dust cap keeps falling off the hub

[j.a.g]

My dust caps keep falling off the hub and I have no clue why. The first on fell off the day after I installed it. I went to launch the boat which is about 2miles from my house and when I got home one cap was missing. I went to Napa and bought a new set and this past weekend I towed the boat to a lake about 100 miles from my house and lost one on the way and another one on the way home. I have been using the caps from Napa that have a zerk fitting. Does anyone know why this could be happening?

 

[Bifflefan]

Re: dust cap keeps falling off the hub

Over filling with grease?
Just use regular caps and check the bearing for water intrusion once a year. I never use those bearing buddies or any other type of mumbo jumbo. I check them once a year, every year when I lay up for the winter and fix as needed. I repack the bearings and replace the seals. I have never had a bearing or hub issue using this method, so why change.

 

[gtochris]

Re: dust cap keeps falling off the hub

My dad kept loosing them for a wile, was told he used too much grease and since then, he re-did them with less and they have never fallen off again.

 

[bigdee]

Re: dust cap keeps falling off the hub

My dad kept loosing them for a wile, was told he used too much grease and since then, he re-did them with less and they have never fallen off again.

Hub cavity and dust cap should be filled 30% of volume....never more than that. Rollers should be hand packed full.

 

[ufm82]

Re: dust cap keeps falling off the hub

If you keep losing caps due to expansion of the grease/air in the hub the easiest way to fix it is to take a hammer and tap around the outer edge of the hub itself to "tighten" up the bore. I've seen it before where the cap fit is loose and even when new they fall off. Don't mash the hub, just give it a series of hard taps around the edge on the outside rim of the hub. This will tighten up the fit of the hub bore on the cap. Be careful not to make a flat spot or you may develop a leak. Jack up that wheel, remove the cap and spin the wheel. Tap the hub as it spins. Give it a couple revolutions and check the fit. Do it until you need to tap the hub to seat it. That should prevent them from leaving you again. I've never heard the 30% thing before. My EZ lube hubs were 100% full and if you use buddies they will be as well. (Although the buddies do allow for expansion via their springs.)

 

[j.a.g]

Re: dust cap keeps falling off the hub

I don't think that it is from over fill because I had to put one on on the side of the road and I did not put an grease in it and it still fell off about 50 miles later. I have a reliable sure lube system on my trailer and I gave them a call and they suggested that I put lock tight in the cap before installing them.

 

[sublauxation]

Re: dust cap keeps falling off the hub

I kept losing the dust cap on one of my bearing buddies. I didn't think about it to much until my dad was towing the boat and the bearing buddy came off. Is something somehow out of balance?

 

[bruceb58]

Re: dust cap keeps falling off the hub

Get a punch and put some dimples in the lip of the dust cap from the inside and reinstall. Can do the same for bearing buddies.

 

[j.a.g]

Re: dust cap keeps falling off the hub

I don't think so I repacked the bearings and put on new seals and spun the tires when the trailer was on jack stands and everything seemed normal.

 

[NESAR]

Re: dust cap keeps falling off the hub

I dont have caps. Is that a bad thing?

 

[seaboo]

Re: dust cap keeps falling off the hub

I dont have caps. Is that a bad thing?

YES!!!! Get some.

j.a.g. Been there done that (inside on one of my hubs was "worn) and wouldn't hold a cap, after lightly sanding the lip of the hub (just to rough it up), cleaning the lip, lock tighting (actually I wound up using a small amount of j.b. weld), and dimpling with a punch I managed to get it to stay on (spent a small fourtune in lost hubs till I got it). I noticed on mine if they were driven on TOO hard it fell off easier. Good luck

 

[mklawz]

Re: dust cap keeps falling off the hub

One thing struck me in your original post, the word "NAPA". My Napa brand bearing buddies fell off too a few weeks ago. I since bought Bearing Buddies proper, and so far so good, but I haven't trailed much with them yet.

 

[roscoe]

Re: dust cap keeps falling off the hub

I'm guessing you might have 1.810 diameter hubs, and are trying to keep 1.781 diameter caps in them.

Or you could have 1.968" hubs, and 1.938 caps.

Roll on past NAPA and have the boys walk out to the trailer and measure the hub inside diameter with their digital caliper.

 

[jeeperman]

Re: dust cap keeps falling off the hub

Get a punch and put some dimples in the lip of the dust cap from the inside and reinstall. Can do the same for bearing buddies.

I am thinking you want the dimples on the outside of the dust cap so they will "bite" the inside bore of the hub.

 

[bruceb58]

Re: dust cap keeps falling off the hub

I am thinking you want the dimples on the outside of the dust cap so they will "bite" the inside bore of the hub.

Exactly, that's what I meant. Use the punch from the inside so that the dimples stick outwards.

 

[jeeperman]

Re: dust cap keeps falling off the hub

Exactly, that's what I meant. Use the punch from the inside so that the dimples stick outwards.

I see what your doing now. That works good on the sheet metal, true dust caps.
Aren't some or most of the good bearing buddies and clones made of a heavier machined or diecast housing?
On those I center punch from the outside so that the upset crater rim bites into the hub bore.

 

[bruceb58]

Re: dust cap keeps falling off the hub

On those I center punch from the outside so that the upset crater rim bites into the hub bore.

That makes more sense on the Bearign Buddies.

 

[j.a.g]

Re: dust cap keeps falling off the hub

Well , I tried true bearing buddies and when I got home the other day one of them was almost off of the hub. I am going to go back to a cheaper dust cap and try to tap some dimples into them and put a little lock tight on them and see how that works.

 

[dingbat]

Re: dust cap keeps falling off the hub

Check to make sure your cotter pins are bent back way from the bore as much as possible. Proper orientation of the cotter pin fixes this problem 75% of the time.

 

[j.a.g]

Re: dust cap keeps falling off the hub

I checked the cotter pins and put some lock tight on the caps and that didn't help. I drove to the lake which was about 5 miles from my house and when i got there I checked the hub caps before putting the boat in the water and both of them had started backing out. Next I am going to try and put dimples in the hubs as suggested on here and hopefully that cures the problem. Its weird this never happened before until I replaced the bearings.