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AtlasShrugged Samba Member
Joined: October 30, 2008 Posts: 1605 Location: Decatur, Ga. USA
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Posted: Tue Mar 20, 2012 10:03 am Post subject: CV joint not staying tight? |
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It is very tough to install CV joints without getting some trace amounts of grease in the flange or bolt holes. Over time..even when doing a re-torque at some time after fitting, they seem to get loose.
I am experimenting and will be using these Nord Lock washers.
Anyone have any experience with them?
Link
Some of the Porsche racing crowd seem to like them.
Not too expensive from McMaster-Carr
91074A130 Zinc-Coated Steel Wedge Lock Washer, 5/16"/M8 Screw Size, .53" OD, .10" Thick, packs of 25
Merchandise $12.14 |
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dubbified Samba Member
Joined: March 03, 2010 Posts: 1406 Location: Redmond, WA
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AtlasShrugged Samba Member
Joined: October 30, 2008 Posts: 1605 Location: Decatur, Ga. USA
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Posted: Tue Mar 20, 2012 10:36 am Post subject: |
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No...those are Schnorr washers. My results with them are mixed.
The interesting thing about the Nord-Locks is they can be lubricated. The lock doesn't require tension on the threads of the bolt to retain the fastener.
Might be helpful in a greasy environment. |
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dubbified Samba Member
Joined: March 03, 2010 Posts: 1406 Location: Redmond, WA
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Posted: Tue Mar 20, 2012 2:06 pm Post subject: |
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Yea.. but that shouldnt be lubed. I'd expect the CV thread shafts and axle threads you're screwing into should be clean, debris free and use some threadlocker.
I'd also question why there is such a issue. These things dont just come loose. I've had oodles of cars with CVs.. mechanical background.. |
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randywebb Samba Member
Joined: February 15, 2005 Posts: 3815 Location: Greater Metropolitan Nimrod, Orygun
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Posted: Tue Mar 20, 2012 2:46 pm Post subject: |
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My sure-fire advice for Porsche 911 CV bolts (dunno if VW spec.s are the same, but likely so):
use brake cleaner & Q-tips to get every bit of grease out
use NEW Schnorr washers each time - NEVER old ones
carefully inspect the wrenching fixture on the cap screw and the threads - reuse if ok; if you replace do not use some junk from a hardware store, get the correct spec. "bolts"
use the correct torque; threadlocker is not required
re torque after ~~ 10 miles
I have never heard of one loosening if the above are followed - every time I hear of one loosening, the above was not followed, or "the PO did it" _________________ 1986 2.1L Westy 2wd Auto Trans. |
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insyncro Banned
Joined: March 07, 2002 Posts: 15086 Location: New York
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Posted: Tue Mar 20, 2012 2:55 pm Post subject: |
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X2 above.
clean well
use new washer each time
proper torque
threadlocker and wire tieing are the ultimate safety features. |
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AtlasShrugged Samba Member
Joined: October 30, 2008 Posts: 1605 Location: Decatur, Ga. USA
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Posted: Tue Mar 20, 2012 2:57 pm Post subject: |
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Modern Moly Grease can cause some tightening torque problems. I never had any problems with VW or Porsche. Maybe I'm just getting old.
Good torque wrench, clean and careful assembly..and still from time to time..even 10k miles later.
The Porsche crowd has had some loose CV problems too. Some interesting solutions on fasteners.
The Nord Locks look to be an easier solution. Won't cost much..cheap insurance.
