I Wonder Why My Wheel Seal Blew?

I did a brake job on the drive axles of an old truck on spokes many years ago and was shocked to find the two nuts literally jammed against each other with no lock ring. I don’t know how they ever got that accomplished but they did and shockingly it worked. It didn’t leave that way though I wasn’t feeling that lucky lol

 

MD Alignment has a tool, and this may be it. I'll argue with MPG and ride claims, but I agree 100% with tire wear.

There really hasn't been a good way to measure pre load, only end play.

In my experience, tighter is better than looser (we're talking minute increments between the two) when it comes to tire wear.

All adjustment procedures out there (besides preload measurement) leave bearings too loose IMO. Resulting in increased tire wear and premature tire failures, mainly inside duals.

 

Tighten inner nut tight , take all the freeplay out , back off , tighten a little over hand tight, lock it down with lock washer and jam nut , has worked for well over 100 years. Don't over think it.

 

Just a satisfied customer and not getting paid for posting this stuff. If you don't believe what I've posted, I really don't care. You do you.

I'm a problem solver, and when I run up on a solution that makes mechanical sense and has a positive financial case, I'll buy in when I can and report the results where it might matter to someone. This time it's worked out as I expected. Sometimes these sorts of things don't, but I don't think it's always a problem with the solution. Precisely set preload is just one of many possible defects to cure, but I think it's one that gets overlooked most often. Who actually performs the repair also matters a lot. Like just about everyone, I've had mixed results hiring these jobs out, usually negative.

What sold me on this system is multiple reports about how the bearing manufacturer procedures have such a wide range of results, and to my eye (and experience) a greater than 50% chance of having preload too loose when completed by the book that nearly no shop technicians even use in the first place. Loose preload starts with funky tire wear and vibration, and ends with a seal failure or worse. @ProfessionalNoticer brings this up having seen it for himself using a dial indicator. The Dr Preload tool is the only one I've found that directly preloads the bearings. Everything else is a torquing process with an estimated outcome that is supposed to be checked with a dial indicator and nobody ever does. If that "range of ok" is acceptable to you, then there nothing I'm gonna post about Dr Preload that's going to change your mind.

Truth be told, there's been a few posts here and there where others have had Dr Preload done at a shop and didn't notice a difference. I can only speak to my two trailers at this point, and have no comment with others' experience not knowing them, their equipment, or the quality of the completed work. All you can do is look at as many accounts as you can and go with what the majority seem to be reporting, of course excluding obviously identical wording or other signs of fabricated feedback.

 

Completely honest though, that's not something you can really tell a difference in over a period of hours, days, even months, unless adjustment was severely out.

You notice it when you run 5 or 6 years without a wheel seal leak or bearing failure. You notice when you get 325k on drives instead of 250k. 200k on steers instead of 125k

 

For somebody that does wheel seals everyday they can probably do things by hand and get it in spec without a dial indicator. Still doesn't seem right not checking to be sure though.

For somebody changing one once every few years, dial indicators are real cheap at Harbor Freight.

Everybody does their own thing but it's best to follow exact procedure torqing, backing off, re-tighten and then check your work. No worries then. Last time I did mine they were on the money .001 and they felt perfect imo driving down the highway.

Technically if you didn't swap in new bearing races you don't have to torque it down all the way to that initial 200 ft lbs or whatever it is. That's just to ensure newly installed races are fully seated.

 

Zero endplay. The standard is "light preload" which is a hair past zero endplay. They don't say it, but my feeling is that bearing manufacturers go with the endplay standard they have, since once you reach zero, endplay obviously cannot be used to estimate preload, and a tiny bit loose is better than too tight. Also worth consideration, the bearing/hub companies only need to outlive their warranty and never have to buy tires. So not exactly any financial obligation to make them perfect. I think the only way to measure this without an actual press device would be a dial torque wrench to measure turning effort. Of course bearing condition, dirt contamination, etc would all affect the accuracy of this. This graphic is taken from their material and illustrates the comparison of the various methods. I embedded a link if you want to read the entire article.

Interestingly, this topic first got my attention 5-6 years ago from an article on the Microblue website. They've since discontinued their truck products and I cannot find the article anywhere. The gist had to do with endplay and loading. If memory serves, a device was set up to simulate a loaded axle then measure deflection at various points. Maybe someone that's a bigger nerd than me saved it and will share it. I'm not promoting Microblue, just pointing out an interesting publication they once had. I did try a set of their bearings on my previous truck. The results were inconclusive because the installer did not follow directions, and probably again when I took it back the second time. At that stage, any expected benefits had been erased by waiting on the shop to do it wrong twice. My conclusion was their advertised gains were more a product of new bearings and races, versus the actual coating on them. One of those innovations I tried that did not pan out.

On the 8 trailer hubs I used Dr Preload on, I did not think to bring a dial torque wrench to measure turning effort. If I had to take a wild guess, the completed hubs took about 5-10 ft-lbs or so effort to rotate them (in the air, wheels and drums off). Less scientifically: snug without feeling tight. All 8 felt exactly the same when completed. These are factory Hendrickson 5 year hubs using synthetic semi-fluid grease. I hand packed the bearings and filled according to the Hendrickson service docs. For the first week or so afterward, I felt hubs for heat and inspected seals closely at every stop for any issues, and never had any problems.