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Discussion Starter · #1 ·
Recently I replaced the inner and outer bearings on the right front wheel of my 81 280ZX.

All was well and good until about 3 days later I started to get a vibration again.. I took the tire back off and noticed that the grease cap had come off, and I surmised that it provided an unbalance that caused the vibration.

Well, with no other ideas, I wrapped some tin foil about the inside of the cap to increase its diameter and give me more of a press fit to keep it from coming off again.

After about 3 weeks it came off again, and I didn't have much off a chance to do anything about it for quite some time, so predictably a couple of months later I was replacing the bearings again..

Well, this time I still didn't have any solution and don't know any trustworthy mechanics in the Annapolis Md. area (I tried contacting the local Z-Car club, but they blew me off for some reason), so for lack of anything sane to do, I just packed paper towels in the rim to push against the grease cap to keep it in place!

Well surprisingly, this worked for about a month and a half, but now the problem is back, and I still don't have any sane ideas.

As far as I can tell, the cap was in perfect condition when I put it back on, so I don't know why a new one would help, and I don't know why it seems that Nissan designed this cap to seemingly just rest in position on a spinning wheel!

My question, then (after this long build-up), is, How do I get a grease cap to stay in place?

Thanks much..

James Meriwether
 

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Discussion Starter · #2 ·
is it possible that the grease cap is interfering with the end of the spindle and not resting right in the rotor hub? if you have a big dent in the top of the cap pound it out. install the cap using a screwdriver or punch to seat the edge of the cap into hub. don't hit the center of the cap with a hammer. i assume the cap fit just fine before you did the bearing job, right?

-casper
 

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Discussion Starter · #3 ·
As for it fitting fine before, yeah, it was on there, and it was good and tight the first time I took it off (it took a good grip and several tries using a rag and my hands).. Once I got it off the first time, it slid on and off quite easily.

I actually think that the grease itself is what's pushing on the cap. Perhaps I use too much, but I was always told to pile plenty bearing grease into that center area. Anyway, it seems that as the wheel spins, the grease gets forced radially outward, and eventually, because it is being pushed radially, it spreads out and creeps axially outward as well, and because the cap slides so easily, the grease just pushed the cap right on out.

As far as I know, the cap is not in contact with the spindle.

Other than just pushing it in (screwdriver on the flanges, or what have you) is there some special trick to get it to seat properly?
 

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Discussion Starter · #4 ·
> As for it fitting fine before, yeah, it was
> on there, and it was good and tight the
> first time I took it off (it took a good
> grip and several tries using a rag and my
> hands).. Once I got it off the first time,
> it slid on and off quite easily.

> I actually think that the grease itself is
> what's pushing on the cap. Perhaps I use too
> much, but I was always told to pile plenty
> bearing grease into that center area.
> Anyway, it seems that as the wheel spins,
> the grease gets forced radially outward, and
> eventually, because it is being pushed
> radially, it spreads out and creeps axially
> outward as well, and because the cap slides
> so easily, the grease just pushed the cap
> right on out.

> As far as I know, the cap is not in contact
> with the spindle.

> Other than just pushing it in (screwdriver
> on the flanges, or what have you) is there
> some special trick to get it to seat
> properly?

the only trick to putting on the cap is to hammer on the outer flange to seat it, not the center. as far as wheel bearing grease goes, here's something most people don't realize. if you load too much grease into the hub when doing bearings, it can create and inbalance problem. as you drive the car the grease will get hot and become a little more thin. when you park the car the grease settles to the bottom of the hub. when you take off with a cold hub, you will have an inbalance. you only need enough grease to generously coat the bearings. any more grease than that just dries out and does nothing. you can skim coat the parts of course, to prevent rust.

-casper
 

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> Recently I replaced the inner and outer
> bearings on the right front wheel of my 81
> 280ZX.

> All was well and good until about 3 days
> later I started to get a vibration again.. I
> took the tire back off and noticed that the
> grease cap had come off, and I surmised that
> it provided an unbalance that caused the
> vibration.

> Well, with no other ideas, I wrapped some
> tin foil about the inside of the cap to
> increase its diameter and give me more of a
> press fit to keep it from coming off again.

> After about 3 weeks it came off again, and I
> didn't have much off a chance to do anything
> about it for quite some time, so predictably
> a couple of months later I was replacing the
> bearings again..

> Well, this time I still didn't have any
> solution and don't know any trustworthy
> mechanics in the Annapolis Md. area (I tried
> contacting the local Z-Car club, but they
> blew me off for some reason), so for lack of
> anything sane to do, I just packed paper
> towels in the rim to push against the grease
> cap to keep it in place!

> Well surprisingly, this worked for about a
> month and a half, but now the problem is
> back, and I still don't have any sane ideas.

> As far as I can tell, the cap was in perfect
> condition when I put it back on, so I don't
> know why a new one would help, and I don't
> know why it seems that Nissan designed this
> cap to seemingly just rest in
> position on a spinning wheel!

> My question, then (after this long
> build-up), is, How do I get a grease
> cap to stay in place?

> Thanks much..

> James Meriwether

Hi James- Chances are the dust cap that you have will never stay on now that it has popped off so many times. I have seen some that looked so beat up that you would think they would never stay on, but they held like a rock. As well, I have seen those that would not stay on. Do yourself a favor and go get a new one from Nissan, make sure you get the o-ring too if your model is suppose to have it. Seat it with a blunt chisel or screw driver on the flanges using a small hammer and you should be fine.

Ken
 

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Discussion Starter · #6 ·
Well, it seems that the consensus is to try a new cap at this point, so I'll do that.
Thanks for the warnings on hammering on the middle, if for no other reason than it gives me a sanity check to let myself know I had been doing it properly.

If you don't see another message from me in the next few weeks, you can safely assume that the new cap worked. :)

Thanks a bunch!

James Meriwether
 

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another use for duct tape...

>remove the wheel, take a strip of one inch wide duct tape, place it over the cap extending over the hub of the rotor, remount your wheel, and it will never come off again...good luck
 
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