Dismantling a ram.

[Gecko]

Finally I got an 18 inch pair of stillsons with a 4 foot tube on the end of them, put it on the cap and then tried to undo it but it just wouldn’t move.

I've done most of the rams on my P8 and my first suggestion is an "18 inch pair of stillsons with a 4 foot tube" is a "start", not "final".
18" Stillsons is absolute minimum size and you'll probably end up bending them.
Several of mine took a 12ft tube with me swinging on the end - yes the sillsons usually suffer and yes, I ended up on my ass when it finally let go.

When you decide heat is the answer, don't be too brutal - you're not aiming for cherry red, just a 50°C rise will make a big difference to what amounts to a thin walled tube. This can be achieved with a jug or two of boiling water if you don't have a torch and has the advantage you can't over heat anything.

 

[Scraperman]

I've done most of the rams on my P8 and my first suggestion is an "18 inch pair of stillsons with a 4 foot tube" is a "start", not "final".
18" Stillsons is absolute minimum size and you'll probably end up bending them.
Several of mine took a 12ft tube with me swinging on the end - yes the sillsons usually suffer and yes, I ended up on my ass when it finally let go.

When you decide heat is the answer, don't be too brutal - you're not aiming for cherry red, just a 50°C rise will make a big difference to what amounts to a thin walled tube. This can be achieved with a jug or two of boiling water if you don't have a torch and has the advantage you can't over heat anything.

Thank you @Gecko, that was very interesting and helpful. I won't use the oxy-acetylene, that would be too harsh I think but I have a couple of canisters of butane and had thought about using that and all the way round the cap. Will I still need a great length of scaffold tube on the stillys even when I've done that ?

 

[Gecko]

I haven't used heat when pulling mine appart, only "brute force and ignorence".
The advantage of Oxy over Butane is the rate you can get heat into a part. You want to get the cylinder warm without heating the gland (nut) - if they both heat, they both expand and most of the benefit is lost.

If your stillsons are still straight, you haven't been trying.

 

[Scraperman]

I haven't used heat when pulling mine appart, only "brute force and ignorence".
The advantage of Oxy over Butane is the rate you can get heat into a part. You want to get the cylinder warm without heating the gland (nut) - if they both heat, they both expand and most of the benefit is lost.

If your stillsons are still straight, you haven't been trying.

Thank you @Gecko . The pipe couplers (I ordered 2) arrived today and I knocked up some bungs for the male pipes on the ram yesterday so I am going to have a go this afternoon. I'll report back.Do

EDIT. Do you think that boiling water would really do the job ?

 

[DaveDCB]

May as well aim the heat gun at it for half a hour rather than wet the place up!

 

[Scraperman]

May as well aim the heat gun at it for half a hour rather than wet the place up!

Today I got lucky. After @Gecko mentioned hot water I thought I would try that first before putting the stroppy hat on. And I poured a kettle full of boiling water very gently all round the cap area, put the stillys on, then the tube on the stillys and I only had to jump on the tube a couple of times and "click" The job's a good un. We'll see how the seal fitting goes and I will report back. Many thanks to everyone for the help.

 

[V8Druid]

Today I got lucky. After @Gecko mentioned hot water I thought I would try that first before putting the stroppy hat on. And I poured a kettle full of boiling water very gently all round the cap area, put the stillys on, then the tube on the stillys and I only had to jump on the tube a couple of times and "click" The job's a good un. We'll see how the seal fitting goes and I will report back. Many thanks to everyone for the help.

excellent result - amazing how much expansion 100C will provide - doesn't need to be much

 

[Scraperman]

excellent result - amazing how much expansion 100C will provide - doesn't need to be much

You're right there @V8Druid . I was pleasantly surprised when it gave way. Just goes to show that you're never too old to learn.

 

[Gecko]

Good result!
Now don't forget there is dowel fiding under one of the wear strips on the piston.
It will probable come out easily, but if tight, I find an M4 high tensile bolt and a claw hammer works well

 

[Gecko]

EDIT. Do you think that boiling water would really do the job ?

