View Full Version : Anybody rebuilt an Enerpac cylinder?

04-22-2014, 11:23 AM
Hi all,

I have a non-working Enerpac benchtop 10ton hydraulic press which I was given and going by the oil dripping from the end of the piston, my guess is that one of the cylinder seals is shot. Seal kits aren't much (~$40 online) but has anyone done this themselves? Is it worth just buying some hydraulic oil (what sort and from where?), filling it up and seeing where it comes out from? Any point in replacing the seals in the jack handle too, they're about $45 a set? How do you bleed the air out of the system?

A more ignorant question - the gap between the bottom of the piston and the lower rails of the H-frame is around 2ft, but the maximum piston extension is 10in. How do you make up the difference if you're pressing out something thin, say a suspension bushing (the main pressing need for this press)? I didn't get any arbor plates with the press and I'm struggling to find any that I can afford online.


04-22-2014, 12:09 PM
I have rebuilt one. Its easy. Just buy the seal kit, it is not worth messing worth. Do watch out on single acting cylinders as the return spring is under the cap. It is not especially strong but it will launch the cap if it gets the chance.

If the pump is not leaking leave it alone.

04-22-2014, 12:26 PM
in the rebuilding business, its not magical, disassemble, polish the chrome rod if there are any scratches in it, check the bore and polish it if necessary. ive used flap wheels that are somewhat fine grit. they are quite tolerant as far as the bore is concerned. is it spring return ? sometimes they can be a real bastard. I don't remember if enerpac has the side screw to release the pullback spring, the part number of the cylinder should be around the fitting, find a parts break down on line. take the fitting out carefully. you may get a minor bath.
for oil, I would use universal tractor fluid, automatic transmission fluid would also work fine. if the jack handle does not leak, leave it alone.
arbor plates ? we need (I need) pictures or more information.
on my home made 40t press there is a height adjustable cross beam that's goes from side to side made from two heavy duty channel irons that are back to back with steel plates keeping them apart about four inches. that cross bar actually rests on a 1" round pin under each end and the pin will go thru the vertical side frames. under the ram, I use various cross pieces to support the work, from a large u-shaped part to a couple of 2" square bars or whatever I need at the time. for smaller things, the bearing races from the front spindle on newer cars work great too. go to your favorite auto repair shop and ask for a scrap spindle assembly and remove the bearings. . free. .
not sure what else your needing, , , , , ,
hope I make sense here.

04-22-2014, 12:36 PM
Watch you dont pinch the seals puttin together, a piston ring band with plenty of oil works

04-22-2014, 12:57 PM
thanks for the help everyone! According to the part sheet from Enerpac and this teardown guide (http://www.wbnoble.com/WN_articles/Enerpac_hyd_cyl_overhaul.htm) you can release the spring tension from the side. It doesn't sound too hard and bleeding it doesn't sound too difficult, although any input into that would be a great help.

Here's my press

I'll give it a clean up while I'm at it too. As you can see, there's no height adjustable beam as there is with floor standing H-frame presses. I did find this picture though - looks like he's just stacked up stuff to raise the height of the work piece:

I don't have access to a ton of steel, although I do have bits'n'pieces of scrap that I've scrounged. For low tonnage requirements (pressing bushings out of suspension arms) would hard wood be safe? Safety is my main concern, I don't want anything grenading on me.

04-22-2014, 02:41 PM
To remove the spring. Retract the cylinder. Remove the quick coupler on the cylinder. The spring is held by a screw.

04-22-2014, 03:04 PM
That is just like the one that I am trying to build! I am using an import porta power and the mounting threads are metric and I still haven't had a chance to attempt threading the mounting plate to 56mm pitch2.

I have some pieces of 3/4" hot rolled plate about 6 by 9" if you want one for the flat rate USPS shipping. I got them at an industrial auction a while back. You would have to saw out some pie shaped notches or drill some through holes to make it useful.

04-22-2014, 03:28 PM
To remove the spring. Retract the cylinder. Remove the quick coupler on the cylinder. The spring is held by a screw.

thanks, that's a great help. Just to confirm - the quick coupler is the black threaded section on the top of the cylinder, just above the hose? It's held on by a couple of socket head cap screws from what I can see. Any idea what the thread is for? Mounting the cylinder to something else?

That is just like the one that I am trying to build! I am using an import porta power and the mounting threads are metric and I still haven't had a chance to attempt threading the mounting plate to 56mm pitch2.

I have some pieces of 3/4" hot rolled plate about 6 by 9" if you want one for the flat rate USPS shipping. I got them at an industrial auction a while back. You would have to saw out some pie shaped notches or drill some through holes to make it useful.

neat! It's a small world :) I'm just happy to have fallen into this for just the cost of a seal kit and some hydraulic fluid (fingers crossed).

thanks for the offer, it's very generous - PM on the way..

04-22-2014, 05:50 PM
The quick disconnect is where the hydraulic hose connects to the cylinder.

The threads on the end are for attaching things like spreaders or cable cutters.

