Blown seals on 2021 320S Boondock axle.

Nessmuk

I have a 2021 that was purchased June 2021. We put about 8,000 miles in a bit more than a year. Since then it has been stored away, but for one short trip.
We are planning on two major trips coming up soon so I decided that it was time to repack the bearings. To my surprise both grease seals were leaking badly.
Thankfully they hadn’t contaminated the braking surfaces or pads. It must have started leaking very shortly before it was parked. I have never used the EZ-Lube on the trailer so that was not the cause.

Dexter has a video that says to use Red RTV when installing the seals. I found no evidence that was done.
Has anyone else found leaking seals on their first bearing maintenance? I am thinking this may have been a Covid era quality control issue?
one thing I noticed was that the brake drums are US made, but the bearings and seals were Chinese (on a new axle). I was expecting a good quality set of bearings and seals.
And this is actually a Dexter and not NüCamp issue.

Citruscountytab400

You really need to replace your seals yearly or every 3-5k miles, regardless of what other's may say.  I pull and repack my 400 seals after 3k miles each year, and I always clean everything with brake cleaner and then lightly coat the metal on the seal, before installing the new one.  A lot of places don't pull/clean and replace the rear seal and bearing.

Maxcamp

Rebuilt our 2021 axle due to Nucamp dangerous brake wiring failure in early 2022**.  Seals were tight, no leakage of purple grease.  Also rebuilt two different cargo trailers' axles.  Used Dexter parts kits.   Measuring cheap bearing/ seal kits from auto zone versus Dexter with a mic there are tolerance and dimensional variances.  Pulling rear seal could require a specialty tool to avoid damaging raceway.  Dexter recommends 12k mi or 12 mo maintenance cycle.
You could measure old and new parts to see if Nucamp provided something off tolerance.  



**(https://tab-rv.vanillacommunity.com/discussion/17161/why-did-why-will-your-brakes-suddenly-fail-on-one-side-lifesafety-issue#latest)

Nessmuk

Maxcamp8 said:

Rebuilt our 2021 axle due to Nucamp dangerous brake wiring failure in early 2022.  Seals were tight, no leakage of purple grease.  Also rebuilt two different cargo trailers' axles.  Used Dexter parts kits.   Measuring cheap bearing/ seal kits from auto zone versus Dexter with a mic there are tolerance and dimensional variances.  Pulling rear seal could require a specialty tool to avoid damaging raceway.  Dexter recommends 12k mi or 12 mo maintenance cycle.
You could measure old and new parts to see if Nucamp provided something off tolerance.  

I do use a seal puller to remove the seals. As far as parts sourcing Dexter obviously used Chinese parts during (at least a) part of 2021. The bearings are clearly marked “made in China”.
My Tab was just a bit over a year and well under 12K when parked. The short trip was for 2 year glycol changeout.
Seems if Dexter had assembled things correctly the seals would have held.
When traveling I also check hub temps with a laser thermometer.

tabiphile

It should not be necessary to use RTV when installing the seals if the seals are rubber faced. A light film of oil should suffice. RTV may be very judiciously used otherwise.  I would suggest going with parts in hand to a trailer shop where they stock and sell parts. Online sourcing or big box auto parts sourcing lacks the hands on knowledge that results in selecting not only the right parts, but also the best ones. 
Asian sourced bearings are not generally problematic presuming they are built to the mfgr. spec. Abec classes are universal and if you are properly following both lubrication and maintenance recommendations, they should comfortably last through numerous repacks before requiring replacement. Properly torquing the castellated nut is critical!
Where you can go wrong (and this may have happened to your seals) is not applying even/equal pressure when they were seated. 

Nessmuk

tabiphile said:

It should not be necessary to use RTV when installing the seals if the seals are rubber faced. A light film of oil should suffice. RTV may be very judiciously used otherwise.  I would suggest going with parts in hand to a trailer shop where they stock and sell parts. Online sourcing or big box auto parts sourcing lacks the hands on knowledge that results in selecting not only the right parts, but also the best ones. 
Asian sourced bearings are not generally problematic presuming they are built to the mfgr. spec. Abec classes are universal and if you are properly following both lubrication and maintenance recommendations, they should comfortably last through numerous repacks before requiring replacement. Properly torquing the castellated nut is critical!
Where you can go wrong (and this may have happened to your seals) is not applying even/equal pressure when they were seated. 

I purchased my new seals from Etrailer. If you look at Dexters own maintenance videos they tell you to use RTV so I did for this repack (a thin film of it). I have never used it on my cargo trailer and have never had a leak. Go figure.
I agree that it was likely installer error at Dexter. I guess they would blame it on troubles during Covid. 🤷🏻‍♂️

gulfarea

I was an 18 wheel meck for 31 years. On front of all the units I worked on they were oil filled. Sure seemed to work well and draining them and refilling was a breeze! I have seen some kits out for our small axles to change them to this. I know it would take some time to see how they would work for our smaller axles, has anyone here gone to them and have feedback to share? Art

Nessmuk

gulfarea said:

I was an 18 wheel meck for 31 years. On front of all the units I worked on they were oil filled. Sure seemed to work well and draining them and refilling was a breeze! I have seen some kits out for our small axles to change them to this. I know it would take some time to see how they would work for our smaller axles, has anyone here gone to them and have feedback to share? Art

I have seen that conversion kit and would be interested in hearing from anyone who has used it.