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Build a clutch disc for your 924S/944
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joecitizennn  



Joined: 12 Sep 2005
Posts: 2096
Location: no mans land

PostPosted: Sat Feb 07, 2009 4:07 am    Post subject: Build a clutch disc for your 924S/944 Reply with quote

Fix your exploded rubber center clutch for less than 50 bucks. I have done this trick several times and it has always worked flawlessly. The best part is, it saves you 300 bucks or more.

Step 1
Buy a ford bronco 2 disc from Advance Auto. Drill out the rivets that hold the disc to the hub.



Step 2
Now you need to offset the hub from the disc so the hub will clear the flywheel bolts. (This is for non turbo models) I Fabricated spacers from 1/2" keystock.



Step 3
Holes must be drilled that match the holes in the hub and disc. The spacers must sit like so.



Step 4
The hub and disc must be solidly attached. I used cold rivets. The rivets were obtained from a farm supply store. They were sold for use on hay cutter teeth. I drilled a recess in a punch so when I peened the rivets they would round nicely. Finished product looks like this.





There have been alot of forum members who have shot me questions about building clutch discs to replace those shitty rubber ones found on the 924s and the 944. Took me a while to post a how to, hope you like it.

This disc is in my Carerra GT body 924s and works like a dream, with smooth let-off and absolutely no chatter.



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Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11356
Location: PacNW

PostPosted: Sat Feb 07, 2009 5:01 am    Post subject: Reply with quote

So you're reusing the OEM friction part of the clutch?

Mayhap you should throw together a kit for this for folks who don't have your fabrication skills.
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Smoothie  



Joined: 01 Jan 2003
Posts: 8029
Location: DE (the one near MD, PA, NJ)

PostPosted: Sat Feb 07, 2009 5:53 am    Post subject: Reply with quote

No, you'd use both friction and center parts from the new Autozone Bronco II disc. You're just
seperating the parts, then adding spacing so the springs don't hit the flywheel bolts, then reassembling..
Cool solution - looks like something I might've tried if I needed to, but as we know, the Bronco II
part can be used without this modification on most 931s (I believe some RoW 931s got the 924s-944
style disc and flywheel).
Looks like a lot of fairly accurate work's required to fabricate the spacers. Get sloppy with those and
you might end up with a malbalanced disc.

About the bar stock - was it bent first, then cut, then each end rounded by grinding?
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Catamax944  



Joined: 14 Jan 2009
Posts: 140
Location: London UK

PostPosted: Sat Feb 07, 2009 11:20 am    Post subject: Reply with quote

For who is not familiar with the ford bronco,what year is that?What make is the disc?A where to buy link would be great.I looked on the Advance Auto site and couldn't find it.
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PORSCHEV  



Joined: 02 Nov 2002
Posts: 1911
Location: Cedar Lake Nova Scotia, Canada

PostPosted: Sat Feb 07, 2009 1:08 pm    Post subject: Reply with quote

Great work!
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Rasta Monsta  



Joined: 12 Jul 2006
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Location: PacNW

PostPosted: Sat Feb 07, 2009 3:27 pm    Post subject: Reply with quote

Catamax944 wrote:
For who is not familiar with the ford bronco,what year is that?What make is the disc?A where to buy link would be great.I looked on the Advance Auto site and couldn't find it.


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morghen  



Joined: 21 Jan 2005
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Location: Romania

PostPosted: Sat Feb 07, 2009 5:54 pm    Post subject: Reply with quote

excelent ! add some details about the ford disk and you're done.
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Catamax944  



Joined: 14 Jan 2009
Posts: 140
Location: London UK

PostPosted: Sun Feb 08, 2009 2:00 am    Post subject: Reply with quote

Rasta Monsta wrote:
Catamax944 wrote:
For who is not familiar with the ford bronco,what year is that?What make is the disc?A where to buy link would be great.I looked on the Advance Auto site and couldn't find it.


Search


Yeah,would you like to explain that,search for what,ford bronco in a 924 forum.
Actually i did a pretty extensive search on google before but i couldn't find the exact same disk type and for shure not for 50$(too many broncos and too many disk manufacturers lol)but i did found out that the Starion's disk is also very similar and not only,many other cars too lol.
The thing is that not all are riveted together like that one here and can't be taken apart,that's why i said that more info and possibly a where to buy link would be great.It's a great thread,excellent job but we need a little more info on that disk.
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CorsePerVita  



Joined: 25 Jul 2008
Posts: 1994
Location: Redmond, Oregon

PostPosted: Mon Feb 09, 2009 3:04 pm    Post subject: Reply with quote

does this work for the regular 924 and not just the 924s or turbo?
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Smoothie  