Ignoring the fact it did work, it's one of those techniques you can try with what you already (probably) have on hand.
It's the equivalent of leaving a bearing in the freezer for an hour before mounting - very easy to do and may improve your life.

 

[Scraperman]

Good result!
Now don't forget there is dowel fiding under one of the wear strips on the piston.
It will probable come out easily, but if tight, I find an M4 high tensile bolt and a claw hammer works well

Thank you @Gecko. I presume that you are talking about item 13 in the diagram below ? I have got a set of drifts that will suffice for that job. They are what I normlly use. BTW, is the piston head as difficult to remove as the cylinder cap was once I've removed the dowel/roll pin ?

 

[Gecko]

Yes #13 is the culprit.
It sits in a blind hole, so you have no option but to pull it.
Mine have mostly come out without a fight - only needed the claw hammer on one.

The piston shouldn't put up too much of a fight.
Firstly it's spent it's entire life bathed in oil, so the thread should be perfect.
Second, although it needs to be very firm, it's the dowel that makes absolutly sure the piston doesn't move on the thread.

When it comes to reasembly, you don't need a torque wrench as you simply wind on the piston until the holes align.

Just so you start to question your own sanity, the seal kits include a seal and a couple of O-rings they had spare in the packing room. These aren't useful, they're just to f#*k with your head.

 

[Scraperman]

You are being incredibly helpful @Gecko Thank you very much. I have been working on mechanical things all my ;ife but I am finding thhat my age (nearly 80 YO ! ) my brain is letting me down a bit these days. I've got the ram apart and I discovered that the dowel (NOT a roll pin as I thought it might be) was very loose and I put a very small Allen key in the head and managed to ease it out. For anyone else reading this it isn't a grub screw, it's just a loose dowel pin which in fact is kept in place by an oil seal (on my machine anyway).

 

[Gecko]

You are most welcome.

 

[Scraperman]

New seals fitted and all put back together again with some Loctite on the threads of the end cap. Put back on the digger and it seems to be working O.K. Time will tell because it was a leaking ram and so I opened and closed the 4 in 1 a few times and wrapped some tissue paper around the cap to see if it is still dry tomorrow.
Next job is the power steering ram. That is leaking as well.

 

[Gecko]

Keep us updated on the PS ram - mine it weeping too, but it hasn't made to the top of the list yet.

Did you have parts left over in the seal kit?

 

[V8Druid]

You are being incredibly helpful @Gecko Thank you very much. I have been working on mechanical things all my ;ife but I am finding thhat my age (nearly 80 YO ! ) my brain is letting me down a bit these days. I've got the ram apart and I discovered that the dowel (NOT a roll pin as I thought it might be) was very loose and I put a very small Allen key in the head and managed to ease it out. For anyone else reading this it isn't a grub screw, it's just a loose dowel pin which in fact is kept in place by an oil seal (on my machine anyway).

's what this place is all about ..... that and mercilessly taking the p*ss out of each other at any and all opportunity

 

[Scraperman]

Keep us updated on the PS ram - mine it weeping too, but it hasn't made to the top of the list yet.

Did you have parts left over in the seal kit?

O.K. I will keep you updated but would it be better if I started a new topic on that one ? And yes, I had one seal left over and also one was missing. And the one left over was a totally different size from the one that was missing.
They are not genuine JCB parts I have bought but the company that I bought them from are well-recognised JCB spares dealers and I have dealt with them for many years.

 

[Scraperman]

's what this place is all about ..... that and mercilessly taking the p*ss out of each other at any and all opportunity

Yes, but I have found that I need a bit more help these days and what people are prepared to do on here is invaluable. And that includes your good self Sir.

 

[Gecko]

I had one seal left over and also one was missing.

Interesting, I've used several brands and never had one missing.
If you buy the OEM JCB kit, it comes with a new dowel - I feel if you've worn out the dowel, you're doing something wrong.