Leaking PortaPower

[Seadog]

In 2017 I finally got round to refurbishing my PortaPower that had been laying outside. I posted the rebuild of the pump on another forum so will just leave post the link in case anyone wants to read it

https://madmodder.net/index.php/topic,12276.msg146288.html#msg146288

There was also an annoying drip from the cylinder, but since it only gets used once in every other 5 blue moons I've never bothered about it. Due to the lockdown there has been a massive surfeit of Round Tuits so I've grabbed my fair share and set to on all manner of diverse and interesting repairs and builds.

One of these Tuits was assigned for fixing the leak.

It's a fairly simple matter to disassemble the cylinder. Being single acting, there is a retracting spring and this is retained with a 6mm machine screw which is accessed once the hydraulic coupling is removed. Remember this, because I didn't

the locking ring can then be unscrewed and the piston rod withdrawn. the seals are retained with a threaded collar, pretty standard practice I would imagine.

There wasn't much wear evident on the sealing lips so I cleaned and reassembled the seal and just tightened the collar down a couple more turns. When slid back into the cylinder there was some slight resistance whereas when I dismantled it it pulled out with virtually no effort.

Job done

Except, some time ago I did think of fitting a pressure to it, because I could. During one of my tidying sessions I came across a couple of pressure gauges that I'd bought when trying to fault find a problem on my Range Rover back in 2007. Well, there's no time like the present, let's do it.

In my dash to get it done I decided to mount the gauge diametrically opposite the input port...

Popped a pilot drill in, all well and good, but there was decidedly less metal to drill through than I had expected. Any guesses as to why?

All I'll say is return spring and screw

Oh well, it's all fun, isn't it?

I intended tapping it BSPT and to that end had worked out how to screwcut it on my Boxford since I don't have a die. Good old Zeus provided me with the tapping drill size (for BSPP ) which is 20 thou larger. At this point I should have stopped, had a cup of coffee and a think, but I didn't. Expecting BSPT, I was going to drill through and then tap. Since it was going to be BSPP, I could have drilled part way and then squared the bottom of the port to allow for a sealing washer on the face. Never mind, there are other ways to skin a cat, fortunately.

I don't like thread tape, unless there's no other way, so I decided to face the cylinder wall to allow seating for a copper or Dowty washer.

What did I do before I bought a boring head? It only has a limited range but it's more than paid for itself over the last couple of months. Once again the Progress was pushed into service as a vertical mill.

The question of how to hold the return spring was easily resolved. A hole was drilled at 90° to its original position, then counterbored and finally tapped. A handy 1/4" BSF machine screw was tweaked and the whole shebang reassembled with a copper washer as a seal.

Now to the question of how to mount the gauge. Usually It's stuck in the top of the cylinder but for a reason known only to my inner mind, I decided that I wanted it on the side. Now I needed a right-angled fitting, which I didn't have. But I did have a lump of cast bronze of unknown origin and composition, So I set to to make one.

And some more silver soldering action left me with this

And the finished article, except that I dropped the gauge during the day and it wasn't until I'd fitted it that I noticed a small problem

Oh well, it's just as well I have a spare

 

[Seadog]

Bright and early I was out and about, fitted the cylinder and tested it and all was OK.

Apart, that is, from the leaky pump

Now this is a problem that I've put up with since 2017, where my refurb obviously didn't cut the mustard.

Time to revisit that can of worms. The pump dates probably to around 1985 and, as such, I was unable to get seals for it as the design has changed markedly. If you read the original thread you'll see what I did.

What I ended up with is this arrangement

From the left: a fibre seating washer, a hydraulic seal seated in a block which sat where the original seal elements sat, a lock ring, then a further lock ring into which I'd fitted a scraper seal ( the wrong way around, as it happens, but it was easier to do and I'd didn't expect much in the way of clag to be getting in there).

Why I thought this very simple arrangement would be effective, I've no idea, but it seemed like a good idea at the time.

With this in mind I hunted through my O-ring drawer and turned up a couple that were just right for the job. The fibre seating washer was replaced with an O-ring by means of turning a reduced diameter on the end of the hydraulic seal block

Then an additional piston seal was introduced between the first lock ring and the top of the block

I also reversed the wiper seal for good measure, but it did make reassembly slightly tricky since despite the radius on the end of the piston, it was inverting the seal. I overcame this by using a guide cut from a Britvic tonic water can

Well, that was simple enough. Reassembly was straightforward and then it was time to test it.....

It still leaked

I couldn't work out why the oil seemed to be flowing down the rod.

Clearly the there was a pathway for high pressure oil between the stainless steel sleeve, that was fitted to prevent any further rusting and the piston

After a strong coffee and several biscuits I came up with a plan.

I found a countersunk screw, 1/4" UNF as it happens, that had a head diameter just about right for my needs. It was chucked up, the compound set and the head was trimmed

Fortunately I was able to mount the piston from the rear of an ER32 collet, which saved a few potential headaches, and drilled, tapped, and countersunk the end

O-ring or sealing goo?

Loctite 577 was to hand and easier than cutting a groove, so it was assembled and dressed and left for a few hours before reassembly

Fingers crossed...

It works, not a leak in sight

Pumped up to 10 tons (about 253 bar) and the pressure relief valve was adjusted

Another one bites the dust. I wonder what tomorrow will bring?

 

[Turbo]

Ages ago I acquired a good portapower set along with a few old pumps & rams. I was going to repair/service one of the old ones to use for a bearing press so your post will help guide me.
Unfortunately the particular roundtuit for that task is missing, so it may be a while before a press is built!

 

[Seadog]

I've a load of spare Tuits if you need any

 

[Turbo]

I've a load of spare Tuits if you need any

But are they the correct tuits? Unless of course they are the ultra rare universal tuits, if so I'll have a box.

 

[Seadog]

They are URTs I have more than my fair share, so I'll pop some in the post to you