Rear wheel bearing change

911FVD · Post by **911FVD** » Thu Dec 03, 2020 5:47 pm

Hi,

Got very slight play on one side rear wheel bearing mentioned verbally by tester on recent MoT but not considered a problem so no advisory just told to keep an eye on it. Not expected really as only 4000 miles since a complete nut and bolt restoration which included all new hubs etc etc...................

That said the MoT centre does look after all my cars and although not many others require an MoT I still get them done so they are aware I am a fastidious owner.

Did not realise that a rear bearing change over on the 911 required a strip down that would also involve geometry set up.........I hate anyone else working on my cars not because of any lack of trust but so many times I always find a few other items along the way that are best looked at but given most things are still like new underneath it may be achievable as shown here in you tube video. https://www.youtube.com/watch?v=W4wpG7dK1zY I have done my rear bearings on my Lotus Elan +2s and 308 which required a special socket but not required any geometry reset

I have a lathe so could make all the parts as shown in the video but thought maybe someone has already produced a kit and if so please let me have details for purchase.

I have bought and put into stock a couple of rear bearings ready to fit but then looking at the video I don't understand what is being changed when it gets to the 6 to 8 minutes period on the video.

I also have hydraulic press so if necessary can do it the long way but would have to have the geometry redone.

Help advice appreciated

Steve

hot66 · Post by **hot66** » Thu Dec 03, 2020 7:07 pm

You don’t need to do geometry’s after a bearing change.

A bearing swap can be done with all, suspension on the car ... just need to make sure you use the correct puller to get the bitch of a bearing out and new one in

It’s just a case of removing the hub and stub axle

911FVD · Post by **911FVD** » Fri Dec 04, 2020 9:50 am

Thanks, yes I have researched both ways that it can be done albeit a few have had issues removing bearing in situ so had to do the full strip down to bench repair with hyraulic press etc.

I think/hope given the condition of the parts as little to no exposure and still looking very clean i can achieve in situ but what is the correct bearing puller required...........as i said I can make up what is shown in the youtube video but nowadays happy to pay for tools as time is more precious.

What I do not understand is what is the mechanic in the youtube video doing with the hub after fitting the new bearing it looks like he is then fitting another part. fastforward to 6-7 minutes where he is fumbling trying to press/insert what looks like a bush............just want to have this part on hand if required as well as the bearings.

So any links to pictures or bearing puller, happy to pay for all shipping/hire return costs if someone loans out or got one no longer required.

I just sold all my classic RR Shadow/Cloud tools as hardly using anything now given the RR is totally restored. That had special bearing pullers too so probably something would have adapted or worked.

Steve

PeterK · Post by **PeterK** » Fri Dec 04, 2020 10:00 am

Hi Steve
At around 6 minutes he is bolting the bearing retainer on with 4off 13mm bolts. Then at about 7 minutes, he is trying to remove the inner bearing race that came out on the hub (mine stayed in the bearing). To give his puller something to press on, he is just using a socket. Is that what you're referring to ?
Peter

911FVD · Post by **911FVD** » Fri Dec 04, 2020 10:51 am

Thanks Peter.

I am probably still sounding dumb on this but the complete main bearing itself gets replaced exactly at 5 minutes on the video. So is that other part which looks like a 'top hat' shape being pressed into the hub at 6.40 mins just a sleeving that fits into the wheel carrier hub casting and becomes an interference fit to the inner main bearing race when installed or just butts up to the main bearing inner race. The reason I ask is that is it possible any slight play could be down to a few other reasons then and maybe not the bearing itself. My history files show new rear bearings official main Porsche supplied fitted 4000 miles ago. It's over 30 years ago I last owned my 911's SC and 84 Carrera and never did much work on the cars then as always had something different every couple of years and the cars were relatively new or low mileage.

On the Lotus' it was quite common to find wear in the hub bearing carrier casting where the outer bearing is pressed in. I have no noise from the Porsche bearing at all.

Steve

PeterK · Post by **PeterK** » Fri Dec 04, 2020 6:49 pm

The inside of the hub carrier is splined for the driveshaft, there is nothing other than the drive shaft that goes in there. I think that at around 6:40 he is just bodging about, trying to get the outer race off the hub, first using the top-hat piece, then a socket to extend the top-hat piece.
Peter

Jonny Hart · Post by **Jonny Hart** » Fri Dec 04, 2020 10:26 pm

New bearings in the freezer for a day will see them push in with ease. Same for hubs.

jaw911 · Post by **jaw911** » Sun Dec 06, 2020 7:19 pm

Not wanting to state the obvious but measure the hub carefully before pressing in the new wheel bearing, They do wear over time, which causes the slight play you may now be getting. If so, you are into oversize and expensive bearings and machining the hub. You might be better just living with the play if it is only marginal.
Regards
John

911FVD · Post by **911FVD** » Mon Dec 07, 2020 7:02 am

Many thanks,

I understand it a little better now as was confused another new part was being fitted as well as the bearing.

