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SirAndy

Convert to real 5-lug using 944 CVs


This Article describes how to convert the rear axles on your 914 to give you real 5-lug hubs using a mix of 914, 944 and 911 components.

Tools and Supplies:

  • BFH
  • Two new 914 rear wheel bearings
  • Four new 944 100mm 6-bolt CV joints including mounting bolts, boots and grease
  • Two 911 ('75 - '79) 100mm 6-bolt coarse spline transmission output shafts
  • Two output shaft seals
  • Two 911 ('75 - '79) 100mm 6-bolt stub axles
  • Four 911 100mm CV gaskets
  • Two 911 ('69 - '73?) hubs, must have same bearing surface width as the 914 hubs
  • Access to a lathe

Step 1: Preparing the axle shafts

Remove the CV joints from your old axles and machine both ends of your axle shafts to allow the wider 944 CVs to slide on.
You'll have to remove 4mm of material to make up for the wider 944 CVs.


4mm of material removed:


Stock 914 CV on the left and a 944 CV on the right




Step 2: Putting it all together

Grease up your new 944 CVs and slide them on the machined axle shaft *without* using the stock spring washer behind the CV!
Make sure the CV slides all the way on and don't forget to put the circlip back onto the shaft to prevent the CV from sliding off.
Note: Make sure the "groove" on the outside of the new CVs always points away from the axle (see picture with the complete axle).
Remove the old stub axles and hub. Remove the old wheel bearings. Install the new wheel bearing in your trailing arms.
Make sure the bearing surface on your new hubs is clean and press in the new hubs. Install the new stub axles and tighten the axle nut.
Remove the old output flanges from your transmission, replace the seals and slide in the new 911 flanges.
Grease up both, the output flange cup and the stub axle cup and install your new axles. Don't forget the CV seals!
Tighten everything to spec and enjoy!


911 coarse spline output shaft and 911 stub axle:


944 CV on 914 axle shaft:


Test fitting the output shaft on the 944 CV:


And at last, the completed axle. The top shows the original 914/4 axle, the bottom shows the new axle:


Mounted on the car:



Info compiled by SirAndy
SirAndy
did i miss something ???

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johannes
QUOTE(SirAndy @ Feb 5 2008, 11:38 PM) *

did i miss something ???

idea.gif


Yes, : This goes to the classics (one vote)

Congrats, this is a great post !

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PeeGreen 914
agree.gif
Wanna9146
QUOTE(SirAndy @ Feb 5 2008, 11:38 PM) *

did i miss something ???



Yes...when are you going to start selling these to those of us who are incapable (or lazy)?

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rebelmdot
QUOTE(SirAndy @ Feb 6 2008, 01:38 AM) *

did i miss something ???

idea.gif



Andy, can you tell me why this is better or more beneficial than the other 5 lug conversions that are on threads here? Thanks.
Joe Ricard
Because you don't have to re-drill a 4 hub.
Gint
Let this go a few days and make all the edits you want Andy and get it all correct. Then I'll create a tech article.
Richard Casto
Andy,

Thanks for the write up. I will probably be using this exact method on my car.

I do have a question. I don't understand the differences in the various transmission output flanges. I am assuming that the course (33 teeth?) flange you mention works with 901/914 transmissions. Does that also work with early 915 transmissions that I think also used a course flange? I think that later 915 transmissions used a fine (43 teeth?) flange. Will this later 915 flange work with this setup?

Overall with the 915, I am concerned if the CV still bolts up (hole pattern and bolt size) and about the output flange to stub axle distance (is the distance the same regardless of which transmission and flange you use. In short, will the 914 axle length always be correct)

I would like to do exactly as you have described, but with my 914 transmission today and then in the future switch to a 915 transmission with hopefully the only potential change is in the output flange.
davep
QUOTE(SirAndy @ Feb 5 2008, 11:38 PM) *

did i miss something ???

idea.gif

I'd add part #'s for the new parts, and spline counts for the output shaft, hubs and stub axles. Also, when machining the drive shaft, how big of a radius can be left on the inside corner (you do not want to have a sharp corner there), and I think I would also round the outside corner so as to remove the sharp edge. Do you require Schnorr washers as well?
anderssj
Great article!

agree.gif It would be helpful to list the actual part numbers under "Tools and Supplies."

