Leaky Hydraulic Fittings

[PoconoTom]

I have a new B2650 (only 20 hours). However, I currently have 2 leaking hydraulic couplings on the front loader (threaded couplings, not the quick disconnects). I tightened these with an 11/16 wrench, but they are still a little wet with new hydraulic fluid.

Two questions: how much force can be applied to these fittings with a wrench? I have destroyed enough plumbing in my house with over tightening that I am scared to use too much muscle. If tightening doesn't work, should I use pipe tape or joint compound? Can I use the same stuff that I use for plumbing, or are there special products for hydraulics? The Kubota manual doesn't provide any advice. Should I be upset with leaks on a new machine, or is this to be expected?

PoconoTom

 

[GWD]

Leaks should not be happening on a new machine. The warranty should be in effect so call the dealer and have him/her send out a mechanic to tighten it.

Explain that you don't want to void any warranty by trying to fix a warranty issue yourself.

Don't put up with "you'll have to bring it in yourself or pay me to haul it" from the dealer. That is not how it works. Contact Kubota USA if the dealer tries this. Dealers get reimbursed for "house calls".

 

[Stubbyie]

I tend to agree that on a new machine there should be no leaks.

That said, there should be no warranty issue(s) if the owner pulls routine maintenance on any unit.

Question is about tightening the threaded hydraulic fitting.

First, you need the right tools. I can't recommend working on hydraulic fittings with a couple of crescent wrenches. Many do, I have and will again, but you'll find life better with the following:

Note this isn't inexpensive, but you'll have the tools for the rest of your tractor-owning life and you can pass them to your kids or get your money back someday reselling to tool nuts like me.

You need (1) a set of 'hydraulic service' wrenches from one of the major brands. These open-end wrenches have oddly-angled heads, and (2) a set of 'flare nut crow foot' ratchet-type wrenches. Note 'flare nut'-type, not plain open-ended crow feet-type.

These last--the flare nut crows feet--you can fine at Sears for almost reasonable prices.

The only place I've seen 'service' wrenches are NAPA, Proto, Mac, Snap On, Blackhawk, and similar top-shelf brands (in this case you'll find all are made by Danaher for the brands listed, no matter what the sales rep tells you). Try prowling tool resale shops and online sources.

As for the fittings themselves, take completely apart. Clean both male and female clean and dry. Place one drop of oil on your finger and smear on the male fitting. Make up. With the proper wrenches. If you are holding good backup with proper wrench you can really squeeze it down tight.

If you don't use the proper wrenches you will round off fittings and bend tubes or snap off a fitting. Trust me on this. Steep learning curve before I figured it out.

Often I've found getting it as tight as I dared just wasn't enough. Crank and operate after first gyration. If leaks shut down and bleed system pressure by manipulating control valve. Reapply wrenches and bump the fitting 1/8-turn in increments until it quits leaking.

Don't use Teflon tape or any paste thread lube or 'plumbing' sealant on hydraulic fittings. If for some reason you can't stop the leak then do it again and use Loctite hydraulic fitting thread locker anaerobic sealing fluid. Follow directions.

Here's something a lot of wrenchers don't realize: when tightening extremely tight, position the wrench handles so that when pulling, you are pulling wrench handles toward each other. Position the wrench handles just one nut-flat apart and use two hands to pull the wrench handles together. Maximum leverage and maximum control. Repeat. Works great.

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

 

[tthorkil]

I have had good success with LeakLock( http://www.highsidechem.com/leaklock.html) on hydraulic fittings that I could not get to seal properly otherwise.

 

[PoconoTom]

Thanks for the very detailed response. I did stop the leaks by using a little more muscle on the wrench (taking care to back up the opposing fitting). Nothing broke! I am looking into the hydraulic service wrenches - very expensive; maybe they are platinum plated. All of the hydraulic fittings on the B2650 and accessories are 11/16", so I only need this size of wrench, not the whole set. I will see if the NAPA guy will sell one wrench. Also, flare nut wrench set is only about $28 at Sears; I can afford this set.

 

[Stubbyie]

The 'hydraulic service' wrenches are terribly expensive, mostly because they're apparently available only from top-line brand-name companies. I can report from my experiences that if working on hydraulics---especially backhoes with hidden or stacked or manifolded or restricted-access fittings---the service wrenches will pay for themselves. And you can resell them or pass them to the kids, either way getting your money back.

One point I wasn't clear on: you mention flare nut wrenches. Handy to have and I think available singly from Sears catalog. BUT--if you ever replace a line you'll find the same 'size' hydraulic fitting will commonly come in one of three possible nut sizes, depending on manufacturer. There are SAE standards, but commonly ignored as much as followed, especially if an odd fitting size saves a few bucks.

If you drop a hose off at the hose place---use a pro-level hydraulic shop, not local auto parts house to be certain to get the 'correct' diameter / pressure---to get a replacement made you've got a high probability of getting the nut size you don't have the one wrench to fit. Might consider the set of wrenches. HF has a similar set, but fewer wrenches (and the 'chrome' flaked on my HF set, badly cutting my hand).

I've learned to not like auto parts houses pertaining to hoses---they tend to sell what they have, not what you need.

Back to the subject: you need a set of ratchet-driven crow-foot flare-nut wrenches. Last time I looked about $80 at Sears. Sooner or later you'll need to either hold back-up or get onto a fitting that you can't otherwise get to without disassembling a lot more than you desire. A set of these wrenches will save a dozen hours when doing hoses on a backhoe.

Please post back your experiences so we may all learn.