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Bazsm
Big Brick Rider
Joined: 09 Aug 2021
Posts: 55
Location: Hayling Island, UK
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 Posted: Sun Aug 29, 2021 3:01 am Post subject: Brake pedal sticking |
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The new bike is in pretty good shape but I knew the rear brake wasn't right as the pedal would stick down....amazing how it passed it's MOT a week before I bought it!
Anyway decided to remove the r/h side footpeg hanger to take a proper look instead of just spraying some lube down there and pleased I did. The brake master cylinder was showing signs of crusty brake fluid around it and the brake pedal was disintegrating (as was the case on my old bike too), luckily I'd bought a used pedal which is in perfect condition so I'm fitting that. I guess the brake pedal is a common complaint on here?
 [/img]
I had also fitted a master cylinder repair kit to the old bike about a month ago so swapped those too. I just have to figure out how to bleed the rear brake now and I'm guessing that metal pipe to the ABS2 isn't gonna make it any easier!
BTW - I had to do a search to see how to upload a photo as I've always uploaded directly to forums so having to use a host is new to me, I've gone with imgur as I didn't have to register but I do wonder how long it will stay on that site and add any (admittedly limited) value here!
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1994 K1100LT |
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Flying Duck
PsyKotic Waterfowl
Joined: 27 Jan 2005
Posts: 10102
Location: Bumf***, WA
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| Posted: Sun Aug 29, 2021 7:14 am Post subject: |
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Holy cow! I've messed with many dozens of Ks and never seen anything remotely like that brake lever.
Most times it's not necessary to buy a rebuild kit for the rear master. I just take them apart and clean them and that usually fixes them.
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93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE |
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Grunter
Flying Brick Rider
Joined: 30 Sep 2015
Posts: 369
Location: North East England
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| Posted: Sun Aug 29, 2021 1:49 pm Post subject: Brake lever |
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That damage is probably all down to the copious amounts of salt that they use on our roads when it is icy or snowy. Then not washing it off when you get home..
I have seen something similar on a drum brake adjuster fitted to a very old R80/7 but not quite as bad as this.
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1997 K1100LT
1994 R1100RS |
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Bazsm
Big Brick Rider
Joined: 09 Aug 2021
Posts: 55
Location: Hayling Island, UK
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| Posted: Sun Aug 29, 2021 4:07 pm Post subject: Re: Brake lever |
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| Flying Duck wrote: | Holy cow! I've messed with many dozens of Ks and never seen anything remotely like that brake lever.
Most times it's not necessary to buy a rebuild kit for the rear master. I just take them apart and clean them and that usually fixes them. |
Pleased to add something new to the forum…..I’d never thought of trying to recover a leaking master cylinder as just presumed it had worn out!
| Grunter wrote: | | That damage is probably all down to the copious amounts of salt that they use on our roads when it is icy or snowy. Then not washing it off when you get home... |
I did wonder if that might be the case but let’s be serious, you can’t hose your car/bike down each time you get home.
Spent this afternoon bleeding the rear system and what a PITA the ABS2 is, I usually use a flare spanner on brake nipples but no chance of getting one on the ABS2 nipples but I found my vortex socket was perfect as it allowed the hose through the socket, dunno how you do it without one of those?
Anyway, rear brake all sorted so very pleased to tick that off my list.
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1994 K1100LT |
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Flying Duck
PsyKotic Waterfowl
Joined: 27 Jan 2005
Posts: 10102
Location: Bumf***, WA
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| Posted: Sun Aug 29, 2021 8:36 pm Post subject: |
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A word of caution when fiddling with the rear brake: If you adjust the lever and get it too tight then a hard application of the brake can cause the piston to travel too far and stick on the set screw in the plunged position. This can lock up the rear brake. Not so much that it will seize the wheel but the bike will be very sluggish and the rear rotor will get very hot very fast. The rotor can even get hot enough to set the final drive rubber boot ON FIRE!
If the rear brake ever locks up like that then it's a good idea to pull over immediately (as soon as it's safe.)
I always leave a little play in the rear brake lever. That allows me to light up the brake light with a light tap when engine braking so that the car behind me knows I'm slowing.
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE |
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Bazsm
Big Brick Rider
Joined: 09 Aug 2021
Posts: 55
Location: Hayling Island, UK
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| Posted: Mon Aug 30, 2021 2:22 am Post subject: |
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| Flying Duck wrote: | | If you adjust the lever and get it too tight then a hard application of the brake can cause the piston to travel too far and stick on the set screw in the plunged position. I always leave a little play in the rear brake lever |
I understand how that might happen if there's not enough pressure in the system and I know the set screw you mention that keeps the plunger assembly in place but surely that can only happen if the system isn't bled properly otherwise you're never gonna have full use of the rear brake?
I've adjusted the pedal up to it's highest position (still below the bottom of my boot) and adjusted the brake so it's just touching the plunger but not pushing it in at all, and I make sure I'm not touching the pedal to inadvertently activate it as I ride.
Tbh I only use the rear brake as a stabiliser for the front brake but in an emergency one tends to stand on everything (which I guess is where the ABS might actually add some value in the wet).
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1994 K1100LT |
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Flying Duck
PsyKotic Waterfowl
Joined: 27 Jan 2005
Posts: 10102
Location: Bumf***, WA
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| Posted: Mon Aug 30, 2021 4:45 pm Post subject: |
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| Bazsm wrote: | | surely that can only happen if the system isn't bled properly otherwise you're never gonna have full use of the rear brake? |
It can happen with a properly bled system. But it's not properly set up if you have that adjusting bolt set too tight because it can push the plunger too far.
With it properly set up there is more than enough brake to lock up the rear tire even on dry clean pavement when "emergency" braking without the plunger sticking.
It's not a bad idea to go out (with no cars behind you of course) and hit the rear brake only fairly hard while riding straight just to see what it's like when the ABS kicks in.
It's an "antique" ABS system so it has a long cycle time and you'll feel the rear end go "chunk, chunk, chunk" when the ABS kicks in. 
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE |
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Flying Duck
PsyKotic Waterfowl
Joined: 27 Jan 2005
Posts: 10102
Location: Bumf***, WA
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| Posted: Mon Aug 30, 2021 8:52 pm Post subject: |
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What's the shift lever look like? Hopefully they used a more salt-resistant aluminum alloy there.
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE |
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