Wheel bearing and driveshaft install

uiceJ · Post by **uiceJ** » Thu Jul 09, 2020 5:54 pm

Hi guys, I'm new to the forum and looking for some advice regarding installing a rear wheel bearing and driveshaft. I have searched online and youtube but not been able to come accross my problem. Any ideas or advice would be greatly appreciated.

The vehicle is question is an e90 BMW. I have removed the hub assembly from the car and been able to get the bearing pressed into the carrier and the outer part of the hub (that the wheel mounts onto) pressed into the inner part of the bearing. The issue I am having is when installing the driveshaft it seems to be introducing some play into the bearing. This has happened twice now with two seperate bearings. It's as if the force required to get the driveshaft splines through the hub has pulled the bearing races away from the balls. Before attempting to install the driveshaft on both attempts there has not been any play in the bearing.

The first attempt was done with the driveshaft on the car and the second attempt was after removing the driveshaft from the car and placing the outer part of the hub on the ground and gently hammering the splines through from the top. As far as I can gather this shouldn't apply any force to the bearing.

What is it that I am missing or doing wrong? I haven't yet done up the hub nut, would this remove any play? I wouldn't have thought so as everything appears to be seated correctly.

Dave54 · Post by **Dave54** » Thu Jul 09, 2020 6:40 pm

I don't know what the setup is on these cars, but generally, you don't want to put any shock loading or pressure onto unsupported bearing inner or outer by hammering anything through the inner etc.
If the shaft is a tight fit, then you need to support the inner while pressing or pulling the shaft into place.
Exactly how to do it I can't say.

When I worked in industry, and I can remember several incidences of seeing fitters take a hammer to something tight in a bearing, and the bearing would subsequently fail.

uiceJ · Post by **uiceJ** » Fri Jul 10, 2020 7:50 pm

It's amazing how fragile they are with a force not in the intended direction!

With the bearing sitting externally of the inner part of the hub and the driveshaft splines fitting inside the hub there is no direct contact between the driveshaft and bearing. The only thing I can imagine causing the issue is forcing the driveshaft too far in and the flat area to contact the inner race and pushing it out. I'll have another attempt tomorrow and deliberatly leave space.