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Bleeding The Rear Brake the Easy Way

20K views 54 replies 20 participants last post by  Boe 
#1 · (Edited)
I've had a lot of issues with my rear brake going totally out on me, and I've had to bleed it a few times. The dealer told me "Gotta remove the rear wheel and flip it upside down.

Removing the rear wheel is too much hassle for me, so I found an alternative way to remove the caliper from the bike without taking the wheel off. Without further ado, let's just jump into it!

Tools Needed:
  • 11mm open-end wrench
  • 4mm hex key long (Bought at Home Depot in a kit)
  • 6mm hex key long (Bought at Home Depot in a kit)
  • 6mm hex short
  • 3” extension
  • Ratchet
  • Gimbal Ratchet (Optional)
  • Ratchet Wobbler
  • Mityvac (Also optional, you can pump up the brake instead if you wish)
  • Some Premium Brake Fluid. I'm using Brembo DOT 5.1 this time.




The first thing to do is to remove the screws under the left side of the bike, that holds the brake line and the ABS sensor cord to the frame. These take the long 4mm Hex Key.



Once those are removed, you'll need to remove the two bolts holding the caliper to the rotor:



To do this, you'll need the 6mm short hex key, 3" extension and the wobbler:



This is where the gimbal ratchet comes in handy, you can just spin it in your hand instead of the typical back and forth of a usual ratchet. But, as I said above, it's optional.



For the next bolt, you'll need the long 6mm key. you'll need to fit the key between two teeth of the sprocket:




Your caliper should now be free from the rotor:



Now, pull it through one of the big gaps between the wheel spokes. There are small and big gaps:




Once you have it through, use something to push the brake pads back, which will push the pistons all the way in. Any air bubbles stuck in there will be forced out. I used a paint stir stick since it won't physically damage the brake pads:




Now turn your caliper upside down and put it back on the rotor. You may need to turn your wheel to get it high enough up on the rotor. I put the 6mm hex key through the bolt hole on the caliper, and through one of the rotor holes. Then, I used the paint stirring stick to jam it under the other side of the caliper to hold it in place. Feel free to get creative here!



At this point, you just bleed your brake lines like normal. I LOVE to use the mighty vac for this purpose. I pump it up to about 15 to 20 PSI, open the bleeder valve and let it suck out the fluid. As it is sucking the fluid out, I monitor the reservoir and just continue to fill it with new brake fluid, until the mighty vac catch cup is filled up. You don't have to do this. You can do it the old fashioned way of pumping up the pedal, opening the bleeder until the brake lever goes to the floor, and then close the valve and release the brake lever, and repeat. Usually, after the mighty vac, I'll do it the old fashioned way once or twice to make sure the brake lever is firm.









Once you get to the point where there are no more bubbles coming out in the fluid, close the bleeder tight (Doesn't need to be herculean tight), and put everything back together in the reverse order. Make sure when you reattach the brake line/abs cable holder to the frame, that the cables are in their correct slots. If you did the bleeding the old fashioned way, you'll likely need to push the brake pistons back in again.

Then, pump up your brake. The first few times you push it, it'll be loose as a goose. However, this is just due to the pistons getting the brake pads re-compressed to the rotor.

Lastly, enjoy your rear brake until this is due to be done again!

Let me know if there's any questions or further feedback!
 
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#11 ·
Great write up with pictures, thanks for taking the time to post it. I have a question though. I am not totally familiar with a vacuum brake bleeder, just purchased one, and only used it on my truck once. But should it not be able to remove air from brake system regardless of where or how caliper is situated on bike? In other words should you not be able to just attach vacuum bleeder device to bleeder bolt with caliper still bolted in position on bike? As long as you can get at bleeder bolt and fit it that is? The reason I ask is my red SSS required rear brake bleeding and my local dealer did it under warranty and did it fairly quickly so I am not sure they even dismounted caliper??
 
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#13 ·
Thanks Jippo, that is what I thought, thanks for confirming.
 
