washers for SC axle bolts

[aigel]

Reading the archives, I conclude that I need serrated washers under my axle bolts. I also would like to get new bolts, since my old ones are mangled in the heads.

I tried but can not find the washers listed for SC on this page

http://www.pelicanparts.com/catalog/shopcart/911M/POR_911M_suspen_pg10.htm

Only years are earlier and later, no washers listed for the SC.

Can someone please help me out here and give me the part numbers for my SC, for the bolts (6 or 12 point allen heads) and the magic serrated washers!?

Thanks!

George

PS: Reason I am asking is that my bolts keep coming loose. Having had the drivetrain out, I now have new cv joint seals installed and they seem to make things worse. They compress to a certain point but it seemst that they yield further, leading to the bolts loosing their proper torque. I may go to RTV instead, eliminating the CV gaskets completely. What do you think?

[Schrup]

George, this is where I got my schnorr washers. http://www.mcmaster.com/ There is a like $30 minimum, so I got an assortment. You can probable get the bolts there as well. I bought mine at a local industrial fastener distributor. BTW I bought the heavy duty schnorr washers & they worked fine.

[3liter914-6]

Hi George.

The SC used M10X48 CV bolts and M10 lock washers. Part numbers 900 067 128 01 and 999 523 103 01 respectively. Just get the parts listed for any pre-SC 911 and you'll be set.

Adam

[surflvr911sc]

Not true, the SC uses M8x50mm bolts. I have not been able to find a reference for washers on the SC anywhere. That doesn’t mean that I don’t think they should be there but it sure doesn’t look like the factory thought it needed them.

I safety wired my axle bolts, haven’t had to touch them since.

[Schrup]

Here is some as well.
FS CV Bolts with Schnorr washers

[RoninLB]

Originally posted by surflvr911sc

I safety wired my axle bolts, haven’t had to touch them since.

ditto

[3liter914-6]

Originally posted by surflvr911sc
Not true, the SC uses M8x50mm bolts. I have not been able to find a reference for washers on the SC anywhere.

Weird, the PET lists those for the SC also. I guess it is M8X50mm. No listing for an M8 lockwasher. Although 914s used M8 bolts so if you wanted lockwashers you could just order those.

[aigel]

Sooo, what do I order on PP now? Numbers???

And if someone can show me how they wire their bolts, that would be cool too. I know, you drill them but how do you wire them?

George

[surflvr911sc]

I used .032 Stainless Steel safety wire. A good set of safety wire pliers will make it go quicker, you can get a cheap set at Harbor Freight. You want to wire two bolts together at a time so that the wire will prevent them from loosening. It might take a little practice, wiring things on the bench a couple times might help you get the hang of it.

I used a mill to drill the holes in my bolts. I would suggest using a drill press and not trying it freehand. A 1/6” bit is perfect but get a bunch of them. Also make sure that you are drilling straight through the flat areas on the inside of the allen head. You don’t want go through at an angle and you’ll break bits that way.

I have the stock numbers for the bolts, and they’re right here in the catalog, but like I said I’ve never seen a reference to 8mm washers for an SC. They have been post on a lot in the past (don’t know the source) and I’m sure a search will bring them up.

[aigel]

I searched the archives and people seem to agree that while not SCs may have come with the washers from the factory, they are recommended. There are people buying these washers and the hardware but not at PP or the porsche dealer. I'd like to buy the stuff from pelican.

George

[Schrup]

I will post a link to this thread because nobody from Pelican responded to it then & I would hate to see somebody pay $.25 for plain ole lock washers.
CV Joint Bolts - reuse, or new?

[KTL]

You can also get the Schnorr washers (Schnorr is the manufacturer, the washers are belleville disc spring washers) from Metric & Multistandard Components Corp.

http://www.metricmcc.com/index.htm

The washers are on page 2-243 of the online catalog. Section 2 is the non-threaded fasteners section.

http://www.metricmcc.com/catalog/catalog.htm

[Randy Webb]

Drilling weakens the bolt heads inviting catastrophic failure -- worse than just having the bolt back itself out. If you are all fired up about safety wire get bolts (cap screws) that have the holes in the head when made. If you've already done this and don't get the right bolts, then at least inspec the area around the holes with a loupe very frequently.

