Replacement Hydraulic Hoses for old backhoe

[jclaudii]

I am contemplating fixing up an old Long 1199A/B Backhoe and one of the things that will need redone are the hydraulic lines, almost all of them! The manual calls for the 90 Degree Elbows at the Cylinders to be 3/4 -16 So I am guessing this is 3/4 inch hose? Most all of the hoses are deteriorated enough to be through to the steel braiding so getting info off of them is almost impossible.

I am also curious on how much of a "safety margin" should there be in the hydraulic lines? Basically, what PSI rating of hose should I purchase? The hydraulics are self contained with a PTO gearbox that pumps 10GPM with a system relief set at 2000psi and the swing circuit set at 2500psi. I'm just guessing that 3000psi replacement hoses would be good, but I am not sure so I am asking for assistance here. There is single wire, Two wire, flex this, etc and I just need some cheap hoses to get going again. I was going to price buying bulk hose and then just taking that to have fittings put on. I have not looked yet to see if the hoe may have reusable fittings on it or not yet.

Any help is appreciated! Thanks!

 

[dfkrug]

I do not know your hoe, but 3/4-16 threads are used on 1/2" ORB (SAE) fittings. 1/2" hose is
plenty big enough for your flow rate. JIC 37 fittings also use that thread, but they can
be readily indentified by the compression end. Do your fittings have O-rings?

A cheaper 3000# hose is fine, one wire or 2, like 100r17.

I suggest ordering them from discounthydraulichose.com a TBN advertiser. I just
ordered a pair from them and two 9.5' hoses were about $70, total, with JIC ends,
shipped.

 

[jclaudii]

Thanks for the reply, I will check beginning of next week for the hose ends as I got tied up playing with a tractor for a bit. The only hose I blew so far was a stabilizer line when I moved it to it's current resting place a few years ago.

I will have to pull the lines and tape the cylinders up so I can measure. The manual for a Long 1199b does not tell info like length of hose or size, just a part number that I can not cross reference anywhere.

 

[Sysop]

I've personally found that taking the old hoses to my local NAPA store and letting them rebuild the lines is the cheapest method around my area. They even beat the online deals...

 

[oldpilgrim]

i got a bunch of hoses and fittings at TSC......cheaper than anywhere else around here.

 

[EddieWalker]

My backhoe 18 years old and some of my hoses are still original, others have been replaced at least once, some twice. In my experience, just about every hose is unique. I would never try to bulk up on hose hoping to have the right size, or try to guess what sized fittings to buy. Just take off the hose and take it to a shop to get a new one made. NAPA does them like mentioned, but they are pricey. I go to a company called Axxion. Best prices and they make the new hose while you wait and get rid of the old one.

Aaxion Incorporated

You never know when a hose is going to fail, or why. If it's not leaking, don't mess with it. Some are a nightmare to remove. Put that off as long as possible!!!

 

[2458n]

I buy my replacement hoses at Rural King cheapest place around here. Hold the taxes for farm use. Take your hose with you and be sure new will work. Some ugly hoes last a long time. As EddieWalker pointed out some of the hoses are hard to remove without removing a couple of other things. Straight forward wrenching.

 

[aircommuter]

That is correct about the threads, and 1/2 hose. Be carefull though you can have -8 fittings or -10 both on number 8 or 1/2 " hose.
The place in Nebraska called Surplus Center has great prices on 2 wire hoses and a tech section to help you verify your fitting sizes. One wire hoses will cause grief on a backhoe because of surge loads. When you hit a rock or swing too fast a stop quickly you may exceed set pressures.

 

[RickB]

-8 fittings are also very often found on 3/8" hose.

 

[dfkrug]

One wire hoses will cause grief on a backhoe because of surge loads. When you hit a rock or
swing too fast a stop quickly you may exceed set pressures.

Your industrial hoes prob have shock-relief valves on all the circuits to protect from that. Even my Bulgarian-made CUT hoe
has them on some of the circuits, including swing and boom. I would get hoses rated at least 500psi more than working
pressure.

 

[aircommuter]

They have releif valves but the pressure goes through hose before it gets to the valve. Not only that the hoses loose strength over time especially on a backhoe where the boom swing works them so much. I have been making my own hoses since 1970 and I found that the 2 wire hoses last longer. Why save a little on 1 wire and change it more often. More down time too. You can get good life with one wire when the hoses are small diameter like #4, or 5 because they automatically have a higher pressure rating due to the smaller internal surface area.