Yes I also appreciate the hub bearing carrier internal can/could be an issue which was very common on the Lotus Elans as these were aluminium casting. We used to run an internal knurling tool on the inner surface if they were really bad and use a loctite(not sure now which number) but that allowed disassembly. The problem years back was the hub carrier parts for the Lotus were not obtainable so repairing was the only option. I am assuming though the Porsche part is a harder ferrous metal cast but as you say if wear can occur here I will check it all out. Again I am preceding with caution as all these parts were supposed to be new during the rebuild but I suppose with the hub this was probably just cleaned up. I will look on the invoices in the receipts file for the part number to see.

My local garage has what they refer to as a FWD hub bearing removal kit about 50 parts Sykes Pickavant and looking at it I think the kit will contain the parts required to strip out the bearing from the hub and refit.

Steve

PeterK · Post by **PeterK** » Mon Dec 07, 2020 7:50 am

Aluminium casting on my SC, so just like the Lotii. I rebuilt a Plus2 (but accidentally put a 2.0 Zetec and full EFI in it) before my current SC

jaw911 · Post by **jaw911** » Mon Dec 07, 2020 4:38 pm

Sorry, may have caused some confusion with definitions, It is the trailing arm itself that wears over time. I have just had to have a steel trailing arm machined to put in an oversize bearing and I know the same happens with the later alloy arms. Changing the wheel bearing in situ is relatively straightforward using a slide hammer - I have watched it being done. Oversize bearings are stupidly expensive from Porsche but some of the independent specialists are having them made.

Jonny Hart · Post by **Jonny Hart** » Sat Dec 12, 2020 8:54 pm

I’m doing a bearing change on the 914 (same as 911) so have been studying the Bisimoto video. He has some engineering cred for sure but I think he messed up but probably got away with it...

When he pulls the hub in, the large round flange at the back of his home brew tool is resting on the trailing arm. This means he is pulling in on the bearing races which isn’t good. Instead the back of the tool should rest on the inner race so that the balls are not taking the load. I would use a socket that is slightly smaller than the inner race.

He probably gets away with it because he only pulls in enough to get the axle in and does the rest using the hub nut.

911FVD · Post by **911FVD** » Sun Dec 13, 2020 11:02 am

Hi,

Thanks everyone for advice.....but.....

I have watched that video now quite a few times and yes I can now see as Jonny says he pulls off the inner bearing race as it clearly appears to show the inner bearing balls themselves become visible. That said I can understand if at the point I don't understand

what he is doing something to the hub maybe if it was a 'puller' removing the inner race but it looks more like he is pressing something into the hub.

I know you are all shouting just get on with it

but I am really electrical/trim speciality and whilst take on the basic chassis mechanics I never really deal with anything like engines/gearboxes or diffs. When doing any mechanics I like to get it all sorted in my head beforehand.

So I have looked at the various parts explosion drawings....well at a few on design911uk site and it shows different ones under the same vehicle selection and I don't know which is the correct one for the 1985 model as they are quite different ones that appear.

So when just looking then at this one exploded drawing https://www.design911shop.com/pages/dia ... ramID=1808 I then see the bearing and retainer plate items 6 and 7............then ask are these shown the right way round is the idea the plate holds the bearing.

Would someone just link me up to the correct schematic explosion for my car please.

Steve

Jonny Hart · Post by **Jonny Hart** » Sun Dec 13, 2020 11:35 am

You slightly misunderstood what I was saying. The mistake he makes is when he is putting the hub back on. He should not be pulling against the trailing arm, he should use the inner race.

If you are unsure, get someone who’s done the job before to help. I’m not an expert but the first time I did this it went 100% smoothly and the second time I had to trash a bearing because I forgot to put the bearing retainer on! We’ve all done it.

911FVD · Post by **911FVD** » Sun Dec 13, 2020 12:52 pm

Sorry Jonny I was thinking of what PeterK had said in his earlier reply.............had too much multi tasking going on. I see what you are saying but I am borrowing a 51 piece bearing hub remover so has what should be the right size discs and I agree it is bad practice to put the pressure just on the inner race of a new bearing

Steve

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