Wheel Bearing Issues / Disc Brakes

[Harkerr]

Based on my experience, 165 degrees bearing temp seems high.

[Chuck460]

Have you shown your photos to Dexter? I think what you are seeing is called "fretting corrosion". I've see this discoloration on my spindles and the mating bearing surfaces on the three 5th wheels I've pulled over the last 18 years with zero bearing problems. Check with Dexter, but I don't think you have a problem.

Chuck

[babock]

Originally Posted by Harkerr

Based on my experience, 165 degrees bearing temp seems high.

That's not hot at all for disc brakes. If I wet my finger and touch it on a hot disc, it will sizzle every time after a stop.

[jeffnick]

How did the grease look?

[dlambers]

The first thing that comes to mind is overloading. If the bearings are pre-loaded too much each time then that would produce results as you describe.

[saskrick]

Spindle shouldn't have any scratches like that so something is moving there. Like others said its too loose and 165 is not too hot for brake temp but is way too hot for bearing temp. Bearing or hubs you should easily be able to put your hand on them and just be warm, not hot at all (thats what bearings are for). This is just a brain wave and maybe been looked at already. But after changing to disk brakes, could there be something with the brackets or mounts for the caliper not lining up that causes hub to bottom out making it seem like the bearing is tightened properly when it isn't. I'm just throwing that out there, but truthfully it seems unlikely because then inner brake pad would rub pretty hard all the time (unless they are floating disk)

[JohnD10]

Originally Posted by KRedburn

You drove way to long after a bearing change on an axle.

OOPs...20 to 50 miles max then recheck.

I've seen this said here many times.

How is it that when we take our trailers to a shop to get the bearings done there is no "after 50 mile recheck"?

I'm sure they don't pull our RV's around for an hour to do a recheck...

[Mad_River]

I am a Mechanical Engineer, and I used to work for Timken although it has been many years and each application is unique. I see several issues not mentioned or that some have hit on incompletely in the thread. A ball bearing assembly diagram was incorrectly posted too. Ball bearings do not have the radial loading capacity of tapered roller bearings. You have two opposed tapered roller bearings on each spindle. The manual linked below has the proper bearing assembly diagram.

Also some critical information is missing. Was there any metal shavings inside the spindle nut in the vicinity of the bearing or in the bearing grease? Did you or your shop rotate the wheels before disassembly and check endplay? This is to see if resistance was encountered or the bearings were too loose? If so, you may have been in bearing failure (not enough for rotors to fall off, but you could have enough resistance to cause lockup of bearing under heavy load). Bearing lock up causes the inner race to rotate on spindle causing the metal discoloration and metal erosion due to excessive heating of the metal on the bottom of the spindle. If metal is not missing on the spindle you got lucky and caught this early before you lost a wheel on the road.

Here is the Dexter manual link for reference.

http://www.dexteraxle.com/docs/defau...4.pdf?sfvrsn=0

1) It is clear the installer did not follow Dexter installation guidance. It says to torque nut to 50ft/lbs. This is to align the bearing and seat it fully on spindle. Back off to remove torque and then finger tighten to snug and align retainer to flat spot on spindle. In fact it states if the above is too tight (restricts wheel rotation) back off 1/12 turn. The 1/4 turn your installer used is clearly too loose. This increases wear and heating of the bearings due to misalignment with the race under axial loading, which makes lubrication all the more critical which brings me to the lubrication part of this.

2) EZ-lube zerk axles have grease passage between the two bearings that are supposed to be filled with grease by design of the engineers. If you don't fully fill it, this allows the hand packed grease in the bearing to flow out of the bearing into the passage likely starving it of sufficient lubrication. Some lighter weight trailers might get away with this practice. Some on this forum astutely point out that the factory sometimes fails to fill them fully, so you should slowly pump grease in on the zerk until you see flow out visually while rotating the wheel on a new trailer. Many dealers do this for you before delivery. The issue with bearing seal failure and flow into brakes probably occurs due to old solidified grease clogging the passages (due to lack of maintenance or trailer use), pumping it in too fast creating higher pressures (power grease guns), faulty seals, or incorrectly installed seals.

3) Bearings are press fit (interference fit), so your bearings should be hard to press into the rotor/drum. Usually a hydraulic press is required to avoid misalignment, but they can be hammered on carefully. If your bearings were truly too big metal would shave off when pressing them onto the brake rotor. If that occurred you would also have misaligned bearings also accelerating the failure.

4) Dexter specifies consistency NLGI No. 2 and viscosity 80. They also have approved supplies listed in the manual above. If you used one of those suppliers meeting the consistency and viscosity your grease is not at fault.

5) You do not have undersized spindles as some stated since you stated these are OEM. That said, make sure the diameter of the spindle meets minimum specifications especially in the spots where heating discoloration occurred. If the bearing seized under load it would erode the metal.

I am sorry this happened to you. Anyway this was a great thread you started.

[JohnD10]

One thing I've always done is that when I pull the trailer out for a trip I drive it slowly around the neighborhood streets for about 15 minutes (usually 15-20 MPH tops for a couple of miles) just to get the grease flowing around the wheel bearings.

Especially if it has been sitting for awhile.

Nobody ever told me to do this, but it just makes sense to me to do this.

[5picker]

Originally Posted by Mad_River

I am a Mechanical Engineer,

Clip...

EZ-lube zerk axles have grease passage between the two bearings that are supposed to be filled with grease by design of the engineers. If you don't fully fill it, this allows the hand packed grease in the bearing to flow out of the bearing into the passage likely starving it of sufficient lubrication. Some lighter weight trailers might get away with this practice. Some on this forum astutely point out that the factory sometimes fails to fill them fully, so you should slowly pump grease in on the zerk until you see flow out visually while rotating the wheel on a new trailer. Many dealers do this for you before delivery. The issue with bearing seal failure and flow into brakes probably occurs due to old solidified grease clogging the passages (due to lack of maintenance or trailer use), pumping it in too fast creating higher pressures (power grease guns), faulty seals, or incorrectly installed seals.

