Grease Cap Troubles

[SoonerFan]

I have a single axle Trailstar trailer with TDE disc brake hubs. A few weeks ago, just after I got off a 80 mile run down the interstate, I look in my rear view mirror and see the plastic lug nut cover on my left wheel flopping, just hanging on by the retainer screw. Upon inspection, I see that the grease cap is gone. Fortunately, there is a pretty good boat dealer in the small town I was passing through. They had the same type grease cap...the kind with the rubber cover over the zerk. They loan me a mallet and I go out and attempt to bang it on. I couldn't make the dang thing go on so I go back in and confirm that it's the right size. The parts guy confirms that there's really only one size so it should fit. A young fellow that worked there offered to help and brought out a 2X4 and squared the cap up on the hub and used the 2X4 to get a good square blow with the hammer and it went on. All was well and I went on. I did recall that when I re-packed my bearings back in February, the cap did go on rather easily, so I just chalked the incident up to a worn part.

Yesterday, I'm out in the garage and I see blue grease dripping out of the lug nut cover on the wheel. Remove the cover and sure enough, the grease cap looks like it's trying to work itself off. There was a good 1/16th to 1/8th inch gap between the cap and the hub. This is the new cap that was so tight that I had to get help to get it on. I used the rubber mallet and banged it back tight against the hub but now I'm going to worry about it.

We may have not got it on completely tight in the parking lot at the boat dealer but I also rechecked the lug nut torque when I replace the lug nut cover. I feel like I would have noticed anything amiss with the grease cap at that time. Only one trip to the lake since then.

Any ideas on what's going on there and what to do about it?

[CatFan]

A very common cause of bearing protector caps working loose is loose wheel bearings. There are a few fixes to keep the cap on like using Loctite and putting a dimple in the hub with a punch, but you want to verify your bearings are tight before treating what might be a symptom.

[SoonerFan]

Good tip. I’ll check it out. Thanks

[Bob G.]

A very common cause of bearing protector caps working loose is loose wheel bearings. There are a few fixes to keep the cap on like using Loctite and putting a dimple in the hub with a punch, but you want to verify your bearings are tight before treating what might be a symptom.

This!

For future knowledge, if your cap is not so tight when installing and it is 1.98", try putting it on a 2" hitch ball and bang it a little to make a tighter friction fit on the hub. A little Permatex high temp red RTV helps too.

[SoonerFan]

I'm sure I tend to err on the side of too loose over too tight when doing the bearings. The TDE website recommends :

1. Place hub on spindle in reverse order as listed above. Rotate the hub while
   tightening the spindle nut to approximately 50 ft. lbs. This translates into full hand
   pressure with a 12” long set of pliers or 12” long wrench.
2. Loosen the spindle nut to remove the torque, do not rotate hub.
3. Finger tighten the spindle nut until snug, backing out only to line up the locking
   tang washer.

I don't have a socket that fits the spindle nut so I have to use a large crescent wrench. I have measured the nut and believe it to be 1⅛"...does that sound right? If I had the correct socket I could use my torque wrench.

If I use something like Loctite, won't it be a bear to get off the next time?

How does everyone recommend removing the cap? I've always gradually knocked it off with a rubber mallet while turning the hub. My son-in-law, who is the lead mechanic at a big RV dealership, says that will distort the cap and that it should be removed with two screwdrivers by prying it off.

[Bob G.]

Your procedure for tightening the spindle nut is correct.

The Permatex High Temp Red RTV isn't permanent and can be removed. I remove the cap on my utility trailer and Trailer Buddies on my boat trailer with a dead blow hammer while rotating the hub.

[SoonerFan]

Looks like you guys called it. I jacked it up and just shook the wheel and could tell it was too loose, la trec. I finally bought a 1 ⅛" socket so I could use my torque wrench to perform the tightening procedure without guessing at it. 50 ft.lbs. is a lot more than I was putting on it with a 12" crescent wrench. The wheel now spins freely with no looseness at all.

Funny thing...the grease cap that was so hard to get on just a few weeks ago, just slipped right on today. What would make it shrink? I used Bob's 2" ball trick and also had some red RTV so I used that as well.

Thanks for the help!

[Bob G.]

Glad it worked out for ya.

FYI, I didn't dream up the cap and ball trick, I saw it online somewhere and had to use it after cleaning the rough surface inside the hubs on my utility trailer. I felt like an idiot when I went to install the caps and they were loose.