Hurth 50 gearbox with dry bearing

[Outinthedinghy]

Hello. I've recently bought a boat with a Lister LPW2 MGR with a Hurth 50 reduction gearbox. 1990 build year. All is clean and working well except that the output shaft bearing on the gearbox sounds like its dry. squeaks a bit when in gear or when turning the prop in neutral. The gearbox itself uses ATF and shows at the correct level on the dipstick. Would this bearing have been a sealed for life unit or is there some way of lubricating it? there doesn't seem to be a grease nipple. Do i need to fit a new bearing - is it likely to seize up?

 

[earlybird]

The Hurth output shaft is carried in a normal ball journal bearing with a separate lip seal outside it. It is lubricated by the oil in the box and requires no special attention. I would think it unlikely that the squeak is the oil seal. Presumably the boat is in the water, otherwise is could be the cutlass bearing. Other than that, can't really suggest anything except to say that it should be quiet.
PS. IIRC, the oil should reach the mark with the dipstick not screwed home.

 

[Outinthedinghy]

thanks for your reply, I just had a closer look at it and there is a spring loaded brush type arrangement pushing against the prop shaft (stainless) which has a lead going to an anode. I guess this protects the stern gear from galvanic corrosion? (GRP Boat). it was the clamp which was squeaking against the prop shaft not the gearbox bearing. I put a bit of grease on it which stopped the squeak but would this reduce the effectiveness of the electrical connection between this and the anode?

 

[1955patric]

The brush gear depends on electrical contact between the shaft and the anode. Grease is NOT a good conductor. Check continuity between the shaft and the anode stud. If it is more than a couple of Ohms then you are not getting a good enough connection for the earthing gear to be effective. If the brushes are carbon, try polishing them up with a bit of fine wet and dry
inserted between them and the shaft and rotate the shaft, ensuring the wet and dry rotates with the shaft (after cleaning all the grease off).