K11 Owners Group

[Jnclem]

I have a 93 K1100LT, ANS 1, with a leaking MC. My Clymers manual says that to remove the MC for a rebuild, I need to drain the entire rear system. Since I flush my brake system with fresh fluid at least once each year, do I really need to empty everything?

I was thinking I would empty the reservoir, remove the MC from the lines, and try if possible to keep some fluid in the line between the MC and the ABS. If I can then rebuild the MC, refill the reservoir, I should be able to get most or all of the air out on that end simply by allowing the bubbles to rise straight up to the the res.

It seems to me that I would then get virtually all the air out at the bleeder on the ABS actuator. I will bleed the line from there to the caliper for good measure, but I would think most of the air would be between the MC and the ABS. Am I missing something here? Any other tips would be appreciated.
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'93 K1100LT, '89 R100GS

[Grunter]

Earlier this year I replaced the brake line to the rear calliper and the whole system was emptied. For what you will save in fluid to be quite honest it isn't worth the hassle.

So long as you are methodical with the way you bleed the line there should be no problem. Bleed to the ABS drum first using the bleed nipple on the top and once air has stopped coming from there, bleed the air from the calliper.

Unless you have not already done so already compress the pistons right back into the calliper before you start to expel any air present, this makes it much easier to avoid trapped air.

One way air can get into the system when bleeding the brakes is through a loosely fitting bleed screw. I always wrap a couple of turns of plumbers PTFE tape around the threads which make them air tight even when unscrewed a couple of turns.
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1997 K1100LT
1994 R1100RS

[N41EF]

Make sure you soak the rubber "cup" seals in brake fluid prior to rebuilding it. Don't use the spray can brake cleaner on the MC, it's aluminum and will start to corrode as soon as the air hits it/ I cleaned the bore out with steel wool on a cotter pin in the drill, whiped it down and rebuilt it.
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2014 R1200RT Water Cooled
2001 R1100S Light
1993 K1100LT. Nissan Ice Blue.(Gone)

[Jnclem]

Ok, all of that makes sense. I always bleed them that way, ABS first, then caliper. I was trying to think of a way to attach some 0000 steel wool, or scotchbrite - something a machinist friend suggested - to a drill. A cotter pin is a great idea. Now I just have to wait for parts. Thanks.
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'93 K1100LT, '89 R100GS

[Grunter]

If you take a 6mm mild steel bolt or a pice of steel rod about 4" (10cm) long and cut a slot on the end about 2" deep, but wide enough to slot a thin piece of steel wool then fit it into an electric drill. Insert the 'tool' into the master cylinder and switch on the drill. A quick 10 second burst will be enough to clean out any crud inside.

It will have to be washed out afterwards with a fluid not likely to contaminate brake fluid.
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1997 K1100LT
1994 R1100RS

[Jnclem]

[Jnclem]

OK, apparently I'm an idiot, but I am having a huge problem getting the brake pedal return spring back on and that front MC mounting bolt back in place, at the same time. In fact, by trying to put the spring over the bolt and the sleeve that it rides on, while putting in the mounting bolt, I managed to screw up the threads on the side plate a bit. They aren't too bad, and I can get them straightened out tomorrow, but what is the procedure for getting that spring back in place. Do you guys remove the pedal and spring from the side plate? I didn't, but this isn't working.

On a happier note, the plunger didn't really look bad, but there was a fair amount of crud inside the bore of the MC. I got that all cleaned up and was going to try just putting it back together with the old parts until I screwed up my threads. I know this shouldn't be this hard.
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'93 K1100LT, '89 R100GS

[John Clauss]

My Master Cylinder leaked so bad when it finally gave up there was nothing in there. But I filled up the cylinder and then used my speed bleeder to remove the old until it was all nice and clean coming through.
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1997 K1100LT
1975 R75/6

It will bring you so close to nausea, it will make you sick! - Big Al

[Jnclem]

The rebuild ended up being extremely easy. In order to deal with the return spring, I just needed to remove the brake light switch, take the side plate completely off the bike and work with it on the bench, then remove the nut that holds the bake lever on. With that removed, I could install the spring fairly easily. The spring setup on the K1100 is nothing like the setup on the K75 or K100, that's what through me for a bit. But all in all, it was very easy.
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'93 K1100LT, '89 R100GS