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insyncro Banned
Joined: March 07, 2002 Posts: 15086 Location: New York
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Posted: Tue Mar 20, 2012 2:59 pm Post subject: |
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The Nords are good, I've used them, Yup on a Porsche. |
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mtwrench540 Samba Member
Joined: October 25, 2009 Posts: 351 Location: monterey,va
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Posted: Tue Mar 20, 2012 3:04 pm Post subject: cv's |
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show me! the wire tying,and what drill bit was used?
insyncro wrote: |
X2 above.
clean well
use new washer each time
proper torque
threadlocker and wire tieing are the ultimate safety features. |
_________________ 87 wolfsberg,74 181w/1915 and lots of patina! learned to fix vw's from hot vw mag in 1964,VWOA instructor,DSM,69 to73,service mgr at different porsche-audi dealers etc,etc,now retired!!! first vw new 64,transplanted 356 eng in 65,400characters are not enough space!! |
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AtlasShrugged Samba Member
Joined: October 30, 2008 Posts: 1605 Location: Decatur, Ga. USA
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Posted: Tue Mar 20, 2012 3:08 pm Post subject: |
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Some different locking techniques.
Link
Link
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insyncro Banned
Joined: March 07, 2002 Posts: 15086 Location: New York
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Posted: Tue Mar 20, 2012 3:12 pm Post subject: Re: cv's |
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mtwrench540 wrote: |
show me! the wire tying,and what drill bit was used?
insyncro wrote: |
X2 above.
clean well
use new washer each time
proper torque
threadlocker and wire tieing are the ultimate safety features. |
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I buy drilled bolts, the four hole ones.
Couldn't find a picture of my 930s all wired up.
Next time I'm at the track I will try to shot a photo. |
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randywebb Samba Member
Joined: February 15, 2005 Posts: 3815 Location: Greater Metropolitan Nimrod, Orygun
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Posted: Tue Mar 20, 2012 3:48 pm Post subject: |
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there are pics on the 911 tech forum at Pelican Parts, but you'll have to do a search and pick thru the results - it is a very active bbs
I would definitely go for ones that are made with holes in them as that should reduce stress cracking.
BUT...
safety wire does not maintain the torque! And it is the torque (tension in the "bolts") on the face of the assembly that provides the friction allowing the rotational torque to be transmitted to the wheel hub. _________________ 1986 2.1L Westy 2wd Auto Trans. |
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randywebb Samba Member
Joined: February 15, 2005 Posts: 3815 Location: Greater Metropolitan Nimrod, Orygun
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Posted: Tue Mar 20, 2012 3:52 pm Post subject: |
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Here are results from one search - did not check for those pics, but you'll find lots of good info in these
pay particular attn. to posts by Jim Sims - he is/was an engineer at one of the National Labs, and seems to really know his fasteners
also, a guy IROC if he is on these threads
http://forums.pelicanparts.com/search.php?searchid=8031660 _________________ 1986 2.1L Westy 2wd Auto Trans.
Last edited by randywebb on Thu Mar 22, 2012 9:02 pm; edited 1 time in total |
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AtlasShrugged Samba Member
Joined: October 30, 2008 Posts: 1605 Location: Decatur, Ga. USA
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Posted: Thu Mar 22, 2012 7:21 pm Post subject: |
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Did some research on "SCHNORR Washers". The style we use as the common replacement parts with CV joints.
There are three safety washer products from Schnorr that fit an 8mm bolt. One is the "S", a "VS" and the other is "HDS"
The difference between the three, supplied for an 8mm bolt as we use is the "S" is 1mm/.8mm thick, the "VS" is 1.2mm thick and the "HDS" is 2mm thick.
The "S" washer is suitable for a 8.8 bolt hardness.
The "VS" washer is suitable for bolts 8.8 to 10.9.
The original CV bolts in the Vanagon was a 10.9 hardness.
Replacement bolts..are a 12.9 as supplied with the CV joints from Lobro and our vendors.
The replacement washers we get are not 1.2mm thick. They are .8mm and probably a "S" washer.
http://www.schnorr.de/uploads/media/Schnorr_Produktprospekt_engl.pdf
See page 28 from the Schnorr catalog.
The problem may be the replacement bolt is now is harder than the schnorr washers..the washer will deform rather than "bite" into the 12.9 bolt. It may not hold the 12.9 bolts as designed.
Inspected some CV joint with 12.9 bolts and there was no marks from the schnorr washer on the bolt. The moon plates are softer and had very clear marks from the schnorr washer.
I have some old 10.9 CV bolts and the original schnorr washer did leave a mark on those bolts.
