Wheel/Brake/Bearing Question

[Poppy_s_5th_Whe]

Hi All,

I was having some poor braking on our last trip so, after scolding myself for failing to adjust the brakes or lube the bearings since we got the trailer (probably 12,000 miles ago) I decided to adjust the brakes and lube the bearings (I have the E-Z Lube bearings).

I got the trailer jacked and I noticed a lot of play in the wheel. By play I mean that if you have your hands at 12 o'clock and 6 o'clock you can get a considerable amount of wobble out of the wheel. I tried both wheels on the drivers side and they both had play.

I went ahead and lubed the rear wheel first and it took a whole 12.5 oz tube before I got fresh lube coming out. I had hoped that might solve my problem but, of course, no such luck.

I went ahead and adjusted the brakes on both DS wheels but didn't lube the second wheel yet until I find out what my problem is. OR, if it is normal on a trailer to have that much play.

So my questions are
1.) is there normally some play in the wheel on trailers? (I suspect not)
2.) if not, do you think my problem is that I need entirely new bearings? (I suspect so)

I race a corvette and if my wheel has play like that, I need to replace the whole hub assembly as they do not have serviceable bearings.

[Jim_and_Barb]

If they were properly installed and lubricated 12 K is break in miles. You may call me nut`z. I had mine replaced all 4 wheels and had them lubricated with a high grade boat bearing grease. This will keep out all of the water and salt laden snow slush. Oh I did forget to note I also had bearing buddies installed too. This will keep a slight constant positive pressure to keep out the muck when they cool off, and the anti corosion properties in the grease will protect bearings and races.

[diesel_man_03]

Your bearings need adjusting, that's what the nut is for on the hub, being loose does not mean that the bearing is bad.

[Vulcaneer]

Based on the responses here, I would NOT recommend you take your trailer to the dealer for bearing service. It seems there are quite a few that don't know how to adjust wheel bearings. And there are a few that know how to do it right.

The Dexter instructions are correct. As are some others that do similarly.
Rotate tire while tightening the nut to 50 ft lbs. When the tire stops turning, back off the nut and retighten with fingers. Then back off to next slot on nut. Insert cotter pin. If you feel a slight 12:00 and 6:00 O'clock rock. that is what you want.

But Scott G seems to think that all experienced mechanics, trade school instructors, and knowledgeable DIY'ers do it his way, is precisely the reason to not trust that job to some unknown someone else. They might do it that way. A tech at an RV dealer is also risky. Might be trained by one of those Trade School instructors.

Now for the grease in the cavity. Most of that grease does nothing but go for the ride. And it is there so that when you pump some more in, the stuff that is already in there gets squeezed into the bearing and race interface. A big waist of grease. Unless you submerge the hubs in water. Best to hand pack the bearings fully. Saves a whole load of grease. And you know you are getting the grease into the bearing...where it needs the grease to be. And when you clean and inspect the bearings for hand packing, you can inspect them for reliability. Can't do that by simply pumping them with grease.

[cruz-in]

Thanks all...great thread...learned lots...

[MTPockets1]

wilber1 wrote:
I've always used the same practice and never had a bearing problem. I tighten the nut down real snug while spinning the wheel in order to seat the bearings. I then back it off until it is loose, tighten it finger tight then back it off just until it lines up enough to install the cotter pin.

. Perfect.

[wilber1]

I've always used the same practice and never had a bearing problem. I tighten the nut down real snug while spinning the wheel in order to seat the bearings. I then back it off until it is loose, tighten it finger tight then back it off just until it lines up enough to install the cotter pin.

[MTPockets1]

OK.... What is preload?.... Just what it says, a forced load imposed on the bearing. The actual load in lbs. plus the preload in lbs equals the total load on the bearing. As long as that total does not exceed bearing capacity, it's fine. However, calculating how many lbs are being applied with that extra turn of the wrench us near impossible. Preload instructions on automobile is probably to eliminate any wheel looseness and is taken into consideration when selection was made by the engineers. It's common to apply a very measured preload in machine applications such as precision grinding and cutting, to eliminate deflection when the cutting tool contacts the material. These preloads are very precise and done so with shims and/or from the bearing mfg when the bearing is ordered. Also, these bearings are running at much higher speeds and require special lube, much thinner and frequently an oil mist due to that high speed and preload. Trailers do not need a preload and that extra gap allows the lubricant to fill that gap and do its job. The bearing rollers actually do not make contact with the bearing raceways. They ride on a cushion of oil from the grease. Exceeding the bearing rated load (preloading could cause overloading) would cause metal to metal contact and damage the bearing. The same thing can happen if the wrong grease is applied. Too heavy and it won't flow properly into the microscopic gap between roller and raceway. Another item you may be interested in, grease does not lubricate - it's the oil in the grease. Grease is made with a carrier, imagine a sponge, that holds the oil in place. The oil finds its way and does the work.

[fj12ryder]

Tvov wrote:
People keep saying "preload"... I take that means snugging the bearings so there is no play at all? Meaning they are tight?

Which I don't do... as all my trailer maintenance guides say, tighten the castle nut, but then back it off to fit the cotter pin in it. That allows for just a very small amount of "play" when you test the wheels.

