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View Full Version : Enerpac P39 hand pump tear down, tool and Qs



mattthemuppet
12-24-2016, 12:42 AM
Right, this thing has been quietly leaking ever since I got it working a few years ago - I picked it and the Enerpac 10t benchtop press it was attached to from my uni as they didn't want to fix the blown piston seal. Replaced the seals in the piston and it was all good, until it gave up the ghost recently. Piston now extends and retracts with the hand pump, so something's off and it wasn't fluid level.

Bought a seal kit and not much seems to add up, plus I can't get the check valve screw out. Also made a tool to get a retaining ring out, which I'm rather proud off.

First - anyone taken one of these apart before? The piston seals consist of (from outside>in): one threaded ring, 4 stacked split rubber washers, another threaded ring, 4 what look like cork washers, then a forming ring at the very bottom. The seal kit included an o-ring and a teflon washer, plus one square of uncut cork and the parts list makes no mention of the 4 cork washers only the o-ring and teflon washer. Any ideas?

cork washers
http://i1349.photobucket.com/albums/p752/mattthemuppet/DSCN1918_zpsgmhoci8w.jpg
http://i1349.photobucket.com/albums/p752/mattthemuppet/DSCN1919_zpsypc8obxw.jpg

forming ring
http://i1349.photobucket.com/albums/p752/mattthemuppet/DSCN1920_zpslaptawx6.jpg

mattthemuppet
12-24-2016, 12:45 AM
the 2nd threaded ring needed a pin spanner I didn't have, so i made one

piece of scrap with a handy hole in one end turned to size and 2 holes drilled and tapped in the end
http://i1349.photobucket.com/albums/p752/mattthemuppet/DSCN1914_zpsidxuutxi.jpg

screws threaded in and cut to length
http://i1349.photobucket.com/albums/p752/mattthemuppet/DSCN1915_zpswi9scmff.jpg

worked a treat!
http://i1349.photobucket.com/albums/p752/mattthemuppet/DSCN1916_zpstwjd81pe.jpg

mattthemuppet
12-24-2016, 12:49 AM
Second question. I can't get the check valve screw out - any tips?

it's this one, near the front left foot
http://i1349.photobucket.com/albums/p752/mattthemuppet/DSCN1911_zpsswbulmow.jpg

I've scrapped off the paint around the screw, tried a few cycles of MAP torch heat/ freeze spray cool and then had a go with the impact screwdriver (the one you smack with a mallet). No joy, just an increasingly mangled screwdriver slot. Gave up before I screwed it up and dabbed some acetone:PS fluid on it as I heard that works well.

More of the same tomorrow or...?

I'd rather not have to make another one, but it shouldn't be too terrible if it has a standard thread. Might even be able to adapt a hex head or socket cap screw, man I hate slotted screws.

gambler
12-24-2016, 09:40 AM
swedish pattern pipe wrench. works good on stuff like that.

reggie_obe
12-24-2016, 10:14 AM
Sorry....obvious question. Enerpac customer service or service department has been of no help?

Maybe Youtube?
https://www.youtube.com/watch?v=Sq-Yrb39ucg

wierdscience
12-24-2016, 12:03 PM
I have the same pump with a Blackhawk logo on it.The washers you are holding are actually V-packing.

http://www.veepacking.com/

That metal ring is the the bottom male adapter and the spanner nut should have the top female adapter machined in it,or it takes a separate top female adapter ring.

It may be that you have an older version of the P39 and the newer version takes the seals in the kit you bought.

Oh,forgot to add,that relief valve screw IIRC has a copper seal ring.Mine required one hit from an impact screwdriver to break it loose.

metalmagpie
12-24-2016, 01:38 PM
I rely extensively on a repair shop in Seattle for things like this. The place is amazing. Back in the '60s southwest Capitol Hill was essentially Seattle's Auto Row. There were tens if not dozens of repair shops. You could get leaf springs re-arced, your headliner recovered, new linings on your brake shoes or clutch plates, and many other things. There were also a lot of car dealers in the area. Back then I was a teenager who was into fixing things. A local gas station mechanic (widely worshiped by the local youth) told me to take something hydraulic down to this particular repair shop. I've been going there ever since. The auto stuff is nearly all gone now. Back then, they made a good living rebuilding stuff like floor jacks or pneumatic impact wrenches. Today they look just the same, and mostly it's the same guys working there, now old graybeards with infinite wisdom and experience. To first order they know everything about Enerpac stuff. If you lose faith, ship your pump to them and they'll rebuild it for you. They stock every part for a P39.

Universal Repair Shop
1611 Boylston Avenue
Seattle, WA 98122
(206) 322-2726
http://www.d1060332-14740.customer.cloud.savvisdirect.com/universalrepairshop.net

Hopefully you have the instruction and parts manuals, if not, post back or PM me.

