How to remove the cap from a JCB hydraulic cylinder.

[Bill Turtle]

I cannot shift the cap on the dipper arm ram on my old JCB 805bt.
does anyone have any tips or tricks to help please? I have made an open ended spanner about 5 foot long to put on it.

 

[Fast Farmer]

Have you taken the pressure off? Turn engine off move handles might help?

 

[Bill Turtle]

Yes. Did that.

 

[Sparkplug]

Hammer like hell all around the outside top 2 inches and as a last resort warm up - you will need big stilleys and a scaffold tube!

 

[Fast Farmer]

Same here big wrench and long tube, got an old JCB 4C wrench here, f**king big and heavy for a reason then

 

[Bill Turtle]

Yes done a lot of hammering. Haven’t tried heat yet. I have just returned my oxy acetylene bottles to BOC because I was so fed up with their charges. Intending to replace them with hobby bottles.

 

[Farmer_Joe]

you could put some weld around ram outter to get heat in it?

did seal on my 526 mai lift ram and bolt came out fine, dont forget on inner nut on ram rod there is a peg or was on mine behind one of the wide seals holding the nut on, wont shift it without removing that!!!

 

[Bill Turtle]

May have to try the weld if all else fails.

 

[Kevtherev]

Heat and big spanner

 

[Brains]

Longer bar I’d say. I have made various sizes ram spanner now for jcb. I plasma cut 5 sides of the hex out of thick plate so you get even pressure around the nut and weld 50mm box to them. With a gap so it just goes over the rod.
If it’s a home made tool not a lot to loose by putting bigger bar on?

 

[derek]

Try and avoid heat if you can , best thing to do is take it to a ram shop or your local jcb dealer they should have a ram press it will save you a hole lot of grief

 

[JD6920s]

Difficult to see on your photo clearly, but many of the old JCB rams have a wire locking device that actually goes into a hole in the cylinder sleeve and circles right round the circumference of the end cap in a groove, it needs to be tapped/pulled all the way round and out of it if it has one. If you’ve undone the cap slightly it’ll need to be tightened again to take the pressure off this wire.
It’s possible it’s here,

And surprisingly, what might seem seized on these old jcb’s come apart looking like brand new inside, they knew how to build em way back then!

 

[ACEngineering]

you could put some weld around ram outter to get heat in it?

did seal on my 526 mai lift ram and bolt came out fine, dont forget on inner nut on ram rod there is a peg or was on mine behind one of the wide seals holding the nut on, wont shift it without removing that!!!

Absolutely DO NOT do this! will have the reverse effect you are looking to achieve! Weld will shrink and make the cap tighter.

 

[Bill Turtle]

I haven’t been able to move it a millimetre so far.

 

[JD6920s]

I haven’t been able to move it a millimetre so far.

Have faith, look for the wire, get a big well fitting spanner, have 3 shredded wheat, and possibly a little heat very carefully applied if absolutely needed in the right place all round evenly and quickly.

 

[Bill Turtle]

May have to buy or borrow a plasma cutter.

 

[JD6920s]

May have to buy or borrow a plasma cutter.

Noooooo!

 

[GeorgeK]

Maybe one of those mapp gas torches and get it slightly too hot to touch so as not to damage the ram, even a little heat can make all the difference. Also try putting pressure on the spanner and have someone give it a belt with the sledge (careful!) to get some shock forces through it. Patience and heating, cooling, and keeping at it usually works eventually.
Last option is to rig something up to keep force on the spanner, apply penetrating oil daily and maybe in a few days it will crack loose. Can't really recommend this though as I have personally taken someone to A&E who was in the vicinity of a dual bottle jack rig when the part came free, it's basically an unexploded bomb

 

[Hilly]

Why you taking it to bits ?

 

[Bill Turtle]

Taking it to bits because the seals are gone. Leaking litres of oil, so unusable as it is.