That basically is what preload means. Some instances will have a lot of preload, and you set the preload by measuring the amount of torque it takes to turn the shaft.

IME wheel bearings need to have the minimum amount of preload: my Dodge calls for 18 in.lbs. That is basically just over finger tight. Like many applications a little loose is better than a little tight. Wheel bearing directions tend to err on the side of looseness.

[Dave_H_M]

Good post Mr MT.

With that being said, I am gonna keep preloading mine with the 18" metric crescent wrench. :W Why heck ole cooter did this all the time way back when. :S

And to think that some people think that cavity between the bearings came filled with grease. Just think how long some folks run the highways without ever lubing the outer bearing cus they think a little squirt will do both sides.

With all the urban legend associated with RVers, it is no wonder the dealers and shops keep in business.

However i gotta admit, some folks did post good info in this thread.

[Poppy_s_5th_Whe]

Thanks all. The trailer was already scheduled to go in to the shop for a problem with the main slide so I think I will just have them check all 4 wheels and be done with it. We go away for New Years and I won't have an open weekend between now and then to get it done myself.

Paul

[JIMNLIN]

ScottG wrote:

Allworth wrote:
Obviously Scott is smarter than all the Engineers at Dexter put together!

"If" they wrote that (I have the procedure for both dexter and Alko and don't see anything that says bearings should be lose..) then not only am I right but every experienced mechanic, trade school and knowledgeable DIYer is smarter.

Howard, you've got the idea. Even "snug" is not lose ie has play.

Loose is your term.
Dexter nor I nor anyone says they need to be loose and anyone that has any experience of using and replacing wheel bearings on heavy vehicles knows a pre loaded or snug bearing won't last long especially when carrying those heavy loads.

The OP will be wise to follow Dexters recommendations. Every new truck or trailer I put in service I pulled the hubs and check for proper grease and reset the bearings. When your on the road making a living its small things that can make for thousands of miles of event free service.

[shadoow]

MTPockets1 wrote:
I spent my entire career in the bearing business. 40 years; Including teaching proper bearing handling/maintenance. Most bearing failures are the result of poor maintenance that includes overgreasing, improper mounting, and contamination caused by improper installation. Do "not" preload your trailer bearings. Follow the procedure from Dexter as posted above. Preload will cause overheating which leads to premature wear and grease failure which leads to bearing failure. Also, pumping in all that grease just fills the cavity and could blow the seal. That extra grease does nothing but make a mess. If you notice, every instruction tells you to simply pack the bearing well with the proper grade of grease. That's all that is needed to provide thousands of miles of service. The bearing actually purges the excess grease in the first few moments of operation. Boat trailers recommend filling the cavity to help keep water out. When the boat trailer wheels are submersed into the water, the temperature change can pull water into the hub cavity, so the extra grease is there to protect from this water intrusion. Other trailers should never see wheels under water, so all that extra grease is needless. You will never have a bearing problem if the "manufacturers" guidelines are followed. Any other advice can be harmful. I would see this in many maintenance training classes where people would tell me "I've been doing it this way for years (the wrong way)and never had a problem".. It was interesting that those were the customers who spent the most on bearing and machine maintenance. Bottom line - proper amount of grease, new seals, clean hands, clean work area, clean spindle, clean hub, proper running clearance (no preload) = no problems.

good post

[Tvov]

People keep saying "preload"... I take that means snugging the bearings so there is no play at all? Meaning they are tight?

Which I don't do... as all my trailer maintenance guides say, tighten the castle nut, but then back it off to fit the cotter pin in it. That allows for just a very small amount of "play" when you test the wheels.

[MTPockets1]

I spent my entire career in the bearing business. 40 years; Including teaching proper bearing handling/maintenance. Most bearing failures are the result of poor maintenance that includes overgreasing, improper mounting, and contamination caused by improper installation. Do "not" preload your trailer bearings. Follow the procedure from Dexter as posted above. Preload will cause overheating which leads to premature wear and grease failure which leads to bearing failure. Also, pumping in all that grease just fills the cavity and could blow the seal. That extra grease does nothing but make a mess. If you notice, every instruction tells you to simply pack the bearing well with the proper grade of grease. That's all that is needed to provide thousands of miles of service. The bearing actually purges the excess grease in the first few moments of operation. Boat trailers recommend filling the cavity to help keep water out. When the boat trailer wheels are submersed into the water, the temperature change can pull water into the hub cavity, so the extra grease is there to protect from this water intrusion. Other trailers should never see wheels under water, so all that extra grease is needless. You will never have a bearing problem if the "manufacturers" guidelines are followed. Any other advice can be harmful. I would see this in many maintenance training classes where people would tell me "I've been doing it this way for years (the wrong way)and never had a problem".. It was interesting that those were the customers who spent the most on bearing and machine maintenance. Bottom line - proper amount of grease, new seals, clean hands, clean work area, clean spindle, clean hub, proper running clearance (no preload) = no problems.

[ScottG]

Allworth wrote:
Obviously Scott is smarter than all the Engineers at Dexter put together!

"If" they wrote that (I have the procedure for both dexter and Alko and don't see anything that says bearings should be lose..) then not only am I right but every experienced mechanic, trade school and knowledgeable DIYer is smarter.

Howard, you've got the idea. Even "snug" is not lose ie has play.