hydraulic cylinder cap end

[MCKDAVID]

Seem to remember we have a few hydraulics experts / heavy plant techs onboard. Had a client drop off some hydraulic cylinders for rebuild, (the others are already done- had the seals in stock so they’re ok), but scratching my head at this one. Not seen this type of end cap before. Seals are gone, no resistance at all, can pull the piston through by hand, so obviously goosed. Need to get the end cap clear to get the cylinder / piston out single action, other end is welded to a plate mount. There was a small threaded end cap with lip seal and behind it which came off easily enough, leaving the thread below which seems locked in place by 4 separate quadrant segments, thought at first they would screw out, but no, they just spin round, and round they’re not held together, individual segments. 48mm dia shaft.

my thinking is that I need to press this threaded assembly back and thinking there's some form of snap ring / internal locking collar behind it holding it in place?. Before I wade in thought I'd better ask the collective experts for their advice.

Have any of you come across this type of end cap fixture before?. any thoughts?

Thanks for your assistance

Dave

 

[Brad93]

Rory or Clive might know

 

[Seadog]

It's probable a locking collar. You'll need a peg spanner to unscrew it. Or try to drift it with a piece of brass or aluminium.

 

[MCKDAVID]

It's probable a locking collar. You'll need a peg spanner to unscrew it. Or try to drift it with a piece of brass or aluminium.

thought that first, but they just spin round, don't seem to be threaded.

 

[Seadog]

In that case -

 

[MCKDAVID]

^^^^ that makes two of us at the moment, but we'll sort it........

 

[Spark plug]

I haven’t seen one like that but I have done one in the past ware you had to cut the bottom off the cylinder then weld it back on. It was a much bigger ram though.

 

[zzr1200]

Does the threaded collar tap back inside the cylinder once the piston rod has been pushed back into the cylinder.

This then might allow the quadrant pieces to drop out of an internal locking groove and be pulled out, thus allowing the threaded collar and piston rod to be pulled out of the cylinder...

The threaded wiper seal collar may just hold/stop the quadrant lock ring from slipping down the outer cylinder tube...



PS.
Try pushing the rod back into the cylinder by about 6 inches then gently tap the threaded collar...

 

[MCKDAVID]

Does the threaded collar tap back inside the cylinder once the piston rod has been pushed back into the cylinder.

This then might allow the quadrant pieces to drop out of an internal locking groove and be pulled out, thus allowing the threaded collar and piston rod to be pulled out of the cylinder...

The threaded wiper seal collar may just hold/stop the quadrant lock ring from slipping down the outer cylinder tube...



PS.
Try pushing the rod back into the cylinder by about 6 inches then gently tap the threaded collar...

pretty much what I was thinking, but the treaded part doesn't seem that keen to move, so before I resorted to mechanical violence, I figured better to check I was hammering it in the right place.... had another look, there seems to be a wee lip behind the segments, difficult to see, but I think we're on the right track..

 

[zzr1200]

Can you slide a tube over the piston rod so that you contact all the surface of the threaded collar???

If the quadrants are bass/bronze they might taken on the thread shape, a good well surfaced drift/punch is required to minimise damage.

 

[MCKDAVID]

^^ great minds think alike.... exactly what I'm raking round the workshop for at the moment, sure I have some 2" tubing that would be ideal as an over sleave, but as usual, can't put my hands on it.... maybe already used for something else...

either way, want to protect the chrome before I start

 

[zzr1200]

pretty much what I was thinking, but the treaded part doesn't seem that keen to move, so before I resorted to mechanical violence, I figured better to check I was hammering it in the right place.... had another look, there seems to be a wee lip behind the segments, difficult to see, but I think we're on the right track..

Push the rod back in about 6 inches then bounce the solid end on the floor and see if anything moves, Oh watch out for your pinkies...

 

[zzr1200]

Try tapping the quadrants there must be an "O" ring sealing the neck bush some how to the cylinder wall and a lip seal for the rod...

 

[zzr1200]

MckD......

Whereabouts are you located?

 

[MCKDAVID]

right, done, as we suspected the threaded part was held in against a groove with the segments, pretty much like the spring retaining collets on a engine valve.

once I got the thread moving, it slid back easily enough, took a bit of PVC pipe, slit it and held it in place with a couple of heavy duty tiewraps... tapped it back, and the first collet came loose, the other three came out easily enough. Then slid the piston and seals out... job done.

a new one on me, but heyho, there you go, live and learn... big thanks to all, for the sugestions, espcially @zzr1200 spot on... great place this...

off to order the seal and ring just now....

 

[MCKDAVID]

MckD......

Whereabouts are you located?

Sunny South West of France......

 

[500e]

So the holes in the tube & the bush align for a locking pin then.
Have seen that style of lock with a spring ring round pipe & pin riveted to it , not on a hydraulic ram though

 

[MCKDAVID]

So the holes in the tube & the bush align for a locking pin then.
Have seen that style of lock with a spring ring round pipe & pin riveted to it , not on a hydraulic ram though

pretty much, the sleave is held back against the pressure / force by the "collets" of what I called quadrants. Then the outer ring (with wiper seal) screws down onto the end of the sleeve which pulls up against the cylinder tube so basically clamping the collets into place. This is then backed up by the hole in the sleeve which has a corresponding hole in the cylinder wall which has a 6mm bolt going through it, presumably to stop it unscrewing out through use. I thought this bolt was for bleeding initially, but it's function became obvious later.

strange set up, but fairly logical really, it's a single acting cylinder, so no hydraulic pressure against that cap end anyway, as there's a sintered bronze vent at the top of the cylinder on the secondary side of the piston...

 

[zzr1200]

Sunny South West of France......

I have a cousin who lives just outside Gourdon in the Dordogne.

Have you managed to get your jabs yet???

 

[MCKDAVID]

had covid at the beginning of the year, asymtomatic... no mention of the jabs here for my age group yet, to be honest I'm not really in a hurry.... already had it, and have the antibodies, so from what I understand that gives me some immunity for a good few months, so probably best to let the rest get theirs and see what happens for getting mine later...

Aye Gourdon would be a fair bit further north of us, we're right down the south, about an hour from the pyrenees..