Boiling rear brake fluid

[Cabernet]

Does anyone else often cook their rear fluid?

As soon as I get a bit spirited I seem to be able boil the fluid.

It first happened on a track day some years back. I modified my braking to use more front and problem resolved. But on the road in the countryside the balance offered by the rear is more critical.

The fluid has been changed a few times. The pad back plates are dressed for free movement. The pistons are free moving.

I also manage to do this on my Breva 750 too.

Interestingly Guzzi is the only marque I have had the issue with, although always been heavy on rear pads.

Myself an ex motorcycle courier and approaching 900,000 miles.

[docc]

Brembo pads or others (more aggressive)?

[Steve S]

It happened to me and other V11s the same day in the Spanish mountains after a lot of downhill bends but never in the UK

[Cabernet]

Brembo pads or others (more aggressive)?

Believe them to be EBC standard.

Certainly the Breva's are EBC.

 

Going to upgrade the fluid to EBC BF307 and see how that goes.

[Cabernet]

It happened to me and other V11s the same day in the Spanish mountains after a lot of downhill bends but never in the UK

Thing is on other bikes I have carried pillions and luggage in a more upright pose.

I have tended to favour the rear for a more balanced comfortable sweeping ride.

Now I have this issue on V11 solo and luggageless.

On the Breva, all occasions have been on long decent passes in the Alps and Black forest and the Breva was facing down some credible bikes at the time, so perhaps I can forgive it.

However, I very underwhelmed by the V11 rear brake performance.

[docc]

 

However, I very underwhelmed by the V11 rear brake performance.

 

Agreed on this, no doubt.

 

Very important that when the rear caliper is bled (regularly) that the caliper is removed and the bleeder rotated topside.

[gavo]

I've had this problem too and I tend to use the front way more than the back, I assumed the fluid was a bit old and probably had moisture in it so I 

replaced the fluid but had a hard time getting a decent pedal.

In the end I removed the calliper, put a small tyre lever in it to imitate the disc an raised the whole lot up above the height of the master cylinder.

It worked , now I have a good rear brake but I'm yet to give it a good workout.

[gstallons]

Google high performance brake fluids and look at boiling points . Then make your choice . Yes the V11 has some exciting rear brakes ! Looking into a cast iron rotor might be a good idea also . Stainless does do a less than stellar job as a brake rotor .

[dl.allen]

mine was a pain the but also. 

 

First I check the rotor with a dial guage set up on it.  It was about .005 out.  I marked it and massaged it with a large crescent wrench and got it within .002   (Do this at your own risk....I saw some youtube videos on this)

 

Then I just took it off, cleaned it up really well.  Lubricated the sides of the pistons with a tiny little bit of high temp brake pin grease from NAPA.  Then I bent the keeper spring until it was almost flat so that it would impart more pressure on the pins/pads. (do this at your own risk..I have never read about this but had to try something).   Then I put the same grease on the pins and the holes in the pads with a small paint brush. 

 

Then I replaced with DOT4 fluid which the manual calls for...I think its high temp.  I wired the caliper up as high on the bike as I could so the nipple was facing up and bled it a lot with an old brake pad stuck in the caliper to clamp on.  I used a vacuum bleeder then finished it off with the pedal. 

 

So far so good.  I have always had problems with the rear pads dragging and heating up the rotor.

[Scud]

I overheated my rear brake midway on a 400 mile loop with lots of elevation changes. When I noticed it (after a major descent), I just rode about 50 miles without touching the rear brake - checked again and it was better.

[Cabernet]

I overheated my rear brake midway on a 400 mile loop with lots of elevation changes. When I noticed it (after a major descent), I just rode about 50 miles without touching the rear brake - checked again and it was better.

My experience is the same only mine came back in around 3 or 4 miles, so I am confident it's not a dragging or binding issue.

 

So glad they did not put a linked system on this model. That would have made life "interesting"!

[Lucky Phil]

If you're boiling the fluid in the rear brake of a V11 then you have a problem with riding technique. As a matter of fact if your using it for any other reason than holding the bike on a hill at the lights you have a technique issue.

Maybe fully loaded 2 up or on a muddy road I might cut you some slack but honestly in normal riding situations its a decoration.

Ciao

[Cabernet]

If you're boiling the fluid in the rear brake of a V11 then you have a problem with riding technique. 

Then why after thirty years and near 900,000 miles of motorcycling has it only shown up on a Guzzi and predominantly on a V11? 

[Alfanatiker]

Did you check your main brake cylinder? Maybe the back flow port is partially clogged and pressure falls to slow, Enough clearance (5-10mm) between brake lever rod and piston.

[guzzi323]

I think it might be the non-exisitant lever return spring on the brake pedal. I put a spring on it and my brake dragging problems went away. I also like having a more solid feel to the pedal so I know I'm not accidenally slightly pressing it with my large, heavy boots.

I use the rear brake very little yet before putting the spring on I was wearing through them faster than the fronts.