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Discussion Starter #1
Installed a set of 4-pot calipers on the front using the SVRacing adapters and Galfer lines.
Added new Dot 4 to the system. A friend and I poured the fluid into the reservoir and sucked it out of the calipers using a vacuum bleeder. Did it until no air came out of both front calipers.
Front brake lever still really spongy. So we reversed the process and added the fluid into the calipers and drew it out of the new banjo bleeder I bought from SVRacing. Pulled a ton of fluid thru the system this opposite direction also. Still have a spongy front brake lever.
All I can think of is that there's still obviously an air bubble somewhere, but can't see how given what we did above. Maybe in the ABS pump, that the shop manual calls the HU/Hydraulic unit?
So I've zipped tied the front brake lever pulled in and will leave it there overnight. Maybe I'll get luck and whatever bubble is there isn't stuck in the HU and will migrate to the top where we can pull it out of the upper Banjo bleeder or hopefully it will just migrate into the master cylinder, who knows?

Any suggestions??!!

Thanks!!
 

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Try holding slight pressure on the brake lever as you slightly loosen the hose banjo bolt at the master cylinder--look for bubbles as the lever is pulled back. Be sure to tighten the banjo bolt before you release the brake lever. Repeat this process at the right caliper then the left caliper, and finally at the bleeder screws under pressure. Air likes to hide in the banjo bolt. This also applies to the rear brake circuit as well. With oem brake hoses I'd recommend using hose pinch-off pliers to isolate each branch of the hydraulic circuit, but I woudnt do that with your SS lines.
Does your brake lever "pump-up" if you pull and release rapidly? If so, look at the caliper pistons being pulled back in their bores(Ive seen that). I did have an issue like that years ago with a GSXR-750--it was a bleeder valve atop the front master cylinder under a rubber boot. Ive also had to loosen and tighten under pressure the pipes at the ABS unit while checking for bubbles. I have had to, but Ive read that sometimes the ABS unit needs to be actuated to remove air. Ive recently flushed brake fluids in my '14 DL1000 and a friend's 'DL650, but I made sure the reservois didnt run dry at any time.
 

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Discussion Starter #3
Try holding slight pressure on the brake lever as you slightly loosen the hose banjo bolt at the master cylinder--look for bubbles as the lever is pulled back. Be sure to tighten the banjo bolt before you release the brake lever. Repeat this process at the right caliper then the left caliper, and finally at the bleeder screws under pressure. Air likes to hide in the banjo bolt. This also applies to the rear brake circuit as well. With oem brake hoses I'd recommend using hose pinch-off pliers to isolate each branch of the hydraulic circuit, but I woudnt do that with your SS lines.
Does your brake lever "pump-up" if you pull and release rapidly? If so, look at the caliper pistons being pulled back in their bores(Ive seen that). I did have an issue like that years ago with a GSXR-750--it was a bleeder valve atop the front master cylinder under a rubber boot. Ive also had to loosen and tighten under pressure the pipes at the ABS unit while checking for bubbles. I have had to, but Ive read that sometimes the ABS unit needs to be actuated to remove air. Ive recently flushed brake fluids in my '14 DL1000 and a friend's 'DL650, but I made sure the reservois didnt run dry at any time.
I wonder if starting up the bike with it on the center stand, putting it into gear, and then stepping on and holding the rear brake pedal would continuously fool the ABS to thinking the rear wheel was locked up and make the ABS pump stay continuously activated thereby pushing out any trapped air. However if that worked, that might just push the air somewhere else into the system, requiring a full flush again just to work it out.
 

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That would be no different than running the bike on the center stand in gear and running the bike--the front wheel would then be stationary. But you can try it. I generally try to make sure the conventional system is 100% before I play with the ABS system.
 

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Discussion Starter #5
That would be no different than running the bike on the center stand in gear and running the bike--the front wheel would then be stationary. But you can try it. I generally try to make sure the conventional system is 100% before I play with the ABS system.
I figure that by doing it the normal way on the road, the ABS pump would only kick in during the period of time that the brakes are automatically released, whereas (maybe.......) doing it on the center stand would allow the ABS pump to continue cycling as long as your on the rear brake pedal, thinking that the wheel is still locked up.

Actually, I just went out to the garage and clipped the zip tie holding the front brake lever in and "gosh darn it" it feels fairly tight now. I think that by tying back the lever, any residual air that was somehow trapped in there even though I pushed 10 tons of fluid thru both directions, may have migrated upwards and dissolved into the air space in the master cylinder, which was my intent by tying back the lever and letting it sit for several hours. Going to push more fluid up from the calipers and thru my new master banjo tomorrow just to make sure, making sure I don't introduce any new air into the calipers.
 

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My 4 pots had the same issue. Zip tie at night for several nights and gravel road abs activation did the trick finally.

Sent from my SM-G930V using Tapatalk
 

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Discussion Starter #7
My 4 pots had the same issue. Zip tie at night for several nights and gravel road abs activation did the trick finally.

Sent from my SM-G930V using Tapatalk
Did the ABS activation allow any trapped air to migrate into the MC, or did you have to bleed it off again?
 

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My guess is that there was an air bubble that I worked out of the abs and up into the MC using the zip tie method. It took a few times.

Sent from my SM-G930V using Tapatalk
 

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WVS and Hatchi, I have to tell you...
In all the years Ive worked on bikes Ive never used the zip-tie method. Never had to.
I realize some service manuals show that, but for sure none of mine do, including my '14 DL1000 shop manual.
In WVS's case I think having the lever tied to the bar has the master cylinder piston closes off the compensating port in the master cylinder, so trapped air can't be released into the master cylinder reservoir, and stays in the hydraulic circuit.
I do know using zip ties during bleeding has been discussed in the past on this forum, maybe in relation to a clutch plate being pushed off its spline. I dont use a zip tie for servicing the clutch hydraulics either.
 

