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PostPosted: Sun Mar 10, 2019 6:20 pm 

Joined: Wed Sep 17, 2008 6:48 pm
Posts: 2805
Location: Indianapolis
Car Model*:
I completely rebuilt the manual steering box that was in the 68 Barracuda. It was originally a power steering car, I bought a used manual box in 2011 and installed it.
From the die cast marking in the manual box the castings date back to April of 1973, so that manual box is old, but not ancient by A body standards.

The adjustor screw was nearly threaded all the way in and I wanted to upgrade from the stock 24:1 steer to a 20:1 ratio.

Prior to disassembly, I used my inch lb torque arm to measure the rotation of the complete assembly at the cross shaft.
FSM spec is 8 to 11 inch lbs across the high spot at the center. Here the reading were erratic the entire time, never less than
15 and would range up to 20 in flashes

I removed the cross shaft and measured just the worm shaft, for that the FSM says between 1 1/8 to 4 1/2 inch lbs, again the
readings were very erratic, the needle on the torque gauge was flashing high to low continuously.

After I had removed everything and cleaned up the worm shaft bearings I could see why, there was much wear and pitting on the
worm shaft bearing balls and races. Both ends were bad, the top end was the worse. Photo is below.

From Firm Feel I ordered:
20:1 worm shaft 275.00
Manual kit, needle bearings and seals 100.00
Worm shaft bearings and races 30.00

405.00 total with me doing the labor,,,

To pull the worm shaft bearing races I got an inside bearing puller / slide hammer from the AZ tool buy and return program.
It worked fine, got them out with out much hassle.
The new races went in. To do the one in the bottom of the housing, you will need a long drift.,
I used the red M1 synthetic grease as the lube.

I installed the worm shaft, using the large end adjustor was quickly able to get the torque to turn of 2 inch LB.
The reading were steady, it was the worn ball and races on the end that were causing the erratic readings.

I then installed the cross shaft, and with a few adjustments got a repeatable reading of 10 inch LB across the
center high spot. The rotation is very smooth.

So my bottom line of $405.00 and me doing the labor is a $149.00 savings over buying a complete 20:1 box from Firm Feel as that complete box is priced at $554.00

And there are other A body manual steering box options available in the standard and 16:1 ratio.
Certainly someone is going to start doing 20:1 ratios in new boxes.
I think it would be interesting to see what those look like inside.

File comment: worm shafts
worm shafts.jpg
worm shafts.jpg [ 22.28 KiB | Viewed 2019 times ]
File comment: worn OE balls and races
box wormshaft bearings.jpg
box wormshaft bearings.jpg [ 18.57 KiB | Viewed 2022 times ]
File comment: setting the screw adjustor
box in lb.jpg
box in lb.jpg [ 37.37 KiB | Viewed 2022 times ]
PostPosted: Tue Mar 12, 2019 4:44 am 
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Joined: Mon Oct 21, 2002 11:08 am
Posts: 13548
Location: Blacksburg, VA
Car Model*:
Thanks for the great writeup, John. I have some of these parts on hand too (e.g., 20:1 assy) and will do this someday. For now, boxes are good in my A-bodies...


"You mean you still have a Slant 6 in that thing?"

PostPosted: Wed Mar 13, 2019 11:26 am 
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Joined: Sat Nov 27, 2004 8:03 pm
Posts: 5233
Location: IRWIN PA
Car Model*:
What did you use for the spanner wrench and the 4" locknut on the box itself?

Those tools or lack thereof always held me back from tearing into one. - I am not retired either so I might lack time to do one correctly.


Greg Ondayko
69 Dart

PostPosted: Mon Mar 18, 2019 11:29 am 

Joined: Wed Sep 17, 2008 6:48 pm
Posts: 2805
Location: Indianapolis
Car Model*:
for the spanner wrench and the 4" locknut on the box itself

for the 4'' locknut I have a really large channel lock plier, probably opens to 6'', handled that lock nut easily

for the spanner, I made a tool, using a 18 inch length of 1x1 rectangular steel.

drilled two through holes in the steel that matched to the center to center distance of the hollow bosses on the adjustor
and put two 1/4 diameter by 2 inches long fully threaded bolts through the two holes.
Put appropriate sized nuts on the two bolts and tighten them to set the bolts firm in the rectangular steel.
I set the body of the spanner out away from the adjustor to clear the steering shaft nub.

when setting the rotational inch lb rotational torque, you a moving the adjustor finely but not applying any significant torque
to the adjustor itself, so being set away is not an issue.

Basically this is the same tool with different center to center distances that I made to tighten the
internal adjustors on an 8.75 differential. However the bolt nubs are short as the 8.75 differential adjustors get some
tightening torque applied and you will need good control over the tool.

I am not retired
some day you will be :D
plan for it.

PostPosted: Tue Mar 26, 2019 12:27 pm 
EFI Slant 6

Joined: Tue Mar 11, 2003 11:47 am
Posts: 481
Location: Illinois
Car Model*:
I remember reading that V8 boxes differed from slant boxes with slant boxes having bushings instead of bearings. Can bearings be installed in place of the original bushings?

Also what did you use to fill it. I remember reading that 80w90 is the theoretical spec but I have never seen anything that thin in one. I remember reading that the closest equivalent was a mixture of 80/90 with chassis gear. Just a couple of questions. I am out of touch with what is available and it is nice to see that the 20:1 is available again. I am definitely considering doing this, because a lightweight early A really doesn't need the ultra slow ratio. Even with my 5 degrees of positive caster it still wasn't hard to turn when moving at any speed.

PostPosted: Wed Mar 27, 2019 5:32 am 

Joined: Wed Sep 17, 2008 6:48 pm
Posts: 2805
Location: Indianapolis
Car Model*:
with slant boxes having bushings instead of bearings.

at one time I had an article that listed the part number difference so one could tell the
bushed and ball bearing boxes apart, but I would need to look to find it..

To find out if a bushed box can be rebuilt as a bearing box, I would call Firm Feel
they should know.

to fill it.

I did a lot of internet searching and the only consensus was to not use liquid oil.
Some recommended a John Deere picker head grease, others wheel bearing grease.

I used the red M1 synthetic grease, I packed the end ball bearing like wheel bearings
and made sure the needle bearing had a good coating then packed the ends of the box full.
Prior to installing the new worm drive I spent some time filling the screw with grease then
spinning the block across the screw, a fair amount of grease worked its way into the block-
internal bearing assembly.
After installing the worm drive but with the cross shaft out, spin the worm drive to move the
notched block back and forth, you will see that the movement of the block really pushes the
grease around the inside of the box.

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