These are
generally fitted to 'Sevens' from 1935 onwards, although are popular as a conversion
for the earlier type.
Test for wear in each joint
Check for wear in the flange bearings,. This can be done by lifting the joint
either by hand or using a length of wood suitably supported. Any circumferential
movement of the shaft to the flange indicates wear in the bearing joint and this
joint will need to be replaced.
Dismantling of the joint
Having unscrewed the dust cap, pull the sliding joint out of the splines. You
will need to carefully clean/remove any paint or dirt from around the circlips/snap rings and the top of the bearing cups. The removal of the older type snap
ring is by using a pair of pliers, and prizing with a screwdriver. The later
type have a circlip which you will need to use suitable internal piers for this.
If the circlip/snap ring does not come out easily then a light tap on the end of
the bearing cup should relieve the pressure on the ring.
Once all
the snap rings/circlips are removed, hold the joint in the left hand with the spline sleeve yoke
lug on the top, tap the radius of the yoke lightly with a copper
hammer (see photograph). The top bearing cup will start to come out; turn the
joint over repeat this until finally the bearing
cap can be removed by hand or a pair of pliers. If necessary tap the bearing
race from the inside with a small diameter bar, taking care not to damage the
bearing bore. Repeat this operation for the opposite bearing.
Cleaning
To ensure that the bearing cup bores are not damaged, I refitted the old cup back
into each of the yoke, using a small drift, to check that the bearing cup goes
completely through the bearing bore smoothly. This way you can ensure that
internal surfaces are not damaged when you go to fit the new bearing cups. If
the bores are slightly damaged then a careful filing will help or better still
you could ream the hole, this will then remove any high spots. Now the old cups
should be able to be gently tapped through; don't be tempted to just fit the new
bearing cups, as this could result in the completely assembled joint having
tight spots and, even worse, you may have caused damaged the surface of the new
spider joint or rollers in the bearing. So be warned; take your time before
assembly.
Assembly
I would strongly advise to fit new replacement bearings which come pre-filled
with grease instead of using the old ones again.
Carefully remove the bearing cups from the new spider joint and ensure that all
the very small rollers inside the cup are in place [very important point]. Start
by inserting the spider in the flange yoke, push it to one side of the yoke.
now using a soft nose drift, ie brass or aluminium, about 1/32" smaller in
diameter than that of the hole in the bearing bore, tap the bearing cup
carefully into position. Do not use too much force if tight (see cleaning
notes above). Then enter the spider joint into the bearing cup as soon as
possible, as this prevents the rollers from becoming dislodged. Once again
I stress it is essential that the bearing races are a light drive fit in the
yoke trunions. Now repeat this operation for the other three bearings. It is
recommend that top of the bearing cups should be coated with a varnish /paint
prior to just fitting the circlip or snap ring to ensure a good seal.
Finally if
the joint appears to be tight or bind, this can be relieved by tapping lightly
with a soft face hammer.
When refitting the sliding joint on the shaft ensure that the trunions on the
siding and fixed yokes are in line. Some times there are marks on the spline
stub shaft but my experience these have gone. It is advisable to replace the
cork washer on the dust cap, if there is one still there.
When refitting the complete propeller shaft assembly back into the car wipe the
companion flanges clean, to ensure that the pilot flange registers properly and
the joint faces bed evenly. insert the bolts all round and are securely locked
with either a spring washer or lock nut. Normally the sidling spline joint is
placed towards the front of the car.
Finally
don't forget to grease the spline joint. Then you are ready for another
40,000 miles or 50 years driving.
This article, written by Mike Davies, originally appeared in CA7C Seven Focus
in May 2007 pp22-24.
