Hydraulic ram rebuild.

[Me.Participant @me]

I’m well into my Burdett 70 surface grinder refurb and have now started looking at the main table ram. Can anyone suggest a good supplier of stock – i want to replace the two rods (1/2) and the main piston seals.

The original seals were almost like a piston ring – sprung metal ! – I’d like to use a vitron rubber type. the internal bore of the ram is 1 1/4

Ive seen others remake the piston to suit a modern type of seal rather than use the original piston and find seals to suit.

What type of materiel should i use for the main rods ?

[HopperParticipant @hopper]

You  can buy hard chromed and ground steel rod for rebuilding hydraulic rams on earth moving and industrial equipment.

Ive no idea of a UK supplier but a google search for hard chrome rod or piston rod etc should find it. It is very common. Not sure if still available in old imerial sizes though? Certainly would be in the USA.

You can buy ready made hydraulic pistons too.

[not done it yetParticipant @notdoneityet]

Not much experience with tiny little hydraulic rams.  Usual choice is a chromed rod if the seal is under high pressure or exposed to moisture.  Is this a double acting hydraulic ram?

If double acting, there is no problem with a little leakage by the piston ring(s) in this application.

[Bob WorsleyParticipant @bobworsley31976]

Don’t use a rubber ring seal, the stiction will ruin the precision of the ram positioning. Rubber seals work fine on an excavator.

Does the grinder have a dither oscillator for the hydraulics? Removes most of the stiction.

 

[not done it yet]

On not done it yet Said:

Is this a double acting hydraulic ram?

If double acting, there is no problem with a little leakage by the piston ring(s) in this application.

Thanks for the prompt replies – I will google the chromed rod suppliers.

 

Yes it is double acting and i wasn’t aware that piston seal leakage would be fine – but when you think about it that makes sense as to why the metal seals where the way they were.

If I can’t source the imperial size rods than metric is fine I can remake the end caps to suit.

[Brian WoodParticipant @brianwood45127]

I also suggest looking under hydraulic spares.

Brian

[noel shelleyParticipant @noelshelley55608]

Piston seal leakage is NOT fine, though as wear occurs some may have to be accepted. In most cases internal leakage will not be obvious until it is serious and then a rebuild will be needed. Re machining pistons, piston rods or cylinder ends to take newer or different seals is common. One company I have used is All Seals at Norwich, very helpful fellows ! Good Luck. Noel.

[Me.Participant @me]

Thanks – I have emailed All seals to see if they can help.

[not done it yetParticipant @notdoneityet]

Piston seal leakage is NOT fine

Expected in this application.  It is not high pressure (even with several piston rings in the case of an engine), compression will leak down slowly past the rings- as there will be a gap on each ring.

[Peter Cook 6Participant @petercook6]

Depending on the size you want, the hardened chromed rod used for linear bearings and building 3D printers might be the cheapest source.

[DC31kParticipant @dc31k]

Please see this thread:

CBN inserts

I suggested a fairly random UK supplier that Google found for me and the OP replied that they had ben extremely helpful to him.

[DiogenesParticipant @diogenes]

..get ’em hard chrome (re-) plated and ground back to any (sensible) size you want..

..it’s an everyday process in all kinds of industry and relatively inexpensive.. ..search it on the ‘net..

[Peter Cook 6]

On Peter Cook 6 Said:

Depending on the size you want, the hardened chromed rod used for linear bearings and building 3D printers might be the cheapest source.

Gas springs or car shock absorbers are probably better sources. I have a couple of 500mm(ish)lengths of 20mm hard chrome rods from some front struts that took about a minute with an angle grinder to harvest. Provided some nice tubing too, although the process is a bit messy…

[Diogenes]

On Diogenes Said:

..get ’em hard chrome (re-) plated and ground back to any (sensible) size you want..

..it’s an everyday process in all kinds of industry and relatively inexpensive.. ..search it on the ‘net..

That’s a good idea too. We do it with motorcycle fork tubes. It is cheaper than buying new ones, but still not cheap cheap. No idea how it would compare with the cost of blank hard chromed rod for hydraulic ram use.

[Nick Wheeler]

On Nick Wheeler Said:

On Peter Cook 6 Said:

Depending on the size you want, the hardened chromed rod used for linear bearings and building 3D printers might be the cheapest source.

Gas springs or car shock absorbers are probably better sources.

Think a little about the age and place of manufacture of the machine. Are the required hydraulic rods more likely to be metric or imperial?

[DC31k]

On DC31k Said:

On Nick Wheeler Said:

On Peter Cook 6 Said:

Depending on the size you want, the hardened chromed rod used for linear bearings and building 3D printers might be the cheapest source.

Gas springs or car shock absorbers are probably better sources.

Think a little about the age and place of manufacture of the machine. Are the required hydraulic rods more likely to be metric or imperial?

If you’re going to scrounge material for pistons to suit new seals, why would that matter?

[David George 1Participant @davidgeorge1]

On J and S grinders the cylinder rod is 3/8″ diamiter and have packing seals on the rods which are a ruberised cloth in a circular V shape with a plastic formed spacer. when under pressure the hydraulic oil presses the seal on to the rod with little friction and loads of wear space so they last for ages. The central piston has two Hydraulic round nosed ruberised cloth seals back to back. O ring seals will cause to much friction and will wear to soon.

David

[HOWARDTParticipant @howardt]

Look at Hallite for cylinder seal set, talk to them if necessary considering the pressure and duty.  Modern seal sets will be completely different to J&S configuration of old.

[duncan webster 1Participant @duncanwebster1]

This company do a huge range of seals, but you would probably fall foul of minimum order charge https://eriks.co.uk/en/products/sealing-and-polymer/industrial-seals/

[old martParticipant @oldmart]

Avoid any bronze in contact with chrome if you are going to refurbish, they are incompatible.

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