01 ST1100 ABS No brakes!

STurgisSTeele said:

The handle pulls back as easily as when the cap and other pieces were removed.

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The cap and internals have nothing to do with the braking force generated by the lever, they simply keep the brake fluid from splashing out of the reservoir while riding. You should be able to generate peak braking power with the lid off and the fluid exposed to the atmosphere. You must still have some air in the system somewhere, keep bleeding until you get it out.

^^^ Was thinking that might be the case with the lid off, but didn't know. Sure can't build any pressure though.


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Did you burp the banjo fitting at the master cylinder? Sometimes air can get trapped in there.

Will have to look to see what is the banjo fitting. I squeezed the brake lever until there were no more bubbles at the reservoir. That took a long time. But no more air came up through the little opening at the bottom.


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The banjo fitting is where the hose is connected to the master cylinder. You can burp it a couple of ways. Tilt the master cylinder until the reservoir is in a slightly upward in relationship to the banjo fitting, then tap the junction with the rubber handle of a screw driver or other device... tap several times, and manipulate the lever several times while taping on it. If that doesn't work, sometimes it may be necessary to loosen the banjo bolt slightly while keeping a little pressure on the lever, then tighten the bolt again before releasing the lever. Be sure to keep some protection over the painted parts of your bike.

STurgisSTeele said:

Will have to look to see what is the banjo fitting. I squeezed the brake lever until there were no more bubbles at the reservoir. That took a long time. But no more air came up through the little opening at the bottom.


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It sounds like you are not familiar with bleeding brakes, you need to bleed out at the caliper end to make sure there are no bubbles, not at the resevoir end.

vinny said:

.... Tilt the master cylinder until the reservoir is in a slightly upward in relationship to the banjo fitting.... loosen the banjo bolt slightly while keeping a little pressure on the lever, then tighten the bolt again before releasing the lever. Be sure to keep some protection over the painted parts of your bike.

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+1 BTDT [tip from my mentor, Rob Parker, thanks Rob!]

John

Slydynbye said:

It sounds like you are not familiar with bleeding brakes, you need to bleed out at the caliper end to make sure there are no bubbles, not at the resevoir end.

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Thanks, I was mentioning this because the master cylinder kit had just been installed, and there was a lot of air in and around the mechanism. I did bleed the brakes according to the manual, however, without getting any pressure at the lever, I wasn't accomplishing anything.

I'll have a look around some more. Seems to me the fluid had to go somewhere when I first lost my brakes late last season. When I took off the cover for the first time last night, the reservoir was nearly empty and the rubber thingy was extended downward as if a vacuum was drawn on it with the loss of fluid(?).

Found the problem! A loose fitting at the ABS modulator has caused all the woes.

Tonight, I was investigating further why there wasn't any brake pressure building up and was determined to find a leak since that really had to be the reason this wasn't working. Finally found the leak because I had pumped enough fluid out that eventually a drip had hit the floor. From there I was able to hunt it down. I didn't see any fluid earlier because it was up inside the fairing and the leakage was getting trapped behind the tupperware. The leak had soaked a part of a wiring loom going to the modulator, so I untaped it and cleaned the wires off with some shop towels. (Those are the colorful wires at the bottom of the pic.)

I noticed that when pulling new fluid with the vacuum pump that it never looked quite right or at least what I thought I would see. Anyway, it makes sense now. With that loose fitting at the modulator, it was allowing air to be sucked into the line as I was pulling new fluid down from the reservoir. That explains why I wasn't getting a good bleed on the brakes and was unable to build pressure at the handle. It sounds so simple now in retrospect.

Hopefully this experience will be helpful for someone in the future since we often don't think about a fitting coming loose at the ABS modulator, nor does this happen very often.

Another photo, only a little further out to see the location.



All better now. New fluid front and rear and fronts are bled. I had to stop short of bleeding the rear. Probably get that tomorrow. Then it's time to change the clutch fluid.

Bigmak96 said:

John, I would look for wet areas and see if a line has loosened up. Or refill and pump to see if you can see it leaking. To loose the peddle and lever,the fluid has to be going somewhere. Good luck.

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Mark, as I was rereading the earlier posts, you hit it right on the head here! Only given the loose fitting location, I didn't pick up on it soon enough. But the suggestion was spot on.


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