lubricant for rudder shaft through nylon bearing

[yelbis]

I have previously posted stiff rudder complaint and had advice to try to get lanolin lubricant down the shaft in order to free up the rudder. The nylon bush/bearing appears to have swelled. The manufacturer tell me that nylon swells in water, bloody sill y choice of material then. The new bush to replace is £200, plus labour at £350 plus craneage. Surely there is a way of lubricating it so that it will turn easily enough for the autopilot to operate? I am happy to try lanolin lube, but if there is a purpose made lubricator for metal on nylon applications please let me know. Obviosly I only get one chance of getting the lubricant into the shaft column so I need to use the best product. Help please.

 

[sailorman]

the wrong material was used when new or replaced
on my MAB its a bronze tube + stuffing box with a s/s shaft + a remote greaser /forums/images/graemlins/ooo.gif

 

[PuffTheMagicDragon]

Unfortunately, lubrication won't help because now that the nylon is swollen, the bore is effectively smaller than the rudder stock.

I could never understand how 'cost-cutting' is taken to such extremes. I might be old-fashioned but, if I were in the market for a new boat, I would insist on tuphnol bushes and a stock make out of 316L stainless - not aluminium alloy as is commonly seen, even if I have to make them myself. Just my opinion.

Be that as it may, it still seems a bit steep as a quotation. Maybe I ought to come out of retirement, emigrate and open an engineering workshop in your country! /forums/images/graemlins/wink.gif

Good luck!

 

[TigaWave]

Fit a composite bearing? some are designed specifically for dry rudder applications. I think I've probably said too much now

 

[PCUK]

Sea-water resistant nylon doesn't swell. Cheap nylon does.
Bronze bearings will last forever with a bit of grease. Worth changing as they'll never need doing again!

 

[srp]

A much better (plastic) material is Vesconite. You could buy a short length and take it to a local engineer who could turn up a replacement for a few pounds - the total would be far less than £200. Can't help with the lift out cost though.

 

[jeremyshaw]

As SRP posts, something like Vesconite is the only real answer - ordinary nylon does swell and is simply unsuitable where it's going to get wet. In fact getting replacement bearings from the builder doesn't always work either since the housing may have worn, so depending on the design very careful measurement may have to be taken.

I had a rudder bearing replaced in Malta and it had to come out again after a few years as it was made of the wrong stuff (nylon). I fear no amount of lube will solve the problem, though it might ease it a bit before the bullet is bitten.

 

[Clyde_Wanderer]

It is most likely that the rudder stock on your Bav is aluminium which has probably corroded and has clumps or blisters of oxidation which are trying to expand the nylon bush, which wont be cured by changing the bush alone.
But I could be completly wrong and you may have a s/s stock, in which case it would be the Nylon bush, which you should replace with one made from Asconite or Delrin, which might work out cheaper than buying an original part just to have the same problem in a few years.

 

[AndrewB]

Consider the cheapskate option of filing out a little of the swollen nylon bearing - alternatively, as it is easier, sand back the diameter of the rudder stock with emery paper where it passes through the bearing. This is what I've done sucessfully with the steel rudder stock on my yacht. The amount necessary is hardly visible to the naked eye. If you can ease the rudder this way without producing a big leak - problem solved, for a while at least.

Although nylon does swell, very often the cause of a sticking rudder is a slightly bent rudder stock. Check this before you waste dosh on a new bearing.

 

[Adamastor]

The Vesconite option is probably the best way to go for now. I don't know the Bav 32 intimately, but I've done a rudder-job on a Bendy f35 by putting 7 ppl on the foredeck (!) to get the rudder-port out of the water and then used a diver to get a new rudder under the counter and steer it into place. You could probably replace your bearings the same way if your rudder isn't too buoyant, or at least get the old bush measured for a refit while you have the rudder-port stopped from the outside.
FWIW, the original bushes are probably acetyl resin which is absolutely unworkable to a fine finish without machinery, btw- sanding it will just make it fuzzy.

 

[flyingscampi]

I'm just about to re-fit my rudder with a s/s shaft and 'nylon' bush and I was also going to ask what lubricant to use.

Is Ramanol advanced grease or Blake's seacock grease suitable?

 

[Tranona]

I am not sure about "nylon" being used which "swells". My Bavaria does not have this problem. I think they use Delrin, or something similar which does not swell in water. They design it so that it is water lubricated so are unlikely to use a material that does not perform in these conditions. I suspect, but I don't know as this is only based on what I have heard and logic that the problem is with the stock, probably a build up of fouling and that dropping the rudder and cleaning the stock will solve it.

Delrin is a superb material. I installed Delrin bushes for the lower bearing of the stock and as a liner to the bronze heel fitting on my Eventide 15 years ago. No wear discernible in all that time and the rudder moves as freely as when it was new.

 

[Loginname]

Are you sure that it is Nylon?
Daft choice of material if it is, but worth checking just to make sure that you really do know what you are working with.