04-22-2014, 11:27 PM
To remove the spring. Retract the cylinder. Remove the quick coupler on the cylinder. The spring is held by a screw. That's right, and the fun part is trying to put the screw back in working down in a 3/8" hole.


04-23-2014, 10:24 AM
does the pushing end of the cylinder have threads on it or in it ? if so, its used for attachments like the small photo shows a wedge for bending or a long shaft to extend the pushing rod closer to the cross frame. I cannot see in your photo whats on that end of the cyl. you have a very nice unit there. . . .

04-23-2014, 12:09 PM
It will just fit in a small flat rate box. Please PM your address for USPS shipping. Good luck with your lucky acquisition! The Enerpac press is a thing of beauty!

My copy of your press is about 5" or so across the bottom bars front to back. I cut my piece into two pieces 4.5" by the width---almost square pieces. I should have drilled or hole sawed the hole in the middle before I cut it into two--much less complicated clamping.

04-23-2014, 12:17 PM
Hi, I am in a similar situation. Found a hollow ram at the scrapyard and I'm trying to identify it and source a seal kit. Any rebuild instructions would also be appreciated.
http://imagizer.imageshack.us/v2/800x600q90/838/0gdi.jpg (https://imageshack.com/i/na0gdij)
http://imagizer.imageshack.us/v2/800x600q90/841/17jy.jpg (https://imageshack.com/i/nd17jyj)

I think the number on it is nw040834

Thanks, Paul!

04-23-2014, 02:14 PM
Did you check the website of the other "porta power" makers? OTC, Simplex?, Blackhawk, etc. Might be able to id it by color and part#.

04-23-2014, 04:00 PM
Yeah, I have looked around but no luck, maybe looking in the wrong places.

04-23-2014, 04:13 PM
a big thanks to Mike for his offer, that'll get me another step closer to putting this big piece of luck into action.

David - I think the cap unthreads, but it's a long time since I've fiddled with it. I've seen threaded extension tubes on eBay for this cylinder so I assume so. I'm off on a job interview, so I'll have a poke around when I get back. I also got a few bits'n'pieces with it that would attach to the ram, so I'll dig those out and see how they fit together. I could probably get a decent amount for this press on ebay, even before fixing it, but when would I ever be able to afford/ justify such an awesome piece of equipment? I have to kick myself every so often to remind myself how lucky I am in so many ways :)

04-23-2014, 05:02 PM

Please PM me with your address to send out the plate!


04-23-2014, 07:30 PM
sorry Mike, completely forgot about that :)

04-23-2014, 09:50 PM
If you have a metal salvage yard nearby, you can sometimes find nice pieces of flat or plate. I have several 10 x 12 x 1 1/8" pieces I use for bed plates and several 1/2" and 3/4" pieces for spacers. You can also use pieces of square tubing (4x4) placed on end for spacers. Or you can weld two pieces of heavy channels or angle together to make a box by welding the openings together - [ ]. I just picked up a 3/4 x 10 x 33" piece of hot rolled at the salvage yard for a full length bed plate on my shop press.

04-23-2014, 10:21 PM
Check the guide as well for scoring , a couple of mine had to have new guides due to scoring from gunk which had gotten past the seal


04-24-2014, 12:12 PM
thanks Michael and Ken. I'll check everything out when I take it to pieces and report back if anything looks out of the ordinary. Just waiting on the next pay check to order the seals.

Unfortunately the scrap metal dealer/ recycler here only accepts scrap, you can't buy anything from there. The other scrappers I found within an hours drive have a similar policy

04-25-2014, 12:30 PM
the plate shipped out today--finally. Good luck--Mike.

04-25-2014, 12:56 PM
Thanks Mike, I'm really pumped about this :) plus I never hurts to have an excuse to get out of the lab into the machine shop!

05-01-2014, 12:11 PM
got the plate Mike, thanks! Also got a free foul look from the wife as she nearly dropped it on her foot getting it out of the mail box :) Steel really is a lot denser than alu.. Just ordered the seal kit and I'll get some hydraulic oil from TS this weekend.

05-06-2014, 12:04 PM
just finished making the plates :) Took a long while cutting out a 2in round using a holesaw, but it made a really smooth hole, then a short stint on the band saw left me with the 2 plates. I need to touch up the edges of the bore when I get home, but that part is done.

Seal kit arrived on Saturday and I managed to find a quart of hydraulic fluid after some effort, so I'll try and crack on to that this week if I have time.

Alistair Hosie
05-06-2014, 01:34 PM
Do as I suggested in my tip, in the tips book.Simply take your screw and put some heated wax or even better hot melt glue if it is required. The wax from a candle does work seal the screw onto the end of the screwdriver and lower carefully into the tight space you mention start the thread and once the thread has started it won't matter if you lose the conection as you will be able to carry on screwing until you have it nice and tight. Alistair

05-06-2014, 04:03 PM
that's an awesome tip, thank you Alistair. I've used magnetic tip screwdrivers before but never thought of using hot melt glue. I'll use that for sure!

