Thread Sealant, Grease Fitting

trlong · Sep 5, 2005

One of the grease fittings (nipples) on the top of my FEL masts is leaking grease back out of the threads. With 376 hours on the JD 4115, I've never had this happen before. I snugged up the nipple as tight as I dare, fearing tightening any further would likely result in stripping the threads, or snapping it off. It is still leaking grease back past the threads when I try to give it a few pumps of grease and no grease is pushing out the ends of the fitting.

I had the FEL and BH off to run the grooming mower. When I put them back on I figured it was a good time to grease and lube while everything was easy to reach. All grease points, except the one, took the grease fine, forcing out old grease and any water in the fitting.

Having not had to use any thread sealant on a grease fitting before, I'm wondering if I should try some thread sealant, such as the blue Loctite (not the red threadlock...can't remember the numbers 271, vs....?) or, if there is a better thread sealant for such a fitting.

I don't know why it would leak back past the threads when it has always taken grease fine. I'm not having to exert much pressure on the hand pump grease gun. The grease just immediately starts flowing back out past the threads /forums/images/graemlins/confused.gif

Tom

RoyJackson · Sep 5, 2005

I'd just replace that zerk fitting. As most of these are aluminum, I'd guess this one may be cracked...just a guess though.
Not a good idea to tighten them too much...aluminum is somewhat soft compared to steel. It's likely you may strip the threads.

trlong · Sep 5, 2005

Roy,

Thanks. I wondered if I should just pull it and go get a new one tomorrow. Probably the best solution. If I remember correctly, they are a tappered thread. If snugging up didn't cure it, you're probably right, some how it must have cracked.

Thanks,

Tom

RoyJackson · Sep 5, 2005

( Roy,

Thanks. I wondered if I should just pull it and go get a new one tomorrow. Probably the best solution. If I remember correctly, they are a tappered thread. If snugging up didn't cure it, you're probably right, some how it must have cracked.

Thanks,

Tom
)

Yep...tapered...it's a pipe thread

Farwell · Sep 5, 2005

Take the old one with you when you go because there are several fitting sizes to pick from as well as metric. I learned the hard way after driving 25 miles one way and bringing home three sizes and none were the right size.
Farwell

trlong · Sep 6, 2005

Farwell, and Roy,

Thanks. Pipe fitting makes sense.

Taking the part with you...yup, I learned the hard way many moons ago. I'll remove the grease nipple and make sure the threads match. With gas prices over the top and diesel unavailable, at the moment here, there's no room for unnecessary trips.

Still seems odd it just failed/cracked,...whatever. I've never had a fitting/nipple fail like that. I've seen plenty rust up or corrode so badly they had to be replaced, wouldn't take grease, ... (especially on cars up here in the winter undercarriage salt storm lattitude). I've just never seen one that took grease in but just spit it back out past the threads. Guess I'd like to take a look at it tomorrow, under a magnifier, just for the heck of it. Life is full of surprises.

Tom

Crutches · Sep 6, 2005

Loc tite, blue, red, green, is used to prevent nuts from backing off of bolts. But, you normally would not use it for a sealant. White automotive pipe dope is what you need. It is oil resistant and should do the trick. It comes liquid or tape. I too would replace the zerk but every time I install a zerk, I use pipe dope and I have never had a leak. We used to do that on all threaded fluid or pressure lines on motorcycles and it works just as well on tractors or automobiles. Keep it dry, good luck.

trlong · Sep 6, 2005

Crutches,

Thanks. I hadn't thought of pipe dope. I may have to try it as the replacement "zerk" (ty, never heard that term) I got from the dealer today is not the correct size/thread. The dealer "tried it" in a "compatible fitting" along with mine, and assured me it was the correct one. Looking at them, I had my doubts...oh well, should have believed my own eyes.

I did look at the failing zerk under a magnifier. There is no apparent damage and, it didn't help cleaning some of the grease out of the joint and tightening as much as seemed reasonable. Just the slightest pressure from the grease gun sends grease back past the threads. I'll try the pipe dope for now but really need to find out why this would just start leaking when none of them have been a problem in the past. I'm praying the mast doesn't have a fine crack at the threading /forums/images/graemlins/shocked.gif.

Tom

awlchu · Sep 6, 2005

use teflon tape, found in a pumbing department. Wrap the tape in the opposite direction with the threads so it will not roll off while tightning the fitting.

trlong · Sep 7, 2005

awlchu,

Yes, thanks for the reminder. I've used a LOT of teflon tape for various fittings. I haven't tried it on a grease fitting before but it does conform well, if given several wraps in the opposite direction of the thread. Just have to cut it REALLY thin to wrap on a short nipple thread, so as not to put strings of it into the grease joint.

