Tuesday, July 3, 2012

Axle Housing Updates

The month of June has come and gone and I’m happy to say it’s been a very good month, even though my work volume on the car doesn’t outwardly reflect it.  Early in the month, I was fortunate enough to take a “real” 2-week vacation with my lady to visit my family in northern Germany and enjoy the many sights available in and around the area.  I hadn’t had a vacation to speak of since about 1996 or so and this trip reminded me how important it is to breathe the throttle once in a while to recharge and put everything back into perspective.  It worked….and I’ll not wait so long to do it again.
The last two weeks of June were spent catching up on business matters that developed while I was away and cultivating some new contacts that have the potential to advance this build more than I could have imagined.  While I won’t spoil the fun just yet, the next several weeks should generate some very exciting things, with a bit of “eye candy” to boot!
As has been the norm for the past few months, I have been concentrating on getting the rear suspension and axle set up under the car.  The custom Bilstein rear coilover dampers are finished and I am selecting rear spring rates as I write this.  I have also sourced all of the components and tools I will require to get the rear trailing arms upgraded to spherical rod ends to allow the 4-link to behave like a proper 4-link should.  While the expense to get the rear suspension system upgraded according to plan has been much more than I had anticipated, I am firmly convinced the results will be worth every cent.
On the “plus” side of the equation, I have been able to complete all of the required axle housing modifications.  The 4 link brackets are complete, the factory welds cleaned up, and the brake line tube tabs shaved.  But there are two modifications I made that I am particularly pleased with that are the feature of this entry.
First, I have always been irritated by the general lack of convenience in servicing gear lube in a 9-inch axle assembly.  Ford was kind enough to provide a place to put the lube, but never a place to drain it out.  I you’re like me, the cost of a few quarts of synthetic gear lube is worth the price of admission given the peace-of-mind I get from knowing the condition of the axle at any given time.
Additionally, the attractiveness of being able to jack the car up from the center of the axle housing is rather undeniable.  That is, until you see the mess a floor jack makes of the finish on the lower housing once all the convenience of the method is spent.  Since I will be powder coating my axle housing, I wanted to devise a way to have my cake and eat it too.  To that end, I designed and machined a combination axle drain and jack point that serves both purposes well.  Now, with a simple urethane jack pad on my floor jack cup, I can lift the car without damage to the housing finish AND drain the axle lube at any time with no more effort than I spend draining engine oil.
Next, I have always disliked Ford’s method of venting the rear axle housing.  The hose nipple and rubber whip hose protruding from the top of the axle tube always appeared very “busy” to me and generally unfinished.  Especially when you consider the nifty way they jam the free end of the vent hose into the upper rear shock bracing to keep it out of the way.  Nope…..that won’t do at all.
Borrowing alternate solutions from other manufacturers and builders, I decided to install a simple, tidy, sintered stainless steel vent fitting that would eliminate all of the production mess and provide adequate venting.  These vents are inexpensive and easily available and can be found on numerous aftermarket axle assemblies.  I chose an all-stainless steel vent for the uniformity of appearance as well as the durability factor and installed it in the location where the original vent nipple was placed.  A simple drilling and tapping operation and the deal was done.
So, as modifications go, there’s nothing earth-shattering here, but in the long run, I expect them to provide small conveniences where before there were none.  Just a few more details to set it apart.
A little time on the lathe is all it took to spin up this combination axle drain bung/jacking point.  Here is the final machining operation:  tapping the hole for the 1/2 x 20 drain plug.

The completed drain plug ready to go.  Note the flange at the base to allow a nice weld surface without distorting the tapped hole.

So simple yet so effective.  Here is the completed bung with the drain plug installed.  The weld flange can be easily seen at the base.

I positioned the bung on the bottom of the housing after drilling a 9/16" hole in the housing at the exact location I wanted the bung positioned.  Then I simply used the drain plug to hold the bung in place by screwing it into the bung from inside the housing.  You can just see the end of the plug inside the threaded hole in this shot.

A few minutes of welding and the bung is in place (still hot when I shot this picture!).

From inside, you can see the nice, clean drain hole with absolutely no intrusion into the housing like many alternative ideas advocate.

Complete and ready for sandblasting and powder coat!

This nifty little sintered stainless steel axle vent is all that will be visible rather than the nasty factory hose barb and rubber hose the factory provided.


  1. As always Sven, beautiful work. Love the drain plug idea. Beats cracking the diff just to change the gear lube!!!

    I came to the same conclusion on my axle vent tube and found one in McMaster-Carr that fit the bill. It's the small details that really make a build.

    Love the new website look!!!! Look forward to hearing the teaser news you mentioned.


  2. Sven, you and your lathe are really starting to tick me off! That is to say I'm jealous of your awesome shop and machine skills. :-)

    Ditto on the new looks and feel! (I might have to figure out how you did the full screen layout and shamelessly copy you. Nice work man!

  3. Sven, Your life sounds like my last 3 weeks...packed to the gills with work, family, and travel. I love the update to your blog. That Boss illustration is killer along with the wallpaper. And that drain for the axle is awesome. Hmmmm....maybe you could make up a couple of them for a few of us???? :-)

    Keep eating that Boss elephant a bite at a time.

  4. I'm with Dennis on this one. That is an awesome little thing. How much to get one of those fabbed up for my 9 inch?

  5. I could probably be talked into making a few of these but I have no idea on a fair price. I can tell you they are MUCH nicer looking than the crappers available in the general retail market.