HYDRAULIC LEAKS

If you're serious about eliminating hydraulic leaks,
then the scourge of your hydraulic plumbing is
the tapered thread connection - NPT or BSPT. I'm a big advocate of eliminating tapered threads
from your hydraulic plumbing - but I also understand
that sometimes, what's ideal is not always feasible.

When they can't be 'engineered out', this is
how I deal with them:

First, don't waste your time with thread tape -
I only ever use it when there's no thread sealing
compound available. I've had best success with
Loctite 567 and 577 (my favorite), which are pastes
rather than liquids like some of the others.

If you're re-sealing a joint, thorough cleaning
of the old adaptor and port is essential. If you're
in your workshop, a brush wheel in a bench grinder
does a marvellous job on the threads of the adaptor.
But the female threads in the port aren't so easy.

Once you've removed all remnants of thread tape
or sealant, the next step is to use the
appropriate Loctite cleaner.
Don't skip this step - you'll regret it.

Next, if you're not able to wait the 6 hours
or so for acceptable cure strength, apply the
Activator 7649 and allow it to dry. If you have
the luxury of leaving the joint overnight
before pressurizing it, you can skip this step.

Starting two threads back, apply a bead of paste
around the entire circumference - completely
filling the threads. Do the same with
the female threads in the port. Don't be stingy -
it's better to waste some product than under fill
the threads and have the joint leak.

Now torque the joint. And don't be afraid to
swing on it either. For larger diameter adaptors,
I use a 3/4" drive socket with a long bar.
This part of the instruction is not very scientific,
but hey, there's nothing scientific about taper threads.

For best results, wait as long as possible before
pressurizing the joint - but at least half an hour -
even when using the Activator.

That's all there is to it. But still no guarantees of course.
Which is why it's always better to get rid of 'em if you can.