Rear Brake MC Rebuild

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IBAJIM

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I bought a nice '83 GL1100I a few years back and I have been working on it, off & on since then.

I thought the last thing I needed to do was have the rear disk re-surfaced. There is a guy in Michigan who does that for $45 and I had that done recently.

After re-installing the rear disk, I thought I'd better replace the brake fluid and re-bleed the rear brake since the bike has been sitting for so long. When I removed the rear MC reservoir cap, it was almost empty. I must have had a leaky MC.

I removed the MC and took it apart and it was pretty grungy inside. But the bore was in good shape, almost like new.

Question : How firm should the rear brake pedal be after the rear and right front ( this bike has a split braking system ) brake is bled ? How far does the brake pedal move when pressing on it ?
 

dan filipi

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On my '83 with linked I never really had what I would call an acceptable 'feel' in the rear brake pedal until I custom fitted an MC from an 1800, or could have been from a 1500. The reason I changed it was because the spring clip groove was corroded away too much to hold the clip in place, so then I wanted to find a suitable replacement for the stock MC that's readily available.
After that though, the pedal has a nice firm feel and the drop is less. The braking performance is not any better but with a firmer pedal it can be pushed harder so that is an improvement I guess.
 

IBAJIM

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Well, it looks like I have an answer - I bled the front right / rear brake calipers and the pedal is nice & firm now. A lot better than it ever has been. It moves only about 3/4 inch when I press it fairly hard with my hand ( less than an inch ).

So, I'm satisfied with that. BTW, removing the MC isn't that difficult to remove IF the brake line can be loosened. I had to cut mine since a 10 mm tubing wrench would spin on the fitting. It was a PITA replacing that brake line since it had some crazy bends in it and I had to use my double flaring tool.

With the trued ( re-surfaced ) rear disk and rebuilt rear MC I'm betting the brakes are going to work a heck of a lot better. Next spring I'll get the bike licensed and insured and do some riding on it.

Dan: What diameter is the 1800 rear MC ? Mine is 5/8 inch - marked right on it. It seems to be the right size judging from the feel of the pedal - not too spongy or too wooden.
 

chilidawg

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Either you knew this information, or you just got lucky when you had your rotor re-surfaced!

But it's important to note that there is only 1mm difference between a brand new GL1100 rotor and one that is right at its service limit, and that's true for the 10mm Aspencade rotors through to the regular 5mm rotor.

I guess that's why it's hard to find anywhere that will do it, but that said, I'm glad yours worked out for you. :salute:
 
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