Press-In zerks

[3930dave]

Has anybody seen press-in zerks used at the factory level for drive shaft U joints ?

DRIVE TYPE GREASE FITTINGS, PRESS-IN GREASE FITTINGS, PRESS-IN ZERK FITTINGS, DRIVABLE GREASE FITTINGS

I'm asking because today, when I went to grease the U joint my buddy installed for me 3 months back, well.... there was no zerk there, just a hole. This vehicle does not go off-road, and there is no impact damage, just a clean hole through into the U joint body. I recall the zerk being on the U joint at the time of installation.

Probing the hole with a pick shows just smooth walls, no threads. My guess is that a poorly fitting press-in (or Drive type) zerk was installed at the factory, then got flung off at highway speed.

Didn't know these fittings existed, till today. With the appropriate materials and QC, I can see how a press-in fitting MIGHT work properly, for low pressure applications. I'm afraid I'm seeing just another cost cutting factor that is introducing a point of failure in a critical part.

D.

 

[grnspot110]

Check Tractor Supply or maybe an auto parts house, they shouldn't be hard to find.

 

[JerryK]

The press in zerks are probably used more now days than the tapped kind. One less step in the manufacturing process, and really nothing wrong with them if they are installed correctly. Yours could have a off sized hole, off sized zerk, or not pressed in all the way when it was built. I have some, but I usually tap the hole and use the old style.

 

[3930dave]

Thnx guys.

Now that I know how current production has been "optimized", I think I'll take your approach Jerry, and tap new parts where I can. Can you undo (rotationally) the pressed in type, or do you have to pry/drill 'em out ?

Rgds, D.

 

[Bird]

I've lost a couple of pressed in zerks in the past and only had threaded replacement zerks on hand, so I found the closest size I could, ground part of the threads off on the bench grinder, then went to a set of socket wrenches, selected one that fit over the end of the zerk the grease gun goes on, but not over the base. One sharp rap with a hammer drove the new zerk into place and I never lost one that I had installed that way.

 

[Rileyroo]

They are commonly used on snowmobiles.

 

[3930dave]

Thnx for the field fix report Bird.

My buddy may be able to warranty the part for me..... I'd prefer to go that way if I can - I'm not sure if the zerk took a flyer 2 days ago, or 2.5 months ago, and it's major snow, rain, salt, plague of locusts type of weather around here lately.....

I seem to recall driving along a while ago, and hearing a "thwack" under the car that didn't make sense (no road debris or gravel) - likely was this zerk taking off for parts other than my car !

Sounds like you've lost a few Bird - I don't really like sealed bearings, but I'm beginning to think they may be no worse than ones with these SlapNStick zerks D.

 

[JerryK]

Thnx guys.

Now that I know how current production has been "optimized", I think I'll take your approach Jerry, and tap new parts where I can. Can you undo (rotationally) the pressed in type, or do you have to pry/drill 'em out ?

Rgds, D.

I have never intentionly removed one of the pressed in ones, but I think you could probably yank it out with vise grips and a pry bar of some sort. You would want to pull straight up on it and try not to oblong the hole too much. Also, once you commit to taking it out...you will probably screw it up enough that you will have to.... Good luck...

 

[slowzuki]

I've never managed to meet a press in zerk in 20 years of working on ag equipment and cars. Know about them being out there, who uses them?

Never seen one in the dozens of u-joints I've changed. Sure it wasn't just overtightened and stripped?

 

[Bird]

The ones I've lost and replaced as I described were on riding lawnmowers; i.e., lawn tractors. At least one pulled out when I meant to just pull the grease gun off of it. Others just simply disappeared; were missing when I went to grease them.

 

[Soundguy]

press a new one in then stake it with a pin-prick punch

soundguy

 

[3930dave]

Thnx for the feedback/suggestions guys.

The hole in the U joint body is super smooth. I'd say it was never threaded. I didn't know about these till yesterday, but given my background in electronic hardware (you'll get your throat cut for 0.00000000002 cents), shoulda guessed these press-in ones would be in use nowadays.

Never thought I'd have to safety-wire zerks on ! (Kidding).

D.

 

[beeforty]

Press in zerks are used a lot on aircraft parts where you have have high strength metal that doesn't tap easily with little holes. You can clean out the hole and reinstall with RED loctite to help keep then in, and don't grease right away.

