Lewmar foot block challenge

Javelin

Javelin

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www.southwoldboatyard.co.uk
The lower sheave on my port sheet foot block is breaking up.
So I decided to strip it and get and fit new sheaves.

Trouble is I can't work out how the pin comes out.
I assumed it would push out of the bottom but hitting it pretty hard has made no progress.
The pin is not seized, it does move up and down about 1/8 in and it will revolve.
Anybody got any ideas?
footblock_1.jpg

footblock_2.jpg
 
I cant see a cir-clip although there is a recess in the bottom of the pin that I guess could accept one.
I've had a good dig around in the area and can get my finger nail in the recess right the way round.
But lets say there was a cir-clip that would make the pin punch out bottom to top.
I had a clobber in that direction once or twice but without much oomff
 
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I would have expected the pin to be fixed and the sheaves to rotate on the pin, rather than allowing the pin to rotate in the casting. Pins in various blocks that I've come across have been firmly riveted over at each end to achieve this. Yours seems different so I'm puzzled.
However, if you've given it a good wallop with no result, I think that you will most likely have to drill the head off the pin, not easy if the pin rotates, and thereby destroying it.
Re-riveting a new SS pin is not easy to do satisfactorily though.
Sorry to be pessimistic.
 
I had some Goiot Genoa track sheaves where I wanted to replace the rollers and tried to drive out the central pin with a hammer and drift.
Eventually I asked a friend who ran a marine engineering business to help and he put them through his hydraulic press.
It took 3, yes 3 TONS of pressure to drive out the pins!
 
If both top and bottom of the pin appear to be free and able to move about so able to slide either way then you can only assume it has seized or is attached in the middle. Sorry I haven't got any ideas though.
Re Early bird comments yes block manufacturers seem to go to some trouble to ensure that when a sheave breaks up from UV and use that you have to replace the whole block. I have had some success after destroying the rivetted pin to replace with 1/4 inch OD stainless steel tubing. Through this I pass a 3/16 screw and nylock nut. The tubing isclamped in by pressure onm the screw and nut and the nylon replacement sheave rolls on that. Not sophisticated but Ok for small loads. olewill
 
Logic would suggest it ought to drive out from the top to bottom, as that way in the event of it failing/coming loose, the base to which it's attached would prevent the pin escaping; just an opinion though. How much side 'float' is thereon the sheaves? Probably not enough; we had a genoa track block break-up and managed to slide a thin hacksaw blade down the side and cut through the pin and remove it easily in two-halves, whereafter we fitted a new roller, secured by a bolt and nylock - we used a 1/4" rather than 6mm as this was a tighter fit.
 
On the lower picture it looks like there is a split collet holding the pin in. Before getting heavy I would investigate if it can be removed. Stick the thing in a basin of hot water as the hole may get bigger faster than the stainless pin and loosen the collets (if that is what they are). This is the sort of application that a collet may be used for, centring and securing a pin. They often hold valves in place on engines although the valve spring and a cap is used to keep the collets secure in that case. In this case they may have been fitted into the cast housing when it was hot. The pin will be recessed to take the collets, then the assembled pin and collet dropped into the cast body and as it cools the collets become secure. Alternatively, pressed in from the bottom, so that when the split faces touch the collet is an interference fit with the cast body, which suggests that it would be pressed out from the top.
 
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If you aregoing down the "bash it " route may i suggest that you place it over a vice with the jaws just wide enough to allow the pin to slide through, thus supporting the alloy as much as possible.
It would be a shame to shear one of the flanges.
Is there a small grub screw in the side of the unit which may be located in a grouve in the pin?
 
BlowingOldBoots said:
On the lower picture it looks like there is a split collet holding the pin in. Before getting heavy I would investigate if it can be removed. Stick the thing in a basin of hot water as the hole may get bigger faster than the stainless pin and loosen the collets (if that is what they are). This is the sort of application that a collet may be used for, centring and securing a pin. They often hold valves in place on engines although the valve spring and a cap is used to keep the collets secure in that case. In this case they may have been fitted into the cast housing when it was hot. The pin will be recessed to take the collets, then the assembled pin and collet dropped into the cast body and as it cools the collets become secure. Alternatively, pressed in from the bottom, so that when the split faces touch the collet is an interference fit with the cast body, which suggests that it would be pressed out from the top.
Click to expand...

If heat had been used during assembly would that not have damaged the plastic wheels?
 
Daydream believer said:
If heat had been used during assembly would that not have damaged the plastic wheels?
Click to expand...

It is common to cool stainless shafts in freezers and warm the hole for an interference fit. Many bearings are assembled like this and the temperatures are not such that plastic components would melt, far from it if the interference is designated towards the lower end of the interference fit.

It might not be an interference fit, it could be that the collet might be tapered, for vey little force on insertion the taper will become very secure. Heat might just break the friction between the taper and the block i.e. a basin of water from a boiled kettle.

The fact that the pin moves up and down suggests that the pin may be undercut over a length and that the collet halves fit into this undercut which would allow the pin to slide up and down by the 1/8" that the OP has measured.

What looks like two slots on the lower picture is why I think it is a collet. I would also try tapping one of the slots anti clockwise to see if that part can be rotated.

Just ideas and thoughts. I would probably buy new ones.
 
A bit more research and I found out that these blocks were called "Ocean Foot Block" the cruising version Lewmar say are a non serviceable part.

Following this new line I found somebody with the same issue with a solution which I include for anyone else in need.

Lewmar Ocean Foot Block Sheave Replacement
The pin can't be pressed out. It's been peened on both sides.
You have to drill it out from the back side. The pin diameter is less than what shows on the bottom, so I used a 5/16" drill and took off the head.
Then the pin will just fall out.
Click to expand...
 
A I said, you won't find re-peening, (riveting) the head easy in SS. Try peening bottom end on the bench and then insert and peen top end.
I'd think about buying new, as previously suggested, for such a load bearing item. Good luck anyway.
 
I had the same problem. As a last ditch attempt before resorting to buying a new one, I ground off the peened end on the bottom of the block. I could then press out the pin, bottom to top with a vice. The replacement sheave then had to be drilled out to accommodate the metal insert/bearing. It was then reassembled and the lower surface of the pin was splayed a little by punching with a centre punch near the edge in several positions.
It is still going strong after three seasons of club racing, and the occasional cruise (tapping wood three times, as I type).
 
when replacing the pin (having dremelled off the top peening) why not tap a thread for a domed machine screw and washer, so that the pin can be removed more easily at a later date ?
 
Drilled one end and sure enough the pin dropped out.

The challenge now turns to finding some nice roller bearing sheaves to replace the old plain bearing ones.
80mm dia, 20mm wide, with a m10 center should do the trick and I will tap the lower section as mentioned above.

footblock_3.jpg
 
Good job, good to know as I have a pair of these on the Rival. What end did you drill?
 
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