Brake issues - Page 2

Luddite · 19-06-2019, 02:46 PM

I think you said earlier, Ryan, that you'd already stripped and cleaned the caliper so you should be able to push the pistons in with your fingers without too much resistance. If you do that with the cap off the reservoir (surrounded by paper towels in case of overflow) you should see the level rise quickly with perhaps a small 'squirt' above the bypass port if it's clear. If the level in the reservoir doesn't rise (or only rises very slowly), then maybe a blocked, or partially blocked, port could be the problem.

You did say that the pushrod looked a little grotty, which might indicate that there could also be corrosion within the master itself perhaps blocking the port.

Mr Gazza · 19-06-2019, 05:48 PM

Looking back through the notes I keep on all the maintenance on my Monster, I note that the highest maintenance item has been the rear brake.
I had persistent problems. Warped disc, high pad wear, wear in the torque rod rose joints, dragging when wheeling the bike around and weirdly a problem discovered at MOT time, where the back wheel could not be rotated backwards. This seemed to be due to the pads wearing to a wedge shape and behaving a bit like a sprag clutch.

Now the rolling road brake test had always showed that the brake was slow to pull off after application, but inspection showed that the pistons were nice and free for their full travel. Fluid flowed into the res' when they were pushed back and the master appeared to work properly.
However the only thing that transformed the operation to a healthy normal was to replace the master cylinder complete.
I think the seals get gradually more draggy or maybe the return spring gets lazy? Nothing you can put your finger on, but replacing the master was the answer after many false trails.

… And yes I fell foul of the old free play thing many years ago on the very first ride out.
I adjusted virtually all the free play out to get a nice crisp lever action, but soon had the brake bind on solid.
I now make sure there is at least 2mm clearance on the stop, which is a lot of free play at the foot end of the lever.

Rrawlings · 19-06-2019, 07:09 PM

The pistons moved around nicely when I gave the caliper a going over, to be fair it wasn’t that bad the pistons were a little sticky one more than the other. When back together and bled up yesterday for he second time I did notice that when the pistons had come out a little pushing one in made the other come out as normal so got my little clamps out to hold one and squeeze the other back in it took a bit more force than I thought it should to push in and the level rise in the reservoir. I cleaned the pushrod and it wasn’t horrendous but wasn’t sparkling either. I then took it for a spin for a couple of miles and it seemed fine. Will try again tomorrow on my way to work which is 9 miles and a mix of all speeds so will know what if anything has changed. If it’s a master I’m going to split the whole system and clean and rebuild the lot just to narrow everything down

Mr Gazza · 19-06-2019, 07:42 PM

I'd say you had plenty of time to change the master. I fannied about with it thinking it wasn't too bad and I'd fixed it, for about three years before I put a new master on.

What a revelation….wished I'd done it three years sooner...just sayin'

Rrawlings · 19-06-2019, 08:05 PM

Gazza if I’m in any doubt tomorrow morning I will take your advice and ring Moto Rapido

Luddite · 19-06-2019, 08:09 PM

Quote:

Originally Posted by Rrawlings

Gazza if I’m in any doubt tomorrow morning I will take your advice and ring Moto Rapido

If you do, don't forget to ask for your 10% UKMOC discount!

Rrawlings · 20-06-2019, 08:00 AM

Just started playing up as I pulled into the car park at work so will ring Moto Rapido

Thanks again for all the help guys. Will let you know when I have it sorted

Luddite · 21-06-2019, 08:43 AM

Master cylinder it is then. If there's any corrosion in the bore, then it will tend to compress the plastic sleeve that the piston slides in and so restrict its movement.

If you're of a curious nature like me, you might want to strip down the old master cylinder to see if you can positively identify the problem and this is a useful article showing the disassembly process http://www.atomicalex.com/?p=139

The master in the pictures is the rear exit model whereas ours is side exit but I think all the internals should be the same. The problem you'll have, if the piston is stuck, is that you can't easily drift it out as they advise because the exit isn't at the end, it's at 90°.