Looking forward to using this info in the near future.

THANKS Andy!
stephenaki
How does this affect the issue with the parking/emergency brake? I understand that the 911 conversion negates the use of the parking brake; does this have the same problem or is it a non issue based on the fact that your not changing out the entire suspension.

Uneducated minds would like to know.
Richard Casto
QUOTE(stephenaki @ Feb 6 2008, 10:00 AM) *

How does this affect the issue with the parking/emergency brake? I understand that the 911 conversion negates the use of the parking brake; does this have the same problem or is it a non issue based on the fact that your not changing out the entire suspension.

Uneducated minds would like to know.


I believe that e-brake issues are more of a function of moving away from the stock 914 rear caliper than a five lug conversion issue. For example you can do a five lug conversion and use a 914/6 rear caliper ($$$$) as the e-brake solution is the same for all 914 (4 or 6) calipers. But it is common to do a five lug conversion and at the same time move to a 911 (or other) rear caliper that uses a different e-brake solution than the 914 rear caliper does.
PRS914-6
Andy, nice write up!

I'm going to add a few things here so that it can be found when searching. Andy's method is a great and economical solution for the wimpy 914 CV's. If you are running big horsepower and large sticky tires you "can" go even bigger. It will cost a lot more though.

I used course flange 108mm stub axles\CV's that came off the early 911's They are the biggest CV's available that will fit and even larger than the 944's. You can snag the early 911 5 lug stub axles that will bolt right on a 914 as well. (mine were off a 69)

To tie it together I bought some Sway-A-Way free floating race axles that can be bought in most any length you desire. Hopefully a bullet-proof system. Sway-A-Way Web Site

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John
QUOTE(Richard Casto @ Feb 6 2008, 07:40 AM) *

QUOTE(stephenaki @ Feb 6 2008, 10:00 AM) *

How does this affect the issue with the parking/emergency brake? I understand that the 911 conversion negates the use of the parking brake; does this have the same problem or is it a non issue based on the fact that your not changing out the entire suspension.

Uneducated minds would like to know.


I believe that e-brake issues are more of a function of moving away from the stock 914 rear caliper than a five lug conversion issue. For example you can do a five lug conversion and use a 914/6 rear caliper ($$$$) as the e-brake solution is the same for all 914 (4 or 6) calipers. But it is common to do a five lug conversion and at the same time move to a 911 (or other) rear caliper that uses a different e-brake solution than the 914 rear caliper does.



This mod has nothing to do with brakes. That would be another topic.

One BIG benefit is that you can still buy NEW 944 CV joints, and they should hold up better with more power.

One can still use 4-cyl rear calipers with 914-6 rear rotors, or one could have 4-cyl rear rotors drilled for 5-lug.




Andy,

Please post Part numbers of the transmission output flanges as these seem to be the item I have the greatest difficulty in obtaining.

Thanks
stephenaki
QUOTE(Richard Casto @ Feb 6 2008, 07:40 AM) *


I believe that e-brake issues are more of a function of moving away from the stock 914 rear caliper than a five lug conversion issue. For example you can do a five lug conversion and use a 914/6 rear caliper ($$$$) as the e-brake solution is the same for all 914 (4 or 6) calipers. But it is common to do a five lug conversion and at the same time move to a 911 (or other) rear caliper that uses a different e-brake solution than the 914 rear caliper does.


OK, got it. My assumption is, correct me if it is wrong, that if I were to do Andy's conversion I would have to re-do the rear brakes or would the stock 914/4 system work with this conversion?

