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ricky racer's Avatar
 
Join Date: May 2010
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Front Brake Woes

I'm struggling with my ABS equipped '99 R1100S front brake. I began having issues last fall. The lever goes to the grip when it is pulled the first time. With the next pump, I have a good firm peddle. If I let off of the lever and wait a couple of seconds, the same thing happens again. Upon the second pump when I get a firm peddle, if i hold pressure on it, it doesn't leak down.
I posted about this last fall and everyone said replace the OEM lines with stainless steel which I have done. No amount of bleeding has corrected the problem. I'm about ready to replace the master cylinder to see if I can get my bike back on the road. Am I missing something?
Old 05-13-2018, 12:21 PM
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Brent
 
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classic air in the system
several posts on bleeding this here and elsewhere on the net
Old 05-13-2018, 12:42 PM
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Did you bleed it from the ABS unit too?
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Old 05-13-2018, 01:48 PM
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Yes, I bled the abs unit first then went to the calipers....
Old 05-13-2018, 03:27 PM
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Quote:
Originally Posted by brentw1 View Post
classic air in the system
several posts on bleeding this here and elsewhere on the net
Classic air in the system to me would mean a spongy peddle. After the first pump, its solid as a rock...
Old 05-13-2018, 03:29 PM
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If you haven't done this already. Put a rag around the grip and handle. (for protection). then tie the handle back to the throttle grip with a tie wrap, heavy rubber band, etc. remove the reservoir cover. put something, rag etc. over opening to keep dirt out. Let set at least over night. For the rear peddle if it needs it. I find something heavy and just set it on the peddle. Might have to tie it to something like frame to keep it from falling off the peddle. This usually works for troublesome air in the brake system. 2 cnts from tjs
Old 05-13-2018, 04:23 PM
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sɹǝʇndɯoɔ sǝʇɐɥ
 
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Quote:
Originally Posted by ricky racer View Post
Upon the second pump when I get a firm peddle, if i hold pressure on it, it doesn't leak down.
^
I've owned a LOT of beater vehicles. I mean beaters. If your brake peddle / lever is
solid your master cylinder shouldn't be leaking.

A method of attaining pressure with low fluid / air in the lines is pumping the brakes,
thus, it does sound like a classic symptom of air in the lines.

If it's not air in the lines, you have something unusual going on somewhere like slow a
fluid leak where you only loose fluid out of one chamber in a segmented system. I've had
this happen on a car. I have no idea how the 1100's brakes are laid out.
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Old 05-13-2018, 04:37 PM
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Sure sounds like an air bubble in the system. And it WILL drive you batty.

Bubbles get trapped in the system, favorite hiding pace is banjo fittings. Bike on SIDE STAND, handlebars turned all the way to the LEFT.

Drop a quarter (25 cent piece) in the MC reservoir to prevent squirting DOT4 everywhere. I just leave them in (clutch and front brake).

Pump from the bottom (caliper bleeder) - bubbles are easier to push UP - with Mity-Vac or similar.

Bump the banjos with a rubber mallet while pumping.

If that doesn't work, try letting it sit overnight, then pump.

If that doesn't work, ride it. The vibration and pumping will sometimes move the bubbles. That worked for me last time.
Old 05-15-2018, 04:09 AM
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Twin Thumper, IYKWIM
 
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Quote:
Originally Posted by tjs View Post
If you haven't done this already. Put a rag around the grip and handle. (for protection). then tie the handle back to the throttle grip with a tie wrap, heavy rubber band, etc. remove the reservoir cover. put something, rag etc. over opening to keep dirt out. Let set at least over night. For the rear peddle if it needs it. I find something heavy and just set it on the peddle. Might have to tie it to something like frame to keep it from falling off the peddle. This usually works for troublesome air in the brake system. 2 cnts from tjs
Also (when doing the front brake lever), turn the wheel all the way to the left. Straightens out the brake line, and levels out the reservoir. Helps air bubbles to rise up and out naturally.
Old 05-16-2018, 09:35 AM
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