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Discussion Starter #1 (Edited)
This blog will be broken down into 3 easy to follow processes to bleeding the brakes on your Scrambler.
  1. Front Brakes
  2. Rear Brakes
  3. Test!
Here is a link to our full video!

Tools Needed
  • 8mm box wrench
  • 11mm box wrench
  • tubing/hose
  • DOT 3,4, 5.1 Brake Fluid (we are using Motul RBF 600 aka the good stuff)
  • Some sort of catch can (cup or bottle works fine)
  • T20 Torx screwdriver or socket
  • Rags or shop towels
  • Optional: Hose clamp
1. Front Brake Flush
Step 1
Remove master cylinder brake reservoir cap with Torx screwdriver or socket. Wrap rag/shop towel around reservoir to make sure that nasty fluid doesn’t get everywhere.


Step 2
Fit an 8mm wrench and hose to caliper bleed nipple, but do not loosen! Also, connect hose to fluid catch.

*Hot tip: try to maintain and upward angle/kink in the hose. This will allow brake fluid and not air back into the system if fluid flow is reversed (usually happens when brake lever is released before tightening the nipple)

Step 3
Make sure reservoir has brake fluid. If not adequate, add fluid.


Step 4
Pump brake lever multiple times (2-3 times should be fine or until firm lever feel). HOLD LEVER!


Step 5
Slightly loosen caliper nipple (you will feel the lever depress). DO NOT RELEASE LEVER YET!


Step 6
Tighten caliper nipple.


Step 7
Release lever. Repeat step 3-6 until fluid comes out clean and brake feel is firm (not squishy or spongy).


Step 8
Fill brake fluid to proper level

Step 9
Put on master cylinder brake reservoir cap. DO NOT OVER TIGHTEN SCREWS!

Note: make sure the rubber under the cap looks like this and not extended!

Step 10
Wipe up any brake fluid. Brake fluid is extremely corrosive and over time it can eat through the powder coating on wheels and paint on the tank! I just spray some brake clean onto a microfiber towel and wipe.


2. Rear Brakes
Step 1
Remove master cylinder brake reservoir cap. Wrap rag/shop towel around reservoir.


Step 2
Fit 11mm wrench and hose to rear caliper bleed nipple.


Step 3
Make sure reservoir has brake fluid. If not adequate, add fluid.


Step 4
Pump brake lever multiple times (2-3 times should be fine or until firm lever feel). HOLD LEVER!


Step 5
Slightly loosen caliper nipple (you will feel the lever depress). DO NOT RELEASE LEVER YET!


Step 6
Tighten caliper nipple.


Step 7
Release lever. Repeat step 3-6 until fluid comes out clean and brake feel is firm (not squishy or spongy).


Step 8
Fill brake fluid to proper level and put on cap.


Step 9
Wipe up any brake fluid.


3. Test
Test! Don't just go out and ride your Scrambler without going through this process. It wouldn't be a lot of fun to pull the lever in to find out your brakes don't work properly.

Step 1

Pull in the front brake and feel for a firm lever. Then go ahead and do the same for the rear.

Step 2

Go for a test ride. Start out slow (I roll the bike forward and try the brakes before riding), then bring the bike to a stop. Slowly build up speed and follow with braking. Repeat and slowly build up speed with each test. I usually give a few CONTROLLED hard stops (make sure where you are not braking on a loose or wet surface).

Step 3

Give yourself a pat of the back for doing such an awesome job and revel in your ability to work on your own bike.


If you liked this thread, comment and let us know what you would like to see!

Cheers,
Team Astroscrambler

Ducati Scrambler Parts and Modifications - Astroscrambler
 

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Just to add to your excellent post.
If the lever still feels a little spongy, apply the brake front or back and tie wrap / zip tie it in place and leave it overnight. Sometimes it’s worth doing it anyway. Is best leaving the top off the master cylinder during this process.
 

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Very nice how-to. You can also use a cheap syringe (couple of dollars at farm supply store) attached to the tubing to pull fluid thru at the bleeder. Just make sure to keep adding new fluid to the reservoir as you do so.

Sarah
 

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Very nice how-to. You can also use a cheap syringe (couple of dollars at farm supply store) attached to the tubing to pull fluid thru at the bleeder. Just make sure to keep adding new fluid to the reservoir as you do so.

Sarah
If you're doing it this way I'm assuming you don't need to pump the brake lever and you just leave the reservoir cap off and keep topping off fluid? You also leave the bleeder valve open?
 

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I changed brake pads, both front/back to EBC Double H Sintered. Bled both lines. Rear feels nice a solid but front still spongy. I'm sure some of this has to do with the fact that it's not a very good brake master cylinder but I'm wondering if I can still do the zip tie method after the fact or am I looking to now bleed the front line again?

Thanks.
 

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I changed brake pads, both front/back to EBC Double H Sintered. Bled both lines. Rear feels nice a solid but front still spongy. I'm sure some of this has to do with the fact that it's not a very good brake master cylinder but I'm wondering if I can still do the zip tie method after the fact or am I looking to now bleed the front line again?

Thanks.
No need to bleed again the zip tie method works for this, assuming it’s only a little spongy.
 

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If you're doing it this way I'm assuming you don't need to pump the brake lever and you just leave the reservoir cap off and keep topping off fluid? You also leave the bleeder valve open?
You seem to have the principle to a tee.
 

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Well, according to my mechanic, he said the brake master cylinder is trash...and showed me a proper one on a bike that was there to be serviced...I did notice the different but not a $500 difference, which is what a good brake master cylinder will cost...so...if I can make the current one a bit more responsive...I'm ok with that..

Forgot to ask...when I zip-tie the brake lever overnight, is it enough to take the screws out of the reservoir cap and leave the cap on loosely, just to avoid any spillage or crap falling in?

