1986 AMC Eagle front axle/CV joint replacement

[OverKnight]

My son's 1986 AMC Eagle had a freak accident tonight.  It seems that the six bolts that hold the inner CV joint to the transfer case all fell out, and the inner axle shaft fell out of the transmission; it's clearly time for some new axle/CV joint assemblies.  He reported no abnormal noises before this happened, except for a loud clunk when the inner axle and "tulip case" (is that what it's called?) finally did fall out.  Since he was less than a mile away from home, we slowly drove it back.  I have no idea how these six bolts, loctited in place by the factory, all came loose without warning.  I haven't been under the car recently, but I never saw any missing or loose bolts; the right side looks fine.

From what I can tell, removal and replacement of the axle shafts looks pretty straightforward (I've read that it can be done in 20 minutes per side; is this true?), but before we start, I have a few questions:

• First, any ideas how this could have happened?
• Are there c-clips on the inner axle?  I'm not seeing them in the factory manual, but wanted to make sure.
• Are both the left and right assemblies identical?  The suppliers I've found list the same part number for each side, but some have separate listings for left and right assemblies.
• Will this car need a front end alignment after replacing the axle assemblies?
• Should the front axle nut be replaced, or can it be reused?
• Has anyone here replaced these before?  Any advice before we start?  Anything in particular we should do, not do, or watch for?

In advance, thanks very much.

[Mernsy]

Usually they had locktite applied at the factory and need a bit of heat to loosen. Maybe yours got missed or is a replacement.
No clips.
Left and right are identical.
No alignment needed.
You'll get a new nut with the shaft but the original can be reused.

Here's a How-To.

http://amceaglesden.com/guide/index.php?title=CV_Half_Shafts

[OverKnight]

This was very helpful, Mernsy; thank you.

[captspillane]

It seems that the six bolts that hold the inner CV joint to the transfer case all fell out, and the inner axle shaft fell out of the transmission

Your wording here would be accurate for a Subaru or Chevy Equinox or a bunch of other newer AWD cars. In an Eagle, however, the drivetrain is literally classified as a light duty truck and it is more robust than those cars. Unlike a Subaru, the Eagle front axle shafts attach to the front axle, not the transmission. The front CV Shafts bolt up to the front axle, which is bolted to the engine, and is connected by the front driveshaft to the transfer case that is bolted to the back of the transmission.

It is common for the front axle bolts to vibrate free and for the front axle to fall out of place, usually resulting in the CV shafts exploding and wiping out the brake lines. It happened to me and it happened to the previous owner of my Kammback immediately before I got it. The root of the problem both times was that the front driveshaft slip yoke had frozen tight.

Make sure your front driveshaft slip yoke is free and able to move. In a sense it isn't necessary because the axle is bolted to the engine and should never move in relation to the transfer case, but in practice that slip yoke takes out vibrations. Without it working you'll have all sorts of bolts getting loose quickly.

[OverKnight]

Thanks, captspillane.  I checked out the right axle, and found that the outer boot was torn, so this axle definitely had a finite lifespan.  We were able to get two new (not rebuilt) axle assemblies from Advance Auto.  There was one bolt broken off in the transfer case flange, but I was able to remove it without extreme difficulty.  The big problem is finding the grade 8 socket head M10 x 1.5 x 1" cap screws; all of these were lost.  I was able to find hex-head bolts of this size at a NAPA store; they told me that the ones they had were stronger than grade 5, but not as strong as grade 8.  Since we won’t be using 4WD in the near future, I'm using these for now, until I can find the correct ones.  Does anyone know where I could find these?  It was suggested that I try a speed shop, because these are used for exhaust manifolds and cylinder heads.

Also, of the six bolts on the right side, three had split lock washers and thee had flat washers.  Split lock washers on a grade 8 bolt with Loctiite seems unnecessary and redundant.  What washers were used out of the factory?

Anyway, we’re back together now.  We'll keep an eye on the front driveshaft slip yoke.  Thanks again.

[OverKnight]

Also, of the six bolts on the right side, three had split lock washers and thee had flat washers.  Split lock washers on a grade 8 bolt with Loctiite seems unnecessary and redundant.  What washers were used out of the factory?

