how to change a seal on cylinder

[Rob-b]

Hi guys

can someone give me some advice on how to change the seals on the bucket dipper cylinder on a jcb 801.4? In particicular making sure the system is not under pressure when doing so? I would imagine you just tuck the cylinder rods back, turn off the engine and relax everything?

Is there anything I should be aware of when chnging them over? is there any footage anywhere? I've looked around youtube etc to no avail.

thanks folks.

[Stock]

Rob
open the bucket fully well maybe 95% open then support the arm turn off the machine and turn on the ignition so as the ignition lights are on, operate the levers and this should release the circuit pressure. On the larger machines you must open the vent on the hydraulic tank to release the return line pressure. then proceed to open the pipes.
What the issue with the ram??

[Rob-b]

Rob
open the bucket fully well maybe 95% open then support the arm turn off the machine and turn on the ignition so as the ignition lights are on, operate the levers and this should release the circuit pressure. On the larger machines you must open the vent on the hydraulic tank to release the return line pressure. then proceed to open the pipes.
What the issue with the ram??

Thanks Stock, it's just a weep from the ram seal, ive got a new seal kit and shouldn't be too difficult. It's just I was watching a JCB mechanic replace one on our 3CX at work but didn't get to see the whole picture and wondered if it is as straight forward as it seems.

[Muz]

Once youve disconnected the lines, your still going to lose the oil thats inside the cylinder so be prepared for some spilliage in this event.

Firstly you need to unscrew the endcap anticlockwise. The correct tool is a 'C' spanner, but most people use a set of stilsons. You will chew the cap slightly, but dont worry about this, I usually just buff mine back down once I'm done. The endcap sometimes has a nylon dowl knocked into the side of it to stop it undoing itself in normal use, so you may find the cap quite stiff all the way out which can be a bit of a pain, but once its off, just pull the rod and cap out of the cylinder, which you should leave attached to the machine, you'll be able to see how the seal pack at the rod end comes off, and that will allow you to slide off the end cap, and gain access to the seals inside it, which will be the ones that are leaking.

If youve got a seal kit for the whole ram just do them all even though theres nothing wrong with the other end

I assume the rod is scored somehow, if its bad its false economy to refit it, as it will just rip the seals again. If its not bad, take a flat file to it to smooth off the rough edges, and you may get another 2-3 years from the cylinder, a pic of the damage would be good so we can assess how bad it is

Keep the file flat, it wont damage the chrome, as its too hard, you just want to remove any burrs that have damaged the seals.

Watch which order they come off the pack, in particular which way round some of them go, i.e. nylon flat before rubber o ring not after .. etc etc

[ianoz]

Check this out ,And or related videos .
http://www.youtube.com/watch?v=GCKVx...feature=fvwrel

[mogman]

When you have pulled the ram apart take the wear bands of the seal block because on some jcb's there is a dowel under one of the wear bands to stop it from unscrewing and the dowel is made from very hard steel (can't be drilled) so just turn in over and tap it so it falls out

worth a look


Mog

[Rob-b]

Thanks everyone

very re assuring.

[Rhinoneil]

JCB 3CX - Change seals .

When you have pulled the ram apart take the wear bands of the seal block because on some jcb's there is a dowel under one of the wear bands to stop it from unscrewing and the dowel is made from very hard steel (can't be drilled) so just turn in over and tap it so it falls out

worth a look


Mog

Hello, My machine is a 1989 3cx and I have an oil leak from the neck of one the cylinders that lifts the front bucket. Is it the same procedure to change the seals on this one?

Many thanks

Neil