On a side note, I broke my first end mill today :( I felt very ashamed. 4fl 5/16 carbide thinning the side of a piece of steel pipe before cutting a slot through it (DIY castle wrench). Fed it into the cut too fast - bang bang bang bang, all the tips are shattered. Turned it around, did the rest, then just a conventional milling clean up of the side of the slot, must have caught a chip which ripped two opposing tips off the fresh end. I'll rummage through my collection of end mills at home to see if I can find a replacement or two for him. I hate breaking my own tools, let alone someone elses!

05-06-2014, 06:39 PM
I felt very ashamed. 4fl 5/16 carbide thinning the side of a piece of steel pipe before.....

Don't use carbide when almost any old HSS endmill will do.

05-06-2014, 08:09 PM
Don't use carbide when almost any old HSS endmill will do.

true. It was the mill in the machine shop at work, so I just used the end mill the machinist who's helping me picked out. I've sorted out a handful of HSS end mills he can pick a couple of replacements from, so if I need to mill steel again, it'll probably be with one of those :)

05-06-2014, 08:43 PM
Don't use carbide when almost any old HSS endmill will do.

Definitely! When you are new to milling, HSS WILL LAST LONGER! Because you'll do something silly and shatter carbide where HSS might survive the abuse, long before you'll dull HSS (Unless you use too high a SFM (will dull carbide too, just takes more SFM) or cut hard steel)

05-07-2014, 10:45 AM
thanks guys, I'm 100% with you there. Took in a selection of 4fl end mills today and he picked out a couple of nice ones and I gave him a 3/8 4fl rougher as I have a couple and he's never used one. I still have more than enough for my drill press "mill" when it gets up and running and he has some new cutters to play with.

here's what the broken one looked like

making this castle nut tool for my bike

and here's my new press plates :)

05-08-2014, 01:08 AM
yay woohoo yippee! I did it! And I'm pretty sure I didn't screw anything up, at least nothing obvious. Long story but it's late and I have to go to bed. Pictures and teardown tomorrow/ today.

05-08-2014, 01:16 PM
now that I've got some sleep...

I followed the procedure outlined
here (http://www.wbnoble.com/WN_articles/Enerpac_hyd_cyl_overhaul.htm) which also has a parts diagram.

Before I go through the pictures, the 2 major PITAs I had were; 1) getting the quick connect fitting out of the cylinder. It took a whole lot more force with a 25mm (prob. should have been 1in, it was pretty tight) spanner than I was comfortable with. 2) I couldn't get the nut off the spring tension screw in the base of the cylinder (piston just rotated), so getting the screw out with the spring under tension was a complete arse ache. That was pretty much it though.

One plus side was that in trying to get the spring tension nut, the captive nut with the wiper seal unscrewed, so that was easy

lower guide showing orientation on the piston


upper spring screw

05-08-2014, 01:19 PM
Piston coming out


seal and spring clip thing

now that I can grip the cylinder I can undo that damn nut

05-08-2014, 01:25 PM
now you can see the copper washer and spring tension screw (that would have made taking out that other screw so much easier)

you don't need to unscrew that screw all the way (just so the slotted head is flush with the bottom of that bore), but I did so I could take the spring out and clean out any crud (there was lots)

everything disassembled and shown in it's assembly order

new seal/ ring/ clip in place (already put a new wiper seal in the bottom ring as it was perished to hell)

05-08-2014, 01:29 PM
I then put everything back together, filled it up with hydraulic fluid, screwed in the quick connect fitting and nada. Checked the pump, lots of oil everywhere but inside it. So I pulled the handle, took out all the split rubber seals that I could get to in the plunger bore and turned them upside down to see if that would give them enough of a seal. They're not directional, just have to line them up so the splits don't all sit in a row. Sometimes you can get a bit more life out of a seal by turning it around :)

Filled up the pump with the rest of my quart of hydraulic fluid and it worked. Woohoo!


not tried out in anger yet, so hopefully it'll all hold up when I need to press something out/ in. Should find out soon enough!

05-08-2014, 03:10 PM
Nice Work!

I recognize the handwriting on the USPS box!

Good luck--Mike.

05-08-2014, 03:22 PM

Found another small piece of steel in the metal recycling bin today (0.75x6x4.5?) so I cut that in half and now have a couple of riser plates.

06-02-2014, 04:13 PM
finally used it in anger this weekend to replace almost all (12 out of 14) of the bushings in the rear suspension of my Focus with a Prothane set. Hopefully that'll cure the uneven tire wear - if it doesn't there's really nothing left to replace!


and in place - it may look like some of the bushings are tilted, but that's just because the suspension is at full droop, at normal ride height they're straight.

got to give my HF 4 1/2in angle grinder a good workout as 4 of the bolts, 2 I knew about and 2 I didn't, were seized the the inner sleeve of their bushings. Fun times. Took about 17h to do the rear (10h to do one side which made the 2nd side much quicker) and 1 1/2h to change the struts on the front. Then 2h sleeping on the couch in the dealership to get an alignment :) Save for a final oil change to use up the oil I have left, it's all ready for its 2500 mile journey in a few weeks.