Forum Discussion

sign_man's avatar
sign_man
Explorer
Apr 18, 2021

Help with zirk fittings

Question: (I hope this makes sense....here goes)
When pumping grease through the wheel zirk fittings, is it fair to say that as long as grease is flowing back out through the front seals that you haven’t pushed any grease out the rear seals and on to the brake drum?
I’m Under the impression that you keep pumping grease until the old grease starts to flow out the front seals and replaces the new grease
  • Huntindog's avatar
    Huntindog
    Explorer
    Apr 19, 2021
    It is actually worse than some have stated.
    Dexter has a video on how this works.... But it only shows part of the story.
    The video shows a hub being greased until a dounut shaped ring of dirty grease exits.... Then they proclaim it finished.

    But wait a minute... That ring of dirty grease was from the outer bearing. The dirty grease from the inner bearing is still in the hub somewhere. Too purge that will require a LOT of pumping and almost a entire tube of grease for each wheel...until a second ring of dirty grease emerges, Everytime you do it.
    Leaving that dirty grease in there would mean that at some point, it will reach the outer bearing, unkown to you.
    Unless you have xray vision, you have no way of knowing just what is going on in there
  • Gdetrailer's avatar
    Gdetrailer
    Explorer III
    Apr 19, 2021
    Sjm9911 wrote:
    Im not a mechanic, but are those closed systems? The zerk fitting isnt. One side is open. I can see in a closed system adding grease or anything for that matter make something give. In an open system the path of least resistance is followed. And i will agree , the people that probably have problems are those that do not do it correctly, or dont use it at all for a long period. The latter could make a blockage with hardened grease, making it a closed system.


    It is both "open" and "closed" system.

    Take a look at the diagram below.



    The axle stub has a long hole bored through the center.

    That bore goes all the way to right before the inside of the grease seal where their is a cross bored hole.

    Grease must be pushed all the way through that bore and cross bore, into the outside of the inner bearing that is against the inner seal.

    Grease then must travel in to the hub cavity, filling the cavity completely before reaching the inside of the outer bearing.

    The grease must be pushed through the outside bearing and the outside of the outer bearing is "open" to atmosphere.

    The grease must travel that long skinny bore then make a hard 90 degree turn into the cross bore, push through not one but two bearings..

    There is going to be resistance the entire route the grease must travel.

    Resistance = pressure build up.

    It is critical that one turns the drum or hub while using this system as that helps reduce the pressure buildup.
  • Sjm9911's avatar
    Sjm9911
    Explorer
    Apr 19, 2021
    Im not a mechanic, but are those closed systems? The zerk fitting isnt. One side is open. I can see in a closed system adding grease or anything for that matter make something give. In an open system the path of least resistance is followed. And i will agree , the people that probably have problems are those that do not do it correctly, or dont use it at all for a long period. The latter could make a blockage with hardened grease, making it a closed system.
  • Gdetrailer's avatar
    Gdetrailer
    Explorer III
    Apr 19, 2021
    Sjm9911 wrote:
    JRscooby wrote:
    Sjm9911 wrote:
    Ok, so i have the ez lube axels or whatever they are called now. I will use them after i finish my break job. I really dont see how a normal hand pumped grease gun will push out the back seal. Hell, i have a hard enough time trying to pry out the rear seal with a hammer to repack them. The new seal is always tight goung in also. I can see if you re use an old seal, or dont put the seal in correctly that you might blow out the rear seal. But under normal operation. I cant see it happening. Now with that said, i would repack by hand every 5 years or so to check the bearings and races and such. But i plan on using the ez lubes for a few years for annual greasing after its set up.


    Do you understand that somebody that does not know what they are doing with a hand pump grease gun can tighten the tracks on a D-6 Cat dozer so tight it will not hardly pull up on a trailer?

    Gdetrailer wrote:


    Which is the "conventional wisdom" that my Dad taught me back when I got my first car and he showed and explained step by step on how to repack the bearings.. Big rule was to not pack the hub center full of grease. Just pack grease around all of the bearing surfaces is sufficient.. Has worked well for me for several million miles of driving across multiple cars and trucks.

