hooking up new backhoe to tractor

[zake1000]

Hi. I am trying to hook up a Woods backhoe bh70-x to an L2800 with an L463 Kubota loader (big learning experience), and I have a couple of questions:
The bolts that are used to hold the sub frame section permanently to the backhoe, indicate that they need to be torqued to 420 lbs-ft. I have a torque wrench, but it only goes to 250 lbs-ft. Can I get away with hand tightening as hard as i can, and check every few days and re tightening if needed? Or is it crucial to achieve that much torque?
This may be a dumb question, but here it goes anyways. The instructions for the initial attachment of the backhoe, have a few warnings about hydraulic fluids and skin penetration. The instructions indicate to connect the hydraulics together, including attaching new fittings to the existing connections. Do i need to worry about connecting the fittings/hoses to connections/lines that are under pressure? I need to attach fittings to the existing block and attach hoses to those fittings. How do I know if a line/fitting has hydraulic pressure on it?
Thank you

 

[koja]

Start with the fel on ground , shut the tractor off . Move all hydraulic controls a couple of times. Go grab a cup of coffee and you should be good to go . The pressure should be relieved. Just work slow and carefully . Follow the directions that came with the hoe and use a good quality sealant on the threaded fittings .

 

[koja]

Oh , almost forgot. For the torque use a two foot breaker bar and get as tight as you can and recheck every so often .

 

[zake1000]

Hi, thank you for the reply. I take it that using the Teflon tape that is used for pipes is not a good idea? I Also have joint seal #6 (black thick paste). It says threaded & flanged joint sealant & gasketing cement.
Would either of those work? Or should i look for something different? The instructions just say used thread sealant on all pipe threads, but not what to use.
Thank you

 

[koja]

Hi, thank you for the reply. I take it that using the Teflon tape that is used for pipes is not a good idea? I Also have joint seal #6 (black thick paste). It says threaded & flanged joint sealant & gasketing cement.
Would either of those work? Or should i look for something different? The instructions just say used thread sealant on all pipe threads, but not what to use.
Thank you

You're welcome Either would work fine . Just be careful not to get too close to the beginning of the threads. You don't want any of the tape or sealer to get into the hydraulics .

 

[D2Cat]

My advise would be to NOT use sealant TAPE on hyd. connections. You get some of that tape loose and hung up (exp. in your hyd. pump) you have a bunch of problems. Just avoid the chance.

Get you some teflon in a tube.

 

[Ezlife45]

The torque values are there for a reason. It's possible a 2' breaker bar won't quite cut it.

Sure you may be able to skirt by with just checking the torque but check your local auto parts stores. See if they can rent you a torque multiplier. It's basically a planetary gear system. It will have an arm that must be grounded and then your torque wrench will work fine. The torque setting on your wrench will vary with the multiplication factor.

 

[Stubbyie]

The warnings about exposing skin or body parts to pressurized hydraulic fluid are meant to be taken into consideration WHEN and IF you have a leak and you're looking for escaping hydraulc fluid under pressure.

If you were to run your hand along a pressurized line or hose and a leak were present the pressure could cause the pressurized hydraulic fluid to penetrate the skin and cause a fluid embolism.

Shut the engine off and move all your controls around repeatedly until all motion or action stops and all fluid ceases to flow: you have now depressurized the system and it is safe to work on.

There is no danger to you when working on DEpressurized hydraulic lines. Exception: before breaking a hydraulic line make certain that whatever that hydraulic fluid supports is itself somehow supported and / or set solidly on the ground.

Even though the system is 'off' and depressurized the way a hydraulic system works is that some fluid 'trapped' may still be supporting some cylinder or part of the machine. Take care, think, and proceed cautiously. Most of it is being careful and excercising common mechancal sense.

Regarding lubrication of hydraulic connections. Long time ago I was taught by a master-level guy to clean both ends completely, place ONE drop of hydraulic oil on the male fitting, smear with a finger, and then make up fitting tightly. Worked for me for years. Nowadays, you can use an anaerobic "hydraulic"-type thread locker but personally I'd save that to use if you can't otherwise stop a drip-leak at a fitting.

