Anyone have axle issue? (2021 T@B 400)

krsmes

We’ve had our Tab for 3 years now and have put a lot of miles on it with multiple multi month trips per year — probably over 50k. We’re home and doing our regular between trip maintenance, fixes, mods and took a look at our tires. 

The inside of the drivers side trailer tire is worn completely down. Outside edge looks fine/normal wear. 

The passenger side tire has normal even wear. 

I’ve done a bit of searching it seems if I had a weight issue I’d have problems with both tires. We have weighed at one of the CAT scales in the past out of curiosity and we were a couple hundred pounds under the max (with the water tank about 1/3 full) so I don’t think we have a weight issue. 

We’ve had the wheel bearings repacked/replaced several times, most recently this past summer by nuCamp they were doing other service. I’m assuming they would have said something if they noticed a problem with the tires then so I’m guessing this is a problem in the last 6 months. 

Talked to the dealer and they hadn’t heard of any issues. We found a Dexter place local but they were just a parts shop and said any axle warranty issue would have to be dealt with by the trailer manufacture. 

Just curious if anyone else has had this experience and what the outcome was?  Are the axles adjustable/alignable or am I looking at an axle replacement? I’ll post pics when I can get them resized for this forum. 

krsmes

Driver’s side tire:

Passenger side tire (even wear):

tabiphile

That wear does suggest an alignment issue. There are no specific alignment adjustments on these axles so this may be an "it is what it is". Having said that, it is possible that that an improperly set preload on a bearing could allow a hub to track just a bit off and enough to permit this wear. The only thing keeping your wheel in alignment is the axle and how tight the bearing sits on it. I would be inclined to pull that wheel to inspect the axle and bearing. Over-confident mechanics often set the bearing pre-loads by feel and in doing so, can either over or under-tighten that castellated nut. One under turn of that nut can put a lot of extra slop into a wheel. 
Having said that, you do not mention how many miles are on that tire. If that wear occurred in 50,000 miles, call it a day and buy more tires. If it happened within the normal life of a tire, same. If it happened in a short number of miles, then and only then would I be somewhat worried. 

krsmes

tabiphile said:

Having said that, you do not mention how many miles are on that tire. If that wear occurred in 50,000 miles, call it a day and buy more tires. If it happened within the normal life of a tire, same. If it happened in a short number of miles, then and only then would I be somewhat worried. 

Thank you that is helpful. The tires are original and do have ~50k. We’re trying to figure out if the damage was all since nuCamp repacked this past summer. I believe that to be the case because we generally keep an eye on things, and they didn’t say anything about the wear  when we got the work done. We’re going to have someone more auto-mechanically minded take a look at the wheel & bearings (and axle). 

pthomas745

There have been a couple of threads about "axle camber".  Your situation may be only wheel related, as Tabiphile pointed out, but it may be a signal about an axle, too.

https://tab-rv.vanillacommunity.com/discussion/11325/axle-camber-seems-excessive/p1

And, another about unusual tire wear.

https://tab-rv.vanillacommunity.com/discussion/16597/tires-wearing-badly

krsmes

The guy that helped me look at it today found the wheel spindle nut to not even be hand tight, he spun it loose with his fingers. He claimed this to not only be unusual but dangerous. Going to replace the bearings in case they were compromised, get new tires, and see what happens. 

tabiphile

As expected. That was my read on that wear. I do not understand why any mechanic might believe that they have an intuitive feel that gives them the ability to sense and apply torque? A hand tightened spindle nut falls far short of the load that is necessary to properly seat and pre-load a set of wheel bearings. Bearings are produced to tenth of thousandths of an inch (microns) of tolerance to perform properly. Mounting these precision devises intuitively is absurd.
Your tire plainly illustrates a possible consequence. At 50,000 miles the tires owe you nothing so yes, replace the bearings (both wheels) and tires and move on. You are extremely lucky that wheel did not escape and go flying off the axle. It could have. 
It sounds like you are having this service done by someone who knows what they are doing. Presumably they are also checking that spindle for wear and damage as part of the bearing service. With the wheel riding (as it was) cockeyed on the axle, spindle damage is very possible. 

krsmes

—

ScottG

I serviced my bearings a couple years ago, and I recall the Dexter service manual being pretty specific about the process for torquing the spindle nut. I also recall that Dexter's torque specs were notably higher than what I saw in some generic DIY videos. I followed Dexter's instructions, but I think this suggests there are a lot of conflicting protocols out there.  

tabiphile

It's 50 foot pounds to set the bearing. Then, without turning the hub, the nut is carefully backed away to permit the cotter pin to slide into the first available opening in the nut.
There are other higher specs for other axles and bearings, but for this one, 50 is the magic number. 

krsmes

 

Ugh, so confusing.  My axle does have the retainer, not the cotter pin  … so the nut should be finger loose

Mickerly

There should be a gold colored "Spindle Nut Retainer" spring clip to hold the nut in place as depicted on the drawing above.

