Just thank'in out loud butt..........would it have been too difficult to grind out the that big spot weld and pulled the axle tube.........cut it.....and slide it back in?
Reason for axe'n is.......I'm think'in about make'in me one of those........some day.
6sal6

Hornman wrote:

Yeah, what Sally said. The on-line instructions I have seen say to pull the tube, shorten it, then reinstall. Takes less precision. Plus, you aren't always worrying about your weld on the shortened tube.

Bob, I know you had a good reason for doing it your way, what was it?

Well, after reading a whole bunch of reports from guys that have gone before me I came to the conclusion that it's about 50/50.  A lot of guys don't like the idea of welding the the replaced tube to the center section which is what many say to do after re-inserting the tube.  Also, there ain't "A" big spot weld...there's two (at least on this axle) and from what I read, getting them ground out is a bear.

Then, my friend who narrowed a 7.5 Chev rear end for his B-Ville '61 Ranchero also agrees that the center section is closer to cast iron than cast steel and will likely crystalize unless you do it just perfect...and maybe even then.  Which is what I read from the guys that prefer to cut the tube.

My friend recommends making an alignment sleeve to push into the tube that will overlap the joint and leave about 1/8 inch between the beveled tube sections, then weld the whole works together.  Some also recommend drilling holes through the tubes on each side of the joint and plug welding to the sleeve...I may do this.

Then there's the fact that I cut it so that the joint will be centered between the spring perch sides and with the spring underslung, as it is on the Mustang, the perch will just add more strength in the right place for any forces on the joint.

So...with advice from a guy that has done it a couple of times and reports from a number of guys that have done it this way.  And knowing what a pia it can be getting tube out of the center section, I decided to go this way.

I keep hearing that a proper weld is as strong or stronger than the surounding steel and I have two ace welder buddies to choose from.  So I really ain't too worried, and it's a whole bunch easier this way.

BB

At the rod shop I used to work I learned that cutting off all the brackets on a rearend housing is done faster (given you have access to it) with a torch or plasma cutter than with an angle grinder. 

We also always shortened the housing the same way BB have started to do it and used the same kind of alignment tool BB describes when welding it back together and for alignment. No reported problems.

 

That sounds like a very well thought out plan.
I really like the idea of welding back together with a jig.
I think the idea of a gap in the bottom of the inner sleeve is a good idea.
Have you thought of going a step further to 9" type axle ends to eliminate the C-clips?

darren wrote:

That sounds like a very well thought out plan.
I really like the idea of welding back together with a jig.
I think the idea of a gap in the bottom of the inner sleeve is a good idea.
Have you thought of going a step further to 9" type axle ends to eliminate the C-clips?

I briefly considered going to the 9" axles but then I though about all the  Fords I've seen along side the highway with missing wheel/axle assemblies and decided that for a non-drag, street/highway car...I'd take my chances.

Sorry to be a wise guy, couldn't help it.

BB

Soooo your putting a thin sleeve inside the housing to act as a "backing-strip for the weld? Good idea.. Never thought about how much space was inside the housing compared to the axle running through it. IF the welder leaves a little space between the two sections of the housing(aka open root) the weld will possibly be stronger than the base material. And the "backing-strip" will prevent any little "hangey-downey" thingees that happen sometimes with weld slag. IF the use stick welding method. With a mig/tig.....no slag!
Good.......skip welding and taking your time will GREATLY minimize any/all warping
Just curious.....how thick is the housing/axle sleeve/base material? About 1/2"? 3/8"?
6sal6

MustangSteve wrote:

Not rocket science.  Just do it.  I have less concern about welding 360 degrees around a tube than just welding the perches on one side of the tube.  Now, when you weld the spring perches back on, that will likely bend both tubes when the welds cool down.  But luckily, it's not rocket science.  And I am sure yours will eventually wind up being straighter than the factory assembly.

The lucky guys are the ones not smart enough to know that what they do might make things out of alignment.  They just do it and assemble it and drive off happy.  (WATCH THIS !!! Syndrome)

The ones in the know tend to worry too much, and their stuff winds up being so much better than it has to be, but they are happy they did it right and got it how they wanted it.

A friend narrowed a Ford 8" rear end to go in his Healey.  He cut the axle tube with a cutoff wheel, then cut the axle with same tool, made a 1" long "step" in the end of the cut axle pieces.  He overlapped the steps and welded the axle together.  The axle tube was welded back together by clamping two pieces of angle iron to the side of the tubes with welding clamps to hold it in alignment.  He has been enjoying driving that car like that (with a 5.0 in it) for many years and puts alot of miles on it!  Not rocket science.
 

MS, you're right about worrying too much about doing it right.  When I mentioned plug welding the axle tubes to the sleeve my friend says "That's over kill, Bob.  Stop worrying, the weld will be good for 70,000 pounds or so and I'll bet the axle tube is only good for around 30, 000."

And he's probably right.  Most of these narrowing jobs are done for drag racers  like Mike's friend or rock crawlers who are abusing things a whole bunch more than most of us do with our old Mustangs. 

Yes Mike, if you are gonna be doing high HP launches you need to change to the nine inch axles.  The ID of the axle tube is 2.875 (more or less since they are slightly OOR).  2.5 inch schedule 40 pipe has an OD of 2.875.  So a little here and a little there will get a chunk of that Schd. 40 in there.  I can either bore the sched 4O to have an 1/8 wall or I can cut a strip about 3/4 wide out of it  and leave the open  part of the remaining "C" at the bottom for lube to pass through...that's prolly what I'll do.

The axle tubes are .186 ...same as the sched. 40...so ever thang should work okay.  My friend suggested leaving about 1/8" between the axle tubes so the initial pass will weld both tubes to the sleeve, then fill the bevel trough with multiple passes.  Tlhen grind it flush.  Then get out the hot wrench and do a couple of heat/quench spots up near the center section to pull it back in to alignment.

That's my plan, Mike.

BB

 

MustangSteve wrote:

Bob, go to SpeedyMetals.com. You can order real steel tubing by the inch in whatever size you want. It will be alot better than sched. 40 pipe. (Not that application would really matter)
Personally, I cannot see any reason to put that piece in there. Just weld the tubes and don 't worry about it.

You are correct-o-mundo MS!! I think just bevel both sides out to a thin landing...and when you weld it back you have ALMOST 100% weld. The heat from the root pass will melt the thin beveled edge and that would make it nearly solid weld.  Its not like he's welding the pressure hull on a submarine!
To take out any possible warping..........heat the tube on the side you want to "draw/pull it" to. Put a cold wet rag on the oposite side. You can make that axle tube wiggle like a snake!!
6s6