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Discussion Starter #1
Not long after purchasing my bike last summer, the rear brake stopped working. I first tried bleeding with my Mitey Vac, but couldn't get the fluid to pull through sufficiently which lead me to believe that their must be a leak somewhere in the system. This weekend, I rebuilt the master cylinder, was hopeful that would be the answer; nevertheless, it still wouldn't pull the fluid through using the bleeder. My next step I reckon would be to rebuild the rear caliper.

Is their anything I'm missing in the shop manual regarding the proper way to bleed with the abs system or else something I may have overlooked?
 

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bleeding?

maybe you need to have the ABS pump on-key on to energize the system? I had the same issue of nothing coming from the bleeder on my 996 recently after resealing the caliper.fix was to detach the caliper & set it on the seat framework,tip it back & forth so fluid fills both piston cavities and use the mityvac at the same time.short strokes on the pedal did the trick.you will know when both cavities fill by the shorter pedal stroke.
 

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Discussion Starter #5
Check out this thread to see what some of the guys did with their rear brakes.
http://www.ducati.ms/forums/40-sport-touring/653185-worthless-rear-brake.html
Yeah, the last two replies on that thread are good ideas when it comes to my situation of having no brake at all. Will try clamping the lever down overnight to see if it makes any difference, starting to think the problem might be within the caliper.

Checked the free play early on in my quest to get a workable rear brake. Will try the bleed technique that 2004 999s described. Does anyone know if it makes any difference to have the abs system on when bleeding? Thanks a bunch everyone for the input.
 

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I don't know it this will be insightful or not. I have bled a lot of ABS equipped vehicles. Energizing the ABS system is not necessary. Whether it is counterproductive or not, I don't know but doubt it. To my knowledge the ABS system never shuts the line off when it is not energized because a power failure would prevent brake operation.

I have only had a couple times when the brakes would not bleed as you describe. That was due to my carelessness. I had to get a computer capable of operating the controller to open the valves to finish bleeding them. The problem is when air gets into the actual ABS valve, the only way to deal with it is to electronically open it to flush the air out. The carelessness was not sealing the lines before replacing hydraulic components and the line evacuated and air got into the valve(s). Since the last one, I have been careful to prevent the fluid from draining and getting air into the valve(s).

I do not see how the rear cylinder could block a bleeding process so if it isn't leaking, I would not mess with it.

Bradblack's comment identifies an important point. If the compensation port is not opened when the lever is in the parked position, you are not going to make any progress even it the master cylinder cap is off. How you would have gotten to that condition from a working system without changing levers or anything, is another matter.
 

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i harp on about the free play issue because often people don't understand it and think they have some when they don't and if it is the issue it'll never work until fixed. but suggesting it really offends some people it seems.

the free play you need gives a two stage sort of feeling. pedal moving against spring, then pushing piston. distinctly different feel. i sometimes remove the pushrod or lever and use a rod to push the piston in and out to see if that helps. or you can pull the pin out and see if the lever pushes back further.

i serviced a s4rs last week that had the pushrod so long that i wound it back maybe 10mm to get the freeplay. luckily, it had a very soft pedal with a heap of air in it so wasn't going to lock the brake on.
 

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Discussion Starter #8
I don't know it this will be insightful or not. I have bled a lot of ABS equipped vehicles. Energizing the ABS system is not necessary. Whether it is counterproductive or not, I don't know but doubt it. To my knowledge the ABS system never shuts the line off when it is not energized because a power failure would prevent brake operation.

I have only had a couple times when the brakes would not bleed as you describe. That was due to my carelessness. I had to get a computer capable of operating the controller to open the valves to finish bleeding them. The problem is when air gets into the actual ABS valve, the only way to deal with it is to electronically open it to flush the air out. The carelessness was not sealing the lines before replacing hydraulic components and the line evacuated and air got into the valve(s). Since the last one, I have been careful to prevent the fluid from draining and getting air into the valve(s).

I do not see how the rear cylinder could block a bleeding process so if it isn't leaking, I would not mess with it.

Bradblack's comment identifies an important point. If the compensation port is not opened when the lever is in the parked position, you are not going to make any progress even it the master cylinder cap is off. How you would have gotten to that condition from a working system without changing levers or anything, is another matter.

Interesting. How would I go about getting the proper software for correctly bleeding?

Since my brake went from sorta working the first time I rode it to nothing at all in a matter of days, it does seem like something within the system failed like the master cylinder, in my mind at least. All the times I tried bleeding prior to rebuilding the master cylinder resulted in very little fluid being pulled through. Hopefully now it's just a matter of bleeding it properly like you described.
 

