eeek! Brakes (?) trying to kill me!

Stuza · Mar 7, 2009

So, some of you may/may not remember that I had a very intermittent power loss problem, usualy in the wet.... well its not and nothing to do with the wet either.

Just happened to me again today - proper style, full on, fast lane of a fast road.

Riding along and it starts so I did whats worked in the past and changed down and back up gears ... no diference, in fact its getting worse. So, as i've still got some speed, i'll bung it in nuet and coast to the kerb. Once in nuet it STILL happened!!! I managed to power my way over to the kerb and pulled up. At that point I realised its the brakes when I tried to push it up a drive way and it resisted being moved. I couldn't tell if its the front or rear as once I was pulled over it quickly released and I also didn't want to feck around trying to diagnose it where it was as I was still on a very fast road.

I then doubly realised that its the brakes and probably the front. As I pulled away I needed to do some gentle braking and there was almost no resistance in the front lever and the front did almost nothing .... doh!

I'm no spanner man so, if you have any ideas what it could be, please make it stooooopid person English :dunno

Please help......

edit: sorry, 07 RSV-R Bol'dor

amb67 · Mar 7, 2009

Oh dear, sounds like you had a friggin nightmare mate, glad you pulled over safely.

Let's get this right:

Brakes came on by themselves?
Released themselves once pulled over?
You then attempted to use the front brake and the lever hit the bar almost?

OK? If that's correct it sounds like your front brake hydraulic circuit has been compromised.

I take it the levels OK, if yes then I would have to say it has to be a master cylinder issue.

Before you do this just make sure that you check that you have no leaks, loss of fluid, low fluid, over filled reservoir, etc.....

Has to be basics first.

LEGS · Mar 7, 2009

One thing to check is that your front brake lever and lever holder are genuine Brembo items, i.e have they every been replaced? Pattern or aftermarket ones can cause the very same problem you are experiencing due to poor manufacturing tolerances

Nadz · Mar 7, 2009

A freind of mine had this on his Tuono a couple of weeks ago, it ended up being the master cylinder not letting the fluid back after braking.

Dont know if it's the same but hope it helps.

A303 · Mar 7, 2009

here's a thought - dr rossi enlightened us about the adjustment in the standard clutch lever

http://www.rsvzone.com/forums/showthread.php?t=6541

is the brake the same?
if this has no free play and is causing your brakes to overheat ... could be worth checking out

amb67 · Mar 7, 2009

I see your train of thought A303 but I'm pretty sure that there is no adjustment on the actuating rod for the front brakes. Well there isn't on mine anyhow!!

chrisvosberg · Mar 7, 2009

No problems here....

I wonder if one or both of the front calipers have air in them. Under heat of use, the air could expand and cause the brakes to apply? I would think the master cylinder would stop this from happening, but IF the piston in the master cylinder was not fully retracted......? Could be a combination of these two problems. Weak spring or foreign objects, (no, dirt or corrosion, not Romanians!:lol) in the master cylinder bore.

Stuza · Mar 7, 2009

the what goes where now?:dunno:biggrin

OK ... i am well and truley baffled by your responses BUT, i do have a spanner monkey mate (im a desk jockey) who I will get to look at this thread. He's already suggested we just change the brake fluid anyway as its a quick, easy job (aparantly?). As far as i'm aware they are oem parts, im the bikes second owner and the first owner was a "born again" who was lucky to be able to spell bike, let alone replace with 3rd party - which is why he only had it 6 months from its birth.

Thanks for the ideas guys, I'll let you know how we get on :thumbup

AREESSMILL · Mar 7, 2009

errrr

Is the resovoir filled up to much resulting in expansion thus leading to binding??

or is the M/C seal shagged?

Stuza · Mar 7, 2009

ahh right, i can answer the first part of that. The fluid level is below the max (just) - assuming thats the level your talking about.

amb67 · Mar 7, 2009

AREESSMILL said:
errrr

Is the resovoir filled up to much resulting in expansion thus leading to binding??

or is the M/C seal shagged?

Bloody hell Tim your picking this up pretty quick mate.

That's quite a technical response mate.

This tends to happen more on the clutch reservoir though, the brake one just pisses out the excess fluid all over your bars.

