I have very low mile original 1.7 (30K). I recently installed a 4 post lift and have begun doing all the 50 year service updates (SS fuel lines, shift bushings, engine refresh etc.). I am certainly a novice mechanic at best. The information on this board most definitely helps close the knowledge gap and encourages me to self perform tasks I would otherwise be unsure of. While inspecting the flywheel, clutch and pressure plate they appear to be in very good condition (no grooves or obvious signs of wear) just some slight discoloration.

Should I reuse or replace? I did purchase a new rear main seal but I do not see any signs of a leak. From other info I have read on this board the newer seals are/maybe somewhat substandard. While I welcome the opportunity to fix everything I can while the engine is out and on the stand don’t want to perform unnecessary work or look for problems that don’t exist.

Would appreciate some advice.

Thanks.


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It’s a lot of work to get to where you are at. Cheap insurance to replace the pressure plate, disk, and throw out bearing while you are there. My thoughts.

Tech Tips 700 (Dr. 914) as a nice writeup on clutch renewal and what should be done.

Was it working properly prior to the teardown? If so, I would leave well enough alone

You will kick yourself later on if you don't replace everything questionable while you have things apart.

Ansbacher

Clutch job on a 914 is easier than on pretty much any other car… But it’s still a pretty big job.

I’m with the others… If it was my car, I would change out clutch, pressure plate and throw out bearing. Maybe add the pilot bearing, too.

For the clutch disc, the Clymer manual recommends replacement if the thickness of the lining is less than 9mm (0.36"). Haynes recommends measuring the rivet depth, and if less than 0.6mm (0.025") then it's time to replace. Otherwise, if no obvious cracks or the lining being oil soaked, then it's OK to reuse. I'd imagine the factory manual has it's recommendations also.
For the pressure plate, look for signs of overheating, cracks, gouges. Haynes recommends using a straight edge on the face to look for visible warping. If the fingers (held on by rivets) are tight and not badly worn where the release bearing contacts, and everything else checks out OK, it should be fine to reuse.
Almost everyone agrees to change the pilot bearing since it is fairly inexpensive and if there's any doubt about the release bearing, change it also. Look at those plastic insulating blocks on the release bearing too and replace if they look like there's any wear or cracks. Oh, and make sure to look at the flywheel face for gouges and uneven wear.
I usually follow the "if it ain't broke, don't fix it" philosophy. It's really up to you. Quick search looks like around 200-300 bucks for a new pressure plate and disc. If that seems like peanuts too you, then sure why not replace it while you're in there. If you feel like that's money that could better be spent elsewhere, the parts look good and you don't mind jumping back in maybe in 10, 20, 30 thousand miles (depends on how hard you drive it) then personally I see no reason the parts can't be reused.

Since it is out do it right. Replace everything. Make sure you get the little stuff. Replace pivot ball if needed. Plastic ball cup on fork along with the spacers on release bearing, Clean up flywheel. Replace rear seal and flywheel O ring. Basic kit $290 Rockauto KF19101

Appreciate all the advice. I think I will keep the flywheel and change everything else out as suggested. This place is such a good resource.

Check this bushing too! Good luck with your project!

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Do the fingernail test, on the metal surfaces, flywheel and pressure plate, run your fingernail the radius of the surfaces, outer edge to the center. Does your fingernail catch on any ridges? Very smooth ridges which are not deep might be ok but sharp and deep, resurface the flywheel and replace the pressure plate. I have replace a clutch in my car during super bowl halftime, using a floor jack. Today I have a lift but I don’t have to rush anymore.

Why should you need a new clutch with only 30K miles on the car?

Welcome to "While I was there" this is the all too familiar rabbit hole we go down.

If you can get good quality parts at $270, probably not worth the effort to do again if it becomes an issue.

You can always do the CSOB way and replace the disk and sand the flywheel and pressure plate . The cost is $20ish. If it truly is a 30k car it should suffice.

BTW I have the cup sockets if you need them.
-Mark

I am in for replacing the complete clutch setup.We have to remember that although it is low miles it is still 50 ish years old. If it’s out….replace it.

Unless it rusts, I don't see how a clutch would go bad just because of age. I would give all the parts a thorough inspection as others have described. If anything is suspect or anywhere near the wear limit, replace the whole kit. If not, replace the RMS and flywheel O-ring and reinstall the rest. There's a good chance that clutch has another 30K of life left on it under normal street use. It's all relative, but $300 is not cheap on my salary and replacing a clutch is just not that much work - especially with access to a lift. I've never had a clutch go out without giving me plenty of warning it was on its way first.

