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K1100LT front brake

 
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petewright1972@gmail.com



Joined: 10 Dec 2014
Posts: 15

PostPosted: Wed Feb 14, 2018 3:28 pm    Post subject: K1100LT front brake Reply with quote

Hi all

My bike is a 1993 K1100LT and I am having problem with the front brakes. I hope somebody can advise ...

This is something that went wrong suddenly between rides - i.e. brakes were working perfectly when I rode home and parked up one evening but the next morning the problem had manifested itself.

As I was pushing the bike out of the garage, I noticed I had no effective front brake - the lever squeezed all the way in with very little resistance. If I pumped the brake, I got a "lever" back and the brakes worked - but if I left it for a few seconds, it would revert back.

We've tried bleeding the brakes through and have taken apart and cleaned the master cylinder - can't see anything glaringly obvious there. Can't see any leaking fluid either nor evidence of it depleting its fluid levels.

Any ideas from here would be appreciated - meanwhile I'll continue to search through these forums in case I've missed an earlier case.


Thanks in advance
Pete
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N41EF
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Joined: 23 Mar 2014
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Location: Aiken, SC

PostPosted: Wed Feb 14, 2018 3:54 pm    Post subject: Reply with quote

Are they the original brake lines?
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1993 K1100LT. Nissan Ice Blue.
2001 R1100S Light

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petewright1972@gmail.com



Joined: 10 Dec 2014
Posts: 15

PostPosted: Wed Feb 14, 2018 4:11 pm    Post subject: Reply with quote

Unfortunately I have no way of knowing this as I have only owned the bike for a few years. There’s certainly nothing in the quite extensive service documentation to say they’ve been changed since the bike came into private ownership.

The bike was originally owned by the Police so you would assume regular routine maintenance .... but then again I did find it still had the original fuel filter last summer so perhaps not Wink
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N41EF
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PostPosted: Wed Feb 14, 2018 10:49 pm    Post subject: Reply with quote

Are the brake lines black rubber? Or some color of braided metal?
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1993 K1100LT. Nissan Ice Blue.
2001 R1100S Light

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petewright1972@gmail.com



Joined: 10 Dec 2014
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PostPosted: Thu Feb 15, 2018 3:03 am    Post subject: Reply with quote

Ha now that one I can answer!

Black rubber.
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Scott_Anderson
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PostPosted: Thu Feb 15, 2018 8:29 am    Post subject: Reply with quote

Being black rubber, they are at the worst still original, or at the best, been replaced with BMW oem hoses.
Not saying that they couldn't be a custom made hose set, but not likely....

Generally there will be 2 issues that historically occur with the oem hoses.

1. they can develop a weak spot that will bulge when you pull the lever and not allow pressure to apply the brakes. Eventually they can burst.

2. internally they can delaminate and begin to act like a one-way check valve such that you apply the brakes, and then they won't release.

Another possible issue could be the ABS unit(being '93 you should have 2, one on each side). If the hoses are starting to delaminate some small rubber bits could be stuck in the ABS control valve and cause your issue as well.
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Mike d
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PostPosted: Thu Feb 15, 2018 2:43 pm    Post subject: Reply with quote

I recall that OEM brake lines had a form of date marking on them. But as Scott has suggested the lines can bulge under pressure.

Mike
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petewright1972@gmail.com



Joined: 10 Dec 2014
Posts: 15

PostPosted: Thu Feb 15, 2018 2:53 pm    Post subject: Reply with quote

Guys, definite food for thought here, thanks for your advice.

I will look into replacing the brake lines and report back Smile


Best regards
Pete
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wuckfitracing



Joined: 09 Mar 2016
Posts: 17

PostPosted: Sat Feb 17, 2018 4:49 pm    Post subject: Reply with quote

As scott said replace them. My front one locked the brake on and threw me off. Only at walking pace so not much damage. Got it back home and saw the black pipe bulge when pressed then it popped !!
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Grunter
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PostPosted: Mon Feb 19, 2018 4:59 pm    Post subject: Brakes Reply with quote

I had the same with my 1998 K1100LT.SE This 1st showed when I was holding the bike on a hill and the lever started to move back towards the bars.

I replaced the lines with stainless braided pipes.

I split open the old ones and the central core no longer existed, the whole pipe was literally a honeycomb of tiny passages where the fluid had somehow managed to work the brake system. Strangely though the pipe did not 'balloon' out when the lever was squeezed

I count myself lucky!
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Ernie-NH
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PostPosted: Thu Feb 22, 2018 2:54 pm    Post subject: Reply with quote

Very Happy Very Happy

Hello Grunter and others...

