GL1000 rear brake master cylinder mounting bolt distance

[toomanybikes]

I've not tried it on a GL, but had success using a Chinabay generic rear master on a CB750F. Just disassemble, clean assemble correctly with fresh brake fluid lubricating the parts. They will be filthy inside when you receive them.

I'll keep that in mind if my current solution doesn't work.

Out of curiosity, I noticed the Can Am RT in your signature and East TN in your profile.

There was an East TN Can Am RT with electrical damage that went quickly on FB marketplace. Was that yours?

I would have snagged it, but space is limited.

[pidjones]

I've not tried it on a GL, but had success using a Chinabay generic rear master on a CB750F. Just disassemble, clean assemble correctly with fresh brake fluid lubricating the parts. They will be filthy inside when you receive them.

I'll keep that in mind if my current solution doesn't work.

Out of curiosity, I noticed the Can Am RT in your signature and East TN in your profile.

There was an East TN Can Am RT with electrical damage that went quickly on FB marketplace. Was that yours?

I would have snagged it, but space is limited.

And, they do take up a lot of space. No, that wasn't mine. Would be very wary of electrical issues on one.

[toomanybikes]

I've not tried it on a GL, but had success using a Chinabay generic rear master on a CB750F. Just disassemble, clean assemble correctly with fresh brake fluid lubricating the parts. They will be filthy inside when you receive them.

I'll keep that in mind if my current solution doesn't work.

Out of curiosity, I noticed the Can Am RT in your signature and East TN in your profile.

There was an East TN Can Am RT with electrical damage that went quickly on FB marketplace. Was that yours?

I would have snagged it, but space is limited.

And, they do take up a lot of space. No, that wasn't mine. Would be very wary of electrical issues on one.

This one was priced low enough for flipping potential ... if I had a barn/space.

[redglbx]

Rubber brake lines should be replaced every 2 or 3 fluid changes (= 5 or 6 years). Modern stainless braided ones last practically forever and double the life of the fluid).

Rubber lines commonly become soft after decades of contact with brake fluid too. If you wrap one hand around a rubber line and squeeze the lever with the other you will feel the tubing expand. This is fluid moved by the master cylinder that doesn't contribute to the movement of the caliper piston(s). In other words: lost braking power.
If you wrap your hand around a braided ss line and apply the brake you will feel the line stiffen, but it will not expand.

Have you ever wondered why brake fluid turns red/brown after a couple of years? it's a combination of oxidization caused by the moisture that finds it's way through the porous rubber and rubber particles suspended in the fluid. I think it is obvious that this reduces the incomprehensibility of the fluid, and thus impairs the function of the brake. Not to mention what can happen if the water boils because the caliper gets hot.

Spot On !

I worked in an automotive brake engineering lab for nearly 30yrs prior to retiring and what Bob says above is pretty much spot on…..in addition to what Bob said part of the reason that brake fluid turns dark is besides moisture collected is that the brake fluid leech’s the carbon (why it’s black) out of the rubber components, and this degrades the rubber over time,,, the expansion & contraction of those parts just speeds that process up.

The braided steel lines also expand some but a much smaller amount, the internal part of the line is basically a teflon tube that doesn’t expand/contract like rubber does plus it doesn’t leach carbon like rubber does. One of the other big points for flex/expansion is from the aluminum bolted together calipers, lots of flex ! Which is why we used pretty much only cast iron calipers,, not as pretty as those aluminum piece’s but actually much better..

I got to see a dyno test of one of our bigger 4 piston cast iron calipers against one of those very pretty 8 piston aluminum Italian calipers that are currently popular , the customer (very large German company)wanted to see the differences for repeated simulated 160mph autobahn stops,,, very interesting ! It all boiled down to heat soak/fade which our cast iron calipers suffered from more than the aluminum calipers although our cast iron calipers really outperformed the pretty aluminum until they became heat soaked ,,,, the pretty calipers were pretty much shite from the start but stayed that way no matter how many stops you did where our cast iron pieces were waaay better for 3 or 4 stops and then just went away …. Anyway if you have nice weather get those bikes out ! Also I would suggest you change your brake fluid when you change your cam belts or every few years,, outside of the US they change the b-fluid pretty much on a yearly basis. My .02

[toomanybikes]

UPDATE - The rear brake is now functional, not yet cosmetically perfect, but roadworthy and safe , with the new Galfer lines.

Still left to be done ...
1. Get that rusted&busted circlip out and replace with a cleaner one. It's not budging at the moment, so I'm not nervous about it spontaneously popping out.
2. Source a longer hose from the reservoir to the m/c so I can ditch this one cobbled together from two shorter lines. The GL1100 hoses are longer than the CB750's, so I'll look for one of those.

PXL_20250725_200720592-EDIT.jpg

[Fred Camper]

Looks good and does not leak, so I would leave it alone until the next fluid swap.

[Sidecar Bob]

You could probably use a piece of fuel line for that.....

[toomanybikes]

You could probably use a piece of fuel line for that.....

I tried some 3/8" fuel line I had on hand, but the barb was too big and/or the casing was too rigid. The current solution is working for now.

[redglbx]

You could probably use a piece of fuel line for that.....

Nope ! You have to use line specifically intended for brake fluid ,, fuel line will dissolve/blister and fail,,, must be brake fluid compatible !

[Sidecar Bob]

OK. I stand corrected.