My mindset is whatever I do will be the last time I would touch it so might as well eliminate any work down the line. Car is not driven a lot so should be the last time during my ownership.

FWIW that is not an original 4 spring OEM clutch disk.

Measure clutch disk per Haynes for lining thickness - if it meets spec it will last quite a while. Especially if the car isn’t driven much.
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I say reuse it. We all need more exercise

Strangely I can’t seem to find a spec in disc thickness in the 914 factory manual

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Sachs quit making 4 spring along time ago. Everybody was using the 911/914-6 disc instead.

True, but I think the point was that the clutch has been replaced on this car before. I have a 4-spring clutch in my car that I bought in the late 80s and they were getting hard to find even then.

Clutch lining thickness from 911 Factory Manual - will pertain to the 6 spring clutch disk

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There are some unknown facts about my car. The paper trail and mileage have been confirmed but there was some discussion on this board about "originality" as members pointed out some concerns about the rear bumper and the color of the rear 1.7 emblem. I have owned the car for 20 years.

Why/when the clutch might have been changed to a six spring unit is just another one.

The car suffered some damage back in 2012 and Joe @ Series9 did a great job of repairing it. If you search under my name "zapisek" the link to the car and Joe's handy work are shown.

Is the car a time capsule.....opinions vary. I know that from working on the car it certainly appears to be an unmolested unit. I'm never selling it....

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If the clutch truly has only 30k miles on it and you know it to be driven correctly, sort of a waste replacing parts that still have years and miles of service left on them. Unless there was some sort of issue, M.I.F. can be a real thing.

Given what it takes to get to the point you’re at, I’d be inclined to replace everything. Also, a lot can happen over 50 years and I like having a known baseline. I made a video on replacing the clutch which should give you a sense of what’s involved. It’s not particularly challenging, though some specialized tools and precision is needed.

https://youtu.be/o1sDHWxTOxk

If you decide to do this, make sure you get a variety of new shims. You can always return the ones you don’t use, but it’s difficult to know ahead of time what combination of thicknesses will be needed.

Be safe and enjoy!

I’m going to go back to the original premise of the post.

What OP has posted:
Claimed 30k original miles.
He has owned car for 20 years
Posted photos show non OEM clutch
Photos appear to show at least 2mm or so lining depth above the rivets
No grooving in flywheel or clutch
No rear main seal leakage

What can be inferred from info provided above:
Owner rarely drives this car or it would have more than 30k miles in 20 years of ownership.
Clutch that came out of the car has much less than 30k miles on it.

What we don’t know:
Were the pilot bearing / RMS / felt seal previously replaced when the clutch disk was?
If yes, then all those parts are far newer and would have far less than 30k miles on them and likewise they would not be 50 year old parts.

So now we are down to the key questions:
Does the clutch meet thickness specification?
Should you disturb the flywheel to replace the RMS?

On thickness spec question - only the OP can answer that. Porsche establishes wear specs. It is black or white. Meets or doesn’t meet. There is no sense replacing parts that are in spec. Especially on a clutch we know has less than 30k miles on it.

On the flywheel / RMS question.
Consider that the flywheel / pressure plate were balanced as an assembly. If the flywheel is removed it MUST be indexed to the crank and hopefully the pressure plate was indexed to the flywheel. If not - OEM balance will be degraded or lost. The only way to regain it would be to send the flywheel and pressure plate out for balance.

Removing the RMS has it’s own risks of future leakage even if the seal is replaced. Especially if the flywheel and pressure plate become imbalanced.

Flywheel pilot bearing. If it is 30k miles on it (or less), has grease in it, and spins freely, it is fine and probably a better quality bearing than anything currently coming out of the aftermarket.

Other considerations:
Environmental / sustainability - if we / you / OP are committed to this concept - why throw away good parts (assuming they meet spec)? Consider the energy used to mine and transport all the raw materials we are talking about. OP - feel free to send me that clutch - I’ll gladly reuse it if meets thickness spec.

So what would I do?
If clutch / flywheel / pressure plate meet spec - put it back together.

RMS - this is one of the few times that I’d say if it isn’t broke - don’t fix it. There are a lot of variables in a RMS replacement that can get messed up. Especially by a novice mechanic. A good part of the advice is based on how little this car actually gets driven.. If I were taking about a daily driver - I would do it. Clutch work / RMS is so easy to do on a 914 - if it leaks in the future fix it then. By then OP will be a bit more experienced mechanic.

