How to remove steering head bearings?

[nhmaf]

LOL!   I had assumed that this would be with a new, clean, degreased bearing - DEFINITELY do not put an oil or greased one in the oven in the house, or you will certainly add some stress to your marital relations!
 

[AlfromNH]

two 5mm holes at each end is hard Swiss cheese : )

There is a lot of metal 'there abouts'

Rev Light

My frame is black, so holes like that would almost invisible.
Interesting...

[georgesgiralt]

Hello !
The better way to heat a bearing is to have a pan, a litre of oil and a thermometer.
Heat the oil in the pan up to 145°C (stay a little below 150 °C) then immerse the bearing attached to a string of steel in order to get it back easily.
During that time prepare the axe and a pair of sturdy gloves.
Get the bearing out of the oil and put it in place. Normally it's as easy as spreading soft butter...
Some notes : We used this to exchange crankshaft bearings on two stroke engines. Heat the pan with something electric because hot oil gasses and naked flames are not good neighbour.... 150° is considered safe for the tempering of the steel. I once was told that above this you'll ruin the bearing. If you do this in the shop and if the oil has no sulphur in it, you'll keep the wife and your neighbour won't call the fire department...
I use an old pot my wife was throwing away. It was used to heat wax for her legs...  Perfect and neat  

[Dave 2]

Buy the tool and follow the directions, the increase in your confidence and self esteem is worth the price [smiley=bmw_smiley.gif] You may find that several hundred miles down the road the bearings will have been fully seated by bumps in the road (Maine has many broken up roads to choose from) and that you will need to retighten the the large ring at the top of the upper fork clamp, at least that is my experience and Duane mentions this as well. D2

[Luca]

bearing attached to a string of steel in order to get it back easily.

One of the best tool investments I ever made was a magnet on a stick.  Great for fishing steel bits out of hot oil, pulling washers off of studs, and much, much more

[AlfromNH]

I've installed new bearings. I bought the cycleworks tool for removing the outer races:





The top came out easily, the bottom took quite a bit of torque on the wrench. But the frame bosses looked good, all is well.

I didn't buy the tool for removing the lower inner race.  Instead I used a Dremel to cut the cage and make a groove in the race, a couple taps with a hammer and chisel and she's free!



I used the old races as a drift to tape the new ones in place



A bit of a milestone, my first re-assembly on this bike!



Question: I saw on the Motobins Tips page an article about electrical erosion on the stearing head races. These are my old races. Is that what I'm seeing on the upper race(the one on the right)?

[montmil]

What you're seeing is bearing races that have been damaged by being either over or under tightened. The term is brinelled. Actual low spots that have been pounded into the races by the bearing rollers. Usually felt as a notchy steering when pushing the bike around the garage. Or, it could be false brinelling...

Proper preload is essential for long bearing life and smoother steering during ops. After you've completed the rebuils and a few miles have passed below th eoil pan, you will want to readdress and adjust the preload on those new bearings.

Brinelling  http://en.wikipedia.org/wiki/Brinelling

False brinelling http://en.wikipedia.org/wiki/False_brinelling

One of the first things I had to do with my freshly purchased '83 R65 was replace the steering bearing. Not too pretty...



  

[AlfromNH]

ouch, that one looks pretty bad!

I was talking about the vertical lines "ghosted" on the upper bearing tho. I can't feel them with a fingernail, I was wondering if they're electrically-caused.

[Barry]

I was talking about the vertical lines "ghosted" on the upper bearing tho. I can't feel them with a fingernail, I was wondering if they're electrically-caused.  

I know the motobins article you mention and the theory about electrical erosion. I also know who wrote those articles and it wasn't Motobins themselves but a guy called Mike Fishwick who was the Technical Officer of the BMW club. Mike is very knowledgable and experienced but on this one I've never been fully convinced or at least I would want to see it better explained.  The idea that there is a fortuitous earth path through the bearings doesn't make obvious sense as there is already a perfectly good earth via the wiring harness.  I have actually tested the earth between the forks and main frame while turning the bars and saw no change in the reading so I assumed the main earth path is fine. The possibility that it is the high voltage impulse to the Tacho that might have something to do with it does spound plausable as that pulse can be 250 Volts but I still don't understand why the forks aren't already earthed via the harness.