What is the principle behind doing this if you don't mind explaining it? How does it work?
 

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I may have this incorrect but as I understand it by bleeding the brakes you remove the air bubbles trapped by the fluid. This leave tiny microscopic bubbles still in the fluid. By compressing the fluid these bubbles escape float to the top and leave the master cylinder if you’ve left the top off or loose as you suggest. It does work I’ve done it many times. I’ve also had many sweary moments bleeding brakes.:angry5::angry4:
 

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I may have this incorrect but as I understand it by bleeding the brakes you remove the air bubbles trapped by the fluid. This leave tiny microscopic bubbles still in the fluid. By compressing the fluid these bubbles escape float to the top and leave the master cylinder if you’ve left the top off or loose as you suggest. It does work I’ve done it many times. I’ve also had many sweary moments bleeding brakes.:angry5::angry4:
Thanks, that's a cool thing to know, seems logical.
 

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I may have this incorrect but as I understand it by bleeding the brakes you remove the air bubbles trapped by the fluid. This leave tiny microscopic bubbles still in the fluid. By compressing the fluid these bubbles escape float to the top and leave the master cylinder if you’ve left the top off or loose as you suggest. It does work I’ve done it many times. I’ve also had many sweary moments bleeding brakes.:angry5::angry4:
Sorry, but this will not really help. As long as the fluid is compressed by the tied lever the connection to the reservoir is closed and no air can get out. You just temporarily widen the brake lining a little bit. That's why it feels better for a short time.
One should also not let the reservoir open the whole night because the fluid will pull water from the surrounding air.

Someone with better English may explain this a little bit better. :)
 

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I've always understood it to work the way Gasman described--pulling the lever pushes the pistons out and allows the lines to be as full as possible, holding it with a ziptie overnight gives the little bitty air bubbles time to gather up and move out. Some folks say you also need to take the reservoir off the handlebar and elevate it so that it is the highest point in the system, you can see how this might benefit us with our big looped brake line.

xPepi, you are exactly right on the syringe technique, except I close off the bleeder each time I stop to top off the reservoir. If not, it seems like the old fluid wants to be sucked back in as soon as I stop pulling on the plunger. I make a point to give this job plenty of time and I try not to be stingy with the new brake fluid, when I think I've pulled thru plenty I make myself pull thru a bit more, that big looped line gives air plenty of places to hide. Good luck, and let us know how it goes.

Sarah
 

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I've always understood it to work the way Gasman described--pulling the lever pushes the pistons out and allows the lines to be as full as possible, holding it with a ziptie overnight gives the little bitty air bubbles time to gather up and move out. ...

Sarah
Just tell me where the bubbles should go out. If this would be possible there would not even be any pressure in the system.
 

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I've always understood it to work the way Gasman described--pulling the lever pushes the pistons out and allows the lines to be as full as possible, holding it with a ziptie overnight gives the little bitty air bubbles time to gather up and move out. Some folks say you also need to take the reservoir off the handlebar and elevate it so that it is the highest point in the system, you can see how this might benefit us with our big looped brake line.

xPepi, you are exactly right on the syringe technique, except I close off the bleeder each time I stop to top off the reservoir. If not, it seems like the old fluid wants to be sucked back in as soon as I stop pulling on the plunger. I make a point to give this job plenty of time and I try not to be stingy with the new brake fluid, when I think I've pulled thru plenty I make myself pull thru a bit more, that big looped line gives air plenty of places to hide. Good luck, and let us know how it goes.

Sarah
Thanks Sarah. I may bleed the front again to be honest and I'll try the syringe method instead of pumping the brake lever. I did the zip-tie last night, not sure if anything is different as I have to go out for a ride. Being a novice with bikes, hard for me to tell what is spongy and what is not, when I have no other experience to compare it to. Also not sure how much of the sponginess I should attribute to the low grade master cylinder.
 

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I'm reading on the internet that instead of pulling the fluid out, you can do reverse bleed. Pull fluid from reservoir and inject fluid into the bleeder valve...this process needs 2 x 60cc syringes....you'd think these things are cheaper than what I've found but nope...and not all that easy to get either.

https://www.theridingobsession.com/bleed-brakes/
 

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Just tell me where the bubbles should go out. If this would be possible there would not even be any pressure in the system.
Sorry rogers, I didn't mean literally move out, I meant to say migrate toward the highest point in the system.
 

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I'm reading on the internet that instead of pulling the fluid out, you can do reverse bleed. Pull fluid from reservoir and inject fluid into the bleeder valve...this process needs 2 x 60cc syringes....you'd think these things are cheaper than what I've found but nope...and not all that easy to get either.

How To Quickly And Easily Bleed Your Motorcycle Brakes
I've read about reverse bleed, but felt it might be over my head. Pulling from the bleeder is cheap, easy, and so far foolproof. Shut off the bleeder to add more new fluid to the reservoir and dump the old fluid from the syringe, take your time and keep an eye on the level in the reservoir so you don't run dry. At the finish make certain to pull fluid down to the fill marks in order to leave the appropriate amount of air space in the reservoir.

Sarah
 

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In case anyone is having trouble finding a large syringe, search for gardening nutrition syringe. I found it on amazon for just under $5CND and it's a 150ml syringe.
 

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You can also use the syringe to remove the old fluid from the master cylinder right before starting to bleed, then fill it back up. Gets rid of the old fluid faster than bleeding it out.
 

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Yep, good tip, thanks. Another thing, make certain to cover the tank so it's protected from any wayward drops of brake fluid. I keep a spray bottle of watered-down Glass Plus handy to wash off the reservoir and switch gear once I'm all done. That brake fluid is mean stuff.

Sarah
 
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