Tom

trlong · Sep 7, 2005

Crutches,

Yup, I was thinking of 545, not the 271, etc... However, the Red " 271" is a good threadlock and sealant. I've used it in production for 100 p.s.i. fittings (high pressure medical test equipment). With decent, and clean, thread machining and cured properly, it will lock and seal the threads very well and hold in excess of 110 p.s.i. to medical spec.'s. Ofcourse, I wasn't dealing with grease and for the 271, if you ever want to get the fittings apart you'll have to heat it a bit. Removal of the old 271 is easiest with acetone but Ooops, there goes any paint /forums/images/graemlins/frown.gif

As for what is actually causing the leak, I'm still at a loss. I had to get some work out of the FEL today. So, I just shot more grease into the fitting with the nipple out and snugged the nipple back in. It's got plenty of grease in it anyway. I'll have more time tomorrow to look into it and try to seal the threads.

Tom

trlong · Sep 7, 2005

Roy, and Crutches,

"Zerk", well I learn something new every day. Interesting term. I've always heard grease "nipple". Risking being a "zerk" myself /forums/images/graemlins/smirk.gif, I think I'll stick with "nipple", I like it better and is easier to relate to........OUCH /forums/images/graemlins/shocked.gif...

.........just got a dope slap from my wife! /forums/images/graemlins/frown.gif

Wait 'til she hears all the terms for electrical connectors and wire cutting tools /forums/images/graemlins/grin.gif.

Farwell · Sep 7, 2005

Just a thought, take a zerk or "nipple" from another area of your tractor and give that a try, this way you may be able to see if it is the zerk/nipple or the hole that it is threaded into that is causing the problem. I have had to drill out a couple of zerk fitting holes to the next larger size in some older well used implements. Buy the new fitting before the hole is drilled and tapped. I have an older very well used draw-bar disc that has all of the zerk fittings rusted off and most of the bearings pretty well shot and I have to slap the grease on them hoping that it helps a little or at the very least stops the squeaks. The disc still works like a champ.
Farwell

Soundguy · Sep 7, 2005

( I haven't tried it on a grease fitting before but it does conform well, if given several wraps in the opposite direction of the thread. Just have to cut it REALLY thin to wrap on a short nipple thread, so as not to put strings of it into the grease joint.
)

Ordinarily I try to avoid using teflon tape in areas where 'thread-shedding' might clog a venturi or oil port.. etc.. however in a grease fitting for a bushing.. I'm guessing the tolerances are 'macro' not 'micro'.. and a small shred of teflon probably won't do anything more than act like a lubricant anyway... Just my opinion..

Soundguy

trlong · Sep 7, 2005

Soundguy, and all,

Thanks. I did put some teflon tape on it today and it took care of the leak. I thought the same...the fitting is designed to push out water, dirt, etc...so shredded teflon shouldn't be an issue. Figured it was quickest fix at this point and I have to get a wall finished before the weather turns.

At some point, I'll try to figure out exactly why it was leaking and may have to tap out for a slightly larger fitting..not sure.

Tom

Holzster · Sep 8, 2005

Farwell gave great advice -

I had the same issue on my Kubota FEL - I just bored it to the next higher size and all was OK - I thought that a couple of the threads were missing alowing the grease to come out under pressure.

trlong · Oct 16, 2005

awlchu, Roy, et. al.,

Jus too tie things up, I took the easy way and used the teflon tape. Worked like a charm (with the original zerk since the dealer replacement was not right). So far, no further leaks. Thanks for the help. Hopefully it will hold for now and, as the FEL will be stored for the winter (blower will be on the front end), I'll try to find the correct replacement zerk in the spring and, maybe pipe dope it.

Thanks,

Tom

escavader · Oct 17, 2005

Teflon tape or thread sealant shouldnt be nessasary with a pipe thread ,the further you wind it in the tighter it grips.If you tryed a new fitting and it still leaked, i would suspect,something not right in the deere itself,perhaps the fitting got wacked and screwed up the hole.probably could drill and tap to a bigger size,but if that tape worked i guess i wouldnt mess with it.
ALAN

trlong · Oct 18, 2005

Alan,

Thanks. The "new" fitting was not the correct fitting. There seemed to be no taper to it (the dealer gave me the wrong replacement). The tape was a stop-gap for now and seems to have done the job. Now that the FEL work is pretty well done for the season, I'll try to get the correct replacement, or re-tap and get a slightly larger, proper, fitting. I still don't see anything that should have caused the leak. Guess it's a Winter Project for now.

Tom