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Hi all, hoping someone can offer some advice here: Bike is a DL1000 K7

So I've replaced my front brake pads, as I've done many times before without issue. Removed and cleaned up pistons, replaced seals and bled brakes through.

What's happening is that when i pump the brake lever, the pistons extend. As i pump, i can feel more and more resistance as expected. Great. But if i let go, wait 2 seconds, my next pull of the lever extends right into the handlebar with no resistance. Again, i pump and pump till i feel resistance, and wait a second, next pull does the same thing again, and we're back to square one.

My rear brakes were done without any issues at all

I've bled the system thoroughly so i'm confident there is no air in there. I'm using the same pads and seals as i always do, and as far as i can see, there is no brake fluid leaking anywhere at all.

Sound familiar to anyone?

Cheers Guys

Creag
 

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If, and that needs to be double checked, there is no leak then you still have air in the system. Sometimes these things can be REALLY hard to get ALL the air out. If you lost all fluid out of the master cylinder, then it is likely that the brake line to master cylinder connection is where the air is trapped.

Try leaving the bike on the side stand with the bars turned to the left. I loosen my master cylinder cap, but I don't know if that matters. Leave alone other than to gently pull on the brake lever about 1/5 of the normal travel. This can help air bubbles escape. Just once but do it whenever you are near the bike.

I have tried both vacuum and bleeding at the caliper without getting all the air out. This method worked. Over 2-3 days you could really feel the difference.
 

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Sounds like air. Tap all the b9lts to dislodge air bubbles. Speedbleaders make it much easier.

Sent from my SM-T700 using Tapatalk
 

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Tie the brake lever and leave over night, to allow any trapped air bubble to escape. +1 on tapping of the banjo connections, etc, to aid the release of any trapped air.
 

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Look up reverse brake bleeding on YouTube and get ready to be amazed. It is the simplest cheapest most effective way to bleed brakes. All you need is a big syringe available at any farm/veterinary store like Tractor Supply and a section of 1/4" aquarium tubing.

Instead of trying to pull the air down through the caliper (a direction air dose not like to go while in fluid) you inject fluid into the caliper and push the air up and out the master cylinder (a direction air wants to travel while in fluid). The added benefit it you are positively pressurizing when injecting fluid you do not suck air in past the threads on the "bleeders" while trying to get air out.
 

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Does your bike have ABS? ABS makes bleeding the brakes notoriously difficult. You really have to have the proper tools and follow the right procedure.

Having said that, when you have air in the system then each pull of the handle should still meet the same amount of resistance. The fact that one pull feels normal and the next goes all the way to the handlebars without any resistance suggests something more sinister is going on.

Question: When you pull repeatedly (with or without resistance), does the reservoir loose fluid? When you pull without resistance, does the fluid level still go down as expected?

The only way I can explain this behaviour is that there's a seal loose/dislodged somewhere, which sometimes lets fluid pass and sometimes not. Or you have installed some springs somewhere near the brake pads incorrectly, which causes the brake pads to retract too far away from the brake rotors. After applying the brakes and releasing the brake handle, there should be virtually zero distance between the rotors and the brake pads, and between the brake pads and the pistons. Is that so in your case?
 

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It might be time to rebuild the master cylinder. If it's not sealing internally the fluid will be passing back and forth around the puck, causing the symptoms you describe. But try more bleeding first before taking the m/c apart, sometimes it can be a real pain trying to get all the air out.
 

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ABS, linked brakes or non-abs brakes are not difficult to bleed IF you reverse bleed them.

ABS brakes are easy compared to Guzzi's linked brakes. I know people who have spend days and quarts of fluid trying to get them bled. When I revived my T3 which included all 3 calipers being rebuild and new SS brakes lines I was dreading bleeding the brakes. As it turned out it was a 20 minute job to have the entire system front and rear completely bled and operating better than new.
 
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