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Discussion Starter #10
WVS and Hatchi, I have to tell you...
In all the years Ive worked on bikes Ive never used the zip-tie method. Never had to.
I realize some service manuals show that, but for sure none of mine do, including my '14 DL1000 shop manual.
In WVS's case I think having the lever tied to the bar has the master cylinder piston closes off the compensating port in the master cylinder, so trapped air can't be released into the master cylinder reservoir, and stays in the hydraulic circuit.
I do know using zip ties during bleeding has been discussed in the past on this forum, maybe in relation to a clutch plate being pushed off its spline. I dont use a zip tie for servicing the clutch hydraulics either.
The instructions that came with the Galfer lines say to do it, but I think that's because they want you to pressurize the lines for a leak check.
Wouldn't zip tying the lever open up a path to the MC allowing air to escape?
 

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No. There is compensating port in the bottom of the reservoir that is closed by the master cylinder piston seal when the lever(or pedal) is depressed. Sometimes you can rapidly repeatedly pull the lever and hold it for 3 seconds...then release it and see bubbles escape. By to this quickly youre not letting fluid back into the reservoir, so it build up behind the piston seal. When you finally release the lever it all comes back through the bottom of the reservoir. Also, look closely at the bottom of the reservoir, pull the lever, and slowly let up--sometimes you'll get bubbles out that way as well.
 

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This is exactly the problem many have when converting to 4 pot calipers. I did too. I don't think the ABS module is the issue, but then again I know mine got better after some hard braking tests to bed the brakes and it might have been that I was allowing air out of the ABS module. I too agree that zip tying the lever down should be counter productive. What I done was leave the bike on the sidestand and the bars turned to the left. That makes the master cylinder the highest point. Then occasionally flick the brake lever about 1/4 way each time I walked by it. That allowed those pesky bubbles between the master cylinder piston and the rubber hose connection to the master cylinder to work out of the system through the fluid port. Which is indeed blocked when zip tied down.

Bear with it! Worth the trouble when you get it right. When you see owners report they were not impressed by the 4 pot conversion, I just know they didn't bleed it right.
 

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Other than suspension, I WILL be doing this brake upgrade.
 

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I had no bleeding problems (other than the process taking MANY hold-open-releases) when I recently did the 2 pot Tokico to 4 pot Nissin conversion on my ABS-less '01 SV. It took a number of miles before the new pads were able to bed in but the results are quite noticeable upon hard braking. Normal braking did not produce noticeable gains. And who knows if the gains upon hard braking are attributable to the 4 pot calipers or the EBC sintered pads. But those gold colored Nissins are very pretty.:wink2:
 

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Reverse bleed the braking system. In stead of the traditional method of trying to pull air down (vacuum) and out of the system you inject fluid into the system at the calipers and push the air up and out of the master cylinder. Air in fluid naturally wants to rise so why not help it do what it wants too.
 

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I know reverse-bleeding works...but Ive never had to do that. I do use an air-powered vacuum tool, makes it quick,easy, and clean. But I do crack open the banjo bolts then the bleeder screws afterwards, never get a soft lever or pedal.
Whatever works, and whatever it takes.
 

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I have an air powered vacuum bleeder tool too. They work good.

But I WILL learn how to do the reverse bleeding and buy the tools to do it. Sometimes things are made too complicated, and by every measure it makes more sense to push clean fluid in from the bottom! Maybe I have been doing it wrong all along!
 

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RS, it isnt wrong if your method works.
Before I got my air bleeder I used MightyVacs, did the reverse-bleeding a few times. It worked. Took longer, more setup and care, used the different plastic attachments, all that. Not worth the extra time involved. But Ive tried both methods and came to my own conclusions.
One of the problems is that some owners will vacuum out until the reservoir runs dry and beyond. Then they spend an hour to purge air in the system that shouldnt have been allowed to enter in the 1st place. I vacuum at the bleeder screws until I have about 3mm fluid in the bottom of the reservoir--no lower. Refill, repeat until the clean fluid flows the old fluid out. Refill, lever or pedal under pressure and crack open each banjo bolt in sequence from the master to the caliper to purge the fittings. Finish with the bleeder screws and DONE. !0 minutes or less start to finish...and I'm not even on the clock at work!
At work we used a machine that pressurised the master cylinder reservoir while at the same time suctioned out the old fluid through the bleeder screw. The job paid 1 hour labor time, it could be done in 15 minutes.
Now I just do it for fun...and to make use of my tools.
 

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Discussion Starter #19
Update:

Test rode the bike today. Despite a slightly still soft lever, the 4-pots are very strong. Absolutely noticeable. Hit the front brakes hard multiple times to activate the ABS, which I did feel kick in.
Going to let the bike sit overnight, then test ride again. If lever still soft, will bleed ONE MORE TIME from all three locations; both calipers and the MC bleeder I installed.
I'm also getting a noticeable rotational noise from the front, so I'm hoping that will disappear after more bedding in of the new sintered pads.
 

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WVS, just asking...
When you apply the front brakes with the bike stationary, do the calipers move on their slides? Ive seen calipers stick and flex slightly on their mounts, and the 1st bit of lever application is used up in getting the calipers to stop then apply the pads. It gives a soft lever feeling.
 
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