Replacing swan neck bearings

[petch]

Hi all, 

 

Been advised by the surveyor to replace the bearings at the base of the swan neck. Thought we'd see how we get on but it seems to be deteriorating after just a few days

 

We've spoken to a chap at a chandlery and he said (from looking at the pictures I've attached here) ours is oval (looks circular to me?) and he will need to weld a new base plate in so that the bearings will fit. He said you can't get oval bearings which is why we would need to swap the base plate out for a round one. Again, it looks pretty round to be but I have no idea what I'm talking about

 

Do we need a new base plate? Can we just replace the bearings themselves rather than the housing? 

Any advice much appreciated

 

[petch]

Well I think he was having us on - there are plenty of oval bearings online that look similar to ours. The question is which size! 




 

[David Mack]

You can certainly get 2 bolt (oval) housings e.g. https://www.bearingboys.co.uk/2-Bolt-Flanged-1127-c.

It's also likely that you only need to replace the bearing, and not the housing, although from the pictures there may be some damage to the housing.

The issue is that the rudder shaft axis is not perpendicular to the baseplate, so you need a setup that can accommodate that much non-squareness.

In any event you need to remove the swan neck to remove the old bearing, so maybe best to remove the housing as well, measure the shaft diameter as accurately as you can, then take the bits to your local bearing trade counter and see what they have.

27 minutes ago, petch said:

he will need to weld a new base plate in so that the bearings will fit. He said you can't get oval bearings which is why we would need to swap the base plate out for a round one.

What he means is he doesn't have the bits you need in stock.

[petch]

1 minute ago, David Mack said:

What he means is he doesn't have the bits you need in stock.

He was looking online, or pretending to I guess. Said they do not make them anymore!

[BEngo]

General comment:

 

A chandlery is the last place to go for this sort of thing, ot any common engineering item like belts, bearings, engine mounts etc.  Even if you have more money than sense, or are in dire straits, there are on-line and on-street suppliers who will have a better range of this sort of thing, at better prices, and usually with some product knowledge to boot.

 

For the OP:

 

On line search for "self aligning bearing housing" or "self aligning bearing".  Bearings are sized by Outside diameter, inside diameter and thickness.  You will need to dismantle the rams head and remove the bearing and housing from the rudder stock  then extract the bearing to measure it.

 

On  the street look for an Erik's, or in  yellow pages for a bearing distributor. There will probably be one in a local industrial estate.  Take the old one in and ask for "one like that".  Tell them you want a good quality one not a budget version.  Either way it is probably Chinese made, but the quality one will last a lot longer, and cost more than a budget one.

 

N

[petch]

Thanks! We've found under layers of paint it says FL208 - which seem to be 40mm bore size. Are we good to buy any FL208 (of which there are a few brands) or is there another specification we may need? This is one we could order, for example https://www.skf.com/uk/products/rolling-bearings/ball-bearings/angular-contact-ball-bearings/single-row-angular-contact-ball-bearings/productid-FYTB 40 TF

[BEngo]

SKF  are a reputable brand of bearing.  Since the SKF specs give detailed measurements of the bearing and housing, I would check the important dimensions (bolt hole spacing and size, shaft size) match the one you have and if these are OK I can see no reason not to order one.

 

As above, I would not buy the cheapest available FL208, unless you like changing bearings...

 

Your current bearing appears well tired.

N

[waterworks]

The rudder bearing doesn't ever get any wear, it doesn't even need a ball bearing just a collar, they just use them because its an off the shelf solution, the sealed bearing is designed for rotating machine at high rpm, just moving it side to side for years won't ever wear it, buying a high grade bearing like SKF would be a waste of money, all you need is the cheapest grade and keep it greased or get stainless and forget about it. 

 

Bearings are stock sizes metric or imperial ID x OD x Thickness so you don't need to replace the housing unless its damaged. It will have a code number on it so you can order another one, Dunlop bearings on eBay are cheap and good enough for this application.