Dust Cap Woes

[dingbat]

Didn’t read the thread but have run in to this problem a few times over the years

Source of problem:
Too much end play
Excess heat, brakes?
Cotter pin too long
Leaking rear seal
Cap and hub mismatch
Used more than once. - reuse twice tops
Not fully seated - 1.5 or 2” PVC pipe….can’t remember which one

 

[l008com]

Too much end play

Both hubs are freshly re-tightened just right so they spin freely but have zero rattle in them.

Excess heat, brakes?

No trailer brakes, I drove 1 mile on smooth back roads where the fastest I was going would have been 25 to 30 MPH and both sides had partially backed out in that distance. I made sure they were totally flush before I left.

Cotter pin too long

I reused the original cotter pins. They are definitely not rubbing on the inside of the caps. I folded the end down nice and flat.

Leaking rear seal

I believe I replaced both rear seals. Although how would this cause the caps to pop off? Like if they only popped off on the way home, it could be that water was getting in and heating up and pushing the cap off. But on the first drive all year, for the caps to pop off in one dry mile of driving, that doesn't seem to add up. Also I know I replaced the rear seals on one of my trailers and I thought it was this one but now I'm second guessing myself.

Cap and hub mismatch

As in the cap is the wrong size/ too small? That's definitely not the case as they are such a tight fit, I've destroyed several of them because the metal of the cap tore and deformed before it would slide into the hub.

Used more than once. - reuse twice tops

This only happens when they fly off while I'm driving down the road. On several occasions, I've heard it happen at night and was able to pull over and find the caps, and squish them back on.

Not fully seated - 1.5 or 2” PVC pipe….can’t remember which one

Yup the PVC is how I seated them, they are without a doubt, 100% fully seated.

 

[airshot]

Are saying these are just the dust caps ? I was under the inpression these were greasable hubs like a bearing buddy. If the metal dust caps, I don't know, as they get tossed as soon as I get the trailer and replaced with greasable hubs.

 

[flashback]

Take a picture of the hub after you service it. With no hub.

 

[l008com]

I was measuring the I.D. of the hub last night to confirm the size. Theres a lot of perspective here because the camera was so close so it looks like its much less than 2" but its actually right around 2".

Yes there are just simple metal caps, no fittings or anything. They pop right off. I don't suppose theres anything I'm missing about this whole situation that's visible here?

 

[dingbat]

I was measuring the I.D. of the hub last night to confirm the size. Theres a lot of perspective here because the camera was so close so it looks like its much less than 2" but its actually right around 2".

Yes there are just simple metal caps, no fittings or anything. They pop right off. I don't suppose theres anything I'm missing about this whole situation that's visible here?

View attachment 399809

Thermal expansion of the grease will pop them right off. What grease are you using?

Hub doesn’t need to fell warm to over heat (boil) the grease in the races

Have you measured both the caps and the hub

 

[04fxdwgi25]

Sure looks like a bunch of rust in there, ie: water in the hub.

Hint: use a caliper to measure, as a ruler won't get close to a 100's of an inch. Your ruler measurement is meaningless in this situation.

 

[l008com]

The grease I used is some marine grease that is specifically rated for use in trailer axles among other things.

And I'm sure theres water in there now, the cap ejected wednesday night and it rained thursday morning.

And regarding the measurements, I agree using a ruler isn't super accurate, but it's accurate enough. Caps don't come in infinitely many sizes. You get 1.785", 1.986", 2.45", 2.72" and larger. Mine are clearly the 1.98"s which is what I've been using, as labeled on the packaging when I purchase them.

 

[dingbat]

The grease I used is some marine grease that is specifically rated for use in trailer axles among other things.

And I'm sure theres water in there now, the cap ejected wednesday night and it rained thursday morning.

And regarding the measurements, I agree using a ruler isn't super accurate, but it's accurate enough. Caps don't come in infinitely many sizes. You get 1.785", 1.986", 2.45", 2.72" and larger. Mine are clearly the 1.98"s which is what I've been using, as labeled on the packaging when I purchase them.

There is an explanation for everything.......you've just not found it yet

Have you checked the hubs/shaft for run out?
Tire(s) balanced?
Doesn't take much to throw a hub out of balance at speed.

Have you mic'd the hub to make sure the bore isn't worn and or damaged?

 

[cyclops222]

Way over tightened bearings. Only way to expand the bearing hubs enough to allow those caps to drop off so quickly.

 

[airshot]

Way over tightened bearings. Only way to expand the bearing hubs enough to allow those caps to drop off so quickly.

