Engine crane replacement master cylinder?

[julianf]

Ive got a generic chinease engine crane. Ive had it for years and years and not used it in at least a couple.

One of these sorts of things -

Came to use it today and the master cylinder was not moving at all. I tried to "encourage" it with increasing force, and broke the end of it anyway.

I figured they would be all over the web, but ive not spotted any.

Any ideas? Ive not tried to unscrew it yet. The wetness is oil that ive put on, not oil from inside. The ram seems fine. If i lift it manually with the valve open, and then close the valve, it performs as you would expect.

Thank you.

 

[Anguz]

It cant be much more than a piston, and a ball bearing non return or 2?

 

[julianf]

It cant be much more than a piston, and a ball bearing non return or 2?

Probably not, but ive smashed off the top of it now also (ie where the pin goes through to connect the handle mech)

Ironically, i was assembling it to lift the lathe workings...

 

[Endeleus]

Search eBay for "8 Ton cylinder"

 

[daedalusminos]

The whole ram used to be available on ebay 8T or so for about £30

 

[pedrobedro]

That's just the pump. Repair the top and drill a new hole in it, free it off and it will go again.

 

[Agroshield]

They seem to be known as 'long ram jack' by Google (and don't call me Jack).

 

[julianf]

That's just the pump. Repair the top and drill a new hole in it, free it off and it will go again.

Yes, I said master cylinder (I think) but the main ram is fine, just the pump is knackered.

The top was broken by me because the rest of it is sized. If I could un seize the part, then I could probably build up the top with weld and drill a hole in it. It's not like it has to be precision.

 

[merryman]

The ram is a precision part, all hydraulic parts are. Nor is it a master cylinder it is a hydraulic hand pump. Probably has had some water down it and rusted up. If you can get the broken ram out of the cylinder (the hexagonal bit) without further damage to the cylinder, you can probably ream it and fit new seals. I would make a new ram, but as long as you don't distort the bit that actually slides up and down in the cylinder when welding it, you may get away with cleaning the rust off and re-use.

 

[James1979]

This one?

Pardon our interruption...

Only because it’s in my watch list for something else

 

[julianf]

It's all done. I'll post some photos in a bit.

Thanks to all, as usual.

 

[julianf]

The bit that took the longest was getting the piston out. Vice etc. but it took a while.

And then the searching through the henry hoover bag for the top bit that had snapped off!

So -

See the o-ring? Its got a little packer behind it. I didnt see that....

It seems to be working without the packer (just the oring). I guess the oring probably wont last as long, but this unit gets so little use (which is why this has happened) that the oring will, i hope, last a while.

Thanks again.

 

[julianf]

This one?

Pardon our interruption...

Only because it’s in my watch list for something else

You wonder how they make (and deliver, and pay fees, taxes etc) on these things for the price.

Ill give my repair a work out tomorrow and see how long it takes to break...

 

[awemawson]

The “ packer” is called a backing ring a gives the O ring a bit of support

 

[Bullet2012]

If that is the Master cylinder where is the slave cylinder ?

 

[Robotstar5]

If that is the Master cylinder where is the slave cylinder ?

It's the tall red thing next to it

 

[Seadog]

It's not like it has to be precision.

Doesn't it? There are hydraulic seals in there which won't last 5 minutes if it's not a nicely finished surface.

 

[julianf]

Doesn't it? There are hydraulic seals in there which won't last 5 minutes if it's not a nicely finished surface.

This -

...is not a precision welding job. But it's nowhere near the seal.

If you read my post back again now, I think you'll realise the comment was in regard to welding up the broken part : )

 

[Seadog]

So you believe that there is nothing to seal the piston?

 

[julianf]

So you believe that there is nothing to seal the piston?

I don't understand your question?

I talked about the oring above and awemawson commented on the backing ring.