43 replies to this topic

[Andrew Warren]

I know there has been plenty of advice on service schedules and how to properly re-pack the front wheel bearings. While spending lots of time searching, I haven't been able to find any clear answers as to what to do with the rears. I've been able to find that they are sealed cartridge bearings and that you can purchase the bearing itself from Mazda Motorsports, or buy complete knuckle & hub assemblies units with re-packed bearings. Other than that, every mention of the rears tends to be short and incomplete.

 

1. How often do people change out the rears?

 

2. Do you simply buy a new OEM bearing and install it, buy a blueprinted knuckle assembly, or try to re-pack the bearing yourself?

 

 

I have a feeling some of these questions may have been answered on the old site but are no longer available on my Google searches.

 

 

Thanks guys!

[Ron Alan]

It's a little effort and you need to have a good press but changing the rear is fairly simple. Repacking the Rears doesn't seem any different than the fronts...they seem to come apart just the same...though for the $30 cost of a new Timken bearing I didn't bother. As far as how often...I don't think there is a perfect answer. For sure there are OEM rear hubs and bearings going strong after a season or 2 on track and the original 150k donor miles on them! I've heard guys swear buy using original used bearings only...something about roundness and hardness(until of course they start making noise!). Until this time just run them and have a pair of spare uprights with new bearings ready to go...or put on new ones and throw your OEM ones in the box of spares...along with a couple front hubs! So the short answer to your question is have spares ready and don't worry! BTW...I stayed at a holiday inn express!

[Keith O]

Just be careful what brand you use. I had Timkens and it was easy to repack them, as Ron said. I happened to pick up a different brand to use (can't remember which) and they didnt seem to have the same design. I wound up destroying the seals when I popped out the inner races. They are fully sealed bearings in the rear, so I don't believe that they need the same degree of attention as the fronts.

[davew]

I do not use Timken rear bearings. Had tooooo many problems. OEM, NAPA good ones, SKF all seem to outlast Timken. 

 

I do not repack rear bearings. Just not enough heat generated by the rears.

 

Replacing a rear bearing requires a press. So at track repairs are difficult. I carry complete uprights as spares.

 

Dave

[Blake Thompson]

You asked how often to check the rears.  I check them at least once a day.  Check the bushings for play, and check the bolts for looseness.  And what dave says is right, a full upright to swap in would be ideal, no alignment should be needed and you can swap one in like 20 minutes if need be.

[SaulSpeedwell]

I do not use Timken rear bearings. Had tooooo many problems. OEM, NAPA good ones, SKF all seem to outlast Timken. 

 

I do not repack rear bearings. Just not enough heat generated by the rears.

 

Replacing a rear bearing requires a press. So at track repairs are difficult. I carry complete uprights as spares.

 

Dave

+1

 

Timkens aren't Timkens when it comes to bearings for our cars.  The good news is the rear bearing is still current production for FWD cars, so some suppliers still actually make good ones.

 

There is one "best" rear bearing in my opinion (with a metal face shield instead of a rubber lip), and it IS a little fiddly to get apart for repacking.  You can and will break the cage if you don't know what you are doing and/or do not have the right tool. 

 

Having said that, the rears are bombproof compared to the fronts.

[Adax]

My last Timken rear bearing boxes contained NSK bearings.

[Ron Alan]

Ok...so no Timkens. Napa is cool? Who makes the ones from mazdaspeed?

[Keith Andrews]

Ok...so no Timkens. Napa is cool? Who makes the ones from mazdaspeed?

Koyo in the two boxes I have.

[Brandon]

To directly answer Andrew's question: I personally replace every year at the beginning of the season regardless.

 

Following-up on other's replies though, checking every weekend is a good idea but also a good ear to listen to what they're doing.

My last event at the Glen involved a fairly hard hit which put a nice dent in front of the rear wheel but ended up causing a nice roar/growl in right-hand turns.

 

Good thing I brought my spare uprights otherwise I'd have been out for the Pro-IT race that weekend!

Now, whether these take-offs are still able to be rebuilt with new bearings is yet to be seen but will be checked.

 

HTH - see you @Pocono mate!

Brandon

[Keith Andrews]

If you are repacking your front bearings with no problem, you will have no problem working on the OEM Koyo bearings from Mazdaspeed.  

 

You definitely want to make sure you can get your axle out of the hubs.  They can be difficult if they have been in there a long time.  That could be a real pain at the track.  

[Andrew Warren]

Thanks everyone for the input! It looks like I'll be picking up some Mazda/Koyo bearings and putting them in the rear knuckles for spares. 

[SaulSpeedwell]

If you are repacking your front bearings with no problem, you will have no problem working on the OEM Koyo bearings from Mazdaspeed.  

 

You definitely want to make sure you can get your axle out of the hubs.  They can be difficult if they have been in there a long time.  That could be a real pain at the track.  

 

You sure?

 

Fronts can be knocked apart with the "standard" 1/4" ID washers inserted between the iner race and a socket slightly less than the axle OD .... but if you try that on some revisions of the rear OEM bearings, you will very likely break an inner cage.  I don't know how many people still do it that way, but people still use the JD Setup Guide

 

For the sake of the peanut gallery, we should probably clarify what disassembly method and rear bearing revision we are talking about.  I'm talking about the one on the far left.