This is absolutely not true.

Bearings have been hand packed for decades without filling the cavity between the bearings with grease.

If you use the proper grease and sufficiently pack the bearings, the grease will NOT "flow out of the bearing into the passage likely starving it of sufficient lubrication."


Some of the other things you stated are at best, questionable as well.

[SlowrideHD]

Originally Posted by 5picker

This is absolutely not true.

Bearings have been hand packed for decades without filling the cavity between the bearings with grease.

If you use the proper grease and sufficiently pack the bearings, the grease will NOT "flow out of the bearing into the passage likely starving it of sufficient lubrication."

Agree X2

[Mad_River]

The key word is sufficiently. We have no way of knowing. If the guy doing the work is highly experienced you are likely right, but the grease will flow out of the bearings to some extent depending on if sufficient air gaps in the grease exist. The grease is a liquid with high viscosity.

[Bama Rambler]

Originally Posted by Mad_River

2) EZ-lube zerk axles have grease passage between the two bearings that are supposed to be filled with grease by design of the engineers....

5Picker commented on the filling the cavity, but you are also wrong about the passage. It's behind the inner bearing, between the bearing and the seal. When you pump grease into the zerk it has to pass through the inner bearing through the hub cavity and then through the outer bearing where you see it. That's why it's so easy to force grease through the seal.

[Mad_River]

Please look at the cross section in the manual. Grease flows as you say to the seal end, then through the inner bearing, then the cavityand then through the outer bearing. It even gives you arrows of the flow I believe.

[Ratchethead]

My suspicion would be the brakes were being overworked and cooking the grease out of the bearings, back off on the brake bias

[B and B]

Originally Posted by 5picker

This is absolutely not true.

Bearings have been hand packed for decades without filling the cavity between the bearings with grease.

If you use the proper grease and sufficiently pack the bearings, the grease will NOT "flow out of the bearing into the passage likely starving it of sufficient lubrication."


Some of the other things you stated are at best, questionable as well.

What are your qualifications to question Mad River?

[97flhtcui]

Originally Posted by tomherb

Thanks for the replys. I talked to Mor Ryde yesterday to see if others reported problems with the disk brake setup. Brian there said no, he hadn't heard of any other issues but he did mention that they are now using Timken bearings on disk brake conversions. Not sure what grease they used on the install but the repack this time last year was with something the tech called "red and tacky" which I had never heard of.

The trailer only had about 4000 miles on it when the disk brakes were installed and I did not check the original bearings and drum brake hubs when they came off.

I have verified that the bearings used are the ones specified for this application.

The end play on the bearings appeared to be set correctly by the tech by tightening and then backing off a quarter turn before locking down.

I'm wondering if the machine shop that pressed the new Timken racecups into the hubs may not have pressed them all the way in and that created the looseness over time that I am now seeing. Is this possible?

I've attached a few photos of the axle stubs showing the scorching. Unfortunately, I don't have good photos of the bearing but they show equivalent scorching on the insides.

I've got an IR thermometer that I use occasionally at a rest stop. I never remember seeing a hub that was over about 165 and they all seemed consistent.

Still figuring out a solution but I'm thinking that the new bearings will need to be checked again for proper tightness after about a 1000 miles, just like you check lugnuts after about 50 miles when a wheel has been removed.

I saw this post and i feel i need to respond.
In April 2017 i lost another brake adjuster on my 2015 34rl with 7000 lbs axles. I decided to install Kodiak disc brakes when we got to our destination in MN. I bought the kit from etrailer.com and installed them. I bought new NTN bearings made in the U.S.A. instead of using the china bearings that came with the kit. We went to the FROG rally in Aug 2017 then made a appt with morryde in Nov to get the IS suspension installed. We had that installed then drove to AZ for the winter. I always lift the rig with the Level up and check the play in the wheels. I noticed a lot of endplay and one of the bearing caps had fallen off and rattling around in the wheel hub cap. when i pulled that wheel I noticed China stamped on the outer bearing. I pulled the rotors and found china bearings and not my NTN bearings. but they left my NTN races in the hubs that where completely pitted and scoured. The outer bearings where #02475 matched to my 14276 race. Not a good match. the inner bearing was a china bearing 25580 matched to my 25520 NTN race. they were also pitted and scored. My original bearing number for the outer should be 14125A. We were lucky we made it to AZ. I called morryde the next morning and they told me they dont know why my bearings were switched out and told me if i would have gotten the disc brake kit from them they would have put china bearings on but for extra they would put timkens in. they agreed to send me new timken bearings but told me they dont have timken races. they ended up ordering me races too.
The rotors in the brake kits have VCA china races already pressed in and if you want timken bearings they match them to the china races that are already pressed in the rotors. They are not a good match. A good match is timken to timken bearing to race. or china to china. otherwise, If they put Timken bearings in.. did they put in timken races.

[D W]

I'm baffled here. Why all of a sudden is it acceptable to mix and match bearings and races? Never was that way before...

[Allisfan]

Originally Posted by D W

I'm baffled here. Why all of a sudden is it acceptable to mix and match bearings and races? Never was that way before...

Still isn't.... Forest River economics [emoji6]

[97flhtcui]

Originally Posted by D W

I'm baffled here. Why all of a sudden is it acceptable to mix and match bearings and races? Never was that way before...

So am I.
When you buy disc brake kits they come with China bearings with the races already installed. It is very easy to re.ove the races and install new ones if you have the right tools and knowledge on how to do it.