Getting grease to rudder pivots

[bluerm166]

These chunky rudder pintle/gudgeon assemblies fully enclose the 1/2 in bolts where lubrication would be beneficial but I would like to improve things.
From records they seem to have required intervention every ten years or so ,At one time having top hat stainless washers welded into the pintle flanges.This winter the worn bolts ( particularly the top at the neck) were replaced with UNC bolts that have a pretty full shank .
The rudder and stock are hefty and not easily removed when the boat is afloat.So having them disassembled I contemplate drilling vertically down through the hex bolt head
plus sideways to meet this through the shank so that the tube within the gudgeon could be reached by oil if not by grease.The bolts themselves can be tightened solid in the pintle frame so that they do not rotate in it.
Any thoughts on this approach to lubrication please, going so far as to add a greasing nipple on top of the hex ?.
Obviously I can grease before refitting the bolts but this is probably insufficient to last the season/s.

 

[philwebb]

What if you put a grease nipple somewhere near the back of the U-shaped piece? Would the nipple foul the back plate? If not grease could be forced in with a grease gun which would then go upwards and downwards in the pivot. How much grease you could get in would obviously depend on the amount of play between the bolt and the housing.

 

[bluerm166]

An idea but can't be achieved because the bolt passes down through a separate tube/piece of barrel welded in and if the bolts are tight over the flanges of the pintle then the barrel/bolt shank is the real bearing.
However I have had a go at drilling down thro the head of a similar stainless hex bolt on a press this p.m. and it does seem doable with plenty of cutting oil..Its a 3mm hole rather than one large enough to tap a nipple in but I see the possibility of applying one of the new WD40 lubricants (spray grease) directly into that and thence out via horizontal drilling in the shank below .I looked at nipples but see that the smallest requires an 8mm + drilling for tapping in.
Thanks for looking at the issue.

 

[2Tizwoz]

An idea but can't be achieved because the bolt passes down through a separate tube/piece of barrel welded in and if the bolts are tight over the flanges of the pintle then the barrel/bolt shank is the real bearing.
However I have had a go at drilling down thro the head of a similar stainless hex bolt on a press this p.m. and it does seem doable with plenty of cutting oil..Its a 3mm hole rather than one large enough to tap a nipple in but I see the possibility of applying one of the new WD40 lubricants (spray grease) directly into that and thence out via horizontal drilling in the shank below .I looked at nipples but see that the smallest requires an 8mm + drilling for tapping in.
Thanks for looking at the issue.

Replace the washers with oilite bushes.One source.

 

[ducked]

Or possibly nylon washers.

Failing a grease nipple installation (or as well as one) I would probably try driving the greased bolt down through one or more layers of polythene sheet, which will provide solid lubricant which wont wash out as quickly as grease will.

I might grease it, drive it, wrap PTFE　tape around it, grease it again, then drive it down wrapped in polythene. The thickness/number of layers of polythene achievable will depend on the clearance, but even if its tight PTFE　ｗｒａｐ　ａｔ　ｌｅａｓｔ　ｓｈｏｕｌｄ　ｂｅ　ａｃｈｉｅｖａａｂｌｅ

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