If you wanted to refurbish it, repair kits are available, not from Brembo or Ducati of course - that would be too easy - but from BMW or KTM. I think this is the kit you'd need https://www.motorworks.co.uk/vlive/S...T=6&Q=BRA36241

Hopefully you'll soon have a fully functioning rear brake again, Ryan, and I'd be interested to know what you find if you do strip down the old cylinder.

vince53 · 22-06-2019, 07:01 PM

hi , it's probably the master ,but I had a very similar problem to this yrs ago and it was a flipping brake pipe brake down inside and causing valving fluid would go one way but not return ,took flipping age's to sus it out ?!! I would guess not in this case and probably is the master , but !!! hope you get it sorted * )

Rrawlings · 23-06-2019, 10:14 AM

Don’t say that! Haha. I’ve had sleepless nights thinking about what else could be wrong and knowing my luck it’ll be the abs pump. Hopefully the master will be here midweek and a new pin and spring for the pads then I’ll get cracking

Rrawlings · 28-06-2019, 06:02 AM

Well it’s done I just need to get a ride to work this morning to test it out. New master on pushrod cleaned but it wasn’t that bad and all bled up fine. Did notice a huge difference in the fact that with the new master on I could push brake through the system from the calliper up using a big syringe to make sure fluid could flow back. With the old master this was impossible. So Mr Luddite you could be correct on the issue you suggested in the old master cylinder. I’ll update in a few hours when I’ve replicated the journey that caused the problem before

Rrawlings · 28-06-2019, 08:28 AM

All good thanks everyone

Luddite · 28-06-2019, 08:49 AM

Quote:

Originally Posted by Rrawlings

All good thanks everyone

Excellent news. Now get out and enjoy it!

Rrawlings · 28-06-2019, 09:20 AM

Hawes tomorrow is my plan

vince53 · 28-06-2019, 12:05 PM

nice one well done ,, always good to resolve a persistent problem … * )

19-06-2019, 05:48 PM	#17
Mr Gazza Lord of the Rings Join Date: May 2013 Location: Norwich Bike: M900sie Posts: 5,796	Looking back through the notes I keep on all the maintenance on my Monster, I note that the highest maintenance item has been the rear brake. I had persistent problems. Warped disc, high pad wear, wear in the torque rod rose joints, dragging when wheeling the bike around and weirdly a problem discovered at MOT time, where the back wheel could not be rotated backwards. This seemed to be due to the pads wearing to a wedge shape and behaving a bit like a sprag clutch. Now the rolling road brake test had always showed that the brake was slow to pull off after application, but inspection showed that the pistons were nice and free for their full travel. Fluid flowed into the res' when they were pushed back and the master appeared to work properly. However the only thing that transformed the operation to a healthy normal was to replace the master cylinder complete. I think the seals get gradually more draggy or maybe the return spring gets lazy? Nothing you can put your finger on, but replacing the master was the answer after many false trails. … And yes I fell foul of the old free play thing many years ago on the very first ride out. I adjusted virtually all the free play out to get a nice crisp lever action, but soon had the brake bind on solid. I now make sure there is at least 2mm clearance on the stop, which is a lot of free play at the foot end of the lever. __________________

19-06-2019, 07:42 PM	#19
Mr Gazza Lord of the Rings Join Date: May 2013 Location: Norwich Bike: M900sie Posts: 5,796	I'd say you had plenty of time to change the master. I fannied about with it thinking it wasn't too bad and I'd fixed it, for about three years before I put a new master on. What a revelation….wished I'd done it three years sooner...just sayin' __________________

19-06-2019, 02:46 PM	#16
Luddite Registered User Join Date: Aug 2011 Location: Southampton Bike: M1100evo Posts: 2,465	I think you said earlier, Ryan, that you'd already stripped and cleaned the caliper so you should be able to push the pistons in with your fingers without too much resistance. If you do that with the cap off the reservoir (surrounded by paper towels in case of overflow) you should see the level rise quickly with perhaps a small 'squirt' above the bypass port if it's clear. If the level in the reservoir doesn't rise (or only rises very slowly), then maybe a blocked, or partially blocked, port could be the problem. You did say that the pushrod looked a little grotty, which might indicate that there could also be corrosion within the master itself perhaps blocking the port.

