Removing stub axles - wheel bearings required?

[evan9eleven]

Hi everyone!

I'm finally getting around to some long overdue CV joint maintenance on my '81 SC. I've read the epic thread on the subject, well worth your time if you haven't seen it:https://forums.pelicanparts.com/porsche-911-technical-forum/222537-reconstructing-constant-velocity-cv-joints.html


While I'm in there, I decided to do the upgrade to the later Carrera 108mm flanges and axles. I've procured the billet transmission flanges from CMS, the '86-'89 rebuilt GKN axles with the integrated stub axle from our host, plus new bolts, Schnorr washers and moon plates. All the parts Grady and others listed up in the thread.

My question is this: Once the castle nuts on the end of the stub axles are removed, how best to remove the old 100mm stub axle flanges from the hubs? Can it be done without damaging the wheel bearings?

Lots of threads about axles and CVs, some mention how easy it is to ruin rear wheel bearings, but I've not found anything specific that answers my question.

Thanks in advance!

[Locker537]

The stub axle should come apart from the hub without damaging the wheel bearing...if nothing is seized. If it comes out easily, you should not need to replace wheel bearing or remove the hub.

You'll likely need to whack the stub axle out of the assembly from the front. I use a large brass punch.

[evan9eleven]

Thanks! Here's to hoping it isn't seized up.

I thought I read somewhere that hammering ithe stub axle out was likely to cause wheel bearing damage. I'm thinking that penetrating oil and caution will be my friends here.

[digdug]

Both times I pulled my axle stubs, once for a worn out bearing and once when restoring my suspension, the bearings came apart. The bearing is a split bearing and one half remained on the stub axle. May want to plan on new bearings while doing the job. With the tool it’s an easy job. It’s actually harder to get the bearing half off of the axle stub vs getting the bearing out of the housing.

[mikedsilva]

I've only done rear wheel bearings a few times.
half the outer bearing race always comes out with the stub axle; new bearings each time.

[E Sully]

Plan on new wheel bearings. Both of mine came apart when I pulled the stub axles.

[A930Rocket]

It seems like if you’ve gone that far, installing bearings would be prudent.

[ccallana]

I just took out one axle to fix boots - bearing stayed where it was, I left it alone...

[evan9eleven]

Thanks everyone! Bearings it is. Probably smart to do them while I'm in there anyway...

[gled49]

The stub axle can be removed without creating any damage to the bearing as long as no weight is put on the wheels while the stub axle is removed. If the wheel flange is removed the bearing will be destroyed.

[evan9eleven]

A little follow up.

Note that I referred to stub axles in my original post. That is the correct term for the part I was referring to-- the stub axles that mate to the half-shafts at the outboard (wheel) end. The other end at the differential is the transmission flange, and the wheel hub is the outer part actually inserted into the bearings.

Many confuse the stub axles and wheel hubs. I had them right, but hadn't ever taken this stuff apart to completely understand how all the parts relate. So for the sake of getting it right for future generations:


1) As several commented here, removing a stub axle from the backside of the wheel hub shouldn't affect the wheel bearings at all, as long as it releases from the hub without drama. Mine slid right out. If a stub axle is seized into the hub, it may be possible to damage a bearing if pounding out the stub. But the stub axle doesn't contact the bearings.

2) The wheel hub is what is pressed into the inner races of the wheel bearings. Removing this part will trash the bearing. Many threads show the process of removing this part and replacing bearings.


In my case, I could have left the hubs and bearings alone and just pulled the axles out. But I went all in and changed them since I had everything apart anyway.

Thanks for the help everyone, I learned a lot doing this job!

[Locker537]

You got it right.

[nsully]

Once the nut is off and the axle is disconnected the stub axle should pull/push out easily.

The hub is easily removed with a slide hammer, correct nut and washer on the end. typically it doesn’t trash the bearing. get a loaner from Autozone.

Use a bearing puller (autozone loaner) for the bearing. The kit, with all of its combinations has the threaded rod, large open ring that goes on the outside of the hub(allows the bearing to come out with maintaining pressure on the washer against the back of the bearing), the correct size washer to sit against the bearing, and the nut that goes on the end of the threaded rod. Tighten it down and the bearing will ease out.

[Matt Monson]

Originally Posted by Locker537

You got it right.

^this.

[digdug]

https://www.pelicanparts.com/More_Info/93033223205.htm?pn=930-332-232-05-OEM

Now I don’t know what to call them. In the link above, Pelican calls the piece that goes through the wheel bearing the stub axle.

[evan9eleven]

Originally Posted by digdug

https://www.pelicanparts.com/More_Info/93033223205.htm?pn=930-332-232-05-OEM

Now I don’t know what to call them. In the link above, Pelican calls the piece that goes through the wheel bearing the stub axle.

Then you do know what to call them, as the part you linked to is the stub axle. Just as I described it above. That part is connected to the outboard end of the axle and inserts into the backside of the wheel hub, which is the part that is actually pressed into the wheel bearing. So there is no contact between the stub axle and the bearing. The stub axle is the centermost part of the assembly, then the wheel hub which is pressed into the bearing inner races, then the rest of the bearing, then the trailing arm the bearing is pressed into.


Trailing arm with bearing removed:



Bearing installed:



Parking brake assembly and bearing retainer plate reinstalled:



Here is my wheel hub as I'm pressing it into the inner races of the new wheel bearing:



Here are my old and new axles; look at the top two. Both of them have the separate stub axles still mounted to them. The bottom one is the later Carrera version where the stub axle is no longer a separate part.

[PopsRacer]

diving into this today, so wanted to say THANKS! for this thread and all the pics. My car is ~135,000mi and the axles look original + boots are crap, so I bought a new pair + bearings. The RH rear bearing is definitely bad (louder than the engine at cruise..) & since my goal is HPDE events this summer and a lot of auto-x there is no sense in putting iffy old drivetrain parts back in.

Anyhow, so far so good, a 36” 3/4 breaker bar from HF and a 32mm 3/4 deep impact socket (~$15 online) took off the axle nut with fuss at all. Totally worth it. Car on ground, HB on and trans in R are all solid advice. Did all that & the car still wanted to move, lol. Since the nut was no problem something else will go very wrong, but we’ll blow up that bridge when we get to it.

[Gonbad]

OK - what is the advantage of the later style Carrera one piece stub for the wheel bearing hub for the rear wheel?

I assume the other end still bolts to the stub axle in the side of the transmission.

Originally Posted by evan9eleven

Here are my old and new axles; look at the top two. Both of them have the separate stub axles still mounted to them. The bottom one is the later carrera version where the stub axle is no longer a separate part.

[Otter74]

Why did you want to change to the Carrera-style axles? I like the older style because removing the axles is very easy.

[evan9eleven]

Originally Posted by Otter74

Why did you want to change to the Carrera-style axles? I like the older style because removing the axles is very easy.

If you go read through the thread I linked to at the top, you'll learn more than you ever wanted to know on the subject. But the short answer is upgrading to the later Carrera axles gives you 108mm transmission flanges with *10mm bolts, and beefier axles. The older 100mm flanges with *8mm bolts handle less power and occasionally come apart.

As an added bonus, the Carrera axles have a grease cap over the inboard CV joint, meaning no mess if disconnecting axles for an engine drop or other reason. This also allows for assembly with no grease accidentally getting on the bolts, potentially reducing their holding power on the older setup.


EDIT: *corrected above, should read 10mm and 8mm bolts not 8mm/6mm as I originally wrote.