    But I get it, not everyone likes to get hands dirty and grabbing a grease gun is very convenient..


    Thank you


    I know nothing of what you speak. Is the cat tracks the same set up as an ez lube axel? If it is i am surprised.


    While my post had nothing to do with "cat tracks", I can see where that is possible to do given the correct parts are put under enough pressure from a grease gun..

    Many folks in the "hit and miss" engine collecting community often resort to using the grease gun method for pushing out badly stuck/frozen/rusted pistons..

    HERE is one mention of that..

    Also have seen folks using same grease gun method to remove stuck brake caliper pistons for rebuilding the calipers..

    HERE

    Using a grease gun to grease wheel bearings are a quick fix for those that do not want to get their hands dirty, but with quick fixes, it comes at some risk.

    Failure to follow the directions from the manufacturer will most likely result in grease bypassing the seal.

    To avoid that you must rotate the wheel while greasing, that means you will need to put a jack under each axle and get it off the ground.

    Grease on a nice warm to hot day, cold grease does not "flow" well and will be stiff.. That will cause pressure to build up higher than when warm.

    Then because grease guns can develop a lot of pressure, you must pull the handle slowly. Hard and fast handle movements are where you develop the high pressure.

    If this is the first time greasing, it may take a lot of grease, the factory does not load them up with grease and it takes a lot of grease to load the center hub chamber.

    When you see grease pushing out the front bearing you can stop, no need to keep pushing.

    Be patient, don't be in a hurry.

    Myself, I have two trailers, one without EZ lube and one with..

    I personally do not care for the ez lube axles, my inspection mechanic loaded them one inspection, now when the mechanic (or myself) pulls a drum we are greeted with a excess of greasy gooey mess to clean up. That grease pulls out in a big long greasy ribbon and leaves globs of grease on the axle stub..

    I would rather pull and inspect my brakes periodically than worry so much about how much grease the bearings have.. Once you grease them the grease does not evaporate or disappear..
  • Huntindog's avatar
    Huntindog
    Explorer
    Apr 19, 2021
    Sjm9911 wrote:
    Ok, so i have the ez lube axels or whatever they are called now. I will use them after i finish my break job. I really dont see how a normal hand pumped grease gun will push out the back seal. Hell, i have a hard enough time trying to pry out the rear seal with a hammer to repack them. The new seal is always tight goung in also. I can see if you re use an old seal, or dont put the seal in correctly that you might blow out the rear seal. But under normal operation. I cant see it happening. Now with that said, i would repack by hand every 5 years or so to check the bearings and races and such. But i plan on using the ez lubes for a few years for annual greasing after its set up.
    I think you are misunderstanding where the grease pushes thru. It does not normally push past the metal part of the seal. It goes past the rubber part. This is a common occurence. The axle manufacturers cover for themselves by stating that a YEARLY diassembly/inspection is requiered.... Definantly not the 5 years you are envisioning... Do you really want to only check your brakes every 5 years?


    Of course if you are pumping grease onto them.... They will never wear out.:E
  • Sjm9911's avatar
    Sjm9911
    Explorer
    Apr 19, 2021
    Oh , and just for arguments sake. Tbh i dont think the zerk fittings are the cats meow, as i said you still need to check the stuff every 5 years or so depending on use. I repacked my stuff 2 years ago, and while I dont do a lot of trips , I usally do 7 or 8 a year, with one ling one from NJ to fl. But most trips are between 3 and 6 hours one way average. My grease was totaly fine. I did not use the ez lube fittings yet, except to test them. I do plan on using them for yearly maintenance. Then inspect every 5 years. So, no need to repack everything every year. At least in my case. The quick connects will do the job or maintaining for every year greasing. If they dont ill let ya know.
  • Sjm9911's avatar
    Sjm9911
    Explorer
    Apr 19, 2021
    Grit dog wrote:
    Sjm9911 wrote:
    Ok, so i have the ez lube axels or whatever they are called now. I will use them after i finish my break job. I really dont see how a normal hand pumped grease gun will push out the back seal. Hell, i have a hard enough time trying to pry out the rear seal with a hammer to repack them. The new seal is always tight goung in also. I can see if you re use an old seal, or dont put the seal in correctly that you might blow out the rear seal. But under normal operation. I cant see it happening. Now with that said, i would repack by hand every 5 years or so to check the bearings and races and such. But i plan on using the ez lubes for a few years for annual greasing after its set up.


