Clutch slave cylinder repair.

Started by kokis, May 30, 2013, 04:11:56 AM

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kokis

Will check tomorrow. Too rainy today in my area, don't want to be covered by mud.
Oh, When I released(I closed bleeder first) lever I heard some sound like something(in master cyl) was sucking air.  I pumped lever few times and made bleeding again and there was no that sound. Don't know what it is. Master is brand new brembo.
I am not pro in tech questions, but as any rider have some experience that I can share without claiming to absolute truth. Please use my advices responsibly.

kokis

I gave it a ride. overnight press did not helped..
So what can it be with slave cylinder?
I checked tech manual and it seems that there is nothing to disassemble.
I am not pro in tech questions, but as any rider have some experience that I can share without claiming to absolute truth. Please use my advices responsibly.

Dirty Duc

Quote from: kokis on May 31, 2013, 03:16:13 PM
Will check tomorrow. Too rainy today in my area, don't want to be covered by mud.
Oh, When I released(I closed bleeder first) lever I heard some sound like something(in master cyl) was sucking air.  I pumped lever few times and made bleeding again and there was no that sound. Don't know what it is. Master is brand new brembo.
when you tie the lever off, do not open the bleeder.  If you opened the bleeder and left it overnight, you definitely got air in there.

On your current fresh bleeding, just tie the lever back and leave it overnight. 

kokis

I tied lever and after 18 hrs opened bleeder. Then I closed it tightly and slowly released lever.
I am not pro in tech questions, but as any rider have some experience that I can share without claiming to absolute truth. Please use my advices responsibly.

Dirty Duc

Don't open the bleeder.  Just check fluid level and top off if necessary.

The plan is that the little tiny bubbles that are giving you fits will work their way up the line and into the master cylinder reservoir.  Then no more bleeding should be necessary.

It sounds like you have one of the stubborn little bubbles that will not move with bleeding.

JimmyTheDriver

I do something silmilar to what these guys are stating, but a little backwards.

I had the best luck doing the following to bleed clutch...

1) Take pee cup top off.
2) Detach slave via three bolts
3) Open bleeder on/above slave and connect small tube to aim the drainage
4) Pump clutch lever while making sure the pee cup is full.  If it reached the bottom, and re-introduces air, you have to start over
5) After you see no more air traveling through during clutch pumps, tape the lever completely compressed to handlebar
5) tap all parts involved, lines included with a screwdriver or whatever, something to get additional air out
6) Make sure pee cup is full before walking off
7) Leave overnight
8 ) As long as pee cup is still full, release lever
9) Put cap on pee cup
10) Tighten bleeder on slave
11) Reattach slave

kokis

I will try that again. Thanks for instructions guys!
For some reason sometimes I could not change gear on stop. Bike did not dragged at all but gearchange pedal would not move at all too. wtf [bang]
I am not pro in tech questions, but as any rider have some experience that I can share without claiming to absolute truth. Please use my advices responsibly.

koko64

With the lever pulled and tied, I tape an old electric hair clipper (with blades removed) to the clutch or brake line I want to bleed. This helps vibrate the bubbles loose. It helps with stubborn bubbles in the line. I tend to tap the components also in the process generally.
Got the idea from ducatiz, but the method he uses is more entertaining! [laugh]
2015 Scrambler 800

kokis

I came back to the thread to ask about tapping\vibrating lines which was said about in previous and the last answer.
What is the point of it??? When one rides a bike all lines receive a lot of vibrations and by your logics all bubbles should rise to master.
I am not pro in tech questions, but as any rider have some experience that I can share without claiming to absolute truth. Please use my advices responsibly.

Cloner

One thing I haven't seen mentioned.....on many Ducatis the banjo bolt securing the line leaving the master cylinder (clutch or brake) is often higher than the master cylinder itself.  This leaves a point inside the joint where air may accumulate as it rises, but it won't naturally go down into the master cylinder and out the reservoir.  Often, to remove the last obstinate bit of air you'll have to dismount the master cylinder and hold it so that the banjo fitting is lower than the rest of the master cylinder so that the air can burp out.

I've seen dozens of these, especially on brake masters, but occasionally on clutch masters. 

You can break the joint (by loosening the banjo bolt), squeeze the lever and hold it, tighten the joint, then release the lever to bleed this joint, but you might not get the air out and it can lead to leaking at the joint.  The method of removing the cylinder is more effective and fool-proof.
Never appeal to a man's "better nature."  He may not have one.  Invoking his self-interest gives you more leverage.  R.A. Heinlein

'64 Ducati Monza 250
'67 Aermacchi/HD Sprint SS (race bike)
'00 Aprilia RSV Mille
'03 Ducati 800 SS (race bike)
'04 KTM 450 EXC
'08 Kawasaki Ninja 250 (race bike)

kokis

Thank you very much, will have to work with it. [leo]
I am not pro in tech questions, but as any rider have some experience that I can share without claiming to absolute truth. Please use my advices responsibly.

koko64

Quote from: Cloner on June 04, 2013, 03:49:28 PM
One thing I haven't seen mentioned.....on many Ducatis the banjo bolt securing the line leaving the master cylinder (clutch or brake) is often higher than the master cylinder itself.  This leaves a point inside the joint where air may accumulate as it rises, but it won't naturally go down into the master cylinder and out the reservoir.  Often, to remove the last obstinate bit of air you'll have to dismount the master cylinder and hold it so that the banjo fitting is lower than the rest of the master cylinder so that the air can burp out.

I've seen dozens of these, especially on brake masters, but occasionally on clutch masters. 

You can break the joint (by loosening the banjo bolt), squeeze the lever and hold it, tighten the joint, then release the lever to bleed this joint, but you might not get the air out and it can lead to leaking at the joint.  The method of removing the cylinder is more effective and fool-proof.

This is correct. I had to do this recently. In fact the brake system would not pressurize without using every method listed in this thread, because the line was replaced allowing alot of air into the system.
There are banjo bolts with bleeders built in which work great.
The vibration method is good with the lever pulled for an hour in the garage, not on the road.
2015 Scrambler 800