In the process of getting my 2000 M750 back onto the road, had a local (reputable!) shop fix a bunch of issues. Unfortunately they also are a race team and are leaving for two weeks. I picked up my bike with everything fixed except the rear brake.
They flushed it out and cleaned the whole system, refilled and bled, took it for a test drive and it just slowly lost pressure. So, I have no rear brake (side poll - how comfortable are you riding without a rear brake?). They suggested replacing the master cylinder and/or caliper. Before I buy a new rear caliper and master cylinder - what is the likely culprit? It's not leaking fluid.
Also, am I correct that this is the rear caliper (http://www.2wheelpros.com/brembo-oe-rear-brake-caliper-p32f-gold-w-07bb0111-ducati-2358199.html) and this is the master cylinder (http://www.2wheelpros.com/brembo-oe-rear-master-cylinder-ps11c-gold-wpush-rod-cagiva-ducati-2358148.html)?
I'd say get the master first, try that.
Quote from: Speeddog on August 12, 2013, 06:08:15 PM
I'd say get the master first, try that.
Well, it's nice that it is the less spendy part too. What causes it to not have pressure, but not leak?
I would wait until I knew what the problem was before replacing parts........
Quote from: SpikeC on August 12, 2013, 06:54:43 PM
I would wait until I knew what the problem was before replacing parts........
Which is good, in theory...but I can replace and bleed the rear break myself. Just not sure how to diagnose it. All the shop said was that it was gunky, so they flushed it, filled it, bled it...worked fine for a little bit of a ride around the block, but just slowly lost pressure. Now you can push the pedal all the way down and get nothing.
rebleed
Quote from: Javamoose on August 12, 2013, 06:41:54 PM
Well, it's nice that it is the less spendy part too. What causes it to not have pressure, but not leak?
Fluid will bypass internally thus pressure will not be optimal. As stated, MC is the logical component start point.
Quote from: oldndumb on August 12, 2013, 07:32:55 PM
Fluid will bypass internally thus pressure will not be optimal. As stated, MC is the logical component start point.
Edit: To add to Raux's advice, when bleeding ensure that the caliper is above the MC. Rear calipers have the annoying habit of trapping air.
Quote from: oldndumb on August 12, 2013, 07:32:55 PM
Fluid will bypass internally thus pressure will not be optimal. As stated, MC is the logical component start point.
Well, that makes sense.
Quote from: oldndumb on August 12, 2013, 07:36:25 PM
Edit: To add to Raux's advice, when bleeding ensure that the caliper is above the MC. Rear calipers have the annoying habit of trapping air.
I saw that mentioned a lot when I searched. I wondered if the shop took the caliper off (they had the rear wheel off to install new rubber) and flipped the caliper when they bled it. Wanted to ask, but didn't want to insinuate that they didn't know how to bleed brakes...
I will try pulling the caliper and re-bleeding. Anything special I should be aware of regarding removing the caliper and bleeding?
The caliper would leak externally. Remove the caliper, pry back the dust seal and visually inspect. Good? Replace the master.
Quote from: howie on August 12, 2013, 08:11:37 PM
The caliper would leak externally. Remove the caliper, pry back the dust seal and visually inspect. Good? Replace the master.
[thumbsup] So, I'm guessing it's not worth the hassle to try a rebuild kit on the MC?
Quote from: Javamoose on August 12, 2013, 09:27:03 PM
[thumbsup] So, I'm guessing it's not worth the hassle to try a rebuild kit on the MC?
Not available.
Quote from: Speeddog on August 12, 2013, 10:18:13 PM
Not available.
Oh, maybe people were talking about rebuild kits for the caliper then and I just misunderstood...
AFAIK, those aren't available either.
If someone has a link to rebuild kits, I'd love to see it. [beer]
Bet there's air in it
Quote from: Raux on August 13, 2013, 04:06:33 AM
Bet there's air in it
Well, I definitely taking your first suggestion of re-bleeding it this weekend before I buy anything. [thumbsup]