|
Subject:
Steering box assembly & adjustment
From: Brian Falkner (New Zealand
This
applies to all boxes from 1937 to '53 [& '54 to '56 F-1 Trucks]
Terminology: Bolts = capscrews, Spring washers = split washers
The
first step in steering box re-assembly, is adjustment of worm bearing pre-load
assuming all parts are spotless, surfaces flat, thread holes de-burred,
sector shaft a nice snug hand-push fit in the housing bushes..... [Later boxes
used needle roller bearings, so did some 1936 car boxes]
Clamp the housing firmly in a vice so the shaft will be angled slightly uphill or near horizontal position & the worm easily visible.
Lube the bearings with a heavy gear oil, I like Wynns gear oil additive which is
thick, sticky and translucent.
The '37-'39 boxes have a lower shim plate
with a brass stator-tube guide [for light switch rod & horn wire]. This is
usually loose and is a cause of oil leaks so solder it up.
The 40-48 car plate has a more solid steel tube for the horn wire only and is
usually leak proof, use one of these if you have a dash mounted light switch in
your '37-'39.
Make sure the shim plate is flat & not
warped, select a wad of shims [if you have the originals, measure the total
thickness, it will be a good place to start from], and place them on the plate
leaving the really thin ones off. These you will need for fine adjustment later.
Always position the thinner shims last. Use two bolts with spring washers as
guides throughout the shim selection process otherwise it can get frustrating.
Bearing pre-load is a 'feel' adjustment. You
don't need any special tools to get it right. This 'feel' will be with your
thumb & forefinger turning the shaft. Manuals will show a mounted steering
wheel & scales to measure pre-load in pounds, usually 3lbs. I prefer feel.
First you get to the stage where obvious play is almost nil then proceed slowly,
replacing thicker shims with the very thin shims you have aside. At this stage
you need all four bolts tightened firmly to obtain the correct feel.
If you can feel the rollers turning in a lumpy sort of way then it's too
tight, it must feel firm but smooth, don't accept near enough, this adjustment
must be exact and the key to obtaining this is the final selection of thin
shims...cut & punch your own if you have to.
If at this stage you notice your hollow shaft is not very straight, you can
improve on this by bending by hand as long as the box is held firmly in the
vice. A little out of line is not a worry, say a half inch at the end, any more
it will pay to mark the spot & bend carefully, as necessary. Take your time,
no hurry, patience is the key here. The shaft is not hardened steel so it's
fairly easy to bend. Any doubt, take
it to an engineer.
Steering Freeplay adjustment: Ford
max is 1.5"
Next is the installation of the sector shaft & adjuster plate assy. Position
the sector shaft into the box, turning the shaft as it slides through the new,
lubed, seal so as not to mark it. Place the sector in the middle of the worm.
Remove the filler cap.
Use some oil or grease to stick the gasket to the plate, guide the adjuster stud
& washer into the slot of the sector,...37-48 washers are offset so you may
notice! ...., screw the adjuster out so the roller won’t bind on the worm then
push the assy down into bolt on position. Use two bolts at first, making sure
while securing that the roller is free of the worm.
Place the drop arm on the sector end & tap it lightly onto the tapered
spline in a position that allows lock-to-lock travel with your hand on it. It
must be enough to require a firm tap with a light hammer to free again. No nut is required, this is for adjustment purposes
only. Later F100's must be clamped.
Find EXACT halfway steering position as that is where all adjustment is done.
No where else. This can be ascertained by measuring the drop arm travel
and or number of turns of the steering shaft. If the roller is clear, place
& secure the other two bolts. To adjust roller to worm clearance you will
need to see through the filler hole to check when the roller makes contact &
starts to turn.
Again, this is a 'feel' adjustment with some visual.
One hand will hold the drop arm firmly, moving it to & fro until all play is
'only just' removed via a screw driver turning the adjuster clockwise.
The
twist travel of your wrist turning the shaft will be enough to feel resistance
when the roller contacts the worm, it will be only about a half turn either way
when resistance/contact is lost, THAT is the adjustment area
. When it feels maybe a little firm, that is
the time to pop on the special Ford star shaped lock washer, Ford part# 78-3564,
[37-48 cars], and tighten the capped nut [11/16"spanner I think].
What happens is, the tightening of the nut pulls the adjuster up a tad, enough
to change the setting you thought you had.
A correctly adjusted box will feel a very, very slight resistance when turning
the shaft through the central position.
If you have a used sector shaft, chances are there is play in the roller, be
careful NOT to try to adjust this play out. This is where visual adjustment is
important. You will be able to see the roller move when you push & pull on
the drop arm. Stop adjustment as soon as the roller contacts the worm. That
[agreed/acceptable]
roller play will equate to about an inch + at the wheel which is quite ok.
So, we are not simply adjusting
freeplay, we are adjusting the
critical roller/worm contact. Get this right, it will be a pleasure to drive and
your box will last for years, get it wrong [usually too tight] and the worm in
particular will wear prematurely.
Take
you time throughout this procedure, try it tight & try it loose, the
experience will guide you to the obvious and correct adjustment.
This should give you the reason why it is very important to have your steering
wheel correctly aligned with the front wheels. The sector needs to be in the
central position on the worm with the vehicle pointing straight down the road.
Adjust your draglink to correct.
More
notes from Brian…….
How much to tighten the shim plate bolts? Snug 'em up is fine. To determine the
correct 'snug' feel, torque those 5/16" NC thread, 7/16" head, bolts
to the normal 25Lbs. It is important NOT to over tighten the shim plate bolts as
the plate will bend, crush the shims and maybe cause a slight leak.
I never used any sealant on these areas, no need if you have flat surfaces &
a gasket. Flattie steering boxes are not subject to temp differences or internal
pressure.
The adjuster cap nut was designed by Ford & never changed from 37-48 because
there was no need to, get used to it.
Hmmm, you probably don't realize that the star washer holds the stud &
itself in place via the outside star pattern resting on the stamping of the
plate. The star washer is designed to go with the sharp, stamped edge, down for
a better grip on the plate. The washer also acts like a gasket.
This system does not normally leak so a gasket is not needed under the nut.
Because the F1 plate is on the side not the top as in 37-47 cars, you could
place some flexible sealant on the washer to be sure. If you use an open nut,
oil WILL leak out & moisture & dirt WILL get in.
The 'finger tight' filler cap usually has some writing on it that says,
"use heavy gear oil", that meant 600w. I don't like dirty black
molasses looking oils but I do like the heavy additive oils like STP, Wynns,
Morey's, Bardahl [is that still available?], or whatever. It's a personal choice
thing, just make sure it's around
600W. The worm & roller can be subjected to an incredible amount of force
especially when parking or moving off. 85-90W
tends to find its way out of steering boxes and doesn't offer enough protection
for the worm & roller.
|