REAR MASTER CYLINDER FAILURE

[griff]

JUST A QUICK QUESTION ??? HAS ANYONE ELSE SUFFERED WITH THEIR REAR BRAKE MASTER CYLINDER SEIZING,MINE FAILED ON SUNDAY (V11 TENNI) AND LOCKED THE REAR WHEEL,ONLY GOING SLOW AT THE TIME

MY BROTHERS FAILED ABOUT 6MTHS AGO IN THE SAME WAY (V11 LEMANS) BUT THEN HE,S HAD MORE REPAIRS TO HIS GUZZI THAN I CARE TO MENTION,4 GEAR BOX SPRINGS,ENGINE PAINTED,ETC

ANY IDEAS????, BIKE IS USED MAINLY IN THE DRY ( I'M A WIMP )BUT FOR NO REASON AND WITH NO WARNING IT SEIZED,ONLY DONE 3000 MILES WAS THINKING ABOUT PACKING WITH SILICON GREASE BUT ANY IDEAS WOULD BE GREATFULLY RECEIVED

CHEERS

GRIFF

[jrt]

The rear brake line sits pretty close to the exhaust pipe. If the line (and fluid) heats up from that source, then it can put some pressure on the rear brake. The rear brake drags, creates frictional heat, and you get more braking. Or, if there is dirt and other crap in the rear brake caliper- and I guarantee there is- then the brake can drag and heat up.

Look at the routing of the brake line and make sure it is very clear of the exhaust. Also, clean out the caliper (even removing it from the perch).

The other adjustment I made was at the pedal itself- I make sure there is a little 'flop' up and down in the pedal.

[griff]

The rear brake line sits pretty close to the exhaust pipe.  If the line (and fluid) heats up from that source, then it can put some pressure on the rear brake.  The rear brake drags, creates frictional heat, and you get more braking.  Or, if there is dirt and other crap in the rear brake caliper- and I guarantee there is- then the brake can drag and heat up. 

Look at the routing of the brake line and make sure it is very clear of the exhaust.  Also, clean out the caliper (even removing it from the perch). 

The other adjustment I made was at the pedal itself- I make sure there is a little 'flop' up and down in the pedal.

56045[/snapback]

 

CHECKED ALL THAT BUT FOUND PISTON HAD SEIZED IN MASTER CYLINDER ITSELF,IT SEEMED UNUSUAL TO SEIZE WITH OUT ANY WARNING,THANKS FOR THE IMPUT THO

[al_roethlisberger]

....we can hear you, honestly

 

 

 

Anyway ..... Question: Clarification, are you saying the rear *master cylinder* failed, or the caliper(technically a "slave") has failed, or both?? And BTW, just in case anyone is unsure, the rear master cylinder is that gold tubular thing attached directly to the rear brake pedal by its linkage located near the heel of your right foot

 

If this is indeed a failure of the rear master cylinder, although I am sure it has happened(especially since this part is used on many makes of motorcycles), I have not heard of any rear brake master cylinders failing via this forum

 

If however you are really saying that your rear *caliper* has been dragging, and now has seized, this indeed has been reported more than a couple times. Do a search on "groan" or "drag" and you are sure to find more info.

 

In fact, we probably need a "rear brake groan" FAQ since it comes up pretty often, but I just haven't had time to get around to it these last few months, what with the new job and getting ready to move

 

 

But anyway, yes, the design of the V11 rear brake caliper seems to be mildly problematic(but sometimes more catestrophic). I think we've only heard of one other rear wheel "lockup", and I think that one was because the screw-in locking pin on the bracket backed out, not because of a brake seize.

 

But, what seems to happen with regards to "groaning", dragging, and sticking of the pistons is that since the caliper is underslung, it seems to accumulate a LOT of brake dust and other crud, quite quickly.

 

The solution I(and many others) have found is to routinely(say every 3-6 months if you ride a LOT, or once a year if not so much) remove the caliper, hang it in a bucket and very liberally spray the heck out of it with brake cleaner.... just empty the whole darned can. You will be AMAZED at the amount of black gunk that comes out of the caliper. And then you'll find it doesn't drag again for another few months.

