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grease fitting for front wheel bearings? opinions please


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i'm doing my front wheel bearings tomorrow.

i've had this idea for a while about drilling into the spindle and installing a small grease fitting, and i'm thinking about it. i'm going to at least see how small they're available, at the hardware store.

 

i got the idea after i noticed an illustration for the front wheel bearings, that the spacer isn't in contact with the inside of the spindle like the bearings are, so if there was a hole drilled through behind the spacer, the grease would have a way to get through.

 

the only thing that i could see to worry about would be the hole itself causing a spontaneous catastrophic structural failure in the spindle.... opinions?

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This idea has been running around for a long while now. I was going to do it to mine on the last bearing change, but somehow forgot, then wasn't going to take everything apart again to do it. I know there have been several others that have talked about it, but I'm not sure if anyone has actually done it yet.

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well, i looked at my spindles while they were off the car.

 

where the spacer rides inside the spindle is right behind the brake rotor, so there's either not enough room for a grease fitting there, or you'd have to take the brakes off to access it, and what'd be the point?

 

the way to do it would be to drill at an angle from behind the spindle and have the hole come out behind the spacer, effectively on the other side. probably better to drill a smaller hole all the way through and just widen out the top to install a small grease fitting.. the store had some that were about 5mm in diameter.

 

i can't get to my dad's drill press for a few days and i need to get my car finished before then, so i won't be trying this now. but there's a little info anyway.

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I would be worried about weakening the spindle. Would also recommend a drill press to ensure the hole is straight and even.

 

Its a great idea, wish I had some grease nipples for my hubs, but i would probably hit something and break them off, or they would be so covered in dirt and mud i would never be able to use them.

 

 

-Brian

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yeah, i'm not going to try this without a drill press. i will use a wire brush on the drill to clean off all the gunk after i knock the old bearings out. got new bearings and ball joints, and changing both axles. the front end of my car looks like it belongs at the parts yard :D

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Yeah - I have to dissagree junkie - water and other contiminates from the abuse that us off-roaders do to our bearings is going to make them fail prematurely. A good regreasing via a zirk fitting on the hub after every couple runs would help to keep them from running dry and failing prematurely.

 

I don't think that drilling a small hole for a fitting would weaken the hub. If the hole is drilled properly, it shouldn't be a problem.

 

GD

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With the seals on the hub, putting more grease in contaminated grease, would only trab bad grease mixed with good. That and blow the seals out, making the bearings prone to further damage.

 

When i was working at United Rentals, our parts room had a TON of different sized grease nippes, or zirts, or whatever they're called. Im sure if you found one with a pretty small thread insert, you could drill a small hole without jepordizing the hub itself.

 

I think if there was one installed, the best way to re-grease the bearings would be to remove the hub and outter seal, regrease pushing all the old contaminated grease out, and then re-installing new seals.

 

-Brian

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Well - the way I figure your at least diluting the contaminates with more clean grease

 

Also - if the bearings are cared for properly, and the car was designed with bearings that could hold it's weight, they should never fail. The metal never actually touches - the bearings ride on a thin coating of grease - the only way a bearing can wear out is it's it's got too much weight on it (thus sqeezing out all the grease), or if it's running dry, or with contaminated grease. So saying that they shouldn't need regreasing till they fail if properly installed doesn't make sense - if they were properly installed, they should never fail.

 

Of course this isn't a perfect world, and they do indeed fail because of either improper installation, or seal failure, which lets in contaminates, and water (even clean water will ruin the grease), and lets the grease leak out.

 

For these reasons I like the idea of a grease fitting - it would allow you to just replace the seals without having to remove the hub and pound the bearings out of it. Just remove the seals from either side, and pump in new grease till it runs clean from either side - new seals, and put it back together. This way you could prevent failure of the bearings for a long time I think.

 

GD

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Yeah, in that aspect your right. I would love to have a grease insert and re-grease and re-seal the bearings every other month. You would still have to pull the rotor and the CV through the hub to replace both seals... but its definatly less time consuming than pressing (or pounding, depends on how you do it) new bearings into the hub.

 

And i do stand corrected. Properly installed bearings, in the perfect driving conditions should never fail. Just look at the Subaru rear wheel bearings, ive never replaced a single one.

 

-Brian

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The rears do last a long time. I've never replaced a set because of failure that did not result from some other problem. I had a set go bad because the little washer with the tab you bend down had sheared it's key off, and allowed the nut to spin off. (this was a 2WD rear bearing). On the 4WD this is much less likely to happen because of the design of the spindle.

 

GD

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Hey, you could do it Jaguar style. Drill the spindle, like you were talking about. Also drill a hole through the hub, and put the zerk in the hub. pump grease into the hub, and old grease exits through the spindle.

