6mm grease zerk adapter

johndeerefarmer · Jul 3, 2019

Hi, not sure where to post this so i put it here. I have a grease zerk on my backhoe that won't take grease. I need an adapter to convert the 6mm grease zerk threads to a n 1/8" NPT so I can use my Milwaukee grease gun to force some liquid lubricant into the pin that won't take grease.

I could drill it out and retap it as 1/8" but prefer not to.

Thank

WranglerX · Jul 3, 2019

Why not just replace it with another 6mm zerk....

METRIC GREASE FITTINGS | METRIC ZERK FITTINGS | METRIC GREASE FITTINGS

Generally I find zerk that will not accept grease has a stick/frozen ball.... Generally use some sort of pointy thing to release ball, general will accept grease after tinkering with it....

Dale

oosik · Jul 3, 2019

Yeah - I have a screw driver that's been ground down to a fine point. Poke and loosen the ball. Still - no joy. Remove the zerk - GENTLY heat with a propane torch. Still - no joy. Replace the dam thing.

texasranger556 · Jul 3, 2019

For $6 you can get a metric assortment.

32 Piece Metric Grease Fittings

Edit: Get a lock n lube if you don't already have one. Wish I'd have bought one a long time ago.

johndeerefarmer · Jul 3, 2019

None of you read the post. It's not the zerk that's bad. It's been replaced. The pin won't take grease and I can't get the pin out to clean it.

Big Barn · Jul 3, 2019

One of these would probably work. I’d send one out to you but I don’t have any left.

Or heat up the bushing (with zerk removed) with a torch before trying with the grease gun again.

RickB · Jul 3, 2019

Heat the bushing up good and hot then pump grease into the fitting.

oosik · Jul 3, 2019

OK - my bad. The pin won't take grease. I have one zerk on one of my pivot pins that is a tough customer. I have to rotate the grapple. Then the zerk will take grease on into the pivot pin.

Sportsman762 · Jul 3, 2019

That is not uncommon. The pin probably only has one hole and when you have the grapple in certain positions the hole is under the pressure point preventing grease from flowing.

WranglerX · Jul 3, 2019

Did you remove pin and try to clean grease channel through pin or rotate pin 90 or 180 degrees.... Problem may not be zerk....

Dale

Alan W. · Jul 3, 2019

Like others have said sometimes you have to change the load on the pin for it to take grease by moving the boom.
I have seen the pin get dry enough to spin the bushing in the frame. If this happens and the grease fitting is not in the pin it will never take grease.
If this has happened you can pull the pin and drive a pin punch through the grease fitting hole to make a new channel.
Most bushings are hardened and will punch easy.

Tractor Seabee · Jul 4, 2019

I have never failed at getting pins out, the bigger they are the harder. Used to work on industrial machinery from time to time (scabbing on the millwrights). Takes time, perseverance, heat, a drift punch just a little smaller than the pin, and a big hammer. We made custom pullers to bolt to the pin (after drilling and tapping for a heavy grade 8 bolt) to adding pulling force to the driving force.

Have had to dive out pins twice on my BX to solve the greasing problem. This was early on when all the factory grease was not displaced yet and it had hardened. Solved that by using Moly based grease.

Ron

johndeerefarmer · Jul 4, 2019

The pin will not come out. It's a 1 1/4" pin about 10" long. The bucket on the backhoe swivels on this pin. I bought this backhoe used. The pin has two bolts which pin it to the bucket. When you curl the bucket the pin is supposed to rotate. Both bolts were broke (because the pin is froze) so instead it rotates at the ends where the bucket attaches. I tried replacing the bolts and they broke. I also welded the ends of the pins to the bucket part and the welds broke as well. In other words I was trying to use hydraulic power to break the pin free. I then tried heating the pin and rotating it- no go.. I then cut off and removed the bracket that attaches the bucket to the pin on one side so I would have something to pound against. I spent half an hour heating up the pin but the pin rides in about 6" of bushing which is welded to the boom. There is so much steel there that I could never get the whole thing cherry red. Nevertheless I heated it up and hammered on it with a large sledge. It didn't budge. All this did was mushroom the head of the pin. So I ground off the mushroom, put the cut off piece back on and welded it back together. I have used it twice and have been oiling each end where it is riding on about 1" of pin. It bugs me that it's not right so I want the pin to rotate like it's supposed to.
I did some research and saw where guys were forcing WD 40 or light weight oil into the pin to unclog it, so that's what I want to try now but need some kind of adapter to thread into the 6mm hole and that would let me connect my grease gun hose to that. I would pressurize it and let it set all night.

Thanks

WranglerX · Jul 4, 2019

Sounds to me like you have a metal to metal bond due to the two surfaces rubbing each other and causing a cold friction weld.... All the grease and oil in the world is not going to release it..... BUT I hope you can prove me wrong....