 

[Ron Alan]

No problem getting one race out when you knock out the hub...errr! An then trying to get that mother off the hub...double errr! Granted I'm not a shop with fancy tools...but what a pain!!

[Bench Racer]

Come on Saul, if you didn't like the peanut gallery you wouldn't expose us to your great learnings.

[Keith Andrews]

Mark- maybe I just got lucky because I didn't know any better but they just came apart similar to the fronts.  I repacked them with my magic grease and popped them back together.  No special tools, just washers, sockets and a hammer.  The cage is more rigid but it wasn't brittle.

 

The one side of the bearing looks like the bearing on the left the other side of that bearing has a flat black seal.  They are Koyo bearings purchased from Mazdamotorsports.  Same part number.  I did this in January so the bearing were purchased then.

 

You know a lot more about this stuff than I do.  If you say they shouldn't be opened up I'll go with with that.

 

 

 

 

You sure?

 

Fronts can be knocked apart with the "standard" 1/4" ID washers inserted between the iner race and a socket slightly less than the axle OD .... but if you try that on some revisions of the rear OEM bearings, you will very likely break an inner cage.  I don't know how many people still do it that way, but people still use the JD Setup Guide

 

For the sake of the peanut gallery, we should probably clarify what disassembly method and rear bearing revision we are talking about.  I'm talking about the one on the far left.

 

[Adax]

Mark- maybe I just got lucky because I didn't know any better but they just came apart similar to the fronts.  I repacked them with my magic grease and popped them back together.  No special tools, just washers, sockets and a hammer.  The cage is more rigid but it wasn't brittle.

 

The one side of the bearing looks like the bearing on the left the other side of that bearing has a flat black seal.  They are Koyo bearings purchased from Mazdamotorsports.  Same part number.  I did this in January so the bearing were purchased then.

 

You know a lot more about this stuff than I do.  If you say they shouldn't be opened up I'll go with with that.

 

Same experience here Keith. My NSK's looked the same with the rubber seal. No problems separating and re-packing. The original ones on my donor have the metal-backed seal that Mark shows.

[Keith Andrews]

One other thought is that I did not remove the bearings from the cage.  I just cleaned out all the original grease and added my grease. 

[SaulSpeedwell]

Mark- maybe I just got lucky because I didn't know any better but they just came apart similar to the fronts.  I repacked them with my magic grease and popped them back together.  No special tools, just washers, sockets and a hammer.  The cage is more rigid but it wasn't brittle.

 

The one side of the bearing looks like the bearing on the left the other side of that bearing has a flat black seal.  They are Koyo bearings purchased from Mazdamotorsports.  Same part number.  I did this in January so the bearing were purchased then.

 

You know a lot more about this stuff than I do.  If you say they shouldn't be opened up I'll go with with that.

 

Thanks for getting back with us.  I know what I think I know, but I don't know everything and sometimes I'm just dead wrong, that's why I asked

 

The metal-shield bearing (in my experience?):  The cage is closer to the inner race than the rubber shielded bearing versions, and while it is quite "flexy" it is also thinner and more prone to break.  This cage is a translucent yellow/brownish in color, not black.   (Is that what you saw in yours, as well?).   If you put the washers in too deep, you can and will screw up that cage while trying to hammer out the inner race.  The cage is closer on the metal shield side, so you may have indeed gotten lucky if you knocked out the side with the rubber seal first.  If you are going to use washers, start with the rubber-sealed side, and knock out the metal-shield side second.

 

Also for the rear bearings with metal shields: if the grease is thick and white, LEAVE IT.  This is a high-quality, quite pricey, OEM "lifetime" wheel bearing grease that you can't buy in small quantities without a hookup.  It is better than the "Vaseline"-looking grease in many bearings, and (in my opinion) better than CV-2 *for this application*. 

[Keith Andrews]

Thanks for getting back with us.  I know what I think I know, but I don't know everything and sometimes I'm just dead wrong, that's why I asked

 

The metal-shield bearing (in my experience?):  The cage is closer to the inner race than the rubber shielded bearing versions, and while it is quite "flexy" it is also thinner and more prone to break.  This cage is a translucent yellow/brownish in color, not black.   (Is that what you saw in yours, as well?).   If you put the washers in too deep, you can and will screw up that cage while trying to hammer out the inner race.  The cage is closer on the metal shield side, so you may have indeed gotten lucky if you knocked out the side with the rubber seal first.  If you are going to use washers, start with the rubber-sealed side, and knock out the metal-shield side second.

 

Also for the rear bearings with metal shields: if the grease is thick and white, LEAVE IT.  This is a high-quality, quite pricey, OEM "lifetime" wheel bearing grease that you can't buy in small quantities without a hookup.  It is better than the "Vaseline"-looking grease in many bearings, and (in my opinion) better than CV-2 *for this application*. 

 

Yes, what you are describing, is exactly what I experienced.  I had no problem taking them apart or putting them back together.  Yes, I did clean out the lifetime grease.  Another lesson learned thanks for the insight.