I found that my nearly brand new front hub has some free play in it after an off-track excusion.

I also found the dust cover is loose and there's a few spots of grease on my wheels.

Is it possible that loose caps would let grease come out and cause the free play? There was still grease in the spindle but it wasn't packed or anything.

Can I just retighten the hub to the torque specs and see if the free play goes away?

 

my experience is with miatae, but we go through hubs a lot.

1. you must start with a Mazda, or Japanese made hub. the chinese ones have a bearing that is much worse, and some lack the extra casting around the lug studs and break.

2. we must take the new hub apart and repack it with good grease.

the difference is huge, if we just put a chinese hub on the car it'll last a weekend, a repacked OEM hub will last half a season.

with the repacked hub it seems to be normal for there to be some grease around, we're probably over packing it.

you can try torquing yours down, but its probably done already. hitting stuff is bad too, that can kill a hub/bearing

 

Not feeling play in the balljoints?

What branding was on the bearings, NSK or NTN do you remember? According to the local Mazda dealer down here, it's a NLA part, although a reputable local bearing supplier who deals in those brands says they are still available....but there's remanufactured rubbish out there too and I'm wondering if that's what would arrive.

At a recent event where one of these shitboxes reaches 165mph, the bearings crapped out, burnt the black paint off the dustcover and destroyed $300 worth of pads and $700 of rotors in a 1hr race from all the movement

 

Not sure... It feels like hub play to me. I will check it later.

No idea what brand the hub/bearing combo was, but it was probably genuine Mazda.

 

i didn't check Mazda, but we show 9 aftermarket brands, it fits a 626/probe/millenia too.

 

Any of those just the bearing? Or cheaper/stronger than FD hub assemblies?

 

Parts guy did mention they were 626 rears, I see there's been some mention of apparent problems with Timken branded ones on here.


The NTN is HUB066-70, which is basically the complete assembly, you buy from the manufacturer. Removing the bearing, or at least the outer race is no simple task...powerful lathe, ceramic tooling probably required.

 

Wish someone would make a hub with easily-replaceable, beefier bearings.

Or some tapered bearings that can be readjusted.

My mechanic is trying to convince me to replace both even though they've both got less than 200 miles on them.

 

no its a sealed assembly. they are all FD hub assemblies, the 626 uses the same part.

the OEM Mazda ones are superior, if you're lucky one of the aftermarket brands is a reboxed Mazda part for less money.

the other option is a cheaper copy, which will have an inferior bearing, and possibly a weaker casting. there was a run of cheap miata hubs that didn't have the extra casting around the lug studs, and on a street car its ok, but on a race car, it breaks.

 

either do it, and keep the good one as a spare, or replace the bad one, and see how far you get. its a wear part

 

Have thought about a tapered bearing hub with spacer. Inner bearing is fine there's one 74x33. When you get to the outer, something in the order of 44x33 doesn't leave much room without making the hub 2 part which I guess isn't a huge obstacle.

I'd be interested to see what hub brand your mechanic removes, if it's that!

Not alone in Mazda problems it seems -

https://www.rx8club.com/rx-8-racing-...ession-265330/

 

Pretty sure it was OEM/genuine, but I did basically drive off road at 60-70 MPH... which also destroyed my aftermarket bumper and bent the **** out of my fenders.

 

I didn't even realize until later that sealed bearings aren't supposed be covered in grease. These seem to have exploded.

I think these are genuine Mazda NTN bearings.

 

Pretty basic stuff. I deal with this on customer cars every week.

The wheel bearing(s) are shot. Replace wheel bearings if there is grease evident, excess lateral play in the wheel or rumbling or screaming noises from the wheel.

Often I see the bearing fail, which makes it run hot. The heat transfers into the wheel center cap and if its a plastic centre cap. it heats up and falls out. Grease flies out radially, flung out of the failed bearing by centrifugal action.
The hardening wears off the bearing race with less grease, and then the wheel bearing starts to scream or whine/roar. If it whines/rumbles during left handers, the left hand side bearing is dying, vice versa.

I've seen purportedly "new, as good as OEM" bearings fail in 200 to 300 miles because despite it being new, its not manufactured to OEM quality. I went through 2 sets of aftermarket front wheel bearings on my E39 M5. Then I paid the money and put OEM BMW ones on and they lasted. (The poor man pays twice sort of deal)

 

There's a wee bit of play in the left bearing, so I'm going to look under the dust cap and replace it myself since it's such an easy job.

 

Btw, can pure heat from speed and the brakes kill OEM bearings?

 

Fuckshitfuck. This is my left bearing.

The dust cap seems to have corroded. Maybe all this grime from the cap damaged the bearings?

It's 100% not normal for grease to escape sealed bearings, yes?

 

Ignore the holes... that was just me getting them off.

 

Can't remember seeing that GMB thing. The brand of the bearing is on the backside. They're not really sealed bearings either. There's a lip that runs around the spindle spigot though.

The NTN here had a tan grease and no where near that quantity, the NSK one had something like a dark moly grease....again much less than that quantity. Your mechanic hasn't packed it or something to be extra sure?

I've come across corrosion in the caps before, I wouldn't worry too much, wouldn't surprise it's been used a few times rather than replaced, you can normally get them out undamaged with a bit of care.

 

No. I watched him put the new one on. No grease.

Where did all that dust come from if not from the cap?

 

Bits of corrosion would have been on the cap, it's only in the grease because it's been disturbed. The 35mm nut will often times have the zinc plating attacked too after a relatively short time, I'm not sure it's moisture in the grease being boiled out and condensing or atmospheric....the humid period over there starts a bit later from memory though.

 

these GMB hubs are chinese, so replace both with something Japanese.

 

You sure? I got charged the Genuine Mazda price...

 

GMB is a Japanese company, btw.

 

not every GMB part is made in china, but this one is.

https://www.opticatonline.com/part/g...mbly&assetName