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-   -   Clutch didn't return, dropped engine/transmission to look inside (http://forums.pelicanparts.com/porsche-911-technical-forum/1028640-clutch-didnt-return-dropped-engine-transmission-look-inside.html)

Walt Fricke 05-09-2019 02:19 PM

How about some photos of the flywheel clutch surface? Unless it was badly worn, I'd leave it alone, which means you don't need to remove and reinstall it. The tricky part about the RMS is getting it installed square. Absent the factory tool, or a home made one of equal efficiency, getting a new one in right is not a trivial exercise. Flywheels can work fine with the clutch even if not a pristine flat surface.

Do you have any evidence that your RMS is leaking? If it is leaking, of course, pull the flywheel and replace.

And how's the wear surface of the pressure plate? Those can last a long time. What I'd inspect on the PP are the ends of the diaphragm fingers, where they engage the TOB. How much thinner are they than the rest of the spring's thickness? I don't have a percentage in mind. If basically no wear, all is well. If, say, only half thickness, easy decision to replace the PP (the diaphragm spring is replaceable, but that is not a DIY job - Clutchmasters or the like can do this). Given what led to all this, perhaps those wore excessively.

Now that you have pulled your engine, you ought not to feel that if, 50K miles later, the RMS starts leaking a little, you should have replaced it now. You can just pull it again - there is probably something else best done with engine and transmission out by then anyway.

If you do decide to replace the RMS, note where on the crank the lip of the old one bore. Try to install the new one so it doesn't ride on that exact place.

OsoMoore 05-10-2019 10:04 AM

Quote:

Originally Posted by Walt Fricke (Post 10454005)
How about some photos of the flywheel clutch surface? Unless it was badly worn, I'd leave it alone, which means you don't need to remove and reinstall it. The tricky part about the RMS is getting it installed square. Absent the factory tool, or a home made one of equal efficiency, getting a new one in right is not a trivial exercise. Flywheels can work fine with the clutch even if not a pristine flat surface.

Do you have any evidence that your RMS is leaking? If it is leaking, of course, pull the flywheel and replace.

And how's the wear surface of the pressure plate? Those can last a long time. What I'd inspect on the PP are the ends of the diaphragm fingers, where they engage the TOB. How much thinner are they than the rest of the spring's thickness? I don't have a percentage in mind. If basically no wear, all is well. If, say, only half thickness, easy decision to replace the PP (the diaphragm spring is replaceable, but that is not a DIY job - Clutchmasters or the like can do this). Given what led to all this, perhaps those wore excessively.

Now that you have pulled your engine, you ought not to feel that if, 50K miles later, the RMS starts leaking a little, you should have replaced it now. You can just pull it again - there is probably something else best done with engine and transmission out by then anyway.

If you do decide to replace the RMS, note where on the crank the lip of the old one bore. Try to install the new one so it doesn't ride on that exact place.

Here are photos of the flywheel. It seemed smooth to my eye and touch. There is no sign of a leaking RMS. Pressure plate seems to have some wear - see the last picture.

http://forums.pelicanparts.com/uploa...1557511166.jpg
http://forums.pelicanparts.com/uploa...1557511166.jpg
http://forums.pelicanparts.com/uploa...1557511166.jpg
http://forums.pelicanparts.com/uploa...1557511166.jpg

SReppel 05-10-2019 11:02 AM

Flywheel
 
If I were you I'd get the flywheel resurfaced. Don't take a chance and put it back together with a new clutch and pressure plate only to have it chatter.
I recently did mine and also changed the RMS.

yelcab1 05-10-2019 12:33 PM

Yes, I would at least go over that flywheel with a power hand sander and some gritty sand paper.

Walt Fricke 05-10-2019 09:28 PM

Flywheel looks OK in photos. The dots on it are rust from the clutch disk. For sure clean it up. If it were mine, beyond some abrasive work I'd leave it alone.

How did this area get so much rust?

You need to measure the wear on the fingers of the pressure plate. I don't know if there is a specification, but they start out the thickness of the diaphragm spring. Any reduction in thickness is going to allow the TOB to move around a bit more than when everything is new. I'd consider replacing the PP based on finger wear if more than a few thousandths, but someone may have a more specific test.

