Jabsco 2955-1001 drive shaft wear

[MikeBz]

The Perkins Prima M50 and some models of Volvo MD22 have a Jabsco raw water pump which is driven by an adapter on the rear of the camshaft. The slot in the shaft which engages on the adapter gets worn - this is what ours looks like, engine has done about 2400 hours but I’ve no way of knowing whether this is original:



Should I be replacing that now or any time soon? Replacement shaft is in the order of £140, EBay versions are less but who knows what the metal quality is like and how soon they will look like the above again.

Complete new pump is around £500! Italian pattern part about half that. Makes more sense to refurb the existing one, bearings seals wear plate etc.

 

[Boater Sam]

If the other mating dog is not worn more than this one, I would not worry about it.
If you want to repair it I would dismantle it and get the dogs brazed back to shape.
A good moly grease should slow down the wear rate.

 

[Plum]

The Perkins Prima M50 and some models of Volvo MD22 have a Jabsco raw water pump which is driven by an adapter on the rear of the camshaft. The slot in the shaft which engages on the adapter gets worn - this is what ours looks like, engine has done about 2400 hours but I’ve no way of knowing whether this is original:

View attachment 202332

Should I be replacing that now or any time soon? Replacement shaft is in the order of £140, EBay versions are less but who knows what the metal quality is like and how soon they will look like the above again.

Complete new pump is around £500! Italian pattern pa[rt about half that. Makes more sense to refurb the existing one, bearings seals wear plate etc.

Can't see from your photo, is the drive fully engaged to almost full depth of the slot in the pump shaft?

 

[MikeBz]

Can't see from your photo, is the drive fully engaged to almost full depth of the slot in the pump shaft?

Yes, almost but noticeably not quite. I guess it shouldn’t be putting any end-thrust on the adapter/camshaft assembly. I have another old pump in a box of bits which is the same, as in showing wear and not quite to the full depth of the slot. The depth of engagement is simply dependent on where you press the shaft to when assembling the pump.

 

[Plum]

Yes, almost but noticeably not quite. I guess it shouldn’t be putting any end-thrust on the adapter/camshaft assembly. I have another old pump in a box of bits which is the same, as in showing wear and not quite to the full depth of the slot. The depth of engagement is simply dependent on where you press the shaft to when assembling the pump.

Yes, you don't want any end loading but you need to have adequate engagement to spread the load, and therefore the wear. Different engine but my shaft also has no location/circlip so entirely dependent on how far down the shaft you press the bearings down to get the correct drive engagement.