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South GA Redneck
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I have used the vacuum pump method more than a few times when changes brakes lines, calipers, or rebuilding master cylinders. It’s also my “go to” method when changing out brake fluid. I have used this method on both ABS and non-ABS bikes. Never had any issues at all. But once done with the bleeding, I always “tickle” the lever as Schmidty says to remove any remaining air bubbles in the master cylinder.


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Patently waiting for the Master to check in ^^^^^^^^^^^^^^^^^ Thanks SCHMIDTY !!!
Obviously there's a trick to bleeding the Harley brakes without a vacuum pump, or even with the pump because the pump doesn't get the system completely bled.
I'll try to keep this post short I swear I'll try, I'm watching the Flintstones and drinking Martinis in between typing!
Remember this: There is a check valve in the master cylinder that only bypasses brake fluid when the pedal or lever is partially cracked open. ALSO do not have the caliper pucks shoved to far into the caliper.
Starting with the front brake system all connected on the bike, bike on side stand, the forks turned all the way left and the master cylinder positioned in its most upright level position.
Fill the master with DOT 5. Put a wrench on the caliper bleeder nipple. Put a container to catch the DOT 5 under or on the caliper bleeder nipple. I always connect a clear hose to the nipple and funnel it into a bleeder jar.
Now you're ready to bleed the brake system. In this case it's the front brake handle you'll be using.
Open the bleeder nipple and give the handle a bunch of pumps, there's a lotta air in the line and caliper. Then close the bleeder and continue. The trick with the handle is to tickle it when pumping ! How the hell do I explain that ?
Tickling is actuating the handle with the finger by tapping it rather than grabbing a fistfull of handle and pulling it full stroke to the grip. The tickling gets the air out of the lines and you should see little bubbles coming up from the master check valve hole, a tiny hole at the bottom of the reservoir.
Now if you're following me with this procedure persevere. Ya gotta do a lotta tickling but when ya see the bubbles coming up from the check valve hole you're making great progress.
If you love your Harley you'll take the time to tickle it !
Following this procedure you'll start getting pressure feel at the handle then continue to bleed the brake as normal. Pump, Pump, Pump, Hold, then crack the bleeder and release fluid into the reservoir, then repeat until the handle is solid.
I told ya I'd keep this short !
Patently waiting for the Master to check in ^^^^^^^^^^^^^^^^^ Thanks SCHMIDTY !!!
 

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I have used the vacuum pump method more than a few times when changes brakes lines, calipers, or rebuilding master cylinders. It’s also my “go to” method when changing out brake fluid. I have used this method on both ABS and non-ABS bikes. Never had any issues at all. But once done with the bleeding, I always “tickle” the lever as Schmidty says to remove any remaining air bubbles in the master cylinder.


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Does this require a fallow-up using the MoCo's Master Tech II ???
 

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South GA Redneck
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Does this require a fallow-up using the MoCo's Master Tech II ???
Some will say yes because the book says so, but in my real world experience and advice from more knowledgeable techs than myself, no you don’t absolutely have to. Especially if you’re just changing fluid. Think about it, if you never let any air into the system, why would you need a computer to bleed any air out. That’s all the Digital Tech does. It activates the ABS module rapidly to remove any small air bubbles that “may” be trapped in the module. Again I’m not expert but I am speaking from my personal experiences.


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Retired citizen
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Sorry to inform ya'll but that's not all the Digital Tech. software does. It's also recalibrates the ABS module to recognize the position of the new brake pads. It was still programmed to where the worn pads were before they were replaced. That's the whole purpose behind the Digital Tech connection, to get the ABS module to recalibrate the position of the new brake pads. The Module and ECM remember where the old pads position was in the caliper. That needs to be recalibrated for the new pads. Ya can't do that with bleeding manually !
 

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Retired citizen
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Note: you can manually bleed ABS brake systems but there's no guarantee the ABS will work the first time ya jam on the brakes ! The ECM and ABS need to be on the same page to function properly when needed.
 

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South GA Redneck
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Sorry to inform ya'll but that's not all the Digital Tech. software does. It's also recalibrates the ABS module to recognize the position of the new brake pads. It was still programmed to where the worn pads were before they were replaced. That's the whole purpose behind the Digital Tech connection, to get the ABS module to recalibrate the position of the new brake pads. The Module and ECM remember where the old pads position was in the caliper. That needs to be recalibrated for the new pads. Ya can't do that with bleeding manually !
Makes sense, but this would mean you need the Digital Tech just to even change brake pads?


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I always thought the purpose of Harley-Davidson's Digital Tech. software was to also actuate the ABS system to FLUSH the old brake fluid out, not just for bleeding when there is air in the system . . . you don't get a complete "flush" just by bleeding the brake lines. That is why the dealership charges around $200 for a brake fluid flush/fill and the labor that goes with that job. That's what I was told the last time I had the brake fluid on my 2016 Ultra Limited flushed.
 

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Retired citizen
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I always thought the purpose of Harley-Davidson's Digital Tech. software was to also actuate the ABS system to FLUSH the old brake fluid out, not just for bleeding when there is air in the system . . . you don't get a complete "flush" just by bleeding the brake lines. That is why the dealership charges around $200 for a brake fluid flush/fill and the labor that goes with that job. That's what I was told the last time I had the brake fluid on my 2016 Ultra Limited flushed.
Yes it does that too, in addition to what I said. I've been trying to keep my posts short without copying the 2 plus pages outta the service manual. That's exactly why that ABS service needs to done correctly.
 