RWebb 05-11-2019 01:03 PM

agree with above but would toss a dial indicator at the flywheel "as long as yer in thar"

OsoMoore 05-14-2019 06:22 AM

Quote:

Originally Posted by Walt Fricke (Post 10455442)
Flywheel looks OK in photos. The dots on it are rust from the clutch disk. For sure clean it up. If it were mine, beyond some abrasive work I'd leave it alone.

How did this area get so much rust?

You need to measure the wear on the fingers of the pressure plate. I don't know if there is a specification, but they start out the thickness of the diaphragm spring. Any reduction in thickness is going to allow the TOB to move around a bit more than when everything is new. I'd consider replacing the PP based on finger wear if more than a few thousandths, but someone may have a more specific test.

The rust on the flywheel may be from 3 years ago when I had everything out to rebuild the transmission. I washed everything and didn't think about drying it carefully. It was out of the car for about 3 weeks.

I'm replacing the pressure plate, clutch, and clutch release bearing. So that should address any PP issues.

Regarding abrasive/sanding the flywheel - do you mean just go at it with some fine-grain normal sandpaper? Is the goal to make it as smooth and non-rusty as possible?

RedCoupe 05-14-2019 06:39 AM

The manufacturers of clutch and brake linings have a recommended surface finish for flywheels/pressure plates just like there is a recommended finish for brake rotors. This allows the new lining to " bed in" without losing too much lining. That's why I usually pull the flywheel and have it surfaced whenever I do a clutch job. That said, as long as your surface finish isn't too glossy or really rough, you're going to be okay. If you shoot for the finish that is on a new pressure plate, it should be the right compromise between roughness and smooth.

OsoMoore 05-14-2019 03:17 PM

Waiting for parts to arrive, got the transmission all clean. But I can't see to get the screws loose to remove the guide tube. I put some PB Blaster on them, and I'm using the proper gauge screw-driver, but I can't get them to budge. Any ideas?http://forums.pelicanparts.com/uploa...1557875790.jpg
http://forums.pelicanparts.com/uploa...1557875790.jpg

RWebb 05-14-2019 03:34 PM

rap the head with a steel hammer

yelcab1 05-14-2019 04:15 PM

Did you try an impact driver?

pete3799 05-14-2019 05:05 PM

Quote:

Originally Posted by yelcab1 (Post 10458995)
Did you try an impact driver?

This.

hughc 05-14-2019 05:07 PM

Quote:

Originally Posted by yelcab1 (Post 10458995)
Did you try an impact driver?

Worked well for me.

chrismorse 05-15-2019 07:30 AM

Impact driver and new bit
 
If you are using an impact driver, (I've got an 18 and 12 volt Milwaukee), use a new bit and lean into it to Keep from caming out, (stripping).
Chris

David Inc. 05-15-2019 08:46 AM

I would be scared ****less to put an impact to a philips head screw. I would suggest instead a philips insert into a 1/4" handle. Much more controllable torque, and probably more than enough to get them out...I think that's what I had to do myself, actually.

shoooo32 05-15-2019 09:39 AM

David - these work awesome for removing those stubborn phillips screws. Smack it with a hammer and Bob's your uncle.

https://www.amazon.com/TEKTON-2905-8-Inch-Manual-7-Piece/dp/B000NPPATS/ref=asc_df_B000NPPATS/?tag=hyprod-20&linkCode=df0&hvadid=312003160272&hvpos=1o4&hvne tw=g&hvrand=9800960495860080190&hvpone=&hvptwo=&hv qmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9018799& hvtargid=pla-420785539586&psc=1

OsoMoore 05-15-2019 12:07 PM

Thanks everyone, now I know about impact screw-drivers. I've got one on order and it looks like it will be fun to use too!

David Inc. 05-15-2019 02:19 PM

I've never seen one of those, cool!

Walt Fricke 05-16-2019 05:16 PM

OSO - on the flywheel surface, what you want to do is break the glaze to increase the coefficient of friction a bit. You don't have to go overboard - your clutch worked acceptably until the TOB pulled off. As pointed out, toward what the new PP surface looks like, or a new brake rotor.

You can't get there with the kind of tools you are apt to have available, but a little will go a long way. We aren't looking at wood sandpaper, more like 3M abrasive pads. I'd use my angle die grinder with the attachment which holds the small round version of those pads. You may not have air tools, so a big rectangular fiber pad might be a good starting point, and elbow grease.

eastbay 05-17-2019 07:23 AM

The rust dust is from the pounded out and hammered clutch disc springs. That disc was coming apart.


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