Before I retired and still had access to the ATE Lab in Frankfurt, we examined brake lines and hoses from all over the world, both new and ruptured.... Until about 1998, nearly all hoses, from Asia, South America, Europe and America had primary liners ( first surface seen by the fluid ) made from PEA ( Polyetheralcohol, which is a viscous compliant polymer) onto which the "weave" is spun. As mineral laden water enters the brake line thru the fittings (more than 70% of water in brake systems enters this way ), it degenerates into an acid via electrolysis which then begins to attack the PEA liner and later the weave, finally weakening the first EDM elastomer overmold, the barrier coat, and lastly the outer NBR elastomer hull which is already UV weakened from the outside. In short: From the day they are installed and exposed to cyclical stresses, fluid degradation due to eddy currents, environmental intrusion via waterborn road salts, and UV exposure..... conventional "rubber brake hose" is on its way out and has one less use cycle in its future every time you pull the lever...

Despite knowing this, and having documented it many many times in the lab, when I got my '95 K1100 I FAILED to change out the hoses. What happened was just as I described...which was hose rupture just above the swage, which i knew would happen and chose stupidly to ignore, though my friend and colleague Dr Rudolph ATE chief chemist and I, had seen this failure hundreds of times. I looked to the sky and saw him shaking his finger at me, and within the week the Spengler lines arrived...

Pete Wright needs to do the same...

Regards all...Ride Safe.....// Ernie in NH
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petewright1972@gmail.com



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PostPosted: Tue Mar 13, 2018 3:53 pm    Post subject: Sorted! Reply with quote

Firstly, a 'THANK YOU' to everybody who took the time to reply - your advice was very much appreciated.

Secondly, to complete the thread in order to help future readers encountering the same problem.

The advice regarding the brake line was spot on. From the information offered I am assuming the brake line was the original and that it had worn. Not that I was able to spot a bulge anywhere but replacing the brake line certainly cured the fault.

I little more complication here though. When I bought the bike I was advised that that ABS II was disabled because it had failed. I've never thought twice about this and never had any issues other than an intermittent warning light and an advisory on the MOT test.

However, when looking into replacing the brake line I noticed that the old line still ran from the cylinder, back to and through the ABS II pump and then on to the splitter above the calipers. So essentially the ABS II pump although "disabled" was still in the loop. I therefore concluded the ABS was only disabled electronically somehow.

I have now completely bypassed the ABS II - installing a new brake line directly from the cylinder to the splitter on the fork brace. This would seem to eliminate the pump as an unnecessary point of failure and also reduce the length of brake line required. This *seems* (I've only ridden 30 miles since the repair) to have eliminated the intermittent warning light too Very Happy

I have left the pump in-situ as I *may* wish at some stage to repair the ABS but having not looked into this i don't know if it is the pump, the sensor or the electronics that is/are faulty.

Anyway - I'm mobile again. Thanks again for your help!!!
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ljjohns
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PostPosted: Tue Mar 13, 2018 6:03 pm    Post subject: Reply with quote

For whatever it's worth: do rehabilitate the ABS.

You only need it once, but then you really, really need it. I was touring in Washington state on my 93 K11LT with Felicity on the pillon. In broad daylight, we encountered some deer darting into the roadway.

Without the ABS, I would not have another 12 years of wonderful companionship (assuming I myself survived).

Larry Johnson
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1993 K1100LT (Washington)
1995 K1100LTSE
1996 K1100LTSE (parts)
2003 K1200LTC
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N41EF
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PostPosted: Tue Mar 13, 2018 8:09 pm    Post subject: Reply with quote

Your '93 has ABS not ABS 2. It should have the two black ABS pumps on each side of the rear frame. I'd hook everything up, bleed it, and go from there. A GS-911 will read and clear ABS codes, you might try that assuming that everything is still hooked up electrically.
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2001 R1100S Light

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Jim
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PostPosted: Wed Mar 14, 2018 12:13 am    Post subject: Reply with quote

Hello Pete - that's an automotive ABS system. If you can find someone in your part of the world that repairs those systems, they should be able to fix yours.
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1997 K1100LTSE 94,000
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abreeze
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PostPosted: Wed Mar 14, 2018 8:39 pm    Post subject: Reply with quote

It sounds like your master cyclinder piston seal has failed...
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