Crab disassembly advice.

[brit plumber]

I’m just breaking down my crab and boy is it proving tough. One of the guide blocks didn’t have pins fitted but it still took a lot of heat, a massive spanner and a 4lb sledge to get it moving. The other side I can’t even get the pins out, every tool I’ve got either bends or breaks so I’m now drilling them out.

I can see I’ve got a woodruff key fitted on one side but this video (below) doesn’t make much sense unless they’ve missed the key. I can just move the volute spring pivot so that bit looks promising.

https://m.youtube.com/watch?v=M74NSwS-_kw

[Monkeypirate]

Or the key sheared off due to the center being completely  stuck... I have read a lot of horror stories of unstucking the pins on the crabs. I dread this step. Best of luck!

[emptyhead]

Sorry can’t be much help as to how to get it off but went through the same ordeal 3 months ago. Those blocks are really hard, bent three punches trying to get the pin out and ruined a couple of drill bits drilling it out. Heated it up cherry red and it still laughed at me. Good luck with it.

[yd328]

Its been a while since I did mine. Check for tapered pins. I think some of mine had tapered and some with straight pins.

Gary

[brit plumber]

Got the pins out after hours of hammering and drilling. The pins were straight but I think they had become bent with the amount of crap inside the grooves on the shaft. They also look like drill rod and not the mild steel I was expecting. Next up is to try and remove the pin. The seat will just about rotate on the pin when i **** it with a FBH.

[brit plumber]

Well it’s done, 2x 4lb sledge hammers broken, 1 home made tool cracked and one broken 44 year old man. I’m not looking forward to the other one.

[big44maghunter]

Those do suck to get out!  Mine were completely locked up. Nothing would move.  I used a 12T press and applied pressure to the pin from one side.  Need to support the crab around the pin on the opposite side though.  I inserted a section of 1" threaded into the pivot part and worked it back and forth until they were moving good.  Then I put everything the press had on the pin and as much heat as I could on both ends of the crab. Eventually they both popped free.  I was also using a lot of penetrating oil! 

[Darth_Kitten]

good deal that you were able to get them out.
Tried everything on mine
Even 100 ton press didn't budge them.
Finally had to have them machined out. Once you get past the hardening on the shaft, the rest was easy.
(according to my machinist fried who did it for me).
Ironically this popped up in my FB memories from 6 years ago.

[brit plumber]

I’ve got a hearth at home so I heated it up quite a few times. It didn’t take much to get the spring seat pivoting and to be honest, it wouldn’t have taken to long to push the pivot out, if I hadn’t forgotten the woodruff key. I had an old brake calliper piston supporting the opposite end but I forgot the key. So as I was belting my home made tool on one end, the woodruff key was hitting the piston on the other. When I realised, I cut a slot in the piston and....hey presto it began to move quite easily. Having the heat really helped, I don’t think Oxy/acet would have got the overall heat into it, but the hearth certainly did. It was still hot to touch after 90 minutes.

I think I’ll need new pivots though as this one is quite corroded and worn.

What size grease zerks do people fit?

[brit plumber]

How important is it for the spring seat to be round? I’m thinking that provided the seat will sit on it, any distortion around the outside shouldn’t be an issue. I’ve got a few flat spots where I beat it forward and back.

[Jesse]

I took mine to a reputable machine shop to be pressed out. They have the right tools, the right guys.

[big44maghunter]

How important is it for the spring seat to be round? I’m thinking that provided the seat will sit on it, any distortion around the outside shouldn’t be an issue. I’ve got a few flat spots where I beat it forward and back.

I would think no issue as long as the springs slide over correctly and don't bind up.

[brit plumber]

I took mine to a reputable machine shop to be pressed out. They have the right tools, the right guys.

That’s the problem around my way, no where wants to take on any kind of work that is out of the norm. If you have a modern Volvo truck or similar you’re fine, but anything they don’t know, they won’t touch. Most places won’t even fit parts you provide due to liability insurance.

[brit plumber]

How important is it for the spring seat to be round? I’m thinking that provided the seat will sit on it, any distortion around the outside shouldn’t be an issue. I’ve got a few flat spots where I beat it forward and back.

I would think no issue as long as the springs slide over correctly and don't bind up.

That’s what I thought, it’s not to bad and I’m tempted to dress off any high points (to be honest I’m not entirely sure it’s all my doing).

[Cleprechaun]

I put a zert in the middle of the spring seats and put some penetrating fluid in it, then I attached a grease gun and put major pressure in the cavity. Then I heated it up hoping it wouldn’t explode. After a few ours I got bubbles. I then put the crab in a holding jig and slid 5’ long, thick walled, pipes over the spring seat nipples and applied a 30 ton jack to the ends of the pipes. It was as stuck as stuck can get. Even after getting the spring seat to budge in the crab, it took hundreds of back and forth moves before it got easier. Once it moved freely, I chose not to take to apart, it was working.