Joined: 01 Jan 2003
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Location: DE (the one near MD, PA, NJ)

PostPosted: Mon Feb 09, 2009 3:35 pm    Post subject: Reply with quote

No, 924NA clutch is a different diameter, its' center hub opening is smaller, and the number of splines is different.
There were a couple of lengthy topics a few years back that include listings of which clutch discs from other cars can be used in place of both the OE 924NA and 931 parts. Once you find one that fits the 924NA, it'll fit without the above modification (, but as I recall they're a bit smaller in diameter than Porsche OE).
The above procedure is only required for the 924S and 944 (and a limited number of RoW 931s, and possibly CGTs) to increase clearance between the discs' center and the flywheel bolts to keep them from hitting.
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Rich H  



Joined: 10 Jun 2007
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Location: Preston, Lancs, UK

PostPosted: Mon Feb 09, 2009 9:34 pm    Post subject: Reply with quote

Look for Audi 100 clutches, a couple of us Limey types have found exact replacements for £30 locally. I don't recall the exact model, but there are only so many combinations! It's an Audi based engine and an Audi based gearbox (Well the end of the torque tube is the same as the front of the box!) so one of the Audi 100 clutch fits perfectly.
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joecitizennn  



Joined: 12 Sep 2005
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Location: no mans land

PostPosted: Tue Feb 10, 2009 4:43 am    Post subject: Reply with quote

Ok. I will try to answer your questions and comments.

First, no Rasta, i am using all new parts.

Second, Catamax, you are correct to state that you cannot do this with any bronco 2 disc. The bronco 2 and the ford Aerostar van in fact, have a 23 spline disc that is 225 mm (8 7/8") across. Exactally what a 944 or 924S require. However the disc must be offset to clear the flywheel bolts. When i first started this project I bought a disc from Autozone. Its center was held by only 4 rivets very close to the hub. Not ideal for rebuilding with an offset and retaining any strength. I then bought Advances' disc which was perfect. It had 16 rivets near the outer edge of the hub, and since there were 3 holes per each of the 8 attachment spots, you could run 24 rivets for extra strength. The part number for this disc is rcf48801 selling for $29.99 at advance right now, listing for $52.48 in the book.

Finally, Smoothie, the barstock was not bent. That would be alot of work!! I bought a long peice, and cut it to the appropriate lengths. I then traced the outline and hole location from the attachment flanges on the inside of the disc. (see photo of disc.) I then used a bench grinder to attain the kidney bean shape you see, and drilled my holes. To attain balance I weighed each spacer on a digital pocket scale, gringing weight off the edges till they all came within one tenth of a gram. The scale cost me around 10 bucks. The even weight ensures perfect balance.

As a final note to anyone interested in doing this, you can approach it anyway you like as long as you achieve the correct offset and your spacers do not strike the flywheel or pressure plate. I went to all the trouble with this disc because I knew I was going to drive the broiling shit out of it and it had to survive abuse.
The first time I did this project I used stacks of washers as spacers and fastened everything with bolts. Not just any bolts, soft grade 2 bolts. The nuts were locktighted and bolt ends peened flat. I was afraid that the bolts might in time stretch loose and sheer off under stress. I was wrong. After 20k miles I removed the disc for examination, to find that the whole unit was as tight as when I put it in. Point is, fabrication means you can approach the project any way you like, the outcome will be as good as your parts and your planning.
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JayZzzz4  



Joined: 24 Sep 2008
Posts: 546
Location: Milwaukee, WI USA

PostPosted: Tue Feb 10, 2009 6:28 am    Post subject: Reply with quote

Looks just like the the original 924s-944, Great Job man!

http://www.paragon-products.com/PhotoDetails.asp?ShowDESC=N&ProductCode=PP944.116.012.11
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joecitizennn  



Joined: 12 Sep 2005
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PostPosted: Thu Feb 12, 2009 3:23 am    Post subject: Reply with quote

some pictures of the same project done with bolts.
This disc was in a 924s for around 20K miles and shows no problems whatsoever.

Note that I put the bolt through the hub and fastened it with a nut before stacking washers. This held each bolt in place while I stacked washers making the job much simpler. The final nut was thread-locked and center-punched to insure it would never unscrew.





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Ian924s88  



Joined: 05 Aug 2008
Posts: 51
Location: Townsend MA

PostPosted: Wed Jun 17, 2009 12:02 am    Post subject: Reply with quote

that is great! how did you ever find that the Bronco II/Aerostar clutch disc was the right fit ? have one laying around perhaps and match them up by luck? you could probably make a few extra bucks just selling those nicely fabricated spacers with holes.

did you keep your old presure plate in place ?
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