To dismantle and rebuild universal joints
The needle bearing type universal joints are so designed that correct assembly is a very simple matter, no hand fitting or special tools being required.
Individual parts of the needle roller bearing assemblies should not be renewed singly. If replacements are found to be necessary, the complete set of bearing parts com-prising journal complete with gaskets and retainers, needle bearing assemblies and snap rings should be fitted. These models having a propeller shaft with sealed bearings, no grease nipples are provided and n6 lub-rication is required a sealing washer is fitted between the cork gasket and the bearings.
The journal and needle bearing assemblies are the only parts subject to wear after prolonged service and when it becomes necessary to replace these for any reason the work should be carried out as follows
To dismantle
Remove snap rings (2, Fig. 8) by pinching ends together with a pair of pliers. If a ring does not readily snap out of the groove, remove enamel from the yoke holes and tap the end of the bearing lightly, which will relieve pressure against the ring.
Holding the joint in one hand, tap gently with a piece of copper or copper hammer on the radius of the ear of the yoke, as shown in Fig. 9.
The needle bearing will gradually emerge and can finally be removed with the fingers. Be sure to hold the bearing in a vertical position and when free remove race from the bottom side so as to avoid dropping the needle rollers (see Fig. 10).
Repeat this operation for the opposite bearing.
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Support the two exposed journal pegs on lead blocks (to protect ground surface) and tap the ears of the flange yoke to remove the race.
Wash all parts in petrol or paraffin.
If parts are not worn, repack the sealed type of bearings with Shell Retinax A. Make sure that the joints of oil channels are filled with lubricant. With the rollers in position fill the race about one-third full. Should any difficulty be encountered when assembling the rollers in the housing, smear the wall of the race with vaseline. Install the new gaskets and gasket retainers on the journal assembly. The journal shoulders should be coated with shellac or other suitable jointing prior to fitting retainers so as to ensure a good oil seal. It is also useful to have spare snap rings available as replacements in the event of damaging a ring In. assembling the joint.
To reassemble
Insert journal in flange yoke holes.
Using a soft, round drift with a flat face, about 1/32in. (.79 mm.) smaller in diameter than the hole in the yoke, tap the bearing into position.
Repeat this operation for the other three bearings. Fit new snap rings and be sure that these are firmly located in the grooves.
When assembled, if joint appears to bind, tap the lugs lightly with a wooden mallet, which will relieve pressure of the bearing on the end of the journal. It is essential that no play exists between the roller races and the bores of the yokes. If the yoke cross-holes have worn oval, the yokes must be replaced. In the case of the inner yokes renewal can only be effected by fitting a new propeller shaft, since this yoke is welded to, and balanced with, the tubular shaft.
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