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Discussion Starter #9
i harp on about the free play issue because often people don't understand it and think they have some when they don't and if it is the issue it'll never work until fixed. but suggesting it really offends some people it seems.

the free play you need gives a two stage sort of feeling. pedal moving against spring, then pushing piston. distinctly different feel. i sometimes remove the pushrod or lever and use a rod to push the piston in and out to see if that helps. or you can pull the pin out and see if the lever pushes back further.

i serviced a s4rs last week that had the pushrod so long that i wound it back maybe 10mm to get the freeplay. luckily, it had a very soft pedal with a heap of air in it so wasn't going to lock the brake on.
Absolutely no offense taken on my part. What you're saying does make a lot of sense, I'll definitely double check everything to make sure it's where it should be.
 

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Interesting. How would I go about getting the proper software for correctly bleeding?
I don't have an ABS Ducati so I can't answer that. In the automotive world, there are vehicles where only the dealer has or can afford the software. There are also vehicles where the software is after market available in a service shop package like you would see at tire and brake places and then there are vehicles where the software is cheap enough even the vehicle owner can afford it. It's possibly a Ducati dealer only item or the controller may be on multiple bikes and the tool more accessible.

I think you've done what you can ASSUMING you have confirmed the compensation port is exposed per BradBlack. (haha, and that you are using the correct port on your Mity Mite.) I would call around and see who can do it for you. Even the worst Ducati dealer can't charge that much for bleeding a rear brake system. A couple months ago a friend of mine did the same thing to the rear brakes on his Ford Ranger and the local tire place (Les Schwab) hooked it up to their computer and bled them for him for free even though he had replaced virtually all the brake components front and rear himself with parts from Rock Auto..

You don't need the back brake to get to to a shop. I know it's kind of like surrendering to take a vehicle to a shop when you do your own work but when you are riding around and through screwing with it, that irritation will evaporate quickly.

Once my ex-wife ran our car over a curb and I said, "jesus, now I have to take it to a damn alignment shop. You know I hate that". She said, "why don't you buy the tools like you do for everything else"? So, I did.
 

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there is no software. it's a basic abs system with no electronic servicing component. you just bleed it.

it may help to get a big syringe and force fluid in from the caliper bleeder until it comes up into the reservoir.
 

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Discussion Starter #12
there is no software. it's a basic abs system with no electronic servicing component. you just bleed it.

it may help to get a big syringe and force fluid in from the caliper bleeder until it comes up into the reservoir.

Thanks. Will do.

I was beginning to think my best bet might be to remove the abs system entirely as described in my shop manual. First bike in 25+ years of road bikes that has even had it, never missed having it before.:grin2:
 

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Discussion Starter #13
" (haha, and that you are using the correct port on your Mity Mite.)"

Jeez! I may have done some stupid sh*& lately and probably misspelled Mity Vac at least once, but I at least know how to use it!:grin2::laugh:

Nevertheless, I'll be the first to admit that I'm a hell of lot better rider than I am a mechanic, probably the main reason I'm somehow still above ground.:grin2:
 

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Brake master cyl.101

Hopefully the GIF file i put in here works.

Attribute to the author:
By KDS444 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=24878290

It demonstrates the need 4 freeplay (or proper adustment) in the pushrod. If the pushrod is adjusted too far in, the piston covers the inlet port, and
1) you can't bleed UR brakes
2) thermal rise (ambient, sun, etc) will allow TRAPPED fluid to expand and place pressure on the servo (brake calipers or clutch slave)

Also note that if you think there's air in the system, I recommend to "think like a bubble". They always migrate to the highest point. If that point happens to be the ABS cube, then you may be forced to bleed there. I've heard of people cracking open the banjo bolts on that unit slightly to eject air from the system. Note that LOTS OF RAGS would be needed for this feat.

edit: just click the link. It's tied to the GIF file.
 

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Discussion Starter #15
Hopefully the GIF file i put in here works.

Attribute to the author:
By KDS444 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=24878290

It demonstrates the need 4 freeplay (or proper adustment) in the pushrod. If the pushrod is adjusted too far in, the piston covers the inlet port, and
1) you can't bleed UR brakes
2) thermal rise (ambient, sun, etc) will allow TRAPPED fluid to expand and place pressure on the servo (brake calipers or clutch slave)

Also note that if you think there's air in the system, I recommend to "think like a bubble". They always migrate to the highest point. If that point happens to be the ABS cube, then you may be forced to bleed there. I've heard of people cracking open the banjo bolts on that unit slightly to eject air from the system. Note that LOTS OF RAGS would be needed for this feat.

edit: just click the link. It's tied to the GIF file.

Your timing and info is perfect for me at this moment, was just getting ready to make another post about my continued frustration. Looks like a covered inlet port might be part of my problem. I took Brad's advice and used a syringe to inject fluid up through the caliper and into the master cylinder, worked great. I then for some reason was finally able to get the fluid to pull through with the Mity Vac. Adjusted my pushrod further in and actually had a halfway decent brake, but decided to give another shot at bleeding in order to be perfect. While doing that I mistaking pressed the peddle, suddenly no brake at all. Was totally unsuccessful trying to pull the fluid through with the Vac as well as injecting fluid through the caliper. Sounds like a covered inlet port might be the culprit. Will give her another shot at bleeding tomorrow with this new info. Thanks.:smile2:
 
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