 

[3930dave]

I might have some Red Loctite in the shop, if not, my buddy probably does.... some people don't want that lying around, in case someone doesn't know the difference in colours....

Over time, a few practices have migrated from aerospace applications to elsewhere. Problems set in when base assumptions/competencies are set aside - I'm willing to bet a decent chunk of Canuck bucks (aka CTC money) B40 that what you are calling high strength metal is (several) worlds away from what is used in aftermarket U joints today.

As my old development lab buddy used to say "All I wanted to do...." was grease a U joint ! I grok having to rebuild old stuff, I get ticked off rebuilding NEW parts - this U joint was only installed 3 months ago. D.

 

[zman007007]

I run across these fittings all the time at work. If you measure the I.D. of the hole you can call Napa and get these grease fittings through them. The most common ones we have are 3/16". Thats the size of the sleeve on the grease fittings. They also have the tool for driving them in, they are not pressed in, in field life. They are driven in, with a hammer. The tool is made by K&D,it is expensive though. You can just use a small deep well metric socket as someone else recommended. hope this helps. zman

 

[Soundguy]

i'd loctite AND stake them in..

soundguy

 

[Gary Fowler]

I had one in my ZTR front mower tire that came out and I ended up taping out the hole and putting in a threaded zerk. Didnt have to worry about the shavings on this, just wiped them all out an regreased the hub. A U joint might cause some concerns on the residue.

 

[3930dave]

Thnx guys. D.

 

[fixit]

There are quite a few of them about

If they fall out i like to tap the hole and thread in a real one

but if its not practical to do so then loctite is your friend:thumbsup:

 

[3930dave]

I'd sized the hole in the U joint with the back end of a drill bit.... buddy gave me a new threaded zerk to use, way too big. (Clue).

Went to Princess Auto (HFreight equiv.) to pick up drive-in zerks, scratching my head a bit as the smallest drive type was 3/16". (Another clue). Got yakking with the guy on the hydraulic counter... he floated the idea that the head may have been sheared off, with the barrel still inside. Bingo.

With enough light and magnification today, I could see the old barrel still in the U joint, the fitting had broken off about 1/16" below the edge/face of the U joint body.

I was prepared for a big fight to get this old zerk barrel out, as I really didn't want to drill it. Put my smallest ez out into a tap handle, started spinning CCW with a bit of pressure.... What's going on here ? Slipping ?

I haven't laughed that hard in a long time ! After getting myself spun up (pun intended) about drive type fittings, it turns out this was a threaded fitting on this U joint ! The old barrel very easily just spun right out using that ez out.

Threaded in the zerk my buddy gave me, pumped in some grease, fighting a bit with that gun (around freezing here today). New seals, so not much seepage on the U joint, effectively pressurized with grease - I know this because after I pulled the gun off, a tiny stream of grease started coming back OUT of the zerk. I'd stocked up with threaded fittings too, so swapped that zerk out - I'll fight with this again in 3 months time. The zerk my buddy gave me was brand new, from a sealed plastic bag - under high magnification you could see roughness/small voids in the face where grease could seep back past the ball under pressure.

What I like: U joint is sealed back up, and greased. :thumbsup:

What I hadn't seen, before last week:

Drive type zerks

Totally sheared off zerk, on a U joint yet ! (I don't off road this vehicle, and even if I did, even serious rock crawlers wouldn't find that easy to do, w/o ripping the whole driveshaft off).

Brand new zerk, with the ball in the end, spitting grease back out.

Did the safety ****'s now mandate that due to the alleged risk of grease projectiles, the zerks now have to have pressure releases ? (Kidding.... I think ?).

Lastly (at the risk of answering my own question) other than going to an aerospace supplier, can anyone recommend a quality source of grease fittings - threaded and drive type ? Come to think of it, I will take aerospace recommendations, I don't mind paying a few $$$, the challenge for me would probably be buying less than x hundred piece lots though.

I've picked up a basic 75 piece assorted SAE threaded kit.... I'll see how they work out, if I find too many dead out of the box fittings, I'll just toss 'em.

I have incredible luck, but unfortunately not the lottery ticket variant !

All I want to do...... is grease these U joints a coupla times a year..... Is that asking too much ????

:laughing: D.