2 disc conversion on 77 R100/7

[sterob]

I fitted a H/Bar master cylinder a few months ago( single ATE disc) and I fitted the front brake light switch into the unused 2nd disc brake line port. Now I want to fit a second disc, and hence a second brake line, whats the convention for installing the front brake light switch?
I suppose I could drill a tap another hole in the rear of the 'splitter' that sits under the tank? Convert to a handlebar operated switch?
Any other options?

Sterob

[Armaguidon13]

the hole in front seems the best way (and genuine way)

[DanielMc]

There's a four-way under-tank splitter designed for the job - BMW part number 34321241568. It's shown as No. 2 on the diagram below:



You might also need to think about the master cylinder diameter - OK for one disk might not be OK for two, and at the least you'll have more lever travel. This can mean more leverage and a better brake, but too much will just trap your fingers against the twistgrip...

[Roy Gavin]

If you have a Jap dismantler close take walk round and look at the front of the firewall- the brake lines are usually bolted to there and with a bit of luck you will find one exactly the same as the BMW Y piece the previous poster has located.

I found one on a compact that GM imported to Oz , made by Isuzi or someone,the guy wouldnt take anything for it- "cant sell secondhand brake parts" was his reason.

[sterob]

the hole in front seems the best way (and genuine way)

I am using that for the 'inlet' from the M/C at the moment. I thought I might have to drill another hole in the rear of the splitter.

Sterob

[sterob]

There's a four-way under-tank splitter designed for the job - BMW part number 34321241568. It's shown as No. 2 on the diagram below:



That looks like a 3 way unit to me ( what I already have.) But I will investigate more and see what comes up. Thanks.

You might also need to think about the master cylinder diameter - OK for one disk might not be OK for two, and at the least you'll have more lever travel. This can mean more leverage and a better brake, but too much will just trap your fingers against the twistgrip...

Yeah, I will see how it goes when I get it working. I hope not. All that gear is near new! ( Motobins kit)

Sterob

[sterob]

If you have a Jap dismantler close take walk round and look at the front of the firewall- the brake lines are usually bolted to there and with a bit of luck you will find one exactly the same as the BMW Y piece the previous poster has located.

I found one on a compact that GM imported to Oz , made by Isuzi or someone,the guy wouldnt take anything for it- "cant sell secondhand brake parts" was his reason.

Good to know Roy, thanks. Our wrecker is not a very 'customer friendly' person, but its worth a shot. Is almost like you are annoying him by wanting to buy parts off him...lol


Has no -one drilled out another port on one of these splitters?

[Ken in Oklahoma]

Has no -one drilled out another port on one of these splitters?

The problem as I see it is that it isn't a simple drilling and tapping operation. I haven't looked closely at the referenced splitter, but I have looked closely at the under tank master cylinder for a single disk setup, with a view to adding another port for a second brake line. The "hole" is complicated with not only the threaded part but also a more or less precision seat for the brake line to seal against.

Plus, here in 'merica I'm not sure how available the metric tooling might be. And then, if I had the tooling, holding the part to be modified would be a problem. And I'm not sure, then, if the job could be done on a simple drill press.

Of course some people here will have the required equipment, but now we're talking about a "for hire" professional job and that's likely to be more costly than the required splitter (if an appropriate splitter can be found).


Ken

[sterob]

Has no -one drilled out another port on one of these splitters?

The problem as I see it is that it isn't a simple drilling and tapping operation. .........a precision seat for the brake line to seal against.
Ken

Yes, I thought that may be the case, thinking about it again. I guess if the pressure switch has a tapered thread I might be able to do it then.

I'll go and see the wrecker and see if he can help first.

Sterob