 

[RickB]

Your industrial hoes prob have shock-relief valves on all the circuits to protect from that. Even my Bulgarian-made CUT hoe
has them on some of the circuits, including swing and boom. I would get hoses rated at least 500psi more than working
pressure.

500 psi above system pressure may not be enough to match circuit relief valve settings. Circuit relief is ALWAYS set higher than system pressure and one circuit relief may be different from another on the same valve body.

 

[aircommuter]

Exactly why the 2 wire hose is best, circuit reliefs are set to protect from the geometric leverage that can occur in multiple cylinder equipment like backhoes and knuckle booms.
The shock reliefs are often in the cylinder piston and do not come into play until the end of the travel. If one is setting a heavy concrete box or manhole he would want a hose failure.

 

[jclaudii]

So the -16 is the fitting size?

 

[UniversalHosman]

A couple of notes here from a late arrival: I cannot speak for other hose and fittings suppliers but we generally make our hose assemblies with 2-wire hose. This is because there is no significant savings between 1 and 2 wire and performance with 2 wire is better.

As far as the -16 goes, if you mean the "-16" in the OP's "3/4-16" - this refers to the thread size. While a -16 COULD refer to a fitting size - depending on the context - here it does not. As posted by DFKRUG, the fitting size in this case would be a 1/2" (sometimes called a -8).

Andy

 

[dfkrug]

500 psi above system pressure may not be enough to match circuit relief valve settings. Circuit relief is ALWAYS set higher than system pressure and one circuit relief may be different from another on the same valve body.

If, by "circuit relief", you mean the shock RV setting in a particular work circuit, then I would agree those are
set higher than the backhoe valve inlet RV. But maybe not higher than the system relief.

I said "working pressure" above, and that means any pressure the hoses would experience while working. If you
have a hoe RV set at say, 2500psi, and shock RVs in the 2600-2700psi range, a 3500psi WP rated hose may
be called for, esp if shock RV pressure levels are frequent.

 

[RickB]

If, by "circuit relief", you mean the shock RV setting in a particular work circuit, then I would agree those are
set higher than the backhoe valve inlet RV. But maybe not higher than the system relief.

I said "working pressure" above, and that means any pressure the hoses would experience while working. If you
have a hoe RV set at say, 2500psi, and shock RVs in the 2600-2700psi range, a 3500psi WP rated hose may
be called for, esp if shock RV pressure levels are frequent.

Circuit relief valves on the mobile equipment I am familiar with are ALWAYS set above the system relief. If not, the circuit relief setting will become the default working pressure for that circuit. The rest of your post quoted here is correct, including the semantic departures.

 

[CJONE]

You don't need to figure a safety factor into good quality hose. There is already a 4 to 1 burst factor in the hose. So if the circuit is a 3000psi then 3K hose is plenty. Now with equipment I always use at least 2 wire. If the outer cover gets damaged and the braid rusts on 1 wire it usually fails. With 2 or 4 wire there are remaining wire layers to keep the hose from failing. CJ
Oh and on the reuseable fittings, I only stock a few to get someone out of a bind and will not install them here at the shop anymore. So my advise is not to use them on new hoses, keep them for a emergency. The cost of a new fitting is not worth the headache of putting them back on a hose.

 

[dfkrug]

Circuit relief valves on the mobile equipment I am familiar with are ALWAYS set above the system relief. If not, the circuit relief setting will become the default working pressure for that circuit. The rest of your post quoted here is correct, including the semantic departures.

Semantic departure? From what? I have tried to avoid ambiguity in my terms.

Shock RV settings are going to be higher than the RV setting for the hoe valve. I said that. The "system RV" setting
is not necessarily the same as the implement setting, as detachable implements with their own valves may have
their own RVs. Those RVs are often set lower than the system RV. Industrial tractors with integrated hoes may
not use a separate RV in the hoe valve. I do not know the LONG 1199 unit, which I have stated.

As for choosing hoses with working pressure ratings, I said that I would choose a hose that is 500psi higher-rated
than my WP. I have no problem with using a hose that is rated right at the WP in some circumstances. The safety
factor is significant, as CJONE says. In my case, the WP is in the 2500psi range, and the quality of smaller hoses
with that low WP rating is not good enough for me.

 

[CCWKen]

If you go to a hydraulics/hose shop, they will charge you for the end fittings, the hose and the labor to build it. The last 1" x 5' suction hose I had made locally was $180! The two end fittings alone were $46 each. But they were the swivel type and unless you mess with a bunch of adaptors, pre-made hoses are not available. And I was glad to get it the same day too. You won't get that through mail order.