Thrust bearing for Gearbox (will fit either end of gear-shaft) for the Vire 6/7/12
The pictured gear-shaft is for context and is not included.
2 Item Items
Warning: Last items in stock!
Common Faults & Replacement Instructions
Noise which is proportional to thrust will be mainly this damaged bearing. If the noise is only in forward gear, it is the rear bearing, if it is in reverse it is the front bearing. you can also check the bearings by hand in the boat:
In neutral, holding the prop-shaft flange in your hand - push it forward and turn back and forth - any roughness is from the forward thrust bearing failure. By pulling the flange, you can also feel the roughness of the reverse thrust bearing.
Overhauling the gearbox, if there has been saltwater ingress (from failed water pump seal and shaft surface usually) these will need changing.
You can check there is no water in your oil by draining it out the lower rear sump bolt. Any water will come out first and is obviously watery (90% will be dissolved into the hypoy).
Since they sit partially in the hypoy gear level and are barely splash lubricated when running they have a tendency to pit if there is any water in the oil or the gearbox is left to dry up in the winter afloat (turn the prop every month if you have to leave it afloat, or add the molyslip).
Of all the bearings in the gearbox, this is the pair that creates the most irritating noise, since it takes almost all the load and are mounted into the exterior castings.
As an expert, I recommend adding a little gearbox-molyslip into the oil - this should give the drying out components some residual covering as it protects much better than pure hypoy. Alternatively use a marine gearbox oil instead of hypoy(expensive) e.g. quicksilver.
If your thrust bearing was pitted or rusted, you probably got water in the gear oil through the pump seals/shaft deterioration - you may need to sort this out, and i can help.
To fit - having removed gearbox from engine you can replace
Front bearing by removing circlip and pulling off inner race with its associated gear. outer race is removed from engine block by two dismantled puller arms levering against a socket you put in the blind hole.
Rear bearing is more difficult since you cant remove the gear-shaft without rotating selector fork(wheel) forward 90 degrees which requires gear stick removal (drift out split/cotter pin). then the rear race may be pulled off with its associated gear, and rear outer race drifted out.
Replace by drifting on, and replacing new rear seal and gasket. check free play of mainshaft is 0-0.25mm when assembled tightened down gearbox or adjust shims behind the outer races accordingly.
Note: Pic shows upgraded bronze bushing i add to rebuilt gearboxes - this wont rust. normally the bush is rusted up to the seal's lips and it is risky replacing the rear lip-seal without a clean non-rusty bush.
For any further assistance please contact me.