Understand the stopping power is reduced with bigger wheels but if your not racing the car or increasing the power is it required to convert the brakes? I am still a novice at this so am trying to learn as I go along.
Richard Casto
QUOTE(stephenaki @ Feb 6 2008, 11:02 AM) *

QUOTE(Richard Casto @ Feb 6 2008, 07:40 AM) *


I believe that e-brake issues are more of a function of moving away from the stock 914 rear caliper than a five lug conversion issue. For example you can do a five lug conversion and use a 914/6 rear caliper ($$$$) as the e-brake solution is the same for all 914 (4 or 6) calipers. But it is common to do a five lug conversion and at the same time move to a 911 (or other) rear caliper that uses a different e-brake solution than the 914 rear caliper does.


OK, got it. My assumption is, correct me if it is wrong, that if I were to do Andy's conversion I would have to re-do the rear brakes or would the stock 914/4 system work with this conversion?


QUOTE(John @ Feb 6 2008, 10:54 AM) *
One can still use 4-cyl rear calipers with 914-6 rear rotors, or one could have 4-cyl rear rotors drilled for 5-lug.


I think John's point above answers your question. Doing the CV and 5 lug conversion does not require you to re-do your rear calipers. You will need to use rotors that have five lugs (either the 914/6 rotors or re-drill the 914/4 rotors)
Wes V
First off, thanks!!

Requested additions;

1. I'd recommend verifying run-out of the of the hub prior to installing. Put it in a lath and use a dial indicator (while rotating the hub by hand). If the source car was in an accident, the hub could be bent and you may not see it by eye. If you don't notice it until installed, you will have to buy new bearings when you replace it with a good one. (BTDT)

2. CV bolts should be replaced with longer ones to match the 944's wider width. It may be recommended to use grade 8 bolts that allow safety wire. At least, locktite the bolts.

3. For us newbies, the 100mm reference is the outside diameter of the CV, not the bolt circle. Of course, that's if that's correct.

Wes
Steve Thacker
Andy,

You have outdone yourself again. I wish I was your next door neighbor. I'd be one smart fucher with these cars. aktion035.gif
stephenaki
QUOTE(Richard Casto @ Feb 6 2008, 08:26 AM) *



I think John's point above answers your question. Doing the CV and 5 lug conversion does not require you to re-do your rear calipers. You will need to use rotors that have five lugs (either the 914/6 rotors or re-drill the 914/4 rotors)


OOPs, I obviously missed that.
Krieger
Andy thanks for your help on this. I did this conversion for my axles last summer following Andy's original post. I have not installed axles in my car yet. I have one difference in how I did this. I bought new complete OEM cv kits. I did used the original spring washer installed on the axle prior to the cv being installed. It went together just as any other cv that I installed. I am not sure why Andy omits this. Hopefully he'll chime in. When I did my conversion I bought a used 944 axle/cv and disassembled it and took the parts to my machinist. He duplicated the exact profile of the 944 axle on my 914/4. I have a technical drawing of what he did if Andy wishes to have it included. Sorry to high-jack. Also FYI if you have 914/6 axles they have the same # splines as 6 bolt 100mm 911 cvs.
SirAndy
Just a quick update. I have been running my axles for a year now, two 2000 mile roadtrips and a few AX events. All with the 3.6L putting quite a bit of torque through them.

So far, no problems at all ...
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-JR-
Based on Andy's notes I've assembled these details on part numbers...

Rear hub 1969 --> 1973 "901 331 065 09" 911 T/E/S *Not Carrera"
Rear Axel 1970 --> 1983 "901 332 232 00" 911 SC/SPM *Not Turbo*

944 CVs Any year, non-turbo "944 331 901 00"

I haven't researched transmission flanges. They will depend on your transmission selection.
-JR-
Alternate method: *no machine work*

I should add that I found this method burried on another website and I haven't confirmed it's validity but here goes...

