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rydor
Flying Brick Rider
Joined: 16 Nov 2006
Posts: 1304
Location: Southern Illinois, U.S.A.
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 Posted: Mon Sep 08, 2008 10:51 am Post subject: Panic stop, now leaky front master cyl. |
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Did a MAJOR panic stop, after which the front brake lever was soggy. Got her home, popped the reservoir and noted the level was low. Added fluid and gave the lever a slow squeeze. Bubbles rose from the rear hole. After that, lever feel was better again, but a day later, this.
Any idea from this pic what my options are? 
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jpberens1994K1100RS
Flying Brick Rider
Joined: 06 Apr 2008
Posts: 784
Location: Hales Corners, WI. / Relocating to central FL.
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| Posted: Mon Sep 08, 2008 11:26 am Post subject: Front brake |
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The piston seal is shot. You gotta replace it. They call it a rebuild, but it is not.
The flippen little piston with the seal is abut $45.00.
The bore needs to be dressed and as smooth as glass. Try to get a new boot too! That little boot BARELY keeps out the moisture and stuff.
I used my OLD boot when I did mine the other weekend, but I used Permatex liquid gasket to seal it to the master cylinder and make a tight seal.
Your system was marginal if this happened. Would have been time anyway rebuild it anyway.
Glad your OK.
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1993 K1100RS that I'd rather be riding FAST!
2014 Moto Guzzi Norge |
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Flying Duck
PsyKotic Waterfowl
Joined: 27 Jan 2005
Posts: 10102
Location: Bumf***, WA
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| Posted: Mon Sep 08, 2008 12:20 pm Post subject: |
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I've found that sometimes it's just crud in the master cylinder. Before spending money, try this:
Pull the piston out of the master cylinder.
Clean any crud off of the seals on the piston if they don't show noticable damage.
Check the wall of the master cylinder to see if it's pitted. If it's pitted then you need to $$$$ a new master cylinder. If the bore isn't pitted then clean it with some 0000 steel wool.
I did that to a VERY leaky master cylinder and it worked.
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93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
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Off the grid
Chaotic Good
Joined: 05 Jul 2006
Posts: 3414
Location: At the local taco truck waiting for Jo.
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| Posted: Mon Sep 08, 2008 1:36 pm Post subject: |
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Did you activate the ABS in the front?
Glad you're ok!
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Bane of your existence since July 2006
2007 Triumph Tiger ABS. "Sabertooth"
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jpberens1994K1100RS
Flying Brick Rider
Joined: 06 Apr 2008
Posts: 784
Location: Hales Corners, WI. / Relocating to central FL.
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| Posted: Mon Sep 08, 2008 3:47 pm Post subject: master cylinder |
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My bore was a little pitted towards the front which tells me also that boot did a poor job keeping the water out. The piston was very clean & the front seal looked very scored & scratched up. Back seal was AOK but of course you need to install the entire piston with both seals.
I should have used a brake cylinder hone, but spent a good 20 minutes redressing it. I first packed a cotton ball all the way in there. Then started with 180 grit sand paper, working to 340 before switching over to 000 steel wool. Used a little brake fluid for lubrication on all steps. Then cleaned it all up before & after pulling out the cotton. Re assembled & bled the system.
Been great so far.
Going to do the rear brake as soon as the parts get here. Expect it to be a little trickier as the resivoir is above the master cylinder instead of being a part of it
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1993 K1100RS that I'd rather be riding FAST!
2014 Moto Guzzi Norge |
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rydor
Flying Brick Rider
Joined: 16 Nov 2006
Posts: 1304
Location: Southern Illinois, U.S.A.
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| Posted: Tue Sep 09, 2008 1:43 pm Post subject: |
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| Off the grid wrote: | | Did you activate the ABS in the front? |
Yeah, bless ABS  I was on the front so hard that the rear did squirm around a bit, might have been lifed up in an unintentional stoppie.
And thanks for all the advice, the MC rebuild kit should be in my hands tomorrow... I may upgrade to braided lines too since there will be brake bleeding happening anyway... |
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jpberens1994K1100RS
Flying Brick Rider
Joined: 06 Apr 2008
Posts: 784
Location: Hales Corners, WI. / Relocating to central FL.
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| Posted: Tue Sep 09, 2008 1:45 pm Post subject: New lines |
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If you upgrade, could you share please where you buy them from?
And of course if the $ is a good deal.
Thanks!
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1993 K1100RS that I'd rather be riding FAST!
2014 Moto Guzzi Norge |
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Jim
Site Admin
Joined: 17 May 2003
Posts: 3841
Location: WHERETHEFUNNEVERENDS
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| Posted: Tue Sep 09, 2008 3:01 pm Post subject: Re: New lines |
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| jpberens1994K1100RS wrote: | If you upgrade, could you share please where you buy them from?
And of course if the $ is a good deal.
Thanks! |
here's one source: http://www.spieglerusa.com/
I got mine from Spiegler - no complaints. They should have a kit for your bike - just pick a color.
_________________
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." |
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chopper_harris
Flying Brick Rider
Joined: 28 Dec 2007
Posts: 232
Location: Nr Wigan, UK
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| Posted: Tue Sep 09, 2008 7:01 pm Post subject: |
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| rydor wrote: | | I may upgrade to braided lines too since there will be brake bleeding happening anyway... |
If you are still on the original hoses, this is a no brainer - your hoses are between 10 and 15 years old, and WILL be degrading.
There was a thread some weeks back about replacing one hose, where a potential failure shifts to the next weakest hose.
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I had supplied Goodridge hose for many years - the prices steadily climbed, whilst service declined.
Have now switched to Earls (part of Holley Corp) whch are top quality at a reasonable price.
http://www.holley.com/index.asp?division=Earls
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The only pain is that you have to remove the tank to get at the front m/cyl to ABS hardpipe joint.
It is buried amongst the wiring connectors adjacent to the headstock tube.
The job requires 14mm and 11mm open end spanners.
You will inevitably want to clean and 'improve' the rats nest of wiring left for you by a previous owner (DAMHIK) 
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