JCB 3c Ram seal question please

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teddyyy
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Re: JCB 3c Ram seal question please

Post #11 by teddyyy » Tue Mar 07, 2017 3:44 pm

Jeremy Rowland wrote:Mike I'd definitely have a go at repairing it, after all you cannot make it any worse than it already is, if you do repair it when you put it back make sure the repaired side is away from where it was in the cylinder, coming to that is the inside surface of the cylinder scored?

Jeremy


Had a look at it today and It is a little scored yes, although it was still working before I removed it so it may seal and be ok in the short term.
I have sent a few emails to breakers yards to see if they have a serviceable replacement but not found much so far


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Re: JCB 3c Ram seal question please

Post #12 by essexpete » Wed Mar 08, 2017 12:18 am

The fluid I suppose will be pushing the O ring towards the undamaged side. I wonder if a back up nylon ring could be squeezed in there?


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Re: JCB 3c Ram seal question please

Post #13 by Mrsmackpaul » Wed Mar 08, 2017 1:48 am

It looks like it was damaged when putting it back together to my untrained eye and that the broken off casting bits have scored the ram and cut the seals
If it was mine I just hone the cylinder and try to clean up the scoring as best you can and bung a fresh set of seals in

I think it will work ok as Pete has suggested the the O ring is pushing against the undamaged side

If you were concerned about it I would just build it up with bronze and file it back to shape as that side isnt very critical to the rams operation



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Jeremy Rowland
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Re: JCB 3c Ram seal question please

Post #14 by Jeremy Rowland » Wed Mar 08, 2017 9:02 am

teddyyy wrote:
Jeremy Rowland wrote:Mike I'd definitely have a go at repairing it, after all you cannot make it any worse than it already is, if you do repair it when you put it back make sure the repaired side is away from where it was in the cylinder, coming to that is the inside surface of the cylinder scored?

Jeremy


Had a look at it today and It is a little scored yes, although it was still working before I removed it so it may seal and be ok in the short term.
I have sent a few emails to breakers yards to see if they have a serviceable replacement but not found much so far



Mike, I would if you can get in there try and use a bit of fine 'wet and dry' paper to remove any high spots from the damage in the cylinder, again if you have a hone that would fit on an electric drill that could be used but only to remove the high spots (assuming there are any) obviously make sure you clean it thoroughly after you have done this. This should help to prevent any damage to the new seal.

Jeremy


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Re: JCB 3c Ram seal question please

Post #15 by teddyyy » Fri Mar 10, 2017 11:29 am

Thanks to everyone for your replies,
As you mentioned I don't have much to loose aside from a seal kit so I will see what I can do as a repair, I was wondering about trying some chemi-metal on the gland next to the O-ring. The cylinder itself is quite hammered in one place just behind the O-ring, possibly a grinding wheel on a drill to get off the worst if I can get it in far enough then a hone or wet and dry.
I suspect it has been apart in the past as the cap was welded on, maybe when at full travel the broken bits pushed the cap off as the threads are not great.


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Re: JCB 3c Ram seal question please

Post #16 by essexpete » Fri Mar 10, 2017 1:44 pm

Mike if the cap has been welded on it might be the threads will let go again. I had a Hymac ram do that and I had to weld on some straps as a tight ass repair.


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Re: JCB 3c Ram seal question please

Post #17 by teddyyy » Sat Mar 11, 2017 1:07 am

essexpete wrote:Mike if the cap has been welded on it might be the threads will let go again. I had a Hymac ram do that and I had to weld on some straps as a tight ass repair.

Yes I will have to weld it on I think, I would not trust the threads alone
It was welded all the way around the cap but straps may be better as they could be welded further away from the O-rings to avoid overheating


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Re: JCB 3c Ram seal question please

Post #18 by essexpete » Sat Mar 11, 2017 1:13 am

teddyyy wrote:
essexpete wrote:Mike if the cap has been welded on it might be the threads will let go again. I had a Hymac ram do that and I had to weld on some straps as a tight ass repair.

Yes I will have to weld it on I think, I would not trust the threads alone
It was welded all the way around the cap but straps may be better as they could be welded further away from the O-rings to avoid overheating


I welded the straps on the Hymac ram like that for that reason. Also you can weld the straps on the cap when the cap is removed and make them long enough to be away from the gland. Welding on with the ram closed so the piston is also out of the way. Not sure of HSE or insurance implications.

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Re: JCB 3c Ram seal question please

Post #19 by FOWLER MAN » Sat Mar 11, 2017 11:55 am

HI,
I don't know if you have room to do something like this but I have got round the problem of stripped threads on the ram or cap by cutting two flanges one to weld to the ram casing and one placed under the cap. Both flanges were drilled to take four or six bolts to pull them together and retain the cap.
I have done this on the bucket rams on a Hymac 880 and a Priestman 220. You can see the flanges in this pic of the 220 though the bolts are not very plain.
Image

This method allows you to do all the welding whilst the ram is stripped so there is no risk of heat damage to the seals and the ram can still be dismantled for repair.


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Re: JCB 3c Ram seal question please

Post #20 by essexpete » Sat Mar 11, 2017 4:31 pm

The proper way Fred! My bodge could be released quite quickly by discing across the straps.


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