CV Bolt Replacement, Best Practice and While I'm in There? Options

[Nogoodwithusernames]

Was going to take the 914 out for a spin tonight (IMG:style_emoticons/default/driving.gif) and two streets from the house *POP* and engine free revs... Figured I broke an axle or something along those lines and sure enough drive side axle is no longer connected to the trans. Haven't dug in to find out if the bolts sheared or backed out but it needs fixing.

I'm planning on replacing all the CV bolts with the safety wire versions from 914 rubber and obviously safety wiring them. But should I locktite them? Antisieze? Neither? Figure I'd clean them and repack the grease, anything else while I'm under there? Might finally put the new shifter bushings I've had sitting around for eons...

(Also how many are there? I think VW has 6 bolts per CV, same for our little NARP? *EDIT* 914 rubber says it right on their site, 16 total.)

[JamesM]

4 bolts + 2 roll pins per CV joint.

Make sure you have the roll pins, I have found them missing on cars before

[wndsrfr]

4 bolts + 2 roll pins per CV joint.

Make sure you have the roll pins, I have found them missing on cars before

No loctite needed if you safety wire....

[914Sixer]

Run the 12.9 bolts instead of the stock ones. Use new Schoor washers every time for a better bite. 4 bolts per CV= 16 total. If you torque them properly no safety wire need.

[roblav1]

If you're running the early 911 CV's with 2 pins and 4 bolts each, Schoor washers for the CVs on a Hummer are better and cheaper.

[iankarr]

(IMG:style_emoticons/default/agree.gif)
Like many things on our cars, it all works as a system. New bolts and schnoor washers should be fine. No loctite or anything else needed. I’ve never had any back out. The safety wire is great for extra peace of mind.

[Bartlett 914]

I too have been through this. I discovered the main culprit causing the CV's to work loose it the output flange on the transmission. What happens is when the CV works loose, the bolts pull on the threaded portion of the output flange. This makes the threaded spots higher than the rest of the flange. It may seem that the CV and the output flange are sitting flat to each other but they are not. If you remove the flange and chuck it in a lathe and make a "clean up" cut you will see the high spots are at the thread holes. Once this is clean and flat, screws and new Schorr washers are all that is needed. I use standard socked head cap screws

[bdstone914]

Clean the holes for the CV bolts. Grease affects the torque value.
If you dont use safety wire put a dot of bright paint on the bottom of the bolt and flange. Check occasionally to see if the dots do not align and they are beginning to back out.

[cary]

My only addition. If you damage the hex socket in anyway. Change out the bolt.

[ClayPerrine]

Run the 12.9 bolts instead of the stock ones. Use new Schoor washers every time for a better bite. 4 bolts per CV= 16 total. If you torque them properly no safety wire need.

(IMG:style_emoticons/default/agree.gif)

Also, break out your torque wrench, and properly torque the bolts. Done correctly, you won't have any issues with them backing out.

[Mikey914]

We stock the safety wire version and the Schoor washers you can start with the new bolts
The wire will definitely hold them, But you can even cheat and go every other if you want to save a buck.

[IronHillRestorations]

As long as you use new Schnorr washers, make sure the treads are free from grease, and torque to spec, you’ll be good. Schnorr washers are one and done, and 100% not reusable. That’s where people have trouble

[michael7810]

I think it’s a good idea to recheck the torque after 500-ish miles as the gaskets can settle a bit. After the retorque I’ve never had one loosen and I don’t use safety wire.

[mepstein]

I think it’s a good idea to recheck the torque after 500-ish miles as the gaskets can settle a bit. After the retorque I’ve never had one loosen and I don’t use safety wire.

The question comes up all the time on Pelican. Porsche doesn't safety wire the cv bolts on their passenger cars. The answer is to follow the correct procedure for install and they will stay tight.

[preach]

Clean the holes for the CV bolts. Grease affects the torque value.
If you dont use safety wire put a dot of bright paint on the bottom of the bolt and flange. Check occasionally to see if the dots do not align and they are beginning to back out.

I thought that true about grease on fasteners for most of my life.

For the last 13 years I have worked as a mechanic and we are required to lubricate fasteners unless we are required to loctite them. Most of the time it is Molykote P-37, but often it is system oil and in some systems another type of lube.

The engineering thought behind this is that a fastener can have small imperfections that can bind and distort the real torque value. The lubrication prevents this as well as minimizes the chance of the fastener to gall.

The majority of the fasteners I deal with have some sort of locking device, wire or locking elements/anaerobic fluid. Additionally many of them are not ferrous metal and will gall pretty easy.

In my shop at home I tend to use a lubricant on all fasteners except for lug nuts.

Not arguing the point just putting up my experience.

[mepstein]

Clean the holes for the CV bolts. Grease affects the torque value.
If you dont use safety wire put a dot of bright paint on the bottom of the bolt and flange. Check occasionally to see if the dots do not align and they are beginning to back out.

I thought that true about grease on fasteners for most of my life.