-Rear hub 1969 --> 1973 "901 331 065 09" 911 T/E/S *Not Carrera"
-Audi 5000 front wheel bearings, three bearings internally compaired to 999-053-021-00 dual bearing for 914's and 911's.
-944 Turbo stub axel (951 332 235 35) mates with 911 hub
-944 Turbo CV joints (951 332 901 00)
-914 axel shaft
-911S,SC / 912E transmission flange (923 332 209 02) 1974 --> 1983

The original author claimed no machining / no spacers / 901 or 915 and the use of 100MM CV joints.

I am not able to find a part number for the Audi wheel bearing. So far my searches indicate that the Porsche bearing is the same for the Audi 5000. But from my Audi days I do seem to recall that the 5000 did have a better bearing option.
SirAndy
QUOTE(-JR- @ Jun 21 2010, 04:48 PM) *

-944 Turbo CV joints (951 332 901 00)
-914 axel shaft

The 944 CVs are too wide to fit on a stock 914-4 axle shaft.

That is why i had mine machined to accept the 944 CVs.
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Krieger
I did exactly what Andy did. Here is the profile my machinist took off the 944 axle and cut into my 914 axle. biggrin.gif
Krieger
Shit! I just noticed the date at the bottom. My axles were done 3 years ago, but my car is....still not done.
-JR-
QUOTE(SirAndy @ Jun 21 2010, 05:16 PM) *

The 944 CVs are too wide to fit on a stock 914-4 axle shaft.

That is why i had mine machined to accept the 944 CVs.


Thanks Andy! Like I said, the author claimed no machine work nessasary. He may have not used the retaining clip. My Audi Coupe never used retaining clips on it's CVs.

Since I have your attention Andy, your post only says 944 100mm CVs. Did you use the turbo ones or the standard CV joints?

BTW - Finally brought my 3.6 home last week. cheer.gif Bought it almost 2 years ago!
jaxdream
There is another twist to the axle / cv delima, machine one end of the axle to fit the 944 cv , bolt that to the wheel side output flange ( 911 or modified 944 stub ) where the cv bolts to, the trans side leave un machined if you can't find the 911 / 915 course splined output flange for the 100mm cv, just use the 914 cv and trans flanges till you can get the proper flange to use the 944 100mm cv . when you get the flange for conversion , remove the axle , tkae to machine shop , have them machine the un machined end to fit the 944 100mm cv , install trans flange , cv , bolt up and go !!

My $.02 ....

Jack / Jaxdream
SirAndy
QUOTE(jaxdream @ Jun 21 2010, 09:29 PM) *
the trans side leave un machined if you can't find the 911 / 915 course splined output flange for the 100mm cv

Or, machine once and run athick washer until you get the correct output flanges ...
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SirAndy
QUOTE(-JR- @ Jun 21 2010, 09:24 PM) *
He may have not used the retaining clip.

That's the only way that would work.

As long as you never jack up the rear of the car, that might work.

Otherwise, the axle shaft will slide right out of the CV ...
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SirAndy
QUOTE(-JR- @ Jun 21 2010, 09:24 PM) *
Since I have your attention Andy, your post only says 944 100mm CVs. Did you use the turbo ones or the standard CV joints?

944-331-901-00-M60
CV Joint Kit With Boot, 924S/944/944S All, 944 Turbo (1986-87)

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jimkelly
•two 911 ('69 - '73?) hubs, must have same bearing surface width as the 914 hubs

can the above hubs be drilled to 4 lug for those that want the strength but want to remain 4 lug ( wheels, calipers, rotors ) ??

found answer in different thread - yes.
matthepcat
What about using 944 hubs?
scotty b
QUOTE(matthepcat @ Apr 10 2011, 12:28 PM) *

What about using 944 hubs?


something else I have on my "too look into list " I have a whole rear from one I junked for yet another special project. shades.gif
matthepcat
Well I am going to give it a try. What do I have to lose as I have 944 hubs on there right now.