Read Carroll Smits' fastener book (aka screw to win) for an accessible account, or go talk to a Mech. engineering prof. for a deeper understanding of the effects.

[surflvr911sc]

Randy, we go around & around this every time it comes up. How many CV bolts have you seen break because they were drilled for safety wire?

It seems common sense to me (no engineering degree but ton of actual mechanics) that when the hole is drilled half way down the inside of the head, which is about two thirds up on the out side, that a hole will not cause any weakness at the torque levels we’re talking about. The bottom of the head is solid at least a quarter (probably more like a third) of the way up. The head and the threads take the torque, not the outside (top) of the head. I can see breaking the hole out while wiring if you drill too far out. I can also see breaking the head while applying torque if you drilled the hole too far down. I can’t see the bolt head failing at 33 ft lbs because of a hole in the least strengthening area of the entire bolt.

Back to the original question… How many have you seen break? I know that on paper it weakens, but in practice it has proven to work very well. Don’t you think it’s time to stop yelling the sky is falling every time somebody drills their CV bolt heads?

[Randy Webb]

Ryan, I am just trying to save people from a lot of money and personal injury (esp. if they are in front of me). Your query is ill-posed: I do not conduct statistical experiments in this area (unlike other areas in which I do have a doctorate -- what is yours in by the way??? - since I see you posting as Dr. Ryan). If you want to take the risk, fine - go ahead. YOu guys can argue all you want but you are not going to change the laws of physics.

Your thoughts about this seem to be based on the amount of material removed -- that isn't the real issue. The main problem is the induction of tiny cracks when drilling. These concentrate the lines ("curves") of stress in the material ("stress risers").

[Ned nyna 11]

Jeff,
Thanks for the note. I got one somr time ago.
Ned

[RoninLB]

I believe that if the bolt head would crack at/from the drilled hole no weakness would result to the fastning of the fastner..
even if the top of the head would vaporize nothing would happen.
and FWIW.. those bolts are high quality tough mothers.


and George..
There are various size tools.. and the Harbor Freight is good enough low quality. Snap-On style can be purchased under another brand name and save probably $20.. I use the 8 1/2in length tool.. good for tight spaces and almost good for thicker than .032 wire.
.032 is routine hot rod diameter. I also use .025 for bs like wraping the two wing nuts on the engine comp elec panel. I use .041 for extraordinary/ once in a great while heavy duty stuff.
I bought a jig from Aircraft Spruce that's OK.. I would check w/Pelican to see if they have a jig to mount the bolt for the drill press or maybe a decent auto parts store that caters to guys who know what their doing.
if doable get at least the .032 & .025 because this saftey wire act gets to be a habit real fast.

[Randy Webb]

"if the bolt head would crack at/from the drilled hole no weakness would result to the fastning of the fastner.."

Eh? The head is what hod the unit together. What do you mean, Ron?

[surflvr911sc]

Randy, I was afraid that my post sounded a bit harsh, and I apologize. I do have the utmost respect for your technical knowledge and opinions.

I also know, and tried to express it in my post (admittedly not very well), that you are technically correct. I also agree that buying bolts that are manufactured w/ safety wire holes is a much better solution. Although I do stand by my opinion that drilling these bolts is safe in our application.

The Dr. in my sig is a SCWDP inside joke, hence the other BS and SCWDP along w/ it. I do not have a degree. I do have years of mechanical experience and training, I deal w/ hardware daily. I will continue to tell people that this works well and try to tell them the best way to do it. You can keep telling them that they are setting themselves up for disaster. They can decide what they would like to do after hearing both sides.

I will continue to listen up to any other comment you make regarding the 911, and have a always appreciated your advice, and I do need to get that book.

[RoninLB]

Originally posted by Randy Webb

Eh? The head is what hod the unit together. What do you mean, Ron?

the top walls that are drilled are above the meat of the bolt head.
If I chisel the top off it would still maintain the load. no hard info.