For the last 13 years I have worked as a mechanic and we are required to lubricate fasteners unless we are required to loctite them. Most of the time it is Molykote P-37, but often it is system oil and in some systems another type of lube.

The engineering thought behind this is that a fastener can have small imperfections that can bind and distort the real torque value. The lubrication prevents this as well as minimizes the chance of the fastener to gall.

The majority of the fasteners I deal with have some sort of locking device, wire or locking elements/anaerobic fluid. Additionally many of them are not ferrous metal and will gall pretty easy.

In my shop at home I tend to use a lubricant on all fasteners except for lug nuts.

Not arguing the point just putting up my experience.

Makes sense but in the case of cv bolts, you want them bone dry and clean.

[ericoneal]

How much torque?

Run the 12.9 bolts instead of the stock ones. Use new Schoor washers every time for a better bite. 4 bolts per CV= 16 total. If you torque them properly no safety wire need.

(IMG:style_emoticons/default/agree.gif)

Also, break out your torque wrench, and properly torque the bolts. Done correctly, you won't have any issues with them backing out.

[76-914]

Clean the holes for the CV bolts. Grease affects the torque value.
If you dont use safety wire put a dot of bright paint on the bottom of the bolt and flange. Check occasionally to see if the dots do not align and they are beginning to back out.

I thought that true about grease on fasteners for most of my life.

For the last 13 years I have worked as a mechanic and we are required to lubricate fasteners unless we are required to loctite them. Most of the time it is Molykote P-37, but often it is system oil and in some systems another type of lube.

The engineering thought behind this is that a fastener can have small imperfections that can bind and distort the real torque value. The lubrication prevents this as well as minimizes the chance of the fastener to gall.

The majority of the fasteners I deal with have some sort of locking device, wire or locking elements/anaerobic fluid. Additionally many of them are not ferrous metal and will gall pretty easy.

In my shop at home I tend to use a lubricant on all fasteners except for lug nuts.

Not arguing the point just putting up my experience.

Makes sense but in the case of cv bolts, you want them bone dry and clean.

I have to agree with Preach here. Unless specified all torque values are not for dry fit. Usually a drop of oil on the 3 starting threads is recommended. Besides, the area is never clean unless you've rebuilt that entire CV and corresponding hub. You're a sharp cookie Mark so I'd like to see where you've read that. For my own enlightenment anyway. I could probably win a bar bet with that knowledge. To the OP. Do not try to loosen the bolts, or tighten for that matter, unless the Allen socket is clean and the 4 square wrench bottoms out completely. (IMG:style_emoticons/default/beerchug.gif)

[76-914]

How much torque?

Run the 12.9 bolts instead of the stock ones. Use new Schoor washers every time for a better bite. 4 bolts per CV= 16 total. If you torque them properly no safety wire need.

(IMG:style_emoticons/default/agree.gif)

Also, break out your torque wrench, and properly torque the bolts. Done correctly, you won't have any issues with them backing out.

37 ft lbs IIRC. I wrote it on my 3/8 torque wrench box so I wouldn't have to look it up every time. Did the same for the lug nuts on my 1/2" TW box. (IMG:style_emoticons/default/beerchug.gif)

[914_teener]

Clean the holes for the CV bolts. Grease affects the torque value.
If you dont use safety wire put a dot of bright paint on the bottom of the bolt and flange. Check occasionally to see if the dots do not align and they are beginning to back out.

I thought that true about grease on fasteners for most of my life.

For the last 13 years I have worked as a mechanic and we are required to lubricate fasteners unless we are required to loctite them. Most of the time it is Molykote P-37, but often it is system oil and in some systems another type of lube.

The engineering thought behind this is that a fastener can have small imperfections that can bind and distort the real torque value. The lubrication prevents this as well as minimizes the chance of the fastener to gall.

The majority of the fasteners I deal with have some sort of locking device, wire or locking elements/anaerobic fluid. Additionally many of them are not ferrous metal and will gall pretty easy.

In my shop at home I tend to use a lubricant on all fasteners except for lug nuts.

Not arguing the point just putting up my experience.

Makes sense but in the case of cv bolts, you want them bone dry and clean.

I have to agree with Preach here. Unless specified all torque values are not for dry fit. Usually a drop of oil on the 3 starting threads is recommended. Besides, the area is never clean unless you've rebuilt that entire CV and corresponding hub. You're a sharp cookie Mark so I'd like to see where you've read that. For my own enlightenment anyway. I could probably win a bar bet with that knowledge. To the OP. Do not try to loosen the bolts, or tighten for that matter, unless the Allen socket is clean and the 4 square wrench bottoms out completely. (IMG:style_emoticons/default/beerchug.gif)

Wait.....check to see if it IS a triple square or a socket head cap screw (allen). 4 square is a kids game. If it.s a triple square and it.s dirty it.s hard to tell. Clean everything there first and make sure. If you strip one of those that be a no fun zone. Take the triple square bit and seat it with a rap with a small hard mallet.

Also...if you use a cv with no recess for a gasket don.t use a gasket.

BTDT.