Good possibility...Check hubs after 10 miles or so, should be warm but not hot or uncomfortable to touch

 

[cyclops222]

I had a fantastic uncle. Took a long time to teach me how to change bearings in hubs. And the rear seals on back side of hubs. We had the seal and bearing races PRESSED IN. at a NASCAR building shop. Can I POUND races in ? Of course. Am I as confident as a press ? Never

 

[stevedan]

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...

this is a normal process when installing Dexter vault (submersible wheel hubs), you put Blue Lock-tite around the spring loaded dust cover, unlike bearing buddies, the cap "when installed correctly" will make the inside pressurized, no water can enter.

 

[bruceb58]

I had a fantastic uncle. Took a long time to teach me how to change bearings in hubs. And the rear seals on back side of hubs. We had the seal and bearing races PRESSED IN. at a NASCAR building shop. Can I POUND races in ? Of course. Am I as confident as a press ? Never

I put my races in the freezer before I install. They go in easily...no press needed. I do use a race setting tool though.

Something like this.

https://www.amazon.com/Alltrade-648996-Master-Bearing-Driver/dp/B00266TST0/ref=sxin_17_pa_sp_search_thematic_sspa?content-id=amzn1.sym.5439bf72-3da4-45fb-a22b-ecb711485806%3Aamzn1.sym.5439bf72-3da4-45fb-a22b-ecb711485806&cv_ct_cx=bearing+race+%26+seal+driver+set&dib=eyJ2IjoiMSJ9.XeUSl-r0JqVC86BvOTknziAv7NSsIRIcEs96OrPoaq2Nh_hT0u0RFf1SOeE6CC3DW1GH5SeBHaHSWvWhHNYrzA._yrT3Gq5r5qniWWvmf6eLsVCvOpsZ9jCo7CbAXoqtKU&dib_tag=se&hvadid=234004502057&hvdev=c&hvlocphy=9031153&hvnetw=g&hvqmt=e&hvrand=16709238516572315994&hvtargid=kwd-528379066072&hydadcr=7540_9880937&keywords=bearing+race+%26+seal+driver+set&pd_rd_i=B00266TST0&pd_rd_r=dad56b9f-ea47-4c56-9e19-8af9a74f3ffe&pd_rd_w=McdRH&pd_rd_wg=6EXYc&pf_rd_p=5439bf72-3da4-45fb-a22b-ecb711485806&pf_rd_r=HG33ENGY89AH5V1E9257&qid=1720497691&sbo=RZvfv%2F%2FHxDF%2BO5021pAnSA%3D%3D&sr=1-1-364cf978-ce2a-480a-9bb0-bdb96faa0f61-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9zZWFyY2hfdGhlbWF0aWM&psc=1

 

[Horigan]

I’ve used the old races to get the new ones in.

 

[cyclops222]

How do some of you get the old races out ?

 

[bruceb58]

Use a punch to get them out...don't use old races to install new ones.

I use the tool in my previous post to install. Using the old races is a rookie move and you may actually shatter the old race by striking it with a hammer.

 

[l008com]

So tonight I tack-welded the caps on! It felt like an absurd thing to be doing. HOWEVER when I was done, I went for a 5.5 mile test drive and when I was done, the caps were all still on tight. And I did touch both hubs, they were barely warm.

Remember that last time I went for a boat ride, BOTH caps had partially backed out after just ONE slow mile drive.

ALSO I *know* those welds are awful. All I have is a 20 year old $99 harbor freight welding machine and it's terrible. Some day I'll get a better unit.

Maybe next week I'll go for a boat ride and see how well they hold on. But so far so good.
So to recap, the caps are definitely the right size, the hubs are not overheating, the pins are not scraping on the inside of the caps, the caps fit on the hubs super tight. So I still have no idea why they were backing out in the first place.

In a few years, if I have some more boat money, I'll probably get a whole new axle and hubs. For now, I hope this works for a while.
And yes, I'm going to need to use a dremel if I ever need to remove the caps to tighten the hubs. I'm ok with that.

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[dingbat]

How do some of you get the old races out ?

Wheel bearings are in hack and whack territory. Use anything “softer” than the race itself (~ RC60) to remove them.

I use drift punches (brass if doing precision work) and a #3 ball peen hammer. A urethane handled, flat head screw driver works as well, if not better, when removing small precision bearings.

The kit bruceb58 posted above is a must for quick and easy bearing installation

 

[cyclops222]

Make the dust caps out of plastic. Drill and tap a set screw set up.
Modern greedy business people RUIN the world.
They are suffering with only 300' yachts.