A similar setup exists on M60 tanks, except there are 2 holes in the hub, and none in the spindle. One hole contains the zerk, and the other has a relief valve. It's fun pumping those up with a pneumatic grease gun. You don't know when it's going to pop off, or where the nasty, old grease will fly. I probably have a few of these relief valves sitting around, if you wanna give it a shot.

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I like your idea Andy. It would help those folks who do not have the time, or ambition to "check and repack wheel bearings", as called for on the maintainance schedule.

 

Personally, I think its worth doing this messy job whenever turning or changing the disks, or any other opportune time (ie axles, bearing noise). The recommended once a year/12,000 miles seems a little too frequent to me.

 

If you've ever had a bearing fail (I have), you'll know that a noisy bearing is not something that should be ignored. My argument against installing a grease nipple is that some people might keep pumping grease into a failing bearing, rather than inspecting and replacing it. Then, the bearing might go out fairly unexpectedly.

 

John

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  • 2 years later...
At the moment, i dont believe Subaru bearings need to be re-greased. If properly greased and sealed upon initial install, you should have no reason to regrease until they fail and need to be replaced.

 

-Brian

Yeah, but- Why not be able to shoot in some new grease now and then? I'd rather grease my bearings than replace them. This idea is interesting. I was working on a way to force new grease into the bearings while the axles were out. But this idea is also worth thinking on. One question I have is- What about too much grease? If grease was fully packed into the housing, all around the spacer, ect., would it possibly cause a failer due to higher pressures or something? Some people say 1/3 full of grease. If it is not any problem to be full, then we should be able to pack all the grease we can into the hub (when we got the axles out) and be ok with it. What do you guys think about that?

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This thread is over three years old....:eek:

 

GD

 

Yeah, talk about a blast from the past...

I've done a few more in those three years, and I'm not sure it's possible to "overpack". The problem though, is that topping off worn out grease will not be enough to protect those bearings from wearing down. Same principle as flushing out engine oil in a high milage "burner".

Repacking is reccomended in every service schedule (for Subes) I've ever seen, and I think it's the way to go. If the grease nipple method holds up over time, it might be worth considering. Let us know how it works out.

good luck, John

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Dangerous idea - overpacking the bearing housing with grease will cause overheating, severely reducing the life of the bearings, not to mention spewing grease everywhere through the seals.

 

A good general rule for bearing housings is to fill them about 1/3 with grease. Over 1/2 will generally cause overheating.

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Hey, I remember this. I never got around to doing this :P

 

Wouldn't the extra grease just squirt out of the slot in the cone washer, when you tighten the axle nut?

I guess I'm assuming that it would be best for the greaseable area to be "full." So if you have the axle installed and in the hub, but haven't yet torqued down the axle nut, you could fill the area between the two bearings to capacity and it would eventually circulate through the bearings and the grease would in theory never get below a certain threshod of quality. You always lose some when removing the axleshaft anyway..

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Hey, I remember this. I never got around to doing this :P

 

Wouldn't the extra grease just squirt out of the slot in the cone washer, when you tighten the axle nut?

I guess I'm assuming that it would be best for the greaseable area to be "full." So if you have the axle installed and in the hub, but haven't yet torqued down the axle nut, you could fill the area between the two bearings to capacity and it would eventually circulate through the bearings and the grease would in theory never get below a certain threshod of quality. You always lose some when removing the axleshaft anyway..

 

Depends on the grease to determine overfill, if it is light like whipped cream (valvoline synthetic) I cram it in, as it dissolves to a super viscosity, its as if they put the magic ingredients in the whipped cream just to hold it, the thicker grease, standard, has to be manually shot in a perfect grease fitting targetting the bearing, or putting it on by the bag with grease trick or even by gloved hand. The grease fitting making things weak is a hoax, it is filling its own hole in a grainless cast steel (iron) like a rivet that isn't holding anything, there must be a sweet spot somewhere- the only means for break is already mentioned- heat, dry, or even overpacked with certain grease, and contaminated. My chore as a boy was to get 23 fittings on my dads old rig- I actually overfilled a universal and it cracked on a hot summer day- while full of good grease, overpacking is bad, only with "thick" grease (it is very easy to tell). I have learned the whip cream synthetics are truly phenomanol with just a "dab'll do ya" mentality- my soob "thiefs" it towards the hotter friction, unlike thicker grease that "runs away". I will take photos (I am bored) of a tower spindle out of a EA82 car- maybe derive a conclusion...:)

Love the idea, risking overfill with synthetic is worry free to my own experience, a grease fitting would be welcome.

 

Edit: here is some photos, this is my best guess . I have forgotten exactly where the race is for bearing, but somehere in this thinner areas seems a spot could be made...

 

greasefitting2ui2.jpg

 

here is front

 

greasefitting1bu2.jpg

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