David-
There are two adjustments, which must be done in the order as listed
below.
1. All play must be removed from the bearings, this is done by
adjusting the number of thin metal shims under the flat plate located on the
forward end of the box. If you want to do this correctly, it is easiest to
borrow a magnetic base and dial indicator and evaluate the worm's motion
when alternately tugging and then pushing on the steering wheel. ( e.g.. Sit
in the car, pull the wheel towards you, then push it towards the front of
the car) Where to make the measurement depends on whether you have a later
TR or an earlier one. The older ones had a one-piece shaft, later ones had a
split shaft.( coupling is found near the ignition coil). In either case, it
is important to loosen the threaded screw/locknut on the top cover of the
box, to eliminate any influence of the worm's 'peg' on the bearing
adjustment process.
If you have the split shaft, you can set up the dial indicator at
the coupling so that it will measure the shafts motion- along the long axis
of the shaft- without opening up the top cover on the steering box. If you
have the one piece shaft, you might be able to make the same measurement
with the dial indicator set to touch the steering wheel hub, ( pulling and
pushing the st. wheel) Alternatively, you can pull the top cover off the
steering box and position the indicator in the worm's grooves and directly
measure the play, again looking for travel along the long axis of the shaft.
This can be tough because the worm will give reading errors if the St.wheel
is rotated even slightly. This is a PITA, but is really important to get a
good adjustment, and avoid damage to the box which can be caused by making
adjustment # 2 (see below) when there is looseness in the bearings. When a
reading has been made, ( you may find .000" to .010" or so) the next step
is to carefully clean the end plate on the box, ( to avoid crap in the
bearings) loosen the sealing 'gland/olive' nut ( where the control head
wiring comes out) and pull out the 4 bolts holding the end plate in
position. Proceed carefully, as you don't want to destroy the thin metal
shims that are already in there, and are probably stuck together. Measure
the thickness of the shims individually, and select the shim(s) that most
closely matches the reading you saw on the dial indicator. Snip and remove
the shim, and with extreme attention to cleanliness, reinstall the remaining
shims and endplate. Try making the measurement again, if you have not
trapped any crud in the shim pack, the play in the shaft should've been
reduced by approx. the thickness of the shim you removed. Be very careful to
avoid taking out too thick a shim- it will cause preload on the bearings,
which in some cases will cause the bearings to fail prematurely. You can
usually tell if the bearings are too tight by gradually tightening the
endplate bolts, while checking the feel of the steering wheel ( rotational
movement). As you approach the recommended torque on these 4 bolts, the
steering wheel will bind up slightly if the bearing clearance is
insufficient ( i.e. you took out too thick a shim). Don't mistake the feel
of the steering peg mating with the worm, insufficient bearing clearance is
evidenced by "stiff or sticky" motion of the wheel ( even a very slight
rotation.) After you've ensured the bearings are neither too tight (
sticky) or too loose ( Dial indicator > .001" approx.) make sure the end
plate bolts are correctly torqued and reinstall the control head shaft
sealing gland/olive.
2. If you took off the top plate, loosen the screw and locknut
that presses on the
top of the steering peg assembly- do this to avoid any pinching inside the
box when reinstalling the top plate. Install the plate, and torque to
recommended settings. Center the steering wheel, ( i.e. left/right) and
very gently tighten the screw that presses on the steering peg assembly.
While doing this, observe that the 'rotational play' in the steering wheel
is decreasing, and when it gets around 1-2", tighten up the screw's locknut
while ensuring the screw itself doesn't turn. Check the steering play, and
rotate the wheel fully left/right to make sure there is no (NONE) spots
where the wheel seems to bind. If it seems OK, loosen up the locknut,
tighten the screw ever so slightly- and retighten the locknut. Run the full
L-R test again. repeat until the wheel barely begins to show a little
tightness, usually seen at 'straight ahead'. Loosen the peg screw just a
bit, and retighten the locknut to the correct torque. Retest. You want to
be REALLY sure that the steering does not bind, as this will really surprise
you if you're making a turn and expecting the steering to self-center as
you exit the turn. That can introduce you to another form of car repair,
known as " Front-apron sheet metal restoration".
Make sure the box is properly lubed, some folks use 90W, some have
had OK results with grease.. it doesn't leak out nearly as fast as the oil.
To Re-emphasize- DO not tighten the steering peg adjustment screw if there
is any play in the worm's bearings. If there is looseness in the bearings,
and the peg is tightened, the loads carried by the worm and peg are
transferred to only a couple of ball bearings, instead of the whole ring.
This will cause flat spotting of the balls, and subsequent damage to the
bearing surfaces of the worm.
Sorry this post went on so long. Then again, if you consider
steering maintenance to be a Quick and Dirty event, make sure you let me
know when you'll be motoring, so I can get my car back to the safety of the
garage!
Good Luck
Bob Westerdale
59 3A TS36967
-----Original Message-----
From: David Templeton [mailto:davidt@opentext.com]
Sent: Wednesday, August 22, 2001 8:50 PM
To: 'triumphs@autox.team.net'
Subject: TR3a steering box
Hi all,
In the continuing adventure, I am at the steering box and have opened it up.
What fluidis used? What are things I should check for, play etc? The unit
appears to be sound. Once I cracked open the seal the unit was completely
full so nothing got in to it. The bearings appear in very good shape like
the box was recently rebuilt. All help is welcome.
David A. Templeton
'59 TR3a-on the road to recovery
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