Do NOT use teflon tape or paste or solids-containing (Kopr-Kote, which I otherwise highly recommend), or plumber's paste on hydraulc fittings.

I think you'll find life easier if you invest in a set of flare-nut crow-foot wrenches and if you are serious a set of quality angle-head 'hydraulic service' wrenches. Try not to use pliers or crescent-type adjustable or pipe wrenches as you'll tend to wreck the fitting.

An aside: embolisms. Working in high pressure environment once in a universe far away and fellow worker wearing gloves ran his hand down a line and caught a leak from a flange, penetrating his glove, into this hand, and had a huge gas bubble form under his skin resulting in reduction of blood flow and light blood poisoning, almost lost his hand. I bet now you can probably Google up plenty of examples. Seeing it firsthand (oh!) convinced me forever.

Please post back and advise your continuing experiences so we may all learn.

 

[zake1000]

Hi. Thank you for the helpful info. Finally getting some time to work on this and we may get snow. Great.
I moved the bucket lever around and let it sit for a couple of days. When i move it around now it makes a squishy sound. Is it OK to work on it?
Also, I have called every rental, car parts stores around andi get the same story. ... We only have up to 250 lbs-ft, which is what i already have. No luck anywhere. I did figure out that if I can get a 12" horizontal extension to the head of the torque wrench, I only have to torque bolt to 233 lbs-ft. Any ideas on if that kind of extension is even available ?
Thank you

 

[MagKarl]

Don't be scared of the hydraulics. Once the tractor is shut down and you've moved the valves and nothing happens, you are fine. Once running, respect the tool, keep you body out of pinch points, don't lean on the controls hooking stuff up, etc. Be confident and safe and you will be fine.

I'd clean the fasteners and holes well with a degreaser like carb or brake cleaner then use blue Loctite when you bolt it up. Blue is pretty resistant to vibration but still easy to break loose by hand if you need to. Red is the next step but can require some heat to break loose.

420 fl*lbs is huge, just get it as tight as you can with a cheater pipe and you should be fine. 420lbs on a 1 foot long lever, 210lbs on a 2 foot long lever, 105lbs on a 4 foot lever, etc.

 

[gpreuss]

Harbor Freight has a 1/2" drive air driven impact wrench for $100, that they say develops up to 700 ft-lbs of torque - they also have 3/4 and 1" drive, with awesome torque. I'd use it as long as it is a nut/bolt combination. I'd hesitate if it is going into a casting...

 

[Tooljunkie]

All you need is 1 lb pressure on a 420 foot long bar. That being impractical, a four foot bar with about the same force as tightening a wheel nut and you will be close. My air impact will pound a bolt to 450 given enough time. Dont add anything to your torque wrench handle to to use it as a power bar. It will destroy it or lose calibration. Be cautious,i had a gear head in my torque wrench fail at just over 200... Was a good jolt.

 

[85Hokie]

You're welcome Either would work fine . Just be careful not to get too close to the beginning of the threads. You don't want any of the tape or sealer to get into the hydraulics .

teflon TAPE should never be used in this situation, and if used - never wrap the first thread, always allow one thread of clear metal. D2Cat explained why tape should not be used in that situation.

 

[Daren Todd]

Thats a good call on the torque wrench. I had mine pop internally and wow. Felt that one from the hand to the shoulder blade. 420 ft/lbs seems a little much if your going into cast. Nut and bolt combo is good as previously stated. I've seen bolts stripped out in cast with a cordless impact that generated around 250 ft/lbs of torque.
Unless you have a 1/2" air line and a really good supply of air, i wouldn't spend the money on the 3/4 or 1" impacts. you'll find they don't generate the butt off a 3/8 air line. Not enough air flow. Coworkers ingersol rand has more butt then the shops 1" impact, and my snapon composite makes the 1" look like a pansy i have the harbor freight model at the house that states they will do 700 ft/lbs of torque. It's actually about 400 ft/lbs breaking torque and about 300 tightening.

