Brand new trailer bearing failed WOF

Forums › Transport (cars, bikes and boats) › Brand new trailer bearing failed WOF

ringbearer

114 posts

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#311005 6-Dec-2023 09:26

Getting my boat trailer warranted this year has been a nightmare, mostly of my own making.
First I replaced the bearing on the wrong side, then missed the cut of date, and now have had a brand new bearing failed by VTNZ.
The tester said he has seen new bearing be faulty before, and I should return it to Repco and replace again.
Before I do that, is there anything I could have done wrong while fitting it that might have the same effect? There is no play in the wheel at all.
Appreciate anyone’s thoughts on this. It’s a simple job I’d like to be able to do myself, but I’m start to second guess myself.

Bung

6487 posts

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#3168706 6-Dec-2023 09:48

If there is no play in the bearing what is it failing on? Is it noisy when spinning?

I'd believe some fault in fitting like not fully home in housing before brand new bearing being faulty.

ringbearer

114 posts

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#3168708 6-Dec-2023 10:00

Apparently it’s rumbling, and there is a slight vibration. I struggled to tell the difference between the faulty one and the one that passed.

MikeB4

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#3168726 6-Dec-2023 10:41

Two things kill boat trailer bearings fast, water and heat. I had ours changed as a master of course each year to save the hassle at warrant time. You could try blocks under the axle if you winterise your boat to avoid flat spots and rotate the wheels regularly.

1yippy1

67 posts

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#3168800 6-Dec-2023 12:16

Did you change your cups as well ?

Ge0rge

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#3168802 6-Dec-2023 12:21

ringbearer: Apparently it’s rumbling, and there is a slight vibration. I struggled to tell the difference between the faulty one and the one that passed.

Have you packed the bearings with grease correctly? I'd be checking that first, and then rechecking the bearing tension. Done up too tight will feel quite rough and lumpy.

I find it hard to believe an out-of-box failure for a bearing, especially when the "tester" is using nothing more than a spin of the wheel and a jiggle of a pry bar to test it.

tweake

2391 posts

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#3168884 6-Dec-2023 14:47

one thing worth looking at is the bearings tend to come a bit loose after the first bit of use. so well worth take it for a spin, then retightening the bearings.

also as above, not changing the cups.

"rumbling" can also be from brake pads rubbing.

tweake

2391 posts

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#3168886 6-Dec-2023 14:52

MikeB4:

Two things kill boat trailer bearings fast, water and heat. I had ours changed as a master of course each year to save the hassle at warrant time. You could try blocks under the axle if you winterise your boat to avoid flat spots and rotate the wheels regularly.

and the water problem is related to the heat. it pays to let the bearings cool down before backing it into the water.

also if your changing bearings change the seals. the bearings on our flat deck are ~15 years old, but the seals had gone rock solid and broke apart. i've started using a bit of rubber grease in the rear seal, to help keep it lubed, sealed and not harden.

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ringbearer

114 posts

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#3168898 6-Dec-2023 16:04

1yippy1: Did you change your cups as well ?

Yep, changed the cups.

ringbearer

114 posts

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#3168899 6-Dec-2023 16:07

Ge0rge:
ringbearer: Apparently it’s rumbling, and there is a slight vibration. I struggled to tell the difference between the faulty one and the one that passed.

Have you packed the bearings with grease correctly? I'd be checking that first, and then rechecking the bearing tension. Done up too tight will feel quite rough and lumpy.

I find it hard to believe an out-of-box failure for a bearing, especially when the "tester" is using nothing more than a spin of the wheel and a jiggle of a pry bar to test it.

That's a good point, it's entirely possible I didn't pack them properly. I followed the steps here on repacking, but did it manually rather than using a tool. Maybe it's worth purchasing one.

tripper1000

1617 posts

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#3168900 6-Dec-2023 16:13

The WOF guys often put their finger on the axle to feel the vibration rather than listen to the rumble (particularly in a noisy workshop). A bearing that vibrates to the touch will still be described as "rumbling". In some cases they might even use a stethoscope (or listen through a screw driver handle), so they will pick up more than the naked ear.

Did you replace both the inner and outer races? The outers can be tough to get out & back in without the right tooling, so some people short-cut it and leave the old outers in/discard the new outers. This is a big no-no and false economy since they'll usually fail again within a year. So perhaps to try and catch this tom-foolery, the WOF guys are looking for a 100% improvement, not just a 90% or 80% improvement.

Also you can ruin a perfectly good bearing by pressing it in wrong by transmitting the forces through the roller/ball bearings (think pressing on the inner race when trying to get the outer race back in position), or simply bashing/pressing directly on the race surface. Both these actions dings up the races, and leads to premature failure.

Edit: grammar.

1yippy1

67 posts

Master Geek

#3168916 6-Dec-2023 17:23

Are they Chinese or Japanese bearings ? Chinese bearing have waxy coating on them which will make them rumble qiick rinse in some turps and a repack with grease usually fixes them.

MikeAqua

7785 posts

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#3169728 8-Dec-2023 12:55

ringbearer:

That's a good point, it's entirely possible I didn't pack them properly. I followed the steps here on repacking, but did it manually rather than using a tool. Maybe it's worth purchasing one.

I purchased a cheap bearing packer from Repco. It works fine. The SCA equivalent is hopeless.

As to your rumbling. If you bought the Trojan bearing kit, they are cheap bearings made in China. If it's still rumbling after you pack it properly and tow it for a few kms ... I would take it back and get a refund. No way it should rumble straight out of the box. That's a major defect and you're entitled to a refund. Not a replacement. I don't buy trojan bearings anymore. I go to a bearing shop and get good ones. They last years.

The other things I do: -

1) I have bearing buddies (just don't over-pack them with grease)

2) When I arrive at the boat ramp: I park up in the staging area, take the tie downs off, put the bungs in, prime the fuel line(s), generally get ready to launch. By the time I actually launch, my bearings have cooled down again.

3) After launching or retrieving the boat I rinse the hubs down. I have my trailer set up with a little freshwater reservoir, 12v pump and strategically located spray nozzles. I just flip the switch and it runs for about 5 minutes.

Mike

MikeAqua

7785 posts

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#3169733 8-Dec-2023 12:58

Also never go to VTNZ. They look for/make up reasons to fail vehicles.

Mike

tripper1000

1617 posts

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#3169736 8-Dec-2023 13:08

In the 80's, testing stations were full of semi-retired mechanics. They knew their stuff, but were past the heavy work and awkward angles. I'm not so confident VTNZ hires experienced mechanics.

ringbearer

114 posts

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#3174018 21-Dec-2023 12:27

Popping in with an update. I repacked the bearings with the help of a neighbour who works as a mechanic, took the trailer for a drive, then tighted and checked again.

Passed the WOF with no issues, so thanks all for the advice.

While it would have been nice not to go through so much frustration, at least I have a much better understanding of who to replace them correctly.