    It’s not going to push the seal out of the hub. It can and will push the grease past the lip of the seal though.
    This maybe why the staunch recommendations to not use this, as many don’t understand what’s going on in the hubs.


    This I can see as more likely to happen, but after you do it a few times you should know how much grease it takes to get it right? If you add more then that then it has to be going somewhere else. Its not a closed system, so if its not pushing out the front, then you have to take it apart and look. I think the biggest problem is people dont rotate the wheels when pumping in the grease. So it builds up in one spot.
  • Sjm9911's avatar
    Sjm9911
    Explorer
    Apr 18, 2021
    JRscooby wrote:
    Sjm9911 wrote:
    Ok, so i have the ez lube axels or whatever they are called now. I will use them after i finish my break job. I really dont see how a normal hand pumped grease gun will push out the back seal. Hell, i have a hard enough time trying to pry out the rear seal with a hammer to repack them. The new seal is always tight goung in also. I can see if you re use an old seal, or dont put the seal in correctly that you might blow out the rear seal. But under normal operation. I cant see it happening. Now with that said, i would repack by hand every 5 years or so to check the bearings and races and such. But i plan on using the ez lubes for a few years for annual greasing after its set up.


    Do you understand that somebody that does not know what they are doing with a hand pump grease gun can tighten the tracks on a D-6 Cat dozer so tight it will not hardly pull up on a trailer?

    Gdetrailer wrote:


    Which is the "conventional wisdom" that my Dad taught me back when I got my first car and he showed and explained step by step on how to repack the bearings.. Big rule was to not pack the hub center full of grease. Just pack grease around all of the bearing surfaces is sufficient.. Has worked well for me for several million miles of driving across multiple cars and trucks.

    But I get it, not everyone likes to get hands dirty and grabbing a grease gun is very convenient..


    Thank you


    I know nothing of what you speak. Is the cat tracks the same set up as an ez lube axel? If it is i am surprised.
  • Sjm9911's avatar
    Sjm9911
    Explorer
    Apr 18, 2021
    MFL wrote:
    Brake job?? You mean brake adjustment? If you are actually doing a brake job, with hub disassembled, then I'd hand pack at this time, and not add grease for several years.

    Otherwise, your plan should work to do a complete check every 5 yrs, depending on miles/use. The obvious though, a brake problem, a hot hub after towing, needs to be checked out.

    I have used the EZ lube on 3 different trailers. I did find one seal that was leaking, causing some contamination, while doing a complete inspection. So yes, it happens, but I am not afraid to use the system as designed.

    Jerry


    Ues break job, no need to repact anything as the hubs come with pre greased bearings. Unfortunately they dont make my size brakes anymore and i need to change out all the assemblys. So, new hub , pre greased , new races, bearings, and backer plate with pads magnets allready assembled.
  • joshuajim's avatar
    joshuajim
    Explorer II
    Apr 18, 2021
    FordMastertech wrote:
    Think about this, if the hub is packed full of grease using these EZ lube bearing buddy type axles on drum brakes what is going to happen when the axles hub gets hot, the grease is going to expand and the only place has to go is in the brake drums past the seal and contaminate the brake shoes.


    In addition to this, the excess grease in the hub is useless as the drop point (temperature which semi solid grease liquifies is about 350 degrees). If the grease in your hub is 350 or higher, your bearings are on their way to toast.

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