Well Porsche was getting a little expensive, so I had my wife start making batches of RS uprights in the oven. Seems to work . Actually, I was just installing some new bearings into a new RS upright set. If you just get some heat into the aluminum, the bearing just falls in. Then when they cool, the bearings are nice and tight. These are off to a lucky Rennlister that is installing them along with a set of Motons in a few weeks... Lucky guy... Thought you would like the pic though...

 

Bob:

Do you pan sear them first?

Mike

 

Ovens and bearings were made for each other!

 

You better get those back in to the garage before your wife gets home.

 

You heat up the aluminum, and when they are cooling you drop them in at just the right time so that you don't heat the bearing as much as you can. This is the factory method for replacing bearings in the uprights. Porsche does not subscribe to the press in and press out method. I try to do it this way whenever I can as the pressing method between the aluminum and the steel bearings is something that you don't want to do a lot....

 

I think I even froze the bearings then heated the uprights. I'm a noob, so I learned the hard way on the tranny mount.

 

I think if you leave the two uprights together long enough they'll reproduce.

I agree that the heat method would be preferable. Installing bearings in jumbo electric motors at my old job, that's always the way we did it.

 

So how long and at what temp? Would this work with removing the old bearings?

 

Wow! The dealership down here uses a sludge hammer, for real. Chris

 

A sledge???? Tell them to

Seriously, pressing them in and out is sort of OK, but you will notice tracks from where the bearing has scratched the softer aluminum. Whenever possible, heating to install or remove works very well. On the other hand, a bad rear wheel bearing can be pressed in and out in an hour or so. If you removed it with heat, you are talking about removing all the rear suspension to the upright and then reinstall. Then an alignment. So it is the difference between 1-2 hours labor and 5-6 hours plus and alignment.

I heat the upright to about 275 for 30 minutes. Then remove and let stand a couple of minutes. Then drop in the bearings. Then they cool for an hour or so.

 

No, no, no, no! Never freeze the bearing!!!

The moment you take it out it will cause water to condense on the bearing and that water will get squeezed into the case.

Also, check the expansion rate for steel and aluminum. Freezing steel has very little impact on the size of the steel, but aluminum's expansion rate is much higher. Heating aluminum is okay.

There is a limit to how much heat before some degradation in the aluminum will occur due to the heat. Different grades have different heat capacities before the properties are impacted.

To do it right you should measure the ID and the OD of the two parts and calculate the required expansion required and then calculate the temperature to raise the material to.

Also, home ovens do not hold a set temperature in their cavities. They are designed to swing 30 to 50 degrees. I forget the period, but it is around 5 to 8 minutes typically. The cycling of temperature is a feature to improve the cooking performance of the food in the oven.

How do I know this? My last job was for Whirlpool and I designed the control in your oven!

 

Marv, that is why I set it for 275... Normally in a real oven we set it for 300.... So the lower setting is to allow for the upswing...

So if it breaks, do you make house calls?

 

Try the "convection" setting for more even heating

 

Small world - a million years ago I sold you the temperature sensors for that control (I used to work for HyCal).

 

RS Uprights with Motons... I want those!

Heating definately is the way to go when dealing with fittings like this.