Dust Cap Woes

[l008com]

I've been having nothing but trouble with my dust caps the past few years. I've gone through half a dozen of them. Either they refuse to go on and get absolutely destroyed while I try to hammer them on, even when using a PVC pipe like you're supposed to. Or I finally get them on nice and tight, and then I'm driving down the street and they fly off! This has happened on both sides!

Here's the thing. The hubs are probably super old, 40 years I'd guess. But they work great. Aside from this, no problems. I don't want to replace the hubs for this. So is there SOME other solution here? Does anyone make some kind of bolt on cap, that slides on effortlessly and has some kind of bold on head that squeezes it tight so it's not going anywhere? Because otherwise I'm completely out of ideas. I guess I COULD try using 5200 to STICK a new pair on there. But somehow I doubt that would really work either.

 

[dingbat]

Have found four issues that can cause caps to come loose over the years

1. Cotter pins too long. Walks caps right out of the hub

2. Wrong size / out of tolerance aka "cheap" caps

3. Excessive end play in bearings

4. Trying to reuse caps

If worst comes to worst you could always "stake" the caps in place. Three equally spaced "dings" on the inside bore of the hub should suffice

 

[l008com]

Have found four issues that can cause caps to come loose over the years

1. Cotter pins too long. Walks caps right out of the hub

2. Wrong size / out of tolerance aka "cheap" caps

3. Excessive end play in bearings

4. Trying to reuse caps

If worst comes to worst you could always "stake" the caps in place. Three equally spaced "dings" on the inside bore of the hub should suffice

I hear you. However......

1) Pins seem normal, they're not touching the caps at all.

2) They are the right size and I bought multiple packs from different popular brand auto stores around. They all are nearly impossible to install and then shortly thereafter, eject themselves while driving.

3) I rebuilt both hubs, they are essentially PERFECT. Just the right tightness, no play, plenty of grease, fresh seals on both back sides.

4) I've actually had better luck doing that, than using new ones But I've gone through at least 6 brand new ones, maybe more, in the last 2 years.

Staking sounds like trouble. Maybe I ought to consider a pair of small tack welds, that worst case I can dremel off when i need to service them.

 

[Alumarine]

How about a small sheet metal screw between the outside of the hub and the inside lip of the cap?

 

[silverbul]

was having the same problem on one side of my trailer, ended up going with the rubber caps that slip over the hubs a put hose clamps on them for good measure. all good. fyi

 

[airshot]

The inside if your hub is provably worn from age. The ID where the cap grabs should have some small light grooves in there for the cap to grip on. Over time and numerous cap replacements make those tiny grooves wear smooth. If there is anyway you can rough up that lip it may help, also the tool you use to install the caps can make a big difference. It needs to be barely larger in dia to slide over the cap but rest against the lip, then drive them in quickly !! Slow hammering them in makes them more loose. In the past, I have used blue loctite to help hold them on, let it dry for 24 hrs before dunking. If you choose to try that, use sparingly !! Easy to get the cap back off...

 

[topgun3690]

The hubs are probably super old, 40 years I'd guess.

Might be time to upgrade/replace the old hubs....just did mine and they were the originals from 1978....don't regret it at all.

 

[04fxdwgi25]

You can use permatex hardening gasket sealer on them. After it dries, they will stay put.

 

[froggy1150]

Maybe try bearing buddies?

 

[l008com]

Maybe try bearing buddies?

What exactly is a bearing buddy? Are they just dust caps with a grease fitting on top or is there more to them than that? Do they press fit in just like normal caps? Cause with more weight and the same attachment, it seems like they would fall off even easier?

 

[Horigan]

Bearing Buddies maintain a little pressure in the hub to help keep water out, but they will fall off just as easily as your basic caps do. Put a rubber cover and band clamp on them, as suggested above, or get new hubs.

 

[JASinIL2006]

If your dust caps, which don’t weigh very much, are flying off your hubs, I’d be concerned that bearing buddies, which are quite a bit heavier, will be even more prone to flying off unless you can get them to fit perfectly. They also are a bit pricey, so the cost of losing them would be substantially more than losing a dust cap.

 

[brodmann]

Go to the plumbing department at your local home depot and look for a pressure test plug. They have a wing nut that tightens to cause it to expand. They come in sized starting at 1-1/2" and go up to 4". The depth might be an issue, but it's worth checking out. The 1-1/2" is $6.

 

[l008com]

Go to the plumbing department at your local home depot and look for a pressure test plug. They have a wing nut that tightens to cause it to expand. They come in sized starting at 1-1/2" and go up to 4". The depth might be an issue, but it's worth checking out. The 1-1/2" is $6.

I know exactly what you mean, I have a few of those in my basement in a spot where there used to be a bathroom. I don't think they will work though, like you said they have no hollow part so they'd hit the lock nut on the hub and I don't think you'd even be able to install it.

 

[silverbul]

a thousand dollar problem with a thirty dollar fix.

 

[04fxdwgi25]

Let's go about this in logical steps. I am curious, as I have never had a cap fly off a hub on any vehicle or trailer.

Can you take a measurement of the ID of the hub, where cap sits, with a caliper and post what it is. Then post what the OD of the cap is.

Either the hub is out of spec, or the wrong caps are being installed. Perhaps they are Chinesium and off just a tad on the mm-inch conversion. Just because they are sold by big name stores, doesn't mean they are in spec.

Plus, those caps come in a mutitude of sizes.

 

[bruceb58]

Pretty easy to dimple a cap from the inside with a punch. Put 3 or 4 dimples in and it will never come off. If it's a Bearing Buddy...A lttle harder to do but supposedly can be done.

I had this problem once and when I switched to higher quality hubs, problem disappeared.

 

[l008com]

Can you show me what you mean because I don't get exactly where you're saying to punch it?

 

[bruceb58]

Can you show me what you mean because I don't get exactly where you're saying to punch it?

Basically using a center punch from the inside to dimple it so you have a small protrusion looking from the outside.

 

[Horigan]

I would add sealant if you're going to salvage the current caps with dimples.