That stuck screw is worrisome. I might try heating the area and then using your impact screwdriver while it is hot, in case some numbnuts used thread locker.

Worst case, used P39 pumps don't cost too much used. I had one I tried to flog for about a year with no luck, even at near giveaway prices. Nowadays people think Harbor Freight or Jet hydraulic stuff is the same quality as Enerpac, so aren't willing to pay for the latter.

metalmagpie

JoeLee
12-24-2016, 02:40 PM
I had a bunch of those pumps apart before, Blackhawk is the same thing. Leather packings and the form ring.
If I remember correctly there is a check ball in the piston well and two different size ones under that screw on the side I think the smaller one goes in first..
There is also a small ball in the hole where the valve goes. Sometime when you take these things apart stuff falls out and then you have to figure out where it all goes. I had to make a couple different spanner wrenches for mine also. A lot of time a leaky seal can be cured just by tightening the spanner that presses the leather seals together. A lot of people tighten the outer spanner thinking that will cure it but that one is just a dust wiper.

JL.................

mattthemuppet
12-24-2016, 05:46 PM
swedish pattern pipe wrench. works good on stuff like that.

neat, never heard of one of those before :) not sure how it would have helped get that ring out, but it's something to bear in mind for the future!


Sorry....obvious question. Enerpac customer service or service department has been of no help?

Maybe Youtube?
https://www.youtube.com/watch?v=Sq-Yrb39ucg

not an obvious Q, hadn't thought to do that at all! I'll give 'em a call after Christmas, as well as the repair shop Metalmagpie mentioned.

nothing on youtube about tearing down a P39 unfortunately


I have the same pump with a Blackhawk logo on it.The washers you are holding are actually V-packing.

http://www.veepacking.com/

That metal ring is the the bottom male adapter and the spanner nut should have the top female adapter machined in it,or it takes a separate top female adapter ring.

It may be that you have an older version of the P39 and the newer version takes the seals in the kit you bought.

Oh,forgot to add,that relief valve screw IIRC has a copper seal ring.Mine required one hit from an impact screwdriver to break it loose.

thanks! yep, that's exactly how it is - the spanner nut has a matching female recess in it. My guess is the same as yours, that it's a much older unit.

still no luck with the screw, even after another couple of heat/freeze cycles and a whack with the impact screwdriver.


To first order they know everything about Enerpac stuff. If you lose faith, ship your pump to them and they'll rebuild it for you. They stock every part for a P39.

Universal Repair Shop
1611 Boylston Avenue
Seattle, WA 98122
(206) 322-2726
http://www.d1060332-14740.customer.cloud.savvisdirect.com/universalrepairshop.net

Hopefully you have the instruction and parts manuals, if not, post back or PM me.

That stuck screw is worrisome. I might try heating the area and then using your impact screwdriver while it is hot, in case some numbnuts used thread locker.

Worst case, used P39 pumps don't cost too much used. I had one I tried to flog for about a year with no luck, even at near giveaway prices. Nowadays people think Harbor Freight or Jet hydraulic stuff is the same quality as Enerpac, so aren't willing to pay for the latter.

metalmagpie

thanks for tip, I'll definitely give them a call after Christmas. I have the instruction and part manuals, thanks.

yeah, I'm worried about that screw. I really don't want to have to use a LH drill to drill it out, but there's a good chance that one of the balls under it is causing the problem. I'll give it a few more days of acetone/PS fluid and heat/ freeze cycles. I'll try giving it a whack while it's hot too.

I'll keep my eyes open for a replacement pump, but I don't hold out much hope - tools are in short supply and vastly overpriced around here.


I had a bunch of those pumps apart before, Blackhawk is the same thing. Leather packings and the form ring.
If I remember correctly there is a check ball in the piston well and two different size ones under that screw on the side I think the smaller one goes in first..
There is also a small ball in the hole where the valve goes. Sometime when you take these things apart stuff falls out and then you have to figure out where it all goes. I had to make a couple different spanner wrenches for mine also. A lot of time a leaky seal can be cured just by tightening the spanner that presses the leather seals together. A lot of people tighten the outer spanner thinking that will cure it but that one is just a dust wiper.

JL.................

thanks Joe. Yep, there's a spring and 2 different size balls under the screw I can't get out and a ball plus a couple of cork seals under the release valve.

good point about tightening up the collar against the v-pack seals. I did exactly what you said and tightened up the outer one before to no effect. Now I have the tool and the knowledge (sort of), I'll try snugging up the seals a little tighter before I look into replacements.

metalmagpie
12-24-2016, 11:43 PM
Try http://seattle.craigslist.org/see/tls/5932216359.html

mattthemuppet
12-25-2016, 01:09 AM
Thanks, 9h+ round trip though :) I'm almost as far from Seattle as you can get and still be in Washington..