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South GA Redneck
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No arguments here as I know what the manuals state. But I also know what has and hasn’t worked for me. I have changed several sets of pads, along with brake lines, and also performed several brake fluid flushes on my personal bike and have not had one single issue other than the ABS wire breaking at the connector mounted to the lower inside of triple tree. Bad design from Harley on the earlier touring bikes. I am in no way trying to get anyone to do anything they are not comfortable with. But I would like to add that those manuals also state to use only genuine Harley parts as well.


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weird member
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Reading this makes me glad I still have non-ABS brakes. Get to use Dot 5 and only have to change every 5 years instead of 2, can do it myself with no issue, no need to worry about a computer not knowing where my brake pad/piston position is...

Then again, if I have to get hard on it, especially in the rain, I might flop back to wishing I had them.
 

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I can see both sides of the coin. I have spent many years performing anti skid and autobrake function test on commercial aircraft. The functions are relative, just much smaller volume and lower flow & pressure, on a bike.

The Digital tech from MoCo will cause otherwise unused components and ports to allow flow that seldom, if ever get utilized. i would imagine for a much longer duration than the system would allow under "normal" operation (during a skid condition). Thus allowing a full flush of otherwise microsecond actuated control valves, while forcing any contaminates from the control valves as well. Most riders don't ride intentionally emergency stop at every opportunity. Therefore the system remains relatively dormant 99.99% of the time. It needs to get flushed as well. Along with the other functions like re calibrating the BCU to any (new conditions). Just as well follow the MoCo recommended two year interval. Just to be on the safe side.

The flip side of the coin; makes sense when changing out a brake line or the like component. Not really modifying the system per se' just changing the volume of the system..

Since my bike is near due for pads and flush. I'm going to bite the bullet and pay the $$ to a shop that has the right toys for the job.

Thank you all guys for clearing up the muddy water in my grey matter! (y)

BTW: (near the topic anyway) I hear those new "Auto-Drive" cars will be requiring some MAJOR $$ for a brake job! For nearly the same reasons...To many computers tied into the brakes!
 

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old scoot coot
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I can see both sides of the coin. I have spent many years performing anti skid and autobrake function test on commercial aircraft. The functions are relative, just much smaller volume and lower flow & pressure, on a bike.

The Digital tech from MoCo will cause otherwise unused components and ports to allow flow that seldom, if ever get utilized. i would imagine for a much longer duration than the system would allow under "normal" operation (during a skid condition). Thus allowing a full flush of otherwise microsecond actuated control valves, while forcing any contaminates from the control valves as well. Most riders don't ride intentionally emergency stop at every opportunity. Therefore the system remains relatively dormant 99.99% of the time. It needs to get flushed as well. Along with the other functions like re calibrating the BCU to any (new conditions). Just as well follow the MoCo recommended two year interval. Just to be on the safe side.

The flip side of the coin; makes sense when changing out a brake line or the like component. Not really modifying the system per se' just changing the volume of the system..

Since my bike is near due for pads and flush. I'm going to bite the bullet and pay the $$ to a shop that has the right toys for the job.

Thank you all guys for clearing up the muddy water in my grey matter! (y)

BTW: (near the topic anyway) I hear those new "Auto-Drive" cars will be requiring some MAJOR $$ for a brake job! For nearly the same reasons...To many computers tied into the brakes!
also y'all you can do a vacum flush yourself, then take it to dealer to put it on digitech. im not sure wheat that will cost but my dlr said he could and would do that. i woll be there to do that on both my bikes. it's sounds like a safer way than activating the abs while riding the bike. i doubt they will charge 200 dollars just to cycle the abs with digitech.l
 

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My other thought . . . $200 is pennies compared to the $20,000 ~ $30,000 (or more) we spent on our bikes. Brakes are just one of the components on my bike that I don't want to fail when I need them most. Just like I wouldn't want anything but the best tires (and mounted correctly) on my bike!
 

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Outlaw
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Reading this makes me glad I still have non-ABS brakes.
Not to get off topic (too far at least) I've got so many miles behind me without ABS that I prefer not having it, even on my truck. I can see where some might enjoy the advantages, but I'd rather have that control entirely in my hands, especially on a bike. Not to mention it's so much easier to work on our bikes. LoL
 

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Discussion Starter #37
Good news it, finally got around to getting the brakes working again. Everything has been stretched out on the bench since the weekend. Tonight, I started a fresh and took it apart, cleaned everything out with brake cleaner and re-assembled. I managed to grab some aluminium washers as they crush better and seal up better in my opinion.

Well, after a lot of pumping and yes I did the tickle trick, lo and behold pressure started building. Then I did the regular bleed cycle and now the lever is rock solid. The pads have grabbed the piece of steel in between.

Very happy, so I've tied back the lever overnight to hopefully get out any remaining air pockets.

Looks like I need new brake pads too!!!

Looking forward to getting the caliper and cylinder back on the bike this weekend and take it out for a ride, weather permitting.

Thanks for all the help.
 

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Fill the reservoir to the full mark & install the cap, zip tie the lever to the grip and let it sit overnight. You don't have to smash the lever into the grip, you just have to open the port in the master cylinder. Tapping the brake hose at the bends with your finger or a screwdriver handle will dislodge any air bubbles and send them upward to the reservoir since the port in the master cylinder is open with the lever tied back. You should have a firm lever the next day without needlessly wasting fluid.

Tech23
 
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