The 944 hub also sticks out a little farther for those running modern offset wheels. This should allow one to use smaller wheel spacers.

QUOTE(scotty b @ Apr 10 2011, 02:03 PM) *

QUOTE(matthepcat @ Apr 10 2011, 12:28 PM) *

What about using 944 hubs?


something else I have on my "too look into list " I have a whole rear from one I junked for yet another special project. shades.gif

pcar916
Having gone through this recently, The 911, 944 and 930 CV's have the same inner-race depth. So technically, you could run the 911(if you could find them) or /930 CV's on modified (as above) original 914-6 axles, or 944 CV's on the 914 axles. Take your pick!

But remember, the 944 stub axles require an inboard spacer so they mate up to the 914 wheel bearings properly. 911 SC stubs work without mods.

Good luck
matthepcat
Is this inboard spacer a custom piece or available somewhere?

Also there are early 944 hubs and late (85.5+) hubs.

Maybe this spacer you are talking about is only for the early 944?

QUOTE(pcar916 @ Apr 10 2011, 02:33 PM) *

Having gone through this recently, The 911, 944 and 930 CV's have the same inner-race depth. So technically, you could run the 911(if you could find them) or /930 CV's on modified (as above) original 914-6 axles, or 944 CV's on the 914 axles. Take your pick!

But remember, the 944 stub axles require an inboard spacer so they mate up to the 914 wheel bearings properly. 911 SC stubs work without mods.

Good luck

matthepcat
Update on 944 hubs.


They don't work becuase they push the brake rotor out too far. This makes the brake caliper to rotor alignment incorrect.

matt
PeeGreen 914
You can use spacers on the caliper to line them up confused24.gif
matthepcat
QUOTE(PeeGreen 914 @ Jun 8 2011, 03:13 PM) *

You can use spacers on the caliper to line them up confused24.gif



Maybe. I guess I feel that this is sort of "janky". Have you seen this method used for a similar application?

SirAndy
QUOTE(matthepcat @ Jun 8 2011, 03:06 PM) *
Update on 944 hubs.

They don't work becuase they push the brake rotor out too far. This makes the brake caliper to rotor alignment incorrect.

I knew there was a reason i didn't use the 944 hubs ... smile.gif
Eric_Shea
Have you tried the 944 rear rotor? Its quite a bit shallower.

matthepcat
No I haven't but I assume this would require me to run a different rear brake caliper?


Matt

QUOTE(Eric_Shea @ Jun 8 2011, 04:47 PM) *

Have you tried the 944 rear rotor? Its quite a bit shallower.
Eric_Shea
Why? I believe they're within 1mm in diameter.
matthepcat
QUOTE(Eric_Shea @ Jun 8 2011, 04:57 PM) *

Why? I believe they're within 1mm in diameter.



Hmm, Thanks for the tip.

I never really payed any attention to them when I pulled the hubs off at the junk yard. I thought the rear rotors on the 944 were vented, and therefore much thicker.


I will give it a try.

Matt
Eric_Shea
Ahhhhh.. That, yes, they are vented. For some reason I though you were using vented with this setup.

Go with the caliper spacers... Good enough for Ferrari good enough for you wink.gif
McMark
If caliper spacers are too janky, then pull your trailing arms, weld more material onto the caliper mounts, mill it, drill it, and tap it. Ahhhh, perfection. biggrin.gif

Or maybe some red anodized billet aluminum spacers. laugh.gif

Just giving you a hard time... poke.gif
PRS914-6
QUOTE(McMark @ Jun 8 2011, 11:06 PM) *

If caliper spacers are too janky, then pull your trailing arms, weld more material onto the caliper mounts, mill it, drill it, and tap it. Ahhhh, perfection. biggrin.gif


Get out the cutting torch.....there's joy in that! Then you can have any thing you want......

Click to view attachment
matthepcat
Haha! Well I think swapping hubs would be a tad easier than metal fabrication smile.gif

Spacers it is.
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