I'm not trying to be a jerk, but I'd really like to know what could happen to a clutch sitting rarely used or unused in an engine for 50 years other than oil leakage on the disc or rust.

Does this mean NOS original clutches stored on a shelf should be thrown out too? And let's remember we don't know how old that clutch is, but it is probably much less than 50 years old given it is not the original.

As usual, Superhawk has applied great deductive logic. Agree that the amount the car will be driven is a key factor as well. As for re-using the clutch disk, is there a downside to how a used clutch disc will “mate” with a new or resurfaced flywheel? I’ve never done that before. Will they eventually match to each other?

Just to be clear I’m proposing reuse of parts as-is (if in spec) without mixing and matching. So flywheel, clutch, pressure plate wear patterns will match up.

Back when I was in college and didn’t have much cash, I did mix & match out of necessity. No problem with the parts I had available. Honestly, mix and match wouldn’t be my first choice today, but I do standby the statement that I wouldn’t hesitate to reuse that clutch based on what I see in the photos.

The analogy is have you ever replaced brake pads with out replacing or turning the rotors? Not ideal but the pads pretty quickly wear to match the rotors. The downside being as they first begin to bed in, you don’t have full contact. It can lead to hot spotting of pads and rotors if not gently bedded in initially. Not ideal but it gets done more often than most of us will admit to.

original clutches look like this.

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rubber core clutches originally fitted at factory to 914s.

pulled one out of my car 3 years ago.

doesn't mean car in question here is not a 30k mile car, clutch might have imploded due to age decades ago.
rubber perishes. but someone has been in there and done the clutch before.

@bbrock - re NOS original clutches. i wouldn't fit one (thats assuming you can even find one). rubber ages even sitting on a shelf. i can tell you what happens when you recommission the car after its been sitting for 16 years. clutch implodes immediately if its a real original one. was ok when i parked it up around 2004.

don't forget to do the rear main seal on the engine while its all out and accessible.
standard VW practice with a clutch.

If the flywheel and pressure plate were imbalanced, would it be something one would notice/hear driving the car?

Right. Rubber hardens with age so agree I wouldn't use a 50 year old rubber center clutch. But that isn't what we are looking at here. Original rubber center discs were replaced by 4-spring, and when they quit making those, people just used the 6-spring 911 clutch assembly as an "upgrade" much as the 19mm MC "upgrade" is about the only choice now. So here we are looking at a 6-spring clutch. What would go bad in long term storage other than rust?

The clutch I have on my car is the 914 4-spring package which I prefer over the heavier 911 package. It was purchased in the late 1980s. The flywheel was resurfaced at that time and the rotating assembly including the clutch was balanced. The short block was reassembled and then the engine with clutch installed was stored in sheds for 35 years while my restoration project hibernated. When I pulled the engine out of mothballs, the clutch disc had rusted slightly to the flywheel but I was able to separate them without damage and clean up the rust. Have been running that clutch for 7K and it works great.

Ignoring the old, old rubber centered clutch discs which most have probably disintegrated by now, I'm just saying the clutch assembly is steel and friction material, neither of which is going to deteriorate with age other than to rust, which is easy to determine on inspection. I'm clearly in the camp that says if the clutch measures well within spec, use it.

Smarter people can answer this better but in my young, poor days, I replaced clutches on two different 1.7s without resurfacing the flywheel or balancing the clutch. Could I feel or hear the difference? No, not then anyway. However, the engine I'm running now was completely balanced and it has been a long time since I drove those old 1.7s or my current 2.0 prior to its rebuild, but I don't remember any of them ever feeling anywhere near as silky smooth as this rebuilt motor. So maybe I did feel a difference with the imbalanced clutches but didn't have a reference to be able to know it.

mostly i was addressing the idea by another poster that a 30K mile car would not need a clutch. when of course it probably would if it was a real original low mile car.

yeah i with you on reusing clutches or keeping the old one in if its fine.

the OP's photos of his flywheel and clutch look pretty good to me.
i'd put them back in.
doesn't sound like he is out there doing burnouts.

i'd still do the rear main seal. may as well. its not hard to do if its all apart.
basically they go with age and also with lack of use.
murphy's law says you put it back together and what will happen......it will fail.
then you curse yourself you did not do it while you were in there.