The Craftmans Shop > New from Old
JCB 803 Saga
awemawson:
So what was the result?
Well, rather like the Parson's Egg - good in parts. The leak is very much reduced, the photo below was taken with the main boom ram fully extended so the the pressure was maximum and the relief valve was working. So the theory worked but the practise didn't :bang:
Frankly if it was like this you'd not notice the leak, but that crack is quite long and can only propagate further and the leak will undoubtedly go torrential just at a critical moment. So I think I'm going to have to stump up for a new block :bugeye:
I've not yet checked the JCB actually have one in stock, just got a price. Maybe if they are out of stock I'll give it another go but I don't want an impending disaster looming!
lordedmond:
Andrew
Now this may be a dumb idea but could you not clamp a patch/ plate on the outside with some suitable gunk on it at the least it would stem the flow in case of a failure
With your cnc machines you may be able to cut a o ring grove into the plate for added seal
Just thinking out loud
Stuart
David Jupp:
Since crack is only a couple of threads down and female thread deeper than male - is there scope to counterbore beyond the crack? Move the whole fitting inboard a small distance?
Trouble with Aluminium is that there is no 'knee' in the fatigue curve - on cyclic duty it will fail eventually, no matter how low the stresses. If re-making the whole block, consider steel.
If you have an industrial hydraulics design company nearby, they probably make custom manifold block routinely - could be another option if you have to replace.
awemawson:
Stuart,
I had considered (see post #50 above) making a clamp plate that straddled the block with bolts down the side of the block into an under plate, and cutting a slight rebate where the leak is. Then bedding it all down using the magic Devcon Titanium Putty that I used to set the main dipper bush, which is pretty amazing stuff.
All these things are bodges though and I'm not too keen on bodges.
BTW it almost looks as though the block is made of layers bonded together, but I can't imagine it really it :scratch:
awemawson:
David,
The extended adapter I made goes in as far as is possible without fouling a counter bore coming in from the side, so it's not really feasible to sink in further.
I suppose it's a design error, as this appears not to be an uncommon failure mode - the block should have had more meat in it above this particular threaded hole.
I suspect that a custom manifold would be a close match in price to the proper one by the time they'd done the design and machining. But thanks for the suggestion.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version