Mick Oliver · Mar 7, 2009

Definately sounds like master cylinder not releasing and leaving the brakes on.

Stuza · Mar 7, 2009

one thing I keep seeing is that "not releasing". Just to clarify, I can be cruising along the motorway and it will start happening without me touching the brakes. Also, it starts off very slight and then increases slowly until the engine is struggling to push me along.

chrisvosberg · Mar 7, 2009

Stuza said:
one thing I keep seeing is that "not releasing". Just to clarify, I can be cruising along the motorway and it will start happening without me touching the brakes. Also, it starts off very slight and then increases slowly until the engine is struggling to push me along.

Theoretically, air in the calipers mounted on the forks or swingarm could cause the braking you experience on the road if the master cylinder does not release.

While riding, the brakes will heat up because the wheel is turning and the brake pads rub on the brake disc, especially if the master cylinder won't fully release. If there is a good amount of air in the caliper, it will heat up and expand. Further, if the master cylinder piston will not fully retract and allow this pressure to bleed off, the brake system will do the only thing it can: push the brake pads against the disc as if you were applying the brakes yourself.

This could also be a brake line whose inner lining has ruptured and now holds pressure as a one-way valve.

whitetrash · Mar 7, 2009

I'd just go for a total strip, inspection and service of the front brake system, inspect both calipers, check the pistons are free and the seals are all fine, check the lines for anything suspicious, if there is any doubt over the master cylinder then just replace it. Now with all due respect...

DO NOT **** ABOUT!!!

Ignorance to this problem and a failure to act on it could result in a serious accident, dont risk your life mate, get it sorted!!

superyellow · Mar 7, 2009

what type of Fluid do you have there? could it be accidently mixed with 5.1 or 5 with old 4? I switched back to 4 since the 5.0 was so messed up and I heard that you have to change that more often. are your rotors okay? warped?? change your fluid! and see if it comes back again
could it be the Atmosphere Sensor on the right intake hole whic is causing your power loss in the rain Just a guess???

Badger · Mar 8, 2009

LEGS said:
One thing to check is that your front brake lever and lever holder are genuine Brembo items, i.e have they every been replaced? Pattern or aftermarket ones can cause the very same problem you are experiencing due to poor manufacturing tolerances

As Legs said check the lever is OE Aprilia NEVER EVER FIT ANY PATTERN BRAKE LEVERS they are deadly for locking up the front of their own accord.

Does not sound like that though as the loss of lever pressure points to the M/C, you must get this stripped and looked at by a competent person or you could be looking at a nasty accident mate.

I would not ride it till this was done and checked out, you can't **** about with intermittent front brakes.

DaveRSV · Mar 8, 2009

A very common mistake owners make is to adjust the rear brake up so that there is very little travel in the pedal. When the disc heats up the brake locks on.

If it is the front as you suspect it sounds as though the fluid has been boiled by too much heat generation. Could be something as simple as the wrong type of brake fluid being used.

Stuza · Mar 8, 2009

again, thank you so much for the replies guys:thumbup

I have no idea what fluid is in there however, here is my plan:

- Im going to go out and get some Dot 4 fluid.
- I have my very own spanner monkey who will be reviewing this thread.
- He will then come over and at the very least, the fluid will be replaced and the calipers will be checked for normal function.

Assuming I have to replace the brake line and mc (which I might just do anyway), are the Aprilia stock equipment the best replacements or are there third party QUALITY products? For example, on my SP1 I replaced the normal hoses with braided, does the R come with braided already? I'm thinking that if this is going to be done, I may as well do it properly as in my opinion, the brakes aren't up to my old R6/Phazer standards.

Of course, I am going to stay off the bike. Already scared the feck out of me yesterday and that was in a straight line... im really, really worried this may occur on a corner and ..... well, you can guess the result of that!

Stuza · Mar 9, 2009

any ideas guys? I'm desperate to get this back on the road as quick as possible. Can anyone recommend a supplier?

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eeek! Brakes (?) trying to kill me!

Stuza

amb67

LEGS

Nadz

A303

amb67

chrisvosberg

Stuza

AREESSMILL

Stuza

amb67

Mick Oliver

Stuza

chrisvosberg

whitetrash

superyellow

Badger

DaveRSV

Stuza

Stuza

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