You might look here but I think you are flogging a dead dog.....

https://www.malonespecialtyinc.com/product-category/adapters-bspp-bspt-metric-npt-sae/

IF the zerk is in end of pin I would remove zerk and run wire or drill bit down the shaft to unclog dead grease....

Dale

Big Barn · Jul 4, 2019

DL Meisen said:
Sounds to me like you have a metal to metal bond due to the two surfaces rubbing each other and causing a cold friction weld.... All the grease and oil in the world is not going to release it..... BUT I hope you can prove me wrong....

You might look here but I think you are flogging a dead dog.....

https://www.malonespecialtyinc.com/product-category/adapters-bspp-bspt-metric-npt-sae/

IF the zerk is in end of pin I would remove zerk and run wire or drill bit down the shaft to unclog dead grease....

Dale

Dale may be right. You may have to cut the pin out. An exothermic lance like mine would do that easily.

texasranger556 · Jul 4, 2019

My backhoe was the same way when I got it, a John Deere 48. Same 1-1/4" pin gaulded in place where the bucket pivots. I cut the plate at the end of the Dipper stick out (the one with the hole for the grease fitting) so I could get heat directly onto the outside of the bushing. I welded a large nut to the end of the pin and threaded longer and longer grade 8 bolts into the nut so I would have something solid to beat on with a big sledge. Took several hours over several days heating and beating but eventually I got it out.

If I knew someone with a thermal lance I'd have gone that route.

johndeerefarmer · Jul 4, 2019

texasranger556 said:
My backhoe was the same way when I got it, a John Deere 48. Same 1-1/4" pin gaulded in place where the bucket pivots. I cut the plate at the end of the Dipper stick out (the one with the hole for the grease fitting) so I could get heat directly onto the outside of the bushing. I welded a large nut to the end of the pin and threaded longer and longer grade 8 bolts into the nut so I would have something solid to beat on with a big sledge. Took several hours over several days heating and beating but eventually I got it out.

If I knew someone with a thermal lance I'd have gone that route.

Thanks for the ideas. I cut two access holes in the dipper stick (one on top and one on bottom) but still couldn't get enough heat on it for it to become or stay cherry red.

I also made a hydraulic press out of two 1/2 steel plates, four 3/4" all thread rods and I used my 20 ton air over hydraulic jack. The first attempt one steel plate bent. I straightened it and put stiffeners on the back of both plates. Second attempt the pin didn't move even after wasting lots of oxygen and acetylene.

I guess I will use it like it is for now and keep the ends greased and when it cools back off work on it some more. I probably only use the backhoe attachment 20 hours a year so it should last awhile

Big Barn · Jul 4, 2019

Perhaps I am reading this wrong, but you’re not heating the PIN when trying to press it out are you?

And I doubt 20 tons will push it out. A big sledge while pressure is applied with the jack would help.

Tractor Seabee · Jul 4, 2019

johndeerefarmer said:
The pin will not come out. It's a 1 1/4" pin about 10" long. The bucket on the backhoe swivels on this pin. I bought this backhoe used. The pin has two bolts which pin it to the bucket. When you curl the bucket the pin is supposed to rotate. Both bolts were broke (because the pin is froze) so instead it rotates at the ends where the bucket attaches. I tried replacing the bolts and they broke. I also welded the ends of the pins to the bucket part and the welds broke as well. In other words I was trying to use hydraulic power to break the pin free. I then tried heating the pin and rotating it- no go.. I then cut off and removed the bracket that attaches the bucket to the pin on one side so I would have something to pound against. I spent half an hour heating up the pin but the pin rides in about 6" of bushing which is welded to the boom. There is so much steel there that I could never get the whole thing cherry red. Nevertheless I heated it up and hammered on it with a large sledge. It didn't budge. All this did was mushroom the head of the pin. So I ground off the mushroom, put the cut off piece back on and welded it back together. I have used it twice and have been oiling each end where it is riding on about 1" of pin. It bugs me that it's not right so I want the pin to rotate like it's supposed to.
I did some research and saw where guys were forcing WD 40 or light weight oil into the pin to unclog it, so that's what I want to try now but need some kind of adapter to thread into the 6mm hole and that would let me connect my grease gun hose to that. I would pressurize it and let it set all night.

Thanks

Post some pictures of several views. It might jog a potential solution. You obviously have more that just hardened grease. It doe not take a lot of heat to soften grease. In fact heating to cherry red may compound the problem by burning into a solid. One problem with the hammer is if there is not solid backing against the arm a lot of the energy is lost due to movement of the arm when force is applied. Is there somewhere that you can back the arm up to a solid vertical and brace the arm against that, like a building frame post? Also a vertical swing with a hammer has more shock value than a horizontal swing due to body mechanics. The thermal torch is a great tool but hard to find in a farm/home shop.

With a 10" long contact I doubt you can get any type solvent thru and around much of the pin. There is possible a lot of rust in there if it wasn't used a lot and lubed frequently by the previous owner. Where are you located? We may be able to steer you to someplace that has a thermal torch as that is probably your best option.

Ron