" are worn more that 25-30% replace the PP.
Inspect the clutch disc.
If the flywheel and PP have never been balance together (locating pins allowing only one way to mount), then get them balanced! While their at the machine shop, replace your rear main seal and the main shaft seal. They are cheap and easy to do.

Those grooves are caused most likely by what Vic has described. The adjustment is described in the factory manual. Probably the most neglected adjustment on the car!

ed
klasse356

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Sean M Rooks
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Re: Transmission weirdness - Groove in clutch fork

#10 Post by Sean M Rooks »

Thanks Ed and everyone! I'm on it!

Dick Weiss
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Re: Transmission weirdness - Groove in clutch fork

#11 Post by Dick Weiss »

Sean,

I forgot to ask--was the flywheel's disc depth cut too deep and not refinishing the face relationship?
Also, the 200mm P/plate doesn't require the 30mm release bearing offset used w'the 180mm P/plate.
Finally, the bearing's fork being backwards on the shaft will make a difference, too--if using the proper bearing.

Dick

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Sean M Rooks
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Re: Transmission weirdness - Groove in clutch fork

#12 Post by Sean M Rooks »

Dick,

How do I identify what I've got re: flywheel disc depth and bearing offset?

Engine is down to the long block. Bought a new clutch fork, and will be replacing that in the next few weeks before I put the motor back in.

Image

-Sean

Dick Weiss
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Re: Transmission weirdness - Groove in clutch fork

#13 Post by Dick Weiss »

Sean,

The F/wheel depth-to-face spec is listed in the shop manual and spec book; The proper T/O bearing
is listed in Stoddard's catalog/website. You can reuse the mounting bolts--torque to 25 ft.lbs.

Dick

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Sean M Rooks
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Re: Transmission weirdness - Groove in clutch fork

#14 Post by Sean M Rooks »

Thanks dick. I've got a shop manual and will check that first. I'd like to think I can keep my existing throw out bearing!

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Sean M Rooks
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Re: Transmission weirdness - Groove in clutch fork

#15 Post by Sean M Rooks »

So my C coupe is back on the road after my engine out work, and I'm sorting through a few issues. Thanks to everyone for your help and diagnosis on my clutch fork problem.

I installed a new clutch fork but kept the old throwout bearing and PP and flywheel. Didn't change anything there. One thing I did do was attempt to adjust the clutch pedal engagement to avoid wearing the same grooves into the new clutch fork.

Here's the pedal symptom after my clutch adjustment: Free play is huge. Maybe 2+ inches before I start to feel resistance. Then it's quite a long way before the clutch fully disengages. So long I had to adjust my pedal stop HIGHER. Which seems counter intuitive to the objective of not overextending the TO bearing. Or at least compared to where I was before.

Here's what I did:
1) Adjusted the cable clevis at the clutch end so that I had maybe 1/4" of very evident play before the TO bearing touches the PP. It's a little bit of movement until I hear the metal click.
2) I noticed the bowden tube was rubbing the bell crank with a lot of pressure. So much I could see a little wear on the bowden tube. So I backed that off until it was just barely touching.
3) Checked the play at the pedal, and it was huge. So big I had to adjust the pedal stop up from where it was.

With the above, I have maybe 1/2" of movement off the stop before I start to feel the clutch grab, and the grab is very short. Almost immediate.

Is this the correct setting? I worry that if the cable stretches I won't get full disengagement of the clutch and shifting will be difficult/gnashing.

What is the right way to get the engagement point further away from the floor? I've seen a lot of advice for the opposite.

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