Time for new steering bearings? Warning-big picture

[DaveBBR]

Hi everybody!

I finally got back on the board, now that I'm putting my 75/6 back together. This was my lower steering head outer race.
I know, I waited too long to service them. But I've been off the bike for almost a year now and had to get it back into shape for my personal sanity.

Dave

DSC_0004.JPG (186.8 KiB) Viewed 2861 times

[Duane Ausherman]

Do you have a question? Be sure the carefully align the forks upon reassembly.

[Rob Frankham]

Hi,

There is a persistent belief that corrosion to the head bearings can be caused in part by electricity passing through them. Of course, the headlamp and most of the electrical bits attached to the steering assembly on these models are grounded in their own right via the loom but it may be significant that the front indicators are not. This means, in the absence of a solid ground from the forks to the frame, that any ground current from them, has to pass through the bearings.

In short, I don't know for sure if it makes any difference but, to my mind, it's well worth running an extra ground wire, either to the forks as a whole or individually to each front indicator. You don't actually have to run a seperate wire past the bearings (where it would flex), you just need to run it to a spare ground terminal on the circuit board in the headlamp shell.

Rob

[Roy Gavin]

On my G/S there was no protruding lip on the outer race - Cycleworks have a relatively low cost tool to to remove them if yours are the same.

[ME 109]

On my G/S there was no protruding lip on the outer race - Cycleworks have a relatively low cost tool to to remove them if yours are the same.

Have you got a piccy of that tool Roy? I'm keen to see what sort of tool can grab 'nothing'
My bike has next to no protrusion, hence the arc welder being the tool of choice.
The bearing cups 'fall' out with a 3/4" bead of weld.
That is of course all very well for those who have a welder......

[dougie]

http://www.cycleworks.net/index.php?mai ... ucts_id=62

[Chuey]

Hi,

There is a persistent belief that corrosion to the head bearings can be caused in part by electricity passing through them. Of course, the headlamp and most of the electrical bits attached to the steering assembly on these models are grounded in their own right via the loom but it may be significant that the front indicators are not. This means, in the absence of a solid ground from the forks to the frame, that any ground current from them, has to pass through the bearings.

In short, I don't know for sure if it makes any difference but, to my mind, it's well worth running an extra ground wire, either to the forks as a whole or individually to each front indicator. You don't actually have to run a seperate wire past the bearings (where it would flex), you just need to run it to a spare ground terminal on the circuit board in the headlamp shell.

Rob

Hi Rob, in answering this question, please know that you cannot talk down to me about electricity as I know so little that it is correct to assume a simple mind. That said, I know wires are how the juice gets from one point to another. On my bikes the turn signals have two wires each. Isn't one of those wires a "ground" wire? I think they trace back into the headlight bucket so I would have thought they were ground.

I will say that in my line of work, the only electricity I have ever been asked to trouble shoot is bicycle light generators. The one and only thing I've ever seen a problem with, and therefore, been able to fix, is a faulty ground connection. In other words, in addition to knowing why we have wires, I have a high regard for a good ground.

Chuey

[DaveBBR]

It isn't the corrosion that bothers me, if you look carefully you can see the indents in the outer race from the rollers settling in. This is the lower, the upper looked ok.

I did a fork alignment when I got the bike, Duane. Are you saying that completely disassembling a structure like that may result in alignment issues when it is put back together?

Shirley, you jest.

dave

[Duane Ausherman]

Dave, I can't remember squat, so I keep on posting the same ole $hesse.

In that case, you know what to do.

That is one of the worst bearings that I have ever seen from the forks. I have never seen a set worn in such a way as to suspect that electric current did it. They were all from the beatings of the rollers. Not saying it can't happen.

[Rob Frankham]

On my bikes the turn signals have two wires each. Isn't one of those wires a "ground" wire? I think they trace back into the headlight bucket so I would have thought they were ground.

Chuey

Hi Chuey,

Depends on the age of the bike... and to a certain extent, the whim of Uncle Hans... According to the diagrams, the 73/74 yesr /6s don't have ground wires to the front indicators but the 75/76 years do. From experience, however, my R60/6 is a '76 bike and which did not have them when I got it. Either something has been changed by a PO or it was never fitted with htem... I suspect the latter. Wouldn't be the first time that BMW wiring diagrams have existed in a different version of reality to the real world. Either way, the bike has ground wires now.

Duane,

I tend to agree that damage is normally down to brinelling (i.e. pressure damage) on the head bearings but that bearing appears corroded to me. While I keep an open mind, I don't think it's unreasonable to suspect that electricity going through a moving connection where moisture can get might cause or worsen corrosion. Either way, I think a positive ground here is a good idea.

Rob