The photos did help remind me how to get the quick connect could off though, which was very helpful. You can forget about in 5 years!

mattthemuppet
01-09-2017, 07:33 PM
finally got the check valve screw out. Not proud to say it, but I drilled it out. I used a small drill to make a pilot hole 1/2in or so deep, then a 1/4in left hand drill. After going about 3/8 of the way in the screw moved a bit. I could then tap it round with a punch and mallet.
http://i1349.photobucket.com/albums/p752/mattthemuppet/DSCN2000_zps21omm9bu.jpg

http://i1349.photobucket.com/albums/p752/mattthemuppet/DSCN2001_zpsqyjyr3vq.jpg

I put it back temporarily by pressing a T40 torx bit into the hole, but I'll either buy or make a new one sometime soon

The copper washers under the screw were really mashed and I couldn't get the bottom one out, so I cut it out with a counterbore
http://i1349.photobucket.com/albums/p752/mattthemuppet/DSCN1999_zpsqr6jfmcn.jpg

then fished out the 2 balls and spring. The lower ball required a bunch of extra magnets to reach down far enough.
http://i1349.photobucket.com/albums/p752/mattthemuppet/DSCN2002_zpspklaz29b.jpg

put it back together, refilled it and it sort of works. Goes down nicely, holds pressure but the ram doesn't want to retract either fast nor fully. I don't know if it was too cold in the garage (it was about 10-15F when I tried it) and the hydraulic jack oil was too viscous or if there was something I didn't do right. I did hold the hand pump above the cylinder while pumping/ opening it to get rid of any air in the system, but that didn't make any difference.

Well, at least it's mostly working now, which is better than not working at all!

metalmagpie
01-10-2017, 12:54 PM
If the ram doesn't retract one possibility is that you have too much fluid in the system. You might try removing a quarter cup or so and see if it goes farther. If not, you may have damage in your ram.

metalmagpie

mattthemuppet
01-10-2017, 02:17 PM
good point, I hadn't thought of that. I did use the dipstick on the fill cap, but it would be easy enough to pour some out and see what effect it has. Grade of hydraulic fluid shouldn't have an effect, should it? The ram retraction is done by a spring in the ram. My wife just got me a quart of whatever jack fluid they had at HD.

EddyCurr
01-10-2017, 02:43 PM
Grade of hydraulic fluid shouldn't have an effect, should it? ... My wife just got me a quart of whatever jack fluid they had at HD.Maybe.

Perchance has an SAE wgt oil been used where an ISO wgt is specified?

.

metalmagpie
01-10-2017, 04:59 PM
good point, I hadn't thought of that. I did use the dipstick on the fill cap, but it would be easy enough to pour some out and see what effect it has. Grade of hydraulic fluid shouldn't have an effect, should it? The ram retraction is done by a spring in the ram. My wife just got me a quart of whatever jack fluid they had at HD.

Not really. I just use non-foaming medium weight oil for mine, don't remember the numbering scheme but it
has a 46 in it, just a bucket of hydraulic oil from NAPA. I use it for lots of things.

metalmagpie

metalmagpie
01-10-2017, 06:19 PM
From the Enerpac manual's troubleshooting section:

Cylinder does not retract, retracts part way, or retracts more
slowly than normal.

1. Release valve closed.
2. Pump reservoir is over-filled.
3. Loose hydraulic coupler.
4. Air trapped in system.
5. Hose I.D. too narrow.
6. Cylinder retraction spring broken or other cylinder damage.

metalmagpie

JoeLee
01-10-2017, 09:31 PM
Could be a weak spring. I've seen it before where they were over stretched.

JL.................

mattthemuppet
01-11-2017, 09:09 PM
Thanks guys, I'll check as many of those as I can this weekend

mattthemuppet
01-16-2017, 07:42 PM
had a quick fiddle this weekend as I needed it to press a bearing back into a pulley. I think it's a viscosity issue - the ram went back up fine (if not quite as fast) once I screwed the release valve out much further than usual. I don't know if it's the oil (no ISO weight on the bottle) or the temperature in the garage (-10C or below). I'll play with it again when the temp goes above freezing.

very happy to have it back in action though!

wierdscience
01-16-2017, 08:17 PM
Probably it,cold does affect jack oil and hydraulic fluid more than it does engine oil.

reggie_obe
01-16-2017, 08:40 PM
According to Enerpac, correct oil should be ISO-15.

http://www.enerpac.com/en-us/industrial-tools-imperial/system-components/hydraulic-hoses-couplers-and-oil/hf-lx-series-hydraulic-oil