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Tight hydraulic fittings

Welder Dave

Senior Member
Joined
Oct 11, 2014
Messages
12,257
Location
Canada
Can hyd. hose fittings become super tight over time? I had to remove the 6 hoses from my backhoe valve that go down the boom and they all needed a snipe to get loose. One almost didn't come loose and started to distort the nut. I've had the hoses off before and put them on snug using the proper size wrench but certainly didn't reef them as tight as possible. What would cause them to be so tight to remove?
 

willie59

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Dec 21, 2008
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Knoxville TN
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Service Manager
If the fitting is out in the open a hammer is your best friend, and I $hit you not. Any fitting, smart whacks of the flats of the fitting nuts, the more flats you can access the better. I'm not talking about beating the hell out of it, just smart whacks on the flats. Does two things, 1) slightly expands the metal of the nut from compressive hammer blows, and 2) disturbs the thread connections, sort of like the difference between a wrench on a nut opposed to an impact gun. Some smart whacks on a fitting nut and I promise you it will come loose with ease.
 

Welder Dave

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Oct 11, 2014
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12,257
Location
Canada
Really hard to smack on a backhoe valve with multiple connections in close quarters and upper and lower fittings. Had to remove the top hoses to be able to get a wrench on the bottom ones. I got them loose but boy they were tight. Never heard of using anti-sieze on JIC hyd. fittings but maybe just a touch would be a good idea?
 

1693TA

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Feb 27, 2010
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Farmington IL
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FAA Radar Engineer, (Retired)
I considered warming them up with a hand held propane torch.

The drawback to using propane is it is slow to warm the metal so both the female, and male threads tend to expand together gaining little. Acetylene, or another fuel gas heats quicker expanding the female threads faster than the male threads making loosening the fitting easier.

I am assuming you have female threads on your hose ends.
 

Cmark

Senior Member
Joined
Jan 2, 2009
Messages
3,176
Location
Australia
Excluding rust, one thing. Overtightening. There's only one thing that boils my p!ss more than a hose fitting that has been reefed on so much that the nipple comes loose when you try to undo it. The recommended torque for a 1/2" JIC fitting is only 40 lb ft. Go easy people.
 

shopguy

Senior Member
Joined
Jul 2, 2011
Messages
502
Location
Alabama
if you Use a open end wrench make sure that it fits the flats really tight or it will ride up the humps and squeeze the nut,I found this out the hard way trying to get by with I had with me at the moment
 

Welder Dave

Senior Member
Joined
Oct 11, 2014
Messages
12,257
Location
Canada
I probably had them a little tighter than 40 ft./lbs. but certainly didn't use a snipe on the wrench like I had to to get them loose. I'll make sure to put them just snug when I put them back on. I also think fittings that have been reused need to be a little tighter to stop any leaks.
 

Welder Dave

Senior Member
Joined
Oct 11, 2014
Messages
12,257
Location
Canada
I'm wondering if there is something that could cause the fittings to become tighter, whether it's temperature changes or just over time they become tighter.
 

funwithfuel

Senior Member
Joined
Mar 7, 2017
Messages
5,519
Location
Will county Illinois
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Mechanic
Like i mentioned earlier, a little corrosion can make things difficult. Aside from that, if the last guy pulled crazy torque and deformed the threads a bit, that'll make things rough.
Now someone mentioned striking the flat with a hammer and punch. I've done that, it has both helped and hurt. I buy the right wrenches cuz, well, I'm a dealer tech and people tend to frown on seeing gouges and dings.
 
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