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I have an 01 SuperSport 750. Ever since I bought it the rear brakes have barely worked. They are super squishy and don't grab very well. I replaced the pads and bled the system (and the old brake fluid was a terrible yellow mess) but the brakes aren't any better. With the bike on the stand, if I spin the wheel and step on the brakes it just slows down. With the brake fully depressed I can still spin the wheel pretty easily.

How can I tell where the problem is? So far I can't find any leaks and everything 'looks' ok. I did some quick searching and apparently the caliper and master cylinder are both very rare for this bike, so a) I don't want to guess and buy one or the other and b) I'm wondering if my only option might be the dealer (The same dealer that charged me $80 to put a gas cap on).

Any way I can test each part individually? And second, any secret locations I can get replacement parts that I'm not aware of? :D
 

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I did some quick searching and apparently the caliper and master cylinder are both very rare for this bike
no they are not, about every ducati has the same rear master
and caliper, they sell so freaking cheap on ebay over here,
as if they were ten year old jap bike parts.

rear calipper sells for ~10m euros used, same with the rear master.

:think:

you could go and buy a wave discs probably, then get some new pads
to suit and give them some time to brake in.
if there is some glass like looking stuff on your pads, they have been
used too hard from the beginning, and will not work no more.

i had several supersports, just the newest one has a brake like yours,
the others were at least working a bit.

:think: :)
 

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Discussion Starter #3
Not sure I agree with you. I found a few Monster rear calipers and they were not the same as what's on my SS. I'll take & upload a pic of mine later. I couldn't find a single one on ebay that matched my bike.
 

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Discussion Starter #4
I should mention that I'm in the USA - Perhaps Ducati parts are cheaper and more plentiful in Europe.
 

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it is more that the rear masters are the same, that is true, but i think a lot
of ducatis share the same rear caliper too, maybe i was looking too much
at my bike at this point.
used ducati parts sell for very little money at this time, should be the same
where you live.

:think:
 

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Test your caliper

Remove the caliper, leaving the hydralics connected. Take a large channel lock plier and gently press the piston back into the caliper. Use a rag to protect the outside of the caliper from getting scratched. It should move back into the caliper without too much force. Watch out for hydralic fluid backing up into and overflowing the reservoir. You may need to remove some of the fluid. After the pistons are seated back into the caliper, GENTLY press on the brake lever and confirm that the pistons are moving out freely.

If you pass this test, the problem is either air in the system or a bad brake master cylinder. If you fail this test, buy a new / used caliper assembly.
 

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i don't know where the bleeder nipple is on the 750. i do know that it needs to be on top when bleeding which on some bikes means taking the caliper off and holding it upside down. the master cylinder needs to be fully retracting in its bore. make sure its adjusted for this.hope this helps.
 

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most definately if bleeder nipple is on the bottom (as on my tuono) you have to pull the caliper off and point it up otherwise air will stay in the system. This is certainly what it sounds like to me, since you can find no obvious leaks.

The other would be a bad master cylinder.

If it turns out to be the master cylinder take a pic and try these guys:

http://www.woundedduc.net/home.html

Chris

i don't know where the bleeder nipple is on the 750. i do know that it needs to be on top when bleeding which on some bikes means taking the caliper off and holding it upside down. the master cylinder needs to be fully retracting in its bore. make sure its adjusted for this.hope this helps.
 

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If you do remove the caliper to bleed you’ll need to stick something the same thickness (or close) between the pads (or if there’s enough line to move it to the top of the rotor) to take the place of the rotor so you don’t pop the pistons out and cause yourself even more problems. You just need to make sure you get ALL the air out or you'll continue having to bleed it from time to time --- even if it seems fine for awhile.

Also: They are designed not to be very strong when working correctly so it doesn't just lock up -- I do believe.
 

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and..... if you were getting a good squirt out of your caliper when bleeding i doubt if your problem is in the master.
 

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get a hand held vacumn bleeder at napa, you dont have to take caliper off or anything. it will suck fluid out with air and takes less than 5 minutes, harbor freight has them as well for less than 50 bucks
 

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get a hand held vacumn bleeder at napa, you dont have to take caliper off or anything. it will suck fluid out with air and takes less than 5 minutes, harbor freight has them as well for less than 50 bucks
i use a large 100ml pump from a pharmacie shop ( drugstore ), that sells
for 1 Euro 50 and does the job perfectly with some 2 inches of clear hose
attached to it.

( safety glasses are recommended for eye protection )


 

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Tips to bleeding - combination of comments so far

This has been posted before, but like many other threads, it gets repeated. Perhaps there should be some more stickies, like this, not starting, batteries etc.

With at least my 01 900SSie there are some issues about bleeding and cylinder location in my opinion.

1 Having the air bleed point as the lowest point in the system is pretty dumb as far as i am concerned - air rises, so it is never going to be at the lowest point during a bleed.

Solution - remove the whole assembly and hold it somehow with the bleed point at the highest point. Put something between the pads to stop them closing, then do a vacuum bleed. The vacuum creates higher velocity of the fluid and removes air bubbles "stuck" to the walls of the pipes. Leave it like this overnight with the brake held on will mean pressure in the system will help force the gas bubbles together and rise to the highest point, then do a quick bleed again.

2 Having the master cylinder close to the exhaust pipe means it gets hot and more prone to gassing. "air" in the system and spongy brakes.

Solutions - use a high boiling point brake fluid and wrap the pipe near the master cylinder with muffler tape or whatever thermal insulation of exhaust pipes is called in your country.
 

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Discussion Starter #14
You guys are awesome, thanks for the tips. I'll head to the garage and try all the suggestions.

I had no idea that the bleeder needed to be above the master cylinder - I'll take the bike back apart and try that first. I'll report back!

(And woundedduc.com looks very cool!)
 

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This is why forums exist

We all had to learn from somewhere - forums, intuition, brilliance, stupidity, breakages and trial and error, thus resulting in "Oh that is why!"

Keep asking questions and the one day you will be be posting, this is how I fixed it!

On a personal note, I really take heed of what Muschi writes, seems like a dude who knows a thing or two about all sorts of Ducs.

Richard
 

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You guys are awesome, thanks for the tips. I'll head to the garage and try all the suggestions.

I had no idea that the bleeder needed to be above the master cylinder - I'll take the bike back apart and try that first. I'll report back!

(And woundedduc.com looks very cool!)
You have the same rear brakes as I do. Most likely, you have an air bubble in the line and the only way I know of getting rid of it is by taking the caliper off, using some wire to hold it up by the grab handle behind the seat, and bleeding it that way. The air bubbles will rise up into the caliper and you'll be able to get them out that way. All hydraulic fluids on our bikes is supposed to be changed at least once per year. Brembo actually recommends more often, like both before and after winter storage, for example. I use DOT 5.1 fluid. Do not ever use silicone fluid, Brembo says it will ruin the seals, particularly in the calipers and prevent the pistons from retracting. Hope this helps.
 
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