#15 ·
Just an update to this thread. I noticed my white SS rear brake was a bit mushy last week, sitting all winter in garage. I decided to try my pneumatic bleeder with caliper still in place on bike, easy peasy. Well not so. It was pulling air from system but never firmed up pedal. I decided I need to try removing caliper to bring bleed bolt to top. Well thanks to the soft bolts on caliper I stripped one, I believe others have noticed Ducati hardware on this bike tend to be very soft as well. Many hours later having to drill it out I was able to replace both bolts with a better quality M8 cap head. Once caliper was positioned on the top of the rotor I was able to manually bleed the rest of the air out easily. Rear pedal is nice and firm now.

So in summary I guess it doesn't pay to try to cut corners by bleeding it the easy way, remove caliper and get it done right the first time. Oh and I removed the rear wheel, quick and painless with Termi on it. It allows so much more room and freedom. So glad I don't try to cut corners...:wink2:
 
#17 ·
Can anybody explain the zip tie thing? How does it work?

I used to very sceptical about it until I has rebuilding the Pantah 500. I just couldn't get pressure in the front brake and in desperation I zip tied the front brake lever, left it for a couple of days, and bugger me it worked! I thought this might be a temporary state of affairs surmising that perhaps under pressure the air dissolved in the fluid and would slowly appear again over the next day or so with the pressure released, but it didn't. The brake line remained firm and had no more problems.

So where did the air go? With the lever pulled back it can't get out as there is no path back to the reservoir. I can only assume that the air ends up at the top of the system and when the lever is released it is ejected through the bleed hole back to the reservoir and out. Can anyone offer a better explanation?

A couple of days ago I noticed that the front brake on my Scrambler had gone soft over the winter with the lever coming nearly to the bars. I tied it up overnight and the next day it was as good as always. But I still don't know how
 
#22 ·
Indeed, but there are often 'high' points in the system. For example the rear brake line on the Supersport goes from the master cylinder up to ABS unit between the cylinders then down to the caliper, the highest point being the ABS unit where you'd think the air would end up at the banjos.
The front brake line is from the master cylinder on the handle bar down to the Abs unit then back up to the steering head before going down again to the calipers. The bubble rising theory would have air trapped in the line at the steering head.
 
#24 ·
On the front bubble can find its way from the master cylinder the reservoir. Reservoir is connected to the outside air as it needs to breath in air in order to compensate for the wearing brake pads. Air is only problem between the master cylinder and the calipers, in the reservoir it is natural occurance. Mushy brake lever is an air bubble compressing under pressure of braking between the master and the calipers.

In the front air in the master can escape upwards to the reservoir when the lever is depressed. In the rear really not, as the reservoir is behind a low bend after the master.
 
#25 ·
In the front air in the master can escape upwards to the reservoir when the lever is depressed. In the rear really not, as the reservoir is behind a low bend after the master.
In a non-ABS set up that would be the case as there is a direct upward route from the front calipers to the master cylinder but that is not the case with the ABS. As you can see from the attached screenshot of the brake line set up.
 

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#27 ·
You are right but I suppose I'm getting hung up on not understanding why zip tying works even on the ABS systems of the Supersport and Scrambler where there is no direct route upward for either front or rear brake. I guess the bottom line is - if it works, it works!
 
#28 ·
I suppose, that just a small, single bubble is enough to mess with the feel of the brakes. And it doesn't need to be at the caliper, but anywhere between the lever and the caliper will cause the issue. A tiniest amount of gas anywhere will compress enough to make the lever feel bad. If that gas is at the very top of the system it just might escape to the reservoir when given the chance.

I guess if it works, it isn't silly

This might be interesting watch:

 
#29 ·
@Jippo I'm well aware of how brake systems work but I'll watch that video anyway, I might just learn something.
Yes, it only needs a tiny bubble to affect the feel of the brakes (and hydraulic clutches). From my own experience air usually gets trapped at the master cylinder banjo and at the ABS unit banjos. Holding the brake lever with a tie wll compress the bubble which possibly encourages it to move when the pressure is released or, because it is smaller it may move to the top of the system more easily.

As a slight aside, while in the Dolomites 4 years ago with a group of Multistrada riders 4 of them had difficulties in finding although the bikes had been ok at lower altitudes. They obviously had air in the lie which hadn't been an issue until the reduced air pressure at altitude allowed the bubble to expand reducing the available lift. I bled the air at the master cylinders restoring the clutch action.
 