tabiphile

Castellated nut or nut retainer, the procedure is identical. You torque to 50 foot pounds and then without disturbing the hub you loosen the nut just enough to allow you to either pass the cotter pin through the first available slot or the first location where the retainer can be located. You should not be totally loosening the nut, just making enough clearance between it and the mating surface to allow it to turn freely. By doing this you are making sure that the races are seated and that there is not so much slop in the hub that the wheel will run cockeyed as yours has done. 
The suggestion to permit a 12 inch wrench or pliers with full hand force is a joke. Apparently, Dexter feels a need to accommodate woodshed mechanics. There is no way, zero, that anyone, not Mitchell Hooper, can accurately tighten to 50 foot pounds with pliers or a 12 inch wrench. Ridiculous. Your tire should be plenty convincing. 

SolidCamper

This is a very interesting thread, clearly with contributions of some knowledgeable tab mechanics. 

My 2020 TaB 320 is now 4 yrs old and the wheels have about 20K miles on them. I have done many automotive repairs, but have never done any wheel bearing work, so would need to learn more before tackling the job. 

 @ScottG You mentioned doing the service yourself after watching some DIY videos and specific Dexter videos beforehand. Could you please post a link or two to the videos that you found most helpful and most applicable to our tabs.  Thanks a lot. 

ScottG

@SolidCamper, check out the resources posted here. There is a video from Dexter, the Dexter axle service manual, and a cross-referenced parts list. Keep in mind my T@B is a 2015--I'm not absolutely certain that parts and protocols haven't changed in later models.

manyman297

@tabiphile is spot on. I’ve done a couple of repacks and was pretty paranoid about getting this particular part of the process correct. Torque wrenches are around for a reason but too many overly-confident mechanics (and there’s A LOT of them) seem to be able to “feel” torque in their arms. Sorry, it doesn’t work that way. 

ScottG

krsmes said:

... 

Ugh, so confusing.  My axle does have the retainer, not the cotter pin  … so the nut should be finger loose

@krsmes, I sympathize with your confusion. I have the castle nut w/ cotter pin, but the basic protocol prescribed in the Dexter video and service manual is the same as what you posted, and that is the procedure I followed. I did use a torque wrench to ensure the bearings were seated to the prescribed 50 ft-lbs.

I think the torquing step is what creates the most confusion. Yes, the instruction say to tighten the nut finger tight (or even a little less) but this is only done after the hub and bearings have been properly seated with an appropriate amount of force, and the nut then carefully backed off. The instructions are very clear NOT to move the wheel during the final loosening/tightening--presumably because doing so could unseat the bearings and create excess play in the wheel.

Although I'm no expert on the matter, if this procedure was followed properly I'd be very surprised if the spindle nut could still be easily loosened by hand at the next disassembly.

Horigan

tabiphile said:

...You should not be totally loosening the nut... 

If folks choose to not loosen to finger tight after torquing, per Dexter and Timken recommendations, I would suggest you check the hub temperature after driving a few miles to confirm you don't have excessive preload in the bearings once they warm up.  The objective in bearing setting is to have some endplay when cold so that when things warm up the metal expands such that the endplay is near zero.  Roller bearings do a good job of distributing load across the roller elements with some endplay (looseness).  Excessive preload can result in premature bearing element fatigue or lubrication issues.

tabiphile

Horigan said:

tabiphile said:

...You should not be totally loosening the nut... 

If folks choose to not loosen to finger tight after torquing, per Dexter and Timken recommendations, I would suggest you check the hub temperature after driving a few miles to confirm you don't have excessive preload in the bearings once they warm up.  The objective in bearing setting is to have some endplay when cold so that when things warm up the metal expands such that the endplay is near zero.  Roller bearings do a good job of distributing load across the roller elements with some endplay (looseness).  Excessive preload can result in premature bearing element fatigue or lubrication issues.

The devil is in the details.....I've done a few lot of these. 
Again, "loosen the nut just enough to allow you to either pass the cotter pin through the first available slot or the first location where the retainer can be located.
You should not be totally loosening the nut, just making enough clearance between it and the mating surface to allow it to turn freely."

The key in this approach is that you are controlling the clearance to the smallest possible spacing without allowing the spacing to become too large. 

Anyone who tows should always check their hubs whenever you stop and especially after a fresh brake and or bearing job, after the first 50 to 100 miles and then again at every subsequent stop. I don't use a temperature probe for this. I use the farm boy approach. I walk around the rig and put my hand on the hub.  
 

Mickerly

Exactly!

krsmes

Thanks for all the advice. Very helpful

krsmes

New bearings installed. New tires (Goodyear Endurance ST). Mechanic did not notice any issues with the spindle. Brakes had most of their life left still. At this point I’m guessing it is mostly just due to the number of miles I had on the tires and I’ll keep monitoring.

Appreciate the advice on checking hub temperatures…I’ve got one of those point and check temperature guns, any advice on what is too hot?