19-06-2019, 07:09 PM	#18
Rrawlings Member Join Date: May 2019 Location: Bradford Bike: M1100evo Posts: 175	The pistons moved around nicely when I gave the caliper a going over, to be fair it wasn’t that bad the pistons were a little sticky one more than the other. When back together and bled up yesterday for he second time I did notice that when the pistons had come out a little pushing one in made the other come out as normal so got my little clamps out to hold one and squeeze the other back in it took a bit more force than I thought it should to push in and the level rise in the reservoir. I cleaned the pushrod and it wasn’t horrendous but wasn’t sparkling either. I then took it for a spin for a couple of miles and it seemed fine. Will try again tomorrow on my way to work which is 9 miles and a mix of all speeds so will know what if anything has changed. If it’s a master I’m going to split the whole system and clean and rebuild the lot just to narrow everything down

19-06-2019, 08:05 PM	#20
Rrawlings Member Join Date: May 2019 Location: Bradford Bike: M1100evo Posts: 175	Gazza if I’m in any doubt tomorrow morning I will take your advice and ring Moto Rapido

20-06-2019, 08:00 AM	#22
Rrawlings Member Join Date: May 2019 Location: Bradford Bike: M1100evo Posts: 175	Just started playing up as I pulled into the car park at work so will ring Moto Rapido Thanks again for all the help guys. Will let you know when I have it sorted

21-06-2019, 08:43 AM	#23
Luddite Registered User Join Date: Aug 2011 Location: Southampton Bike: M1100evo Posts: 2,465	Master cylinder it is then. If there's any corrosion in the bore, then it will tend to compress the plastic sleeve that the piston slides in and so restrict its movement. If you're of a curious nature like me, you might want to strip down the old master cylinder to see if you can positively identify the problem and this is a useful article showing the disassembly process http://www.atomicalex.com/?p=139 The master in the pictures is the rear exit model whereas ours is side exit but I think all the internals should be the same. The problem you'll have, if the piston is stuck, is that you can't easily drift it out as they advise because the exit isn't at the end, it's at 90°. If you wanted to refurbish it, repair kits are available, not from Brembo or Ducati of course - that would be too easy - but from BMW or KTM. I think this is the kit you'd need https://www.motorworks.co.uk/vlive/S...T=6&Q=BRA36241 Hopefully you'll soon have a fully functioning rear brake again, Ryan, and I'd be interested to know what you find if you do strip down the old cylinder.

22-06-2019, 07:01 PM	#24
vince53 Registered User Join Date: Sep 2018 Location: taunton Bike: M1100s Posts: 41	hi , it's probably the master ,but I had a very similar problem to this yrs ago and it was a flipping brake pipe brake down inside and causing valving fluid would go one way but not return ,took flipping age's to sus it out ?!! I would guess not in this case and probably is the master , but !!! hope you get it sorted * )

23-06-2019, 10:14 AM	#25
Rrawlings Member Join Date: May 2019 Location: Bradford Bike: M1100evo Posts: 175	Don’t say that! Haha. I’ve had sleepless nights thinking about what else could be wrong and knowing my luck it’ll be the abs pump. Hopefully the master will be here midweek and a new pin and spring for the pads then I’ll get cracking

28-06-2019, 06:02 AM	#26
Rrawlings Member Join Date: May 2019 Location: Bradford Bike: M1100evo Posts: 175	Well it’s done I just need to get a ride to work this morning to test it out. New master on pushrod cleaned but it wasn’t that bad and all bled up fine. Did notice a huge difference in the fact that with the new master on I could push brake through the system from the calliper up using a big syringe to make sure fluid could flow back. With the old master this was impossible. So Mr Luddite you could be correct on the issue you suggested in the old master cylinder. I’ll update in a few hours when I’ve replicated the journey that caused the problem before

28-06-2019, 08:28 AM	#27
Rrawlings Member Join Date: May 2019 Location: Bradford Bike: M1100evo Posts: 175	All good thanks everyone

28-06-2019, 09:20 AM	#29
Rrawlings Member Join Date: May 2019 Location: Bradford Bike: M1100evo Posts: 175	Hawes tomorrow is my plan

28-06-2019, 12:05 PM	#30
vince53 Registered User Join Date: Sep 2018 Location: taunton Bike: M1100s Posts: 41	nice one well done ,, always good to resolve a persistent problem … * )