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#32 ·
I just got my SSS out of moth balls for 1st ride of the season Friday. (Wisconsin) No rear brake. Nothing. You could drag a stick and do more. I had the same thing last spring after having my motor rebuilt. (another story) The dealer bled out the air in the rear lines and it was fine for the rest of the season. Now absolutely nothing at the rear again after sitting all winter. Not a glazed pad issue. I called my Dealer. He said good news, Ducati has just issued a fix for all SS's. Ducati says that the installation of the rear lines were not crimped properly from the factory and some of the seals allow for air to get into the lines. Odd because I see no sign of any leaking. Ducati will replace all the rear brake lines. They did not say anything about a master replacement. Bad news is that one of the lines is on back order, so I'll be waiting a while. I might be doing a bleed myself. At least it isn't the front!
 
#33 ·
I just got my SSS out of moth balls for 1st ride of the season Friday. (Wisconsin) No rear brake. Nothing. You could drag a stick and do more. I had the same thing last spring after having my motor rebuilt. (another story) The dealer bled out the air in the rear lines and it was fine for the rest of the season. Now absolutely nothing at the rear again after sitting all winter. Not a glazed pad issue. I called my Dealer. He said good news, Ducati has just issued a fix for all SS's. Ducati says that the installation of the rear lines were not crimped properly from the factory and some of the seals allow for air to get into the lines. Odd because I see no sign of any leaking. Ducati will replace all the rear brake lines. They did not say anything about a master replacement. Bad news is that one of the lines is on back order, so I'll be waiting a while. I might be doing a bleed myself. At least it isn't the front!
Thank you for the post. @Gempeler

Would you please ask the dealer if there's a TSB (Service Bulletin) for replacing the rear brake line...
 
#34 ·
Ed, I will ask my dealer if there has been an official TSB yet and post it if there is. I did find this complaint on the NHTSA website that talks about the rear brake line being routed to close to the catalytic converter that might contribute to this:

https://www.nhtsa.gov/vehicle/2018/DUCATI/SUPERSPORT

TL* THE CONTACT OWNS A 2018 DUCATI SUPERSPORT. THE CONTACT STATED THAT HE HAD TO BLEED THE REAR BRAKES THREE TIMES WITHIN THE PAST YEAR. THE CONTACT RESEARCHED THE FAILURE ONLINE AND FOUND THAT THE BRAKE LINE RAN TOO CLOSE TO THE CATALYTIC CONVERTER. THE CONTACT STATED THAT THE REAR BRAKE CABLE HAD HYDRAULIC FLUID IN IT, WHICH BECAME HOT AND CAUSED AIR TO ENTER. THE FAILURE CAUSED THE REAR BRAKES TO MALFUNCTION. AZ MOTORCYCLES (15500 NORTH HAYDEN ROAD, SCOTTSDALE, AZ 85260, (480) 609-1800) SERVICED THE BRAKES, BUT THE FAILURE RECURRED. THE MANUFACTURER STATED THAT THERE WAS NO FAILURE AND SUGGESTED THAT THE CONTACT CONTINUE TO BRING THE VEHICLE IN FOR SERVICE. THE FAILURE MILEAGE WAS 1,386.
 
#35 · (Edited)
Thank you @Gempeler

Interesting, took a quick look at the bike and although the brake line is fairly close to the engine, it does not appear to be near CAT. Maybe better visible though diagrams.

Also interesting that it seems like quite a few cases reported on this Forum related to these types of rear brake issues after winter storage...
 
#36 · (Edited)
To me it does sound very reasonable assumption.

I believe that the brake line goes in between the swing arm and the top of the cat. It's a very hot spot, especially if the bike is not moving and there is no airflow. To me, it is very plausible that the fluid boils in that spot. Running engine warm in the garage might actually heat the cat quite a bit. Running 20 minutes around a track at full throttle and coming into pits definately will heat up the cat enough. I believe that cooked my fairly new fluid once, as I really don't use the rear brake that much. In fact, that (and the bloody flap & servo thingy) prompted me to get rid of the cat altogether. I haven't had problems with the brakes boiling after going with the Termignoni. There is loads more air under the bike, nevermind the fact that the cat runs hotter in the first place.

Problem with boiling can be managed with a very high boiling point fluid in the rear or by removing the cat.
 
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