benpak hydraulic joint sealing

[Raul.P]

Hi

What is your opinion how to seal hydraulic joints. Bendpak has pretaped them but everyone who sell hydraulic components say that tape is not ok and I should use some sort hydraulic locking sealant instead. The problem is with 2 L-shaped fittings that go to the bottom of the hydraulic cylinders. They should be at correct angle to connect the hose but that means that I can not tighten them as much as I would like to because then the angle is not suitable anymore.

 

[RPH]

Loctite for hydraulics, also for pneumatic systems. It’s the purple stuff.

 

[matt_i]

Sometimes that's solved with an SAE hydraulic fitting where the elbow is oriented first and then the o-ring seal pushed into place by what's basically a jam-nut.

In a tapered pipe thread the only choice is to go another turn with a longer lever.

Hopefully most of the other fittings are JIC (swiveling tube nut) which are best balance of low cost, leak-free, and easy to orient, in my opinion.

 

[finn]

Sometimes that's solved with an SAE hydraulic fitting where the elbow is oriented first and then the o-ring seal pushed into place by what's basically a jam-nut.

In a tapered pipe thread the only choice is to go another turn with a longer lever.

Hopefully most of the other fittings are JIC (swiveling tube nut) which are best balance of low cost, leak-free, and easy to orient, in my opinion.

That additional 3/4 turn has some pucker factor in it, but it works.


Usually without incident....sometimes.

 

[Raul.P]

In a tapered pipe thread the only choice is to go another turn with a longer lever.

That additional 3/4 turn has some pucker factor in it, but it works.


Usually without incident....sometimes.

I put some loctite on and turned into the required position. I hope the locktite seals it. This joint should be stright and there would be no problems with tightening.

 

[Raul.P]

I took a picture of that joint. I can turn it with a wrench more than half a turn from this point but then the resistance goes so strong that a wrench just keeps going over the holding edges. I hope the loctite will hold it in this position.

 

[ItsNemo]

Bendpak at their best...*sigh*

The loctite hydraulic sealants are pretty good, I used them on all the fittings on my lift just to be certain they'd stay sealed up.

 

[jtbinvalrico]

....the resistance goes so strong that a wrench just keeps going over the holding edges. I hope the loctite will hold it in this position.

The tapered end of that fitting is different from some others that may be on your lift. The thread diameter is thinner at the bottom and thicker at the top, meaning that resistance is going to increase as it's tightened. There's a point at which the fitting will give and fail if it's overtightened....but that mechanical pressure and resistance is how it's stopped from loosening, and part of how it seals. I believe that tapered fittings generally should not be reused because they deform/stretch as they are tightened (think torque-to-yield bolts meant to not be reused)....that said, some folks reuse both without incident.

The sealant you should use on that tapered thread moreso aids in sealing than it is intended to prevent backing out. Combined with the deforming of the threads and fitting body, you get a good seal. Additionally, the sealant will serve to lubricate the threads as you tighten them to the desired position.

Order some extra elbows (expect tapered on one end and straight on the other) to see if you can clock them where you want using the proper sealant....I just wouldn't count on the sealant overcoming a poor mechanical connection caused by insufficient tightening. The way your hose is oriented won't let it back out, but the sealant won't be able to do it's job unless the fitting is tight.

Sent from my SM-G960U using Tapatalk

 

[Bretny]

You shouldn't need a Hyd sealing compound on any normal hydraulic fittings beside NPT. Even then some female NPT fittings have a male sealing surface in them. But in this case the cyl to 90* long fitting most likely dosnt.

 

[Raul.P]

How hard is to machine a NPT thread ? I would let a metal worker to make me a suitable straight fitting but I am not sure if it is possible to machine with home equipment.

 

[finn]

Bendpak at their best...*sigh*

The loctite hydraulic sealants are pretty good, I used them on all the fittings on my lift just to be certain they'd stay sealed up.

The Bandpak bashing gets kind of tiresome after a while.

A 90 degree NPT elbow will always have this issue. Most homeowners and quasi mechanics don’t have a feel for how tight an NPT fitting can ce turned. If you snug it up and alignment isn’t ok, the alternative is to go another full (almost) round. Hydraulic Loctite or hydraulic thread sealer helps somewhat, and I suppose Bendpack should include fittings with the sealant pre-applied.

The other solution would be to use a 90 degree face seal fitting, but a lift isn’t something subject to a lot of high cutlery vibration. These lifts, and their competition are homeowner devices built to tap that market. A market that wasn’t served in my youth when lifts were affordable only by business or the very wealthy.

This forum itself wouldn’t be viable if all we has were Mohawk lifts, Snapon tools, Saylor Beal compressors, and Hilton cordless to work on our Ferrari’s and Mercedes Benz.

 

[claymont]

I took a picture of that joint. I can turn it with a wrench more than half a turn from this point but then the resistance goes so strong that a wrench just keeps going over the holding edges. I hope the loctite will hold it in this position.

Use a pipe wrench; an eight or six inch should do. They make what's called an 'end pipe wrench' that helps in close quarters. Just look at it as an opportunity to buy a tool or two

Ridgid 31055 8-Inch Heavy-Duty End Pipe Wrench

 

[ItsNemo]

The Bandpak bashing gets kind of tiresome after a while.

A 90 degree NPT elbow will always have this issue. Most homeowners and quasi mechanics don’t have a feel for how tight an NPT fitting can ce turned. If you snug it up and alignment isn’t ok, the alternative is to go another full (almost) round. Hydraulic Loctite or hydraulic thread sealer helps somewhat, and I suppose Bendpack should include fittings with the sealant pre-applied.

The other solution would be to use a 90 degree face seal fitting, but a lift isn’t something subject to a lot of high cutlery vibration. These lifts, and their competition are homeowner devices built to tap that market. A market that wasn’t served in my youth when lifts were affordable only by business or the very wealthy.

This forum itself wouldn’t be viable if all we has were Mohawk lifts, Snapon tools, Saylor Beal compressors, and Hilton cordless to work on our Ferrari’s and Mercedes Benz.

If they didn't design **** to be so awkward it wouldn't matter and I wouldn't "bash". I had problems with line routing on mine too, the design where the lines ran into the hydraulic rams would cause a silly amount of bending right on the fittings (scissor lift).