Autoprop bearings

[JonJon]

Anybody attempted to replace the bearings on one of these. The ball bearings on mine have "brinelled" themselves into the bearing track on the hub. Its the old open ball style. The unit is 15 years old. Not sure how easy it would be to replace the track as a DIY effort, I note a number of you Brunton owners have spare bearing kits from doing a search on here, anybody tried it yet? Grateful any tips otherwise I fear its back to Bruntons and mucho dinari.

 

[npf1]

FWIW - I had to send mine back to Bruntons for a repair and they could only do it by modifying the prop to take the new style of bearings and locking mechanism. Cost about 25%-30% of a new prop but will hopefully prevent it screwing up in the same manner again. Not cheap but looks to be a job well done, which in my experience is quite rare in the marine industry!

 

[JonJon]

Many thanks for that - significant they changed style of bearings. They do have a good reputation tho and are pleasant to deal with - that alone makes me more inclined to part with dinari. I bought this unit on ebay (another pig in a poke! will I never learn!)

 

[npf1]

The reason they changed the design is that the old mechanism can come unscrewed if it is not maintained correctly. That's what happenned to mine and we lost a blade in a narrow channel between coral reefs in 45+ knot squall - was not fun at all!!!

 

[JonJon]

Funnily enough I thought that was a bit of a risk. Mine appears to havea non locked allen headed bolt holding in the screwed bearing retainer. I guess this is supposed to be locked in some way (loctite?) but nothing obvious. All this talk of "adjusting" bearings worries me too - presumably the heavy handed 'adjuster' could force the balls into the seat leaving the blades to take up position in a rather notchy fashion exarcebating the problem of vibration etc.

 

[npf1]

Seem to recall the issue is that if any of the existing grease hardens the locking mechanism tends to unscrew. When I had the problem, my prop had been regreased, after a the boat had been laid up for several years, but it had not been stripped down and cleaned first to get rid of any old/hard grease. Seem to recall Bruntons saying that there shouldn't have been an issue if it had been greased on a regular basis per the instructions.

 

[npf1]

Is the non locked allen headed bolt you mention the grease outlet ie supposed to pump grease in one hole unitl t comes out of the other?

 

[JonJon]

mmmm! not often you hear about grease stopping things unscrewing is it?

 

[JonJon]

Could be - I dont have a set of instructions for the unit but its the allen bolt in the centre of the screwed bearing retainer The threads of the retainer have slots cut in them maybe for grease mobility.

 

[Robin]

We have an older Brunton with open bearings and I don't recognise the comments being made here, maybe there was an early early model! Our open bearing one has NO grease, the adjustment is easy enough (instructions can be downloaded from Brunton's website) and there are locking tabs. Ours had done 10,000 miles when we bought the boat so I bought a bearing kit as a matter of course, but found no appreciable wear as when I followed the adjustment instructions it all went back to the same spot, I never have replaced the bearings. However at tickover in gear (like going as slowly as possible) occasionally you can hear the blades 'rattle' so it is possible someone might try and adjust this out and tighten it too much? The bearings are only for blade alignment remember not rotational bearings under any load, they just allow the blades to feather/pitch freely.

If I were you I would ring the guys at Brunton who are very helpful.

 

[JonJon]

I reckon I have the original Brunton here could be worth something oneday ( I wish!). I have phoned Bruntons and they are very professional and they are not going to tell me all the bad points of my unit. There are no locking tabs on mine and I can see the designs on their web site but mine is slightly different.