 

The theories about the brake line getting hot are a good preventative measure too. As long as the line is correctly routed/clipped to the swingarm, you should be fine. But I've found mine incorrectly routed and loose from its clips on a couple occasions, so it's good to check this issue every so often also.

 

But all-in-all, if this is indeed just the "dirty caliper problem", this should not be a major issue to correct/maintain.

 

If your master cylinder has failed though, that is a different story, and is just probably "bad luck". In that case, check eBay for a used one from a Guzzi, Ducati, etc... as again, this is a very common unit.

 

Good luck!

al

[dlaing]

You will want to be sure to check your wheel bearings.

Many have too short of a spacer, causing premature bearing failure, which I imagine may cause brakes to rub, get hot, seize, crash, etc.

[al_roethlisberger]

That's true.

 

The brake issue can by a symptom of the also oft-mentioned "rear bearing/spacer" issue.

 

So, if cleaning your caliper does not help, you should do as suggested above(or do it at the same time just to be sure).

 

al

[jrt]

Also- didn't Carl Allison have the master cylinder sieze up on him? Water intrusion through the boot or some such cause.

Might want to do a search on that.

[al_roethlisberger]

Also- didn't Carl Allison have the master cylinder sieze up on him?  Water intrusion through the boot or some such cause. 

Might want to do a search on that.

56069[/snapback]

 

 

...he may have. Between him and Joe Camarda, I'm pretty sure they've had just about everything go wrong that can

 

 

al

[callison]

...he may have.  Between him and Joe Camarda, I'm pretty sure they've had just about everything go wrong that can 

al

56079[/snapback]

 

Hey. Wait a minute. I resemble that remark...

 

 

It's covered over on the guzzitech site.

[griff]

....we can hear you, honestly 

Anyway    ..... Question:  Clarification, are you saying the rear *master cylinder* failed, or the caliper(technically a "slave") has failed, or both??  And BTW, just in case anyone is unsure, the rear master cylinder is that gold tubular thing attached directly to the rear brake pedal by its linkage located near the heel of your right foot 

 

If this is indeed a failure of the rear master cylinder, although I am sure it has happened(especially since this part is used on many makes of motorcycles), I have not heard of any rear brake master cylinders failing via this forum 

 

If however you are really saying that your rear *caliper* has been dragging, and now has seized, this indeed has been reported more than a couple times.  Do a search on "groan" or "drag" and you are sure to find more info.

 

In fact, we probably need a "rear brake groan" FAQ since it comes up pretty often, but I just haven't had time to get around to it these last few months, what with the new job and getting ready to move 

But anyway, yes, the design of the V11 rear brake caliper seems to be mildly problematic(but sometimes more catestrophic).  I think we've only heard of one other rear wheel "lockup", and I think that one was because the screw-in locking pin on the bracket backed out, not because of a brake seize.

 

But, what seems to happen with regards to "groaning", dragging, and sticking of the pistons is that since the caliper is underslung, it seems to accumulate a LOT of brake dust and other crud, quite quickly.

 

The solution I(and many others) have found is to routinely(say every 3-6 months if you ride a LOT, or once a year if not so much) remove the caliper, hang it in a bucket and very liberally spray the heck out of it with brake cleaner.... just empty the whole darned can.  You will be AMAZED at the amount of black gunk that comes out of the caliper.  And then you'll find it doesn't drag again for another few months.

 

The theories about the brake line getting hot are a good preventative measure too.  As long as the line is correctly routed/clipped to the swingarm, you should be fine.  But I've found mine incorrectly routed and loose from its clips on a couple occasions, so it's good to check this issue every so often also.

 

But all-in-all, if this is indeed just the "dirty caliper problem", this should not be a major issue to correct/maintain. 

 

If your master cylinder has failed though, that is a different story, and is just probably "bad luck".  In that case, check eBay for a used one from a Guzzi, Ducati, etc... as again, this is a very common unit.

 

Good luck!

al

56056[/snapback]

yes its the master cylinder not the caliper, i just thought it was strange because my brothers lemans did the same about 6mths ago and now mine has failed,striped it and there is no sign of corrosion or anything to indicate a fault but the piston is jammed in the housing

fitted a new master cylinder and its now all ok

thanks to everyone for their input