lower steering shaft

The lower steering shaft connects the shaft in the steering column with the steering gear box (3504 in the drawing below) and it is frequently a source of slop in the steering.  One problem that creates the slop is the "rag joint", which is shown as 3A525 in the illustration on that tab.  Over time the rag joint becomes loose and introduces flex in the steering.  Another problem is the boot over the u-joint at the top of the shaft.  The boot is needed because the u-joint in the Bullnose shafts needs protection from the elements.  But the boot frequently splits and the u-joint gets sloppy.  And there's a spring (3E664 in the illustration) that can break.  If it does the inner shaft will rattle inside the outer shaft and cause some slop.

Fortunately there are at least four ways to remove the slop:
  1. Bullnose Shaft: You could replace your worn lower shaft with another Bullnose shaft, but finding a good one is difficult and a new one next to impossible.  And even if you do it'll still have the problematic boot and rag joint.  Still, if that's what you want to do see the Part Numbers tab below.
  2. 1988 - 1991 Shaft: Replace the lower shaft with the later one that has a better rag joint and a u-joint that doesn't need a boot.  In 1988 Ford introduced a new lower shaft with part number E8TZ 3B676-A, which should carry the ID # on it of E8TA 3E751-AA.  That part was used through 1991 on the pickups and is a direct bolt-on for Bullnose trucks.
  3. Borgeson: This company makes a high quality unit which has open u-joints on both ends and no slack whatsoever.  But they currently sell for about $250.
  4. Make It:  On the Make It tab below you can see how Jim/ArdWrknTrk made his own Borgeson style shaft for far very little expense.  He used a replacement lower shaft for a 2009 - 2010 F150 and welded the proper fittings on the end to make it fit his truck.  But this does require cutting and welding, so it needs to be done well.

​Anyway, in the picture below we have two Bullnose lower shafts at the top and a 1988 - 91 shaft at the bottom.  You can see that the boot on both Bullnose shafts is split, so the u-joint inside is going to go bad.  And you can see that part of the rag joint on the top shaft has been removed.  That's the part that slips on the input shaft of the steering gear box and is what Jim welded onto the end of his 2009-14 shaft.  Also, the top shaft is the E0 version that has a replaceable rag joint while the middle shaft is an E1 or E2 version as its rag joint is riveted on and is a bit smaller than the top one.
Picture
Top lower steering shaft is the E0TZ 3B676-A version with the removable rag joint - which is off on this one. The 2nd one is either an E1 or E2 version with the non-removable rag joint. The third one is the 1988 - 1991 version (E8TZ 3B676-A) that is a direct replacement for a Bullnose unit.
Picture
Anti-rattle spring in the lower steering shaft, usually hidden by that rubber collar.
  • Illustration
  • Part Numbers
  • Make It
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This is the Bullnose lower steering shaft.
This is a section from Ford's 1980 - 89 Master Parts Catalog, and I've included just the info for the lower steering shaft (3B676) and the rag joint (3A525).  But I find it confusing so offer this to explain what I think it is trying to say:
  1. All trucks built before 2/81 take E0TZ 3B676-A.  This apparently means power and manual steering and tilt as well as non-tilt columns.
  2. Trucks built from 2/81 to 12/81 the manual steering trucks take E1TZ 3B676-A and power steering takes E1TZ 3B676-B, regardless of tilt or not.
  3. Trucks built from 12/81 to the end of the catalog, meaning 1989, take E2TZ 3B676-A for manual steering and the power steering trucks use E8TZ 3B676-A.  However, that must surely have originally been E2TZ 3B676-B as E8 means it was introduced in 1988. And then there's the part that says "1982/88 - also replace 3524 & 3E715, tilt wheel only." 3524 is "Shaft assy, (steering column)", meaning the upper shaft, the one in the steering column.  And 3E715 is Actuator (steering column lock lever).  So if you replace the lower steering shaft you are supposed to change out some parts in the column as well - on trucks with a tilt column. 
As for the rag joint, 3A525, note that it was replaceable on trucks built prior to 2/81, meaning the E0TZ lower steering shafts.  But from 2/81 it was an integral part of the lower steering shaft.
As said, Jim/ArdWrknTrk made his own Borgeson-style lower shaft.  He ordered a 2009-2010 replacement shaft, which Rock Auto says should be one of these part numbers: 7L1Z3B676A, 7L1Z3B676B, 7L1Z3B676C, 8L1Z3B676A.  But its ends wouldn't attach to his steering column shaft nor the input shaft of the steering gear box.  So he removed the pieces from a shaft that would fit, but the pieces that didn't work off the 2009-14 shaft, and welded the correct fittings on the new shaft.
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The follow pics explain how he did it, and you can click on any of them to get a larger image.
Bullnose shaft on the bottom vs the 2009-2010 shaft.  They are basically the same length, and since they accordion for safety it is easy to use the later one - after you add the proper fittings.
But Jim found that the input fittings weren't clocked the same way they are on a Bullnose shaft.  On the left the paint stick is laying across the bottom u-joint, and it makes an angle with the table.  But in the picture on the right the paint stick resting on the top u-joint and it is parallel to the table.  But a Bullnose requires that the top and bottom connections be in phase or the steering wheel will be turned a bit when you are going straight ahead. 
Here are pics showing how he attached the splined fitting from a Bullnose shaft to the bottom u-joint on the 2009-2014 shaft.  Note that he cut away a lot of material so he could get good penetration.  And note that he had the u-joint in the vise to absorb some of the heat of welding.  But he also covered the u-joint with a wet rag to further protect it from the heat.
These pics show the upper fitting being welded on.  Again note the heat protection. But since the fitting is a stamping rather than a casting he had to turn the heat down on the welder to prevent burning through it.
And here's how the shaft looks installed.