Pardon the bump, but I need to order the correct hardware ASAP.  Does anyone know what kind of washers were used by the factory for the CV flange bolts?  Did they use just flat washers, split lock washers, or a combination of both?

Thank you.

[AMC of Houston]

Well, now this is weird -- but the parts book (page 26.30.5) shows only split lock washers on the right side, but both lock and flat washers on the left side.  And even more weird, the left side shows the flat washer going between the bolt head and the lock washer.

[eaglefreek]

Use flat washers and Loctite. A mechanical engineer buddy of mine opened my eyes to the ineffectiveness of split lock washers. They actually may cause the bolt to get loose easier than a flat washer.

[profeagle]

Also, of the six bolts on the right side, three had split lock washers and thee had flat washers.  Split lock washers on a grade 8 bolt with Loctiite seems unnecessary and redundant.  What washers were used out of the factory?

Pardon the bump, but I need to order the correct hardware ASAP.  Does anyone know what kind of washers were used by the factory for the CV flange bolts?  Did they use just flat washers, split lock washers, or a combination of both?

Thank you.

Also, of the six bolts on the right side, three had split lock washers and thee had flat washers.  Split lock washers on a grade 8 bolt with Loctite seems unnecessary and redundant.  What washers were used out of the factory?

NO washers where used from the factory ! , I just checked my car to be sure and I have a set of original bolts as well - again no washers. Also I have done axel R&R a number of times.  Ok now somebody tell me I am wrong  [LOL] . Locktight only, bolts must be clean and thread holes also .Although the factory manual does not indicate this. Correct torque also - 45ft lbs. and hub nut - 175ft lbs. Now in all honesty I have never bothered with loctite, just torqued em down and never any trouble    I would disregard a mixed up manual like yours AMC of Houston .      But that's just me. 

[AMC of Houston]

Hard to disregard the AMC factory parts books; IMHO.    Must have been some reason for it.

[carnuck]

I use the double serrated in and out lock washers.

[OverKnight]

Thanks, everyone.  As eaglefreak said, I too had heard that the effectiveness of all forms of lock washers isn’t as good as we've been led to believe.  Based on experience, though I still think that a good-quality hardened steel (not cheap common steel) split washer can provide some insurance to a bolt loosening.  I also suspect that split lock washers could decrease the accuracy of critical torque readings, which I don’t know how to compensate for.  Fresh blue Loctite is pretty good stuff, and the red Loctite is the really serious stuff, i.e., much more permanent.  Since one of these joints has already come loose, I’ll try to do things as correctly as possible.  That means getting an M10 x 15 tap to clear the old LocTite from the flange threads, cleaning all grease and oil of off everything, using FRESH blue Loctite (I understand that Loctite had an open shelf life of about one year), torquing everything correctly, and giving the flange bolts a look at every oil change.  I’ve got to sleep on whether to use flat or split lockwashers; I’m still 50-50 on which I’ll use, but I’m probably leaning towards some good hardened steel split washers.

Thanks again.

[carnuck]

http://en.wikipedia.org/wiki/Washer_%28hardware%29

I used these in the military to keep Humvee axles on.

[OverKnight]

Thanks, carnuck.  I’m familiar with serrated, or star washers, but my impression has been that the best indications for these are relatively low-torque electronic applications, because they can enhance an electrical connection.  I’ve never seen these large or heavy enough for a front axle application.  My usual go-to source for hardware, McMaster-Carr, has internal OR external star washers, but they do not appear to carry the internal/external star washers.  The ones you used in the military may have been designed and produced specifically for the military, and aren't available to the rest of us civilians.

A few nights ago I was leaning towards using split lock washers.  Now I’m thinking I’ll use just the flat washers (I ordered both).  Ask me again in a few days…

[captspillane]

Its funny you mention they are for electronics. In the CNC machines I fix those washers have done a great deal of damage and we now use plastic washers and toss those. They dig into the laquer and connect the ground traces to the machine ground. On a home computer ground is ground. On a high voltage machine the low voltage is generated by a transformer that sometimes is intentionally not referenced to ground.

Basically the star washer ends up connecting machine ground of 0V to a neutral of 60 volts and fire, smoke, an brimstone erupts.