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Gardner 2UC reverse problem


Matt B

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Hi, I have a problem with reverse on our 2UC box and wondered if anyone has any pearls of wisdom to offer.

 

It looks like the hinge block that holds the two brake shoes (or the shoe itself) has broken as one of the shoes is loose and when I adjust them (as per the manual) I can see that the stbd shoe is not making contact at the bottom and is generally wobbly. Also its adjusting nut doesn't sit properly in the socket suggesting that it is misaligned . Port side shoe seems fine.

 

Also noticed that the friction material doesn't go right around the shoes, covering just the top third. Pictures in the manual and common sense suggest that it should cover the whole shoe? Maybe they have been over-tightened to compensate for the lack of friction?

 

Anyway, looks like the engine needs to come out as I think the reduction box has to come off to get the top half of the 2UC off.

Unless there is a way to remove the brake shoes without removing the top of the box? - ever the optimist.

 

Anyone been through this?

 

Any advice, thoughts, comments welcome.

 

cheers

Matt

 

 

 

 

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Could be that the pivot pin at the bottom of the shoe has worked its way out. From memory, they are held just with split pins which are bl**dy awkward to fit, maybe somebody failed to secure them properly?

 

I think sometimes the lining is in two pieces on each shoe, with a gap between, maybe you're just not able to see the lower piece.

Edit - just checked my parts book, it shows exactly that arrangement of linings.

 

It might be possible to remove the upper casing without completely removing the reducing gear, not sure. I take it you have no room to remove the reducing gear in situ?

 

If you need bits, I've got a complete box gathering moss in the garden.

 

Tim

Edited by Timleech
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Yes, sort of hoping that it was the pivot pin, awkward to fit but will only need a new split pin!

 

The arrangement is very tight and when I had to remove the reduction box previously I had to notch out a V from the rudder and draw the prop back to give me room. I may be able to move the engine forward an inch and the prop back an inch so the reduction box can drop back just enough to clear the studs.

 

Im no longer in tidal waters so cant get to the underwater parts. Wish I hadnt bothered welding the notch back in!

 

Thanks for the offer of bits, will let you know how it goes.

 

As the shoes need to come out I presume its worth replacing the friction material? It looks about 4/5mm thick but has presumably been slipping for a while?

 

Matt

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Update:

 

Im going to lift the engine from the back and chock it up so the flange clears its opposite number on the prop shaft as the reduction box needs to come off.

 

I have removed the shaft that engages forward/reverse and can now see that the problem is with one of the shoes which has broken near the hinge at the bottom. It looks like it has been repaired in the past as does the other one. It also looks like both the shoes have only around 1/3 of the lining that they should have, so not sure what that's about.

 

Tim, I will PM re that box in your garden.

 

Its never just a split pin is it!

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Some time later.....

may have spotted the problem

 

DSC06146.JPG

 

Been repaired before, and I think its safe to say that the shoe has been cracked for a while as one side is much blacker that the other.

 

Lots of repair made to the outside of the shoe but so sign of damage or welding to the inside. edit- looking again inside may have been refaced

 

 

DSC06151.JPG

 

 

The other shoe has same repair at the base but looks to be holding up. friction material is down to the rivets too.

Matt
Edited by Matt B
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Can you get new/good secondhand ones ok? Looks like it could be tricky to repair those ones properly.

 

Hoping Tim's gearbox (see post#2) will have a good pair in it, but also spoke to Tony Redshaw who seemed confident about a repair if necessary. I would like to get to the bottom if why they broke though seeing as they have been repaired before. ie abuse from previous owner, badly adjusted, badly repaired or just pure old age. My worry is that putting an old pair that look OK in may be worse than using the existing ones with a good repair. Its quite a job to get them out and I would prefer not to have to do it again.......

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I wonder whether they've been assembled with the hinge block height incorrect & that's put extra strain on them? Either that or over-adjusted to try to compensate for worn linings? That's the block at the bottom on which both shoes pivot.

 

When you get to reassembling whatever shoes you end up with, it would be a good idea to check that as per the book.

 

Tim

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  • 2 weeks later...

The lining on the shoes is down to the rivets so they need relining. Currently they are evenly worn to around 5mm and I'm wondering what the as new thickness should/would have been. Looking at the attached pic they look around the same thickness (if anything slightly thinner) as the adjacent casting but that is around 5mm? I have been advised that the norm is to countersink down to 1/3 which would make the original thickness around 15 mm (suggesting 1/2"?). Room in there is tight though and the thicker the lining the smaller the diameter so I dont want to go too thick.

 

Any thoughts

 

cheers

 

 

 

 

2UC.jpg

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I very much doubt that they were anywhere near to 15mm.

I'll try to get a rough measurement of what I have here, in due course, and let you know.

Probably 1/4" or 5/16" at a guess. Probably not expected to wear much in normal service.

 

Tim

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  • 4 weeks later...

Have you offered the shoe up to the drum to see if it fits?

 

Richard

 

Yes, and it wasn't great, but with a bit of work its getting there. Its taken hours to get just one of them right shaving it down with a rasp (now very blunt) and the edge of a large chisel to hone it down. Ive been using the drum with a smear of oil as a guide to find the high spots. Im a bit worried about it all to be honest, dont want another broken shoe. I guess as long as the pad touches evenly all around and there is the specified play in the hinge block it should be fine. What can possibly go wrongwink.png

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  • 3 weeks later...

Having finally managed to get the shoes fitting nicely all the way around (using thinnest feeler gauge to check contact/high spots, i have finally got the whole thing back together, engine back in and re aligned and all seems good. As a bonus, having had the bearing housing at the forward end of the reduction box sleeved the whole plot runs much quieter that before. We are yet to venture out but having run in forward and reverse for a while, so far so good.

 

having to remove the reduction box (and therefore the engine) to lift the top half of the gear case off seems a bit daft as replacing the top 4 studs with bolts would solve this but perhaps there is a good reason for using studs rather than bolts!

 

Thanks for interest and advice, much appreciated. Fingers crossed for first trip out.

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