Inner CV joints seem to be the occasional problem..probably due to engine/transmission vibration. The outer CV joints never seem to loosen.
Schnorr "HDS" safety washer..I cant find any specs aside from a reference that they are suitable for a 12.9 bolt. They are 2mm thick.
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hege Samba Member
Joined: November 14, 2007 Posts: 59 Location: Finland
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Posted: Sun Mar 25, 2012 4:28 am Post subject: |
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I've also had similar problems with cv joints coming loose. Maintaining racing cars it has been common practice that we retightened cv joints every day as regular maintainance. I've tried locktite, but cleaning the threads is a real pain. Even when being really careful I've had bolts coming loose. I have bad results with different washers, and I've used ones that look like the schnorr washers. In the end we just accepted that CV joints come loose and have to be retightened to keep them tight. Like mentioned in the post before, it's always the inside joints that loosen. The driveshaft seems to dampen the vibrations so it's no problem on the outside. The outside CV seems to wear faster also (in the rear).
I've since retired from racing so I don't have any "real" experience of norlocks, but I've started to use them everywhere that I want to keep tight. I've had to reuse them a couple times because I didn't have new ones with me and they seem to work as well the second and third time. When you open the bolt you can feel them working. When opening you can feel the bolt becoming tighter until they release.
The patent went out on nordlocks, so nowadays they can be had for a fraction of the price they used to be. I've used genuine nordlock, so can't comment on copies.
I'm very interested in this because it's something I've never got sorted. I will be checking the pelican parts forums. Jim Sims has over 5000 posts and IROC has over 8000 posts so the search. I tried quick searches and got almost 1000 results with each. I'll have to look into this with better time... |
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minsk Samba Member
Joined: March 17, 2008 Posts: 899 Location: pittsburgh
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randywebb Samba Member
Joined: February 15, 2005 Posts: 3815 Location: Greater Metropolitan Nimrod, Orygun
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Posted: Sun Mar 25, 2012 12:41 pm Post subject: |
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hege - Locktite now makes a product that can be use on slightly oily threads - IIRC, it is a blue
I have not used it as I always use brake cleaner to get the male & female parts clean.
also, the Schnorrs have a very unusual profile - no idea re their biting ability on 12.9 fasteners
some people do like the Nordlocks - whether they are engineers or not, I don't know... _________________ 1986 2.1L Westy 2wd Auto Trans. |
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locke999 Samba Member
Joined: May 01, 2007 Posts: 223 Location: california
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Posted: Sun Mar 25, 2012 3:41 pm Post subject: cv bolts |
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cheap fix
just drill a little hole in all the bolts and
thread a wire thru,they will never fall out again.
al |
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randywebb Samba Member
Joined: February 15, 2005 Posts: 3815 Location: Greater Metropolitan Nimrod, Orygun
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Posted: Sun Mar 25, 2012 7:46 pm Post subject: |
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randywebb wrote: |
there are pics on the 911 tech forum at Pelican Parts, but you'll have to do a search and pick thru the results - it is a very active bbs
I would definitely go for ones that are made with holes in them as that should reduce stress cracking.
BUT...
safety wire does not maintain the torque! And it is the torque (tension in the "bolts") on the face of the assembly that provides the friction allowing the rotational torque to be transmitted to the wheel hub. |
_________________ 1986 2.1L Westy 2wd Auto Trans. |
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AtlasShrugged Samba Member
Joined: October 30, 2008 Posts: 1605 Location: Decatur, Ga. USA
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Posted: Sun Mar 25, 2012 7:58 pm Post subject: |
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[/url]
The Nord-Locks are about 52 cents per bolt from McMaster-Carr, part number 91074A130. For both inner CV joints less than $7. (sold in packs of 25 for about $13)
They are also 2.6mm thick. Best to ditch the OEM 47mm long CV bolts and switch out to the more common 50mm 12.9 allen bolts ( about 40 cents each). When the Nord-Locks are fitted to the 50mm bolts they still do not protrude out the back of the CV flange. Much firmer fit too.
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