Thread Sealant, Grease Fitting

[trlong]

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]

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]

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]

</font><font color="blue" class="small">( 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
)</font>

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

 

[Farwell]

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]

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]

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]

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]

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]

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