Home Forums Hunting & Shooting Hunter's Campfire Hydraulic Fitting Question

My old zero turn has JIC 37 degree steel flare fittings with steel lines. The male flare face has small O rings. One decided to leak, I tightened it a bit with no success. Removed the line, no cracks at flare or anything else visibly wrong. Ordered new O rings and reassembled.

Can't find a torque value for that type fitting.

Just scrunch it down with a swag and see what happens? Its old and hard to find parts for so I hate to fug it up worse than it is.

I'm not sure how to bleed air from that type system other than run it with no load for a bit?

TIA for any help.

I use the snug plus one flat of the nut tightening method. The O ring should be able to seal without a great deal of torque unless the seating area is damaged. If it is scratched or grooved, no amount of tightening will stop a seep leak.

Since the o-ring is doing the seal where the flares go metal to metal and o-ring is compressed to design spec I would wag that your scrunch & swag is correct.

The o ring fitting looks like this on the face.

Yep, thats the ticket.

Tight is tight, too tight is broken off.
If you find too tight, then back off a 1/4 and try again.

I went with the turn it one flat after contact. Plenty tight I think, the steel flare on steel fitting don't have much "give" or "crush" like copper/brass.

Now I gotta figure out how to get the air out. Found some procedures for other machines that use separate pumps and wheel motors with oil reservoirs, they are all slightly different but most involve blocking up the machine and running the pumps/motors forward and backward slowly with the pump bypass on and off for several reps. Can't see the oil at all with this tank design so I won't know if its frothy or not. I'm thinking this system is old and its all still wet not like any new components are in place so don't think I"ll do any damage either way.

Might could pull the spark plugs and turn the system with the starter first?

I don't know my azz from a hole in the ground when it comes to hydraulics. When I was a teenager I helped my dad some with old tractors but don't remember anything about bleeding air after having opened up a system.

Thanks for the replies and any insight on bleeding air out of it.

As far as bleeding goes...don't worry, just run it, air will work itself out eventually, even trapped air at high points will saturate the hyd oil and settle out eventually.
In the future, as leaks develop at fittings, don't worry about torque, just change the o-rings...o-ring is designed to seal by OIL pressure...not mechanical torque. The fitting only need be tightened to prevent loosening up under use and vibration.
Those MAY be 'SAE O-ring Boss'...you can get them at most parts stores that crimp hyd hoses, or buy a small kit from somebody like Grainger. They are a smaller cross section than a standard ARB o-ring.

Thanks

Yep, took me a while to find them. Parker fittings. There were some listed on the evil bezos store that claimed to be BUNA n in the right size, ordered them also. Can't tell any difference but used the ones from Parker.


If I can get this ancient chit running w/o leaking its going down the road if I have to give it away.

Shopping for a new mower with a nice suspension seat. My lower back is a mess and our yard is rough.

when changing "O" rings put a little skiff of silicone or better "O" ring sealant on it.

No, don't do that.

Used a thin film of oil on the rings. Made sure everything was clean.The top fitting at the motor is the culprit. If my back allows I'm gonna fill the tank and try it today.

I hear you on a suspension seat.

My folks could use a new mower for just that reason.

The boys do a lot of their mowing.....not all of it.

No, put Vaseline on to hold the oring in place if needed. You shouldn't need anything, just a clean fitting.

JC, the old seat ain't terrible, I'm adding this hemorrhoid cushion lately .

My f-i-l could be a real adz, but he used a term that made sense.
"Cleverly Tight"!

My neighbor called. He had a water leak he couldn't get to stop leaking.
Steve was one of those "double y chromosome" apes that had no idea just how strong he was! 😖
When I got there, he would thread a 1/2" PVC fitting onto a black iron pipe. Then he would tighten the fitting until the PVC split and the leak started all over.
He used Teflon tape as a sealant, which worked fine, but he thought as long as "he" could turn the fitting easily, it wasn't "tight"!
"Tighten it until it quits leaking Steve. Then stop!"

Excessively "tight" can cut, damage, distort or displace rubber gaskets.
Get the fitting "cleverly tight". Continue tightening in increments and testing until the leak stops.
Apeing down on a fitting isn't always the answer.

I thought the tape or Teflon dope was just a lubricant for npt fittings.

That arrangement looks just like my folks Dixie Chopper.

It's kinda both....especially if you can't properly distort the threads.


Pipe is kind of a bummer....because even when "tight" there is still a pathway for fluid to escape.


You can either distort the threads, or you can use a sealant. Or both!

Looked at Dixie Chopper and Grasshopper when I bought that Bush Hog 26 years ago.

Wish I'd went with one of those instead, the Bush Hog has been OK but they discontinue models quick making it hard to find parts sometimes.

The shaft driven out front deck is nice for getting under bushes and such but its noisy (90 degree gear box) and more maintenance. Makes the machine longer as well, my dad ripped a heat pump off its pad with it first time running it.

Wish he was still around tearing chit up.....