[How-To] Hydraulic plumbing: how do I stop this from leaking?

[Papa Charlie]

The time will vary depending on the product used. Refer to the directions. I must admit I am not up to date on current products.

Most people rate their systems pressure based on the pump output, which is greatly reduced by restrictions down stream. I have seen as much as 30% reduction in some systems. Calculating pressure drop is important and is effected by every fitting, 90, value, orfice, spool and the length of pipe or hose.

The hardest design work I had to do was to redesign systems that did not perform. Generally it was due to not taking into consideration the entire systems affect on flow and pressure and what was required, Flow or Pressure. Customers use to get very upset when I told them that the hydraulic system had to be totally reworked to get the performance. Too often this ended in a compromise between what they wanted and what they were willing to pay for.

 

[Papa Charlie]

That's definitely low pressure in the world of hydraulics. Years ago i built an articulated end loader from scratch. The standard pumps for that type of application are 3,000 psi. At work most of our presses used "medium range" hydraulic pumps which put out 10,000 psi. When building my loader I used Loctite 567 sealant with PTFE on all the hoses and hard lines with pipe fittings. The loader has been working about 17 years with no leaks at any of those fittings. Here are a few pictures of the machine. As you can see there are dozens hoses and pipes in the hydraulic system.View attachment 357053View attachment 357054View attachment 357055View attachment 357056

I remember you showing us this once before. Impressive build.

 

[pacifica]

So I recently got a hydraulic shaper and I'm trying to get it back to tip top shape. I noticed it is taking a bit to build up pressure, so I pulled the side off and noticed it is leaking quite a bit at the angle coming out of the block here(top left):View attachment 357019

This required quite a bit of careful disassembly to get out, but I eventually did. It says cat40 on the side of these pipes.

Getting this back together is likely going to be a bear, so I was hoping someone could give some advice. The biggest problem is that I have to install the "near" 90 alone, overtighten it (so there is clearance to tighten the straight/other 90), then "loosen" the 1st 90 to get the pipes lined up right.

I presume this is why it was leaking as much as it was at that junction.

So I guess my questions are:
1: is there a trick to doing this? Is there some expanding, slow drying goop you put on the pipe threads that wouldn't let it leak?

2: could I be better to replace them with a different type of fitting? Perhaps a flexible hose of some sort? I have a pipe thread on both sides ( see the balck pipe on the other hose), but perhaps I could use AN fittings and some braided line for this instead?

Any other thoughts to make this an easier assembly?

View attachment 357020

Not sure if it is appropriate but nylog blue definetly does a superior job of sealing. I use it for air lines but it is specificly made of
A/C

So I recently got a hydraulic shaper and I'm trying to get it back to tip top shape. I noticed it is taking a bit to build up pressure, so I pulled the side off and noticed it is leaking quite a bit at the angle coming out of the block here(top left):View attachment 357019

This required quite a bit of careful disassembly to get out, but I eventually did. It says cat40 on the side of these pipes.

Getting this back together is likely going to be a bear, so I was hoping someone could give some advice. The biggest problem is that I have to install the "near" 90 alone, overtighten it (so there is clearance to tighten the straight/other 90), then "loosen" the 1st 90 to get the pipes lined up right.

I presume this is why it was leaking as much as it was at that junction.

So I guess my questions are:
1: is there a trick to doing this? Is there some expanding, slow drying goop you put on the pipe threads that wouldn't let it leak?

2: could I be better to replace them with a different type of fitting? Perhaps a flexible hose of some sort? I have a pipe thread on both sides ( see the balck pipe on the other hose), but perhaps I could use AN fittings and some braided line for this instead?

Any other thoughts to make this an easier assembly?

View attachment 357020

I use Nyloq blue for air lines in my shop. It is designed for A/C but definitely seals well. https://smile.amazon.com/Refrigerat...ning+sealant+pipe&qid=1614282269&sr=8-11&th=1 .

 

[aliva]

Never ever use Teflon tape on hydraulics. Pieces to tape can dislodge and get into the valves , and small passages. You then have a real problem removing it. Always use a paste type thread sealant, Loctite 567 come to mind. The fitting type with an O ring is called a Boss fitting. The threads are usually straight not tapered, so it wont seal. The sealing comes from the O ring that is snugged down with a backing nut. This type of fitting requires spot facing of the female port, otherwise it will not seal. The advantage of this fitting is that you can point the fitting in any direction, then tighten the O ring down to seal. From the pictures you posted you have NPT threads. I would clean all the male threads, check for cracks in the threads or body. You may want to replace the short nipple with a new one. Be sure its for hydraulics, regular black pipe nipples can split open on high pressure. Check the ends of the JIC fittings to be sure there are no nicks as this will cause leakage. Take all the fittings apart, clean, and apply sealant. Here's a pic of a Boss fitting Also check the flare on the hydraulic tube. If its deformed or cracked it'll have to be replaced.

 

[ErichKeane]

So... It went bad today. To start, the reason I started leak hunting (and found some mild leaks) was because the machine wasn't building pressure enough, and tended to get stuck easily.

I followed the suggestion here and used the permatex. I got it reassembled quickly enough, and spent about 90 minutes on another project, then fired it up. Unfortunately one of my connections were leaking like a bandit, and the couple of existing leaks I had just washed away the pipe sealer.

Additionally I noticed another leak that I probably caused while disturbing things.

So I said, Erich, why are you bothering going through that small hole, only a bit more work and you can get that massive side panel off and work with plenty of room!

How wrong I was... Seemingly EVERYTHING is attached to it, and the casting is way larger than I thought.

So, I took a half step forward and 20 back:

 

[ErichKeane]

Oh, the biggest fly in the ointment? 3 of the bolts that held that plate on broke/were broken. One looks like I can vice grip it out, but the other two are below the surface :/

 

[Nutfarmer]

Forget the Teflon tape. Use an anaerobic pipe sealant . The one in my tool box is FasSeal ATS from federal process. Lock tite also makes a good one. If it will hold hydraulic fitting from leaking on a shaker it should work on a shaper. One note it will set up like locktite and my take heat to take apart.

 

[FOMOGO]

I use them in conjunction, seems to work well for me, especially if your running out of thread due to tapper. Those jamb nuts are usually used in conjunction with a machined recess and o-ring. Mike

use Teflon paste for hydraulic fittings not tape. there is also a nut with a rubber seal that you can use with on the male pipe fitting to help seal it. I don't remember what they are called

 

[whitmore]

Oh, the biggest fly in the ointment? 3 of the bolts that held that plate on broke/were broken. One looks like I can vice grip it out, but the other two are below the surface :/

Then it's a good thing you have both the plate off and the innards disassembled; a right-hand drill
applied from the inside is likely to spin the bolt fragments right out.

Just thought of something: if a pipe sealant was applied originally, the parts won't seat right
until/unless you use a NPT tap to clean the threads (remove the old broken sealant).

 

[ErichKeane]

Then it's a good thing you have both the plate off and the innards disassembled; a right-hand drill
applied from the inside is likely to spin the bolt fragments right out.

Just thought of something: if a pipe sealant was applied originally, the parts won't seat right
until/unless you use a NPT tap to clean the threads (remove the old broken sealant).

Huh, interesting! I'd not thought of that (the pipe sealant). I THINK it was all teflon tape, I peeled a lot of it out of each thread. That said, I now have plenty of access :/