Insane Hydraulics
Bold and audacious blog about fluid power
OK, my friends, today is the day when I, as promised, will show you how to make another hydraulic cylinder gland nut wrench from scrap, and this one is going to be a super-fast version that can be literally made in half an hour (with coffee breaks). If you missed my last gland wrench post - I highly recommend checking it out - because there, aside from the said wrench, I describe a unique rod clamp that uses cylinder action to keep the wrench secure against the face of the cylinder gland nut, completely eliminating the chance of it slipping out of the holes/grooves. I will be using this clamp today as well, and I should say that this technique works surprisingly well.
I won't be talking about safety issues - everything I have to say I already said before, but I do want to repeat one thing: the best and the easiest way to undo a gland nut of a hydraulic cylinder is to do it in a proper hydraulic cylinder repair bench, period. A good cylinder shop should have one.
And for the record: I fully realize that the procedure that I am about to show you falls under the category of jury-rigging, but in my opinion it has every right to coexist with "legitimate" practices, because being able to make tools from "scavengeables" is an invaluable skill for situations when you need to repair something fast and on the spot, but don't have access to proper tools. Believe me - if you choose this profession - sooner or later you will find yourself in one.
So, here's the cylinder in question and here's the gland nut that we will be "busting" with our DIY solution. As you can see, I already removed it, which means that the tool that I am about to show you works.
These nuts can be really stubborn, especially on older machines, so you do need a strong wrench to undo them. Something like this will not work (especially after the sides of the grooves had been smacked repeatedly):
This gland nut is actually pretty well designed - the grooves are wide and strong and they extend to the face of the gland, which means that if you have a tool that can fit into the face side of the grooves - you can employ the rod-clamp technique to press it against the face with compressed air, and then apply the naughtiest torque you can generate without worrying about the wrench slipping out.
So, the first thing that you will need is a piece of a thick steel plate of adequate size. In my case it is going to be this random 10 mm steel plate:
Then you need to make a "U-cut" in it slightly wider than the rod diameter, with a tool of your choosing. I'm using an oxy-torch because it's the fastest way to cut steel, and I really like setting things on fire. The exact dimensions aren't too important.
Then you drill and tap two holes - in my case it's going to be two M8 holes, because M8 socket screws have heads of just the right size for the grooves of this gland.
As you can imagine - this plate can be later drilled and tapped in more places to accommodate for different gland nut sizes and configurations. And, finally - you add "leverage" - which, in my case, will be this random M24 - 12.9 bolt I found at the bottom of my toolbox (a piece of a scrapped hydraulic cylinder rod would've been better, but I couldn't find one of a suitable size at the moment). Note that I also reinforced the neck of the bolt with a weld bead (just in case):
Let's all agree that this is not the prettiest of things, but check out how nicely this "15-minute tool" fits the grooves:
And this is the rod clamp and the wrench in the "starting position":
Then I took a 1.8 meter cut of a BQ drilling rod (old core drilling rods make excellent cheater bars), fit it over the shank-bolt, torched the gland end "until smoke appeared", and then asked my wife to keep injecting compressed air in the rod-end port (to keep the wrench pressed against the nut) as I was throwing all of my weight at the end of the long lever. Look at the angle the shank ended up at - I had to almost suspend myself in the air to get closer to the lever end, and, after several extremely violent tugs, the gland nut squeaked and gave up:
I must say I am really surprised how well the cheapo Jonnesway vice took this abuse. My previous "bench helper" - the Irwin Nº6 - had to be retired to the hose-assembly section with a nasty welding scar across the slide after I snapped it in half in a similar fashion. In fact - I even said to my wife: "Stand aside and keep pressing on that trigger, honey, and if the vice snaps - just let it fall! Do not, I repeat, do not try to catch it!"
So, as you can see, a simple steel plate with a U-cut, a couple of tapped holes, and a welded shank can become a pretty capable tool. Also, the trick of using compressed air to close the cylinder and press the spanner into the gland nut with the help of a clamp-on piece is an absolute success.
P.S.
Following up on my last week's post - the original piston seal is, indeed, a seal with a stepped cut, and it was in perfect condition:
Now I have a confirmation that it is possible for such a seal to bypass low-pressure compressed air (if you haven't read my last week's post, I extended the cylinder with compressed air and detected a slow but steady stream of bubbles appear from the rod-end port). They seal oil perfectly fine, though. I also (finally!) received a confirmation of what was really going on with the cylinder - it was not drifting in the working position - as it turns out, when the machine was parked for several days with raised stabilizers, one of them would drop down and leave a puddle of oil on the floor, which means that the rod seal was, indeed, the culprit.