How to use Sir Tools B90 to replace wheel bearing

[mnickson]

This article describes with photos how to replace a wheel bearing using the SIR Tools B90-P2 tool.  There are no other "step by step" articles on any forums, so this article complements the others you find on the Internet to show how exactly to do it with this particular tool.

 

Step 1. Remove the wheel carrier from the car.  This photo shows where this article starts, it is specific to removing the bearing, not removing the wheel carrier.

 

 

Step 2.

 

Remove the wheel hub from the carrier, these three photos show how to put the tool in place.  Basically, you draw the wheel hub out of the inner bearing race, it comes out easily.

 

 

Step 3.

 

Remove the bearing from the wheel carrier.  Heat the aluminum wheel carrier to 100 degrees Celsius, do it evenly, it takes about 3 minutes, measure the temperature with an infrared thermometer.  Note, there are other articles on the Internet which use the wrong standard for temperature (they incorrectly say Fahrenheit, it should be Celsius as per the Porsche Workshop Manual).  Your basically drawing the bearing out, into the large cylinder.  You can use the wheel hub as a support and conveniently turn the bolts with your 24mm and 27mm spanners.

 

Step 4.

 

Insert the new bearing into the wheel carrier.  Prior to doing this, clean the bore of the wheel carrier with polishing cloth (your just cleaning it, not removing any aluminum).  Put the new bearing in your kitchen freezer overnight prior to inserting it.  This is an alternate approach to Porsche Workshop Manual which has you heat up the wheel carrier to 100 degrees Celsius. The freezer method is easier on your hands since you don't have to touch hot metal (if you do use the heating method instead of the cooling method, wear work gloves as usual).  The tools in this step apply force on the outer part of the bearing and the aluminum casting.  The photo shows the bearing half way in.

 

 

 

Step 5.

 

Insert the wheel hub into the bearing.  Remember to put the splash shield in place prior to actually installing the wheel hub into the bearing.  Notice how the tools thrust bearing which is silver in the second photo below is used with the smaller circular die.  Basically you draw the hub into the bearing with force being applied between the inner race of the bearing and the cast iron wheel hub.

 

 

 

Step 6.

 

Re-install the newly restored wheel carrier into the car (this is not covered by this article since there are many others on the internet).

 

 

Step 7. 

 

Enjoy your car - Mark Nickson, Member of SAE, PCA, and MBCA for over 30 years.

[dporto]

That's pretty much the dea, nice write upl! I created my own tool with a bearing puller and a "Bridge" that I made out of some 1" stock I had lying around - It worked flawlessly and it sure beat laying out $600 for the SIR tool - $90 (for bearing puller set) and a little welding time. It's certainly not as pretty as the sir tool, but I'm not using it on "customer cars" so cost was a major concern...

[JFP in PA]

An interesting write up with one "minor" difference:  the B90 system was designed to be able to replace the bearings without disconnecting or removing the hub carrier.  Once the carrier is off the vehicle, it is far quicker to just use a standing bearing press.  The B90 saves techs a significant amount of time by allowing your to pull the bearings with the carrier still in place.....

 

We use it this way every day:  How to use the B90 on a Porsche

[dporto]

^Good point^ !!! I think my DIY build will work on the car as well - I was replacing the entire suspension so I wound up taking the carrier off (I aslo had a heck of a time removing the bolt that holds the shock body on so I had to take that one off). In any case, for the "pro's" who do this job on a fairly regular basis $600 and change is a very reasonable price for a well designed/constructed tool - I'm sure it pays for itself in short order.