 

[zake1000]

Thank you again for the good info. It is basically two metal plates one has a welded nut on the back side (on the backhoe itself) and the other (part of the subframe) has a hole for the bolt to fit through that screws into the welded nut.
I have an 18" breaker bar. Using that with blue loctite and a 2 foot pipe (not cast) on the breaker bar, would that be OK?
Thank you

 

[ShaunRH]

Hydraulics should never need tape or dope for true hydraulic fittings, they mate at angled surfaces to handle the pressures. At flat surfaces they usually have O-Rings and seals.

If you are using standard NPT pipe threads for some joints, you will need dope or tape, dope is easier if you make sure NONE of it gets into the internal pipe structures, only apply to male side of a pipe thread. Tape, use gas or hydraulic rated tape, standard stuff is too weak.

 

[Stubbyie]

Zake1000:

I'm going to try to answer your question and don't wish to sound overly instructional in the process. That said...

You seem tentative. Can't say I wouldn't be if I hadn't accomplished something like this previoulsy. 400+ foot-pounds of torque is a lot.

Personally, I admire you for trying to get the installation 'right'. When I tighten my loader brackets once a year or so I hang a breaker bar on each 1-in Grade-8 bolt and use a 4-ft cheater and with my 200+ lbs step on it once then move to the next one.

Torque when using a torque wrench is measured as length in feet times the pounds applied at the end of the wrench handle, or (Ft-Lbs) read as foot times pounds.

You mention an 18-in breaker bar and a 2-ft cheater pipe. Think of it this way: swallow the pipe all the way up on the breaker bar handle. Now you've gained 6-inches and now you have a handle 2-ft long. On the end of that 2-ft handle you need a 'weight' of 210-lbs------this would be 210-lbs times 2-ft = 420-ft-lbs. If you weigh 210-lbs, stand with one foot on the end of the 2-ft long (total length of pipe on handle) cheater. You have just applied 420-ft-lbs of torque to the fastener.

You can jiggle the numbers to suit your situtation: lengthen (or shorten) the 'handle' using the cheater to "match" the length needed to use your weight to furnish the torque force. Or be patient and eat more pie. I'd go for the pie if the tractor could 'wait'.

Torque values are important but in this application aren't critical. Critical might be if reassembling a cylinder head and making sure it's pulled down tightly consistently over its entire mating surface.

There is one other aspect of 'measuring' torque. Make certain the force (number of pounds) being applied is actually being applied perpendicular to the wrench hung on the fastener.

In your case of standing on the 2-ft cheater, all you have to do is make sure the wrench handle (your 2-ft total lengh handle using the cheater) is parallel to the Earth: make the handle 'flat' to the Earth. Doesn't have to be perfect, just close. Move the socket around on the fastener head until the cheater handle is pretty close to being 'flat level' and parallel to the Earth's surface. This is really simpler than trying to explain it.

Here's why the 'flat' handle is important: if you hang the handle on the fastener say sticking up at 45-degrees you introduce an error based on trigonometry and actually obtain less force (lbs) pushing down. The closer you get to zero-degrees (flat level) the closer you get to a 'correct' torque value. Just step on the 'flat level' 2-ft long wrench handle using your 210-lbs and you'll be fine.

As you can see, if the fastener is vertical and the wrench is being pulled through a horizonal arc, you'll be unable to stand on it so well. That's where a torque wrench comes in. In such a case---just to prove the concept of torque---if you can rig a snatch block where a non-stretchy cable runs from the very end of the horizontal wrench handle, over the sheave, to a foot stirrup...you stand in the stirrup and the wrench still 'sees' itself having a force (weight) of 210-lbs applied, you still get the desired torque value. The only thing to remember doing this is to keep the 'flat level' thing in mind: make the cable connects to the 2-ft long wrench at a 90-degree 'flat level' square right angle and it works like it's supposed to.

If you use Blue LocTite work fairly quickly. Once you start making up the threads once the LocTite is sealed from air it starts to gel up.

Please post back your continuing experiences so we may all learn.