3CX JCB 1997 Maintenance questions

[V8Druid]

My boom ram has had in internal leak for some time. Despite having the seal kit on hand, I've been happily ignoring it.

Now the rod seal has sprung a leak which it rather forcing the issue.

My question: is it possible to extract the boom ram without disassembling the boom from the king post?

dig a deep hole to drop the back end into at full extension of the boom ram, pop the rod pin and close the ram ... should have plenty of room ... could help the hole depth by jacking up full, but then you're working up in the air ... TBH with the dipper extended and the bucket off, it'll not need much of a hole - alternatively do it down a bank (and loosen the gland nut, 'fore you dismount it from the king post)

 

[V8Druid]

What machine?

3cx

 

[Gecko]

dig a deep hole to drop the back end into at full extension of the boom ram, pop the rod pin and close the ram ... should have plenty of room ... could help the hole depth by jacking up full, but then you're working up in the air ... TBH with the dipper extended and the bucket off, it'll not need much of a hole - alternatively do it down a bank (and loosen the gland nut, 'fore you dismount it from the king post)

Thanks.
I'll have a play and check the geometry.
I don't think there is any chance of exposing the gland nut with the boom I've got while the cylinder pin in still in place.

 

[V8Druid]

Thanks.
I'll have a play and check the geometry.
I don't think there is any chance of exposing the gland nut with the boom I've got while the cylinder pin in still in place.

no -- don't think you will, but with the rod retracted I think it'll manually lift enough to get at it .. if not, pick the arse up on the legs, to give you some more clearance, leaving the boom on the deck with the rod pin out ... can always put some blocks under the feet to give you even more height ... that end cap'll be TIGHT and secured to the king post is as solid as you'll get it to slack it off

 

[Mick-the-fitter]

no -- don't think you will, but with the rod retracted I think it'll manually lift enough to get at it .. if not, pick the arse up on the legs, to give you some more clearance, leaving the boom on the deck with the rod pin out ... can always put some blocks under the feet to give you even more height ... that end cap'll be TIGHT and secured to the king post is as solid as you'll get it to slack it off

More chance like that, don’t forget when you get the rod and piston out remove the middle piston seal and undo the grub screw, before undoing the piston!

 

[Gecko]

undo the grub screw, before undoing the piston!

Yep - don't want to forget that!
For this one, I'd ordered the JCB kit before asking the price (100gbp).
Unlike the alternatives, the OEM kit comes with a new dowel which acts as a reminder.

 

[Gecko]

Ok, made a start - that's a beast of a cylinder.
You are right - once the cylinder is retracted, the extraction angle improves a lot.
One part of the track has quite a high crown, so I was able to tilt the machine one way and stretch the boom out to give the best access.

Surprisingly, the pins were wet with grease and tapped out easily.
(the kingpost pin shows scars suggesting it put up a fight last time)

I had another look at the seal kit - which I bought from a JCB dealer and it's not an OEM kit, but from INTERPART.
Now I have no reason to think there is anything wrong with the kit, but it is irritating to pay the premium price only to get (exactly) the same part available for 25% from a non-OEM supplier

 

[Gecko]

Cylinder is out (not a one man job). Got it pinned where the tipping link top pin should be.
Dropped an 18" stilson onto the nut and added a 3 meter pipe.

Now I've got bent stilsons and a bent pipe
(the nut didn't move)

 

[topkit]

Spay a load of plusgas or similar release agent and let it soak around the thread, I had a similar problem with a Fermec a few years back, if you dont have the correct spanner you could do what Some people do and that is make a bracket and weld it to the end cap. I am not sure with Jakes but the end cap may have thread lock on it.

 

[Quattromike]

Can you get a flogging spanner on it?

 

[Mogman]

Give it a good beating around the collar where the gland screws into the barrel

 

[Mick-the-fitter]

If I remember rightly the end cap has shallow drillings and nylon plugs in the thread acting as nylock when it’s wound in!

 

[V8Druid]

Spay a load of plusgas or similar release agent and let it soak around the thread, I had a similar problem with a Fermec a few years back, if you dont have the correct spanner you could do what Some people do and that is make a bracket and weld it to the end cap. I am not sure with Jakes but the end cap may have thread lock on it.

almost certainly --- **** knows why

Cylinder is out (not a one man job). Got it pinned where the tipping link top pin should be.
Dropped an 18" stilson onto the nut and added a 3 meter pipe.

Now I've got bent stilsons and a bent pipe
(the nut didn't move)

View attachment 43759View attachment 43760

slogging ring spanner almost certainly needed by the sound of it .... can't beat the shock of a sledge

 

[Mick-the-fitter]

Nope forget my last comment, they are just F/T, find someone with a good eye/ hand and a plasma cutter, make a spanner with plenty of body and of hardox!

 

[Gecko]

Can you get a flogging spanner on it?

I bought a slogging spanner for the job - then realised it won't go over the rod eye.

the end cap may have thread lock on it.

The manual says to use a locktite sealant. Unsure if it's intended to act as a thread lock or sealant, I've used the lowest grade I've got.

 

[Gecko]

find someone with a good eye/ hand and a plasma cutter,

Seriously considering this option.
The tip of my torch is 5mm diam. I've successfully cut a guide using 3-ply (just add 5mm to all outside dimensions).
Clamped that to a sheet of steel and ran the torch around the inside.
It's not a CNC finish, but beats a drill and hacksaw.

 

[Mick-the-fitter]

I bought a slogging spanner for the job - then realised it won't go over the rod eye.


The manual says to use a locktite sealant. Unsure if it's intended to act as a thread lock or sealant, I've used the lowest grade I've got.

That’s why I said make a spanner! The rend of the ram is bigger than the nut

 

[Canal Navvy]

Something like a flare nut spanner cut out of thick material but with the end of the jaw drilled to take a clamp bolt would be good.

If it was slogging spanner sized you could slip it over the rod, bolt it up tight, slip a tube over and while leaning on it get a mate to hit it with the sledge.

The great thing about going to the trouble of making up a special tool is that you'll only ever need it the once

 

[Quattromike]

If you do have someone putting pressure on it while someone else swings a hammer make sure it’s someone who won’t survive to old age as the percussion that comes through the bar rattles all your bones

 

[Shovelhands]