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

I have used all the chemical and tape thread sealants. I prefer to use one of two things as I mentioned before.
Hardening and locking might seem like a great idea......BUT.......the threads on both sides must be oil free and I prefer something that when I have to change its position or remove it isn't chemically locked in place.
I feel if you are depending on a product to stop a leak you have another problem...damaged threads, not clean enough, previous sealers stuck on threads, not tight enough...whatever.
Pipe thread sealers are only there to stop the slight weeping of the fluid along the threads.
 
sdelivery said:
I have used all the chemical and tape thread sealants. I prefer to use one of two things as I mentioned before.
Hardening and locking might seem like a great idea......BUT.......the threads on both sides must be oil free and I prefer something that when I have to change its position or remove it isn't chemically locked in place.
I feel if you are depending on a product to stop a leak you have another problem...damaged threads, not clean enough, previous sealers stuck on threads, not tight enough...whatever.
Pipe thread sealers are only there to stop the slight weeping of the fluid along the threads.
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Well, getting them oil free is going to be basically impossible unfortunately. There is only so much wiping down I can do, and I can't really do any chemicals without risking getting it into my hydraulic system. There is old thread sealant in each of the threads, but I spent a bit picking it out as I could (and will do more as I can).

I'll say that the threads were TIGHT, but it was still leaking out around that male thread in the 90.
 
Probably dirty or a damaged thread.
There are occasions when you have to run a tap in the hole.
Inspect the fitting as well. Damaged threads will make it feel tight when it is not.
I use brake clean to spot clean threads but this is why I use form a gasket #2, it does not require the threads to be be oil free, which you realize is very difficult.
 
Do you have a hose and fittings store or bobcat dealer near you?

Take your stuff there and let them look it over and give advise.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 
CRC red brake cleaner will clear up any oil . It evaporates and doesn't contaminate the system . As far as hydraulic fittings ( at least the hose crimped fittings ) , I couldn't find any made in the USA 3 years ago . I have a complete crimping set here . The Chinese fittings are darn near a half inch shorter than the USA fittings which doesn't give them much bite . I never trusted them on the presses .
 
I have designed and built many hydraulic systems up to 10,000psi (Most at 2500 psi). Never use Teflon tape. The tape when being installed can fray and can cause pieces to break off and travel through the system. Eventually, these pieces can find there way to critical areas and cause system failures.
Use paste only.
On the threads, make sure that they are in good condition, no burrs or nicks. Clean carefully if you do so as not to reduce their size. Ensure everything is very clean when assembling and then let the dope cure a bit before pressurizing the system.
Don't use any fittings not rated for the pressures and for hydraulic oil.
 
ErichKeane said:
According to the manual, it is 800-1000 PSI!

I think perhaps the Teflon late is the magic goo I was hoping existed.
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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.Dcp00329.jpgDcp00350.jpgDCP00714.JPGDCP00720.JPG
 
projectnut said:
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
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I was thinking afterwards that my Kubota BX tractor does ~2k PSI, so my amazement at 800-1000 PSI was ill-founded :)
 
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