K11 Owners Group

curve_in · Posted: Mon May 13, 2013 5:55 pm Post subject: Brake Lever losing pressure

I did my longest day yesterday - 300 miles. I had a brake issue come up. At a light, I was holding the front brake lever and when I increased the pressure, the lever would slowly move towards the bar. In my old car fixing days, I'd think it was the master cylinder. Any ideas?
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Kervin

K1100RS Mystic Red 1993

Stoked Steve · Posted: Mon May 13, 2013 6:13 pm Post subject:

Hi Kervin, that would be my guess too. I rebuilt that M/C about 6 years ago, the dealer supposedly had done it 2 years earlier but did a shoddy job of it.

So I got the kit from Beemer Boneyard (I think) and completely took it apart and cleaned and steel wooled it and got it back proper. But, it's been awhile. Might just need a good cleaning....some crud in there might be allowing some fluid to leak around the wiper seal.

Also, has the fluid been changed since you got it? If not, that fluid is 2-3 years old and is due to be changed.
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Steve
Virginia Beach, VA
93 K1100RS Mystic Red SOLD
12 Suzuki DL650A VStrom

Scott_Anderson · Posted: Mon May 13, 2013 7:36 pm Post subject:

+1 on the fluid change, but like Steve suggested might be due for a seal kit.

I also moved it here to Tech.
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1995 K1100LT 0302044
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1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold)

Number 6 · Posted: Mon May 13, 2013 8:09 pm Post subject:

Did you see any fluid leak?
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I am not a number, I am a free man.

94 K1100LT

curve_in · Posted: Mon May 13, 2013 10:45 pm Post subject:

Jim · Posted: Mon May 13, 2013 11:32 pm Post subject: front mc

Kervin - I rebuilt mine once, Anton rebuilt it twice. At some point, it's time to replace it. These things don't last forever. I think your bike is a few years older than mine.

I'm sure if there was a way to insert a brass sleeve in the master cylinder, that would probably resolve a lot of the problems...
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Jim
1997 K1100LTSE 94,000 - still has gremlins!
1995 R100RT Classic 16,650 crashed - repaired!
1992 K75RTP 46,000

"We shall not all die, but we shall all be changed."

Number 6 · Posted: Tue May 14, 2013 12:09 am Post subject:

Sometimes just cleaning it will do the trick.
Be aware that there are 2 versions of the master cylinder, the new one is anodized (32722352190) and wears much less. Also the repair kit should match the type of master cylinder (anodized or not), so if you have the old version, it's better to find a used anodized one.
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I am not a number, I am a free man.

94 K1100LT

drikko · Posted: Tue May 14, 2013 8:17 am Post subject:

Rebuilding the master cylinder is real easy. Mine was leaking although very slowly, a drop a day at res. Fixed it doing a set of seals and it aint rocket science. If it was anything but the master cylinder you'd see a flood of brake fluid out of the splitter or one of the calipers.
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K1100RS '97
Laverda RGS 1000 '84
Jim Young Trailer Sailer 5.7M WB

DISCLAIMER:- Anything I say may have been when I was drunk so please don't take it personally.

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curve_in · Posted: Tue May 14, 2013 9:18 pm Post subject:

I'm getting a new master cylinder. There is corrosion both inside and out plus it has been rebuild before. I do know that a rebuild would work for now, but I'm really grooving on this bike and I want to just fix things once. Thanks for the replies!
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Kervin

K1100RS Mystic Red 1993