Front Brake Shudder

[enzo906]

Hi Guys

I can't work out where the shudder comes from
The wheel lugs are within 6 thou
The Rotors are even and straight
I have replaced the wheel bearings
The only thing I have n't checked is the steering head. But it doesn't seem to be from there.

has anyone had this issue? or know of a fix?

[Desmo_Demon]

I have the same issue with my Paso 750. Mine only shudders with light braking, though. It has new wheel bearings, new steering head bearings, and the wheel was straightened, as were the rotors. The next thing I'm going to chek are the brake pads themselves. I don't know if they are contaminated with rust, or maybe even some of paint overspray, as I painted the carriers. I have a spare set of slightly used brake pads, so I may swap those and see if the pads are causing the pulsing and grippiness.

I wish you luck in troubleshooting yours!

[DonaldoDuck]

My 907 does this when it reaches the last 1/3 of the brake pad and below, but as mentioned in previous post only under light to moderate braking. I changed the pads and it went away.

[JWilliam]

I had something like this when I was still running the cast iron front rotors. Since I have had some floating steel rotors made this has never happened again. My guess is the cast iron rotors are developing ridges (we're only talking microns) so I don't think you will get rid of it unless you get some new discs made.

[ducapaso]

The only thing I have n't checked is the steering head. But it doesn't seem to be from there.

You are sure about bearing torque tightening?
I had it leak on my smooth and it was very hard to ride!

[jcslocum]

Some kind of ridge or brake deposit on the rotor?? Maybe on the inside where it's hard to see?

[spaynenda]

I've had it for a long time, so it can't be a factor of pad wear. For me it occurs under moderate to hard braking. I'm getting new (correct) tires so we'll see if that has any effect.

[JWilliam]

Vibration when using a brake is all but always associated with an oval drum or warped disc. With the material for the Paso disc being Grey grade cast iron which has a much lower tensile strength than carbon steel and also being prone to cracking it cannot be any suprise that a braking problem occurs given the age of components. The only reason our bikes pass the road safety test with this is because testers can run a car on a rolling road and find out these sort of faults, whereas the bikes are less likely to be road tested.

[persempre907]

Vibration when using a brake is all but always associated with an oval drum or warped disc.

I also had the same problem.
There was a little ovalisation of the rotor, which a good mechanic wasn't able to see too.....
So, try again to see at the rotor.

Ciao

[enzo906]

thanks for the suggestions,
I have a new tyre - didn't help
Checked for run out - not the issue (used dial indicator)

will try new pads as I have had a rusting issue due to lack of use,
Also noted that as the disc are CI, then possibly the rusting may have created hard spots / softer spots changing the grip level, causing the shudder?

Anyone know where I can get those 851 style floating CI rotors (In Australia) ? are they even available anymore?

If I solve it I'll post the solution, hopefully new pads will do it, mine are about 60% worn

[persempre907]

Anyone know where I can get those 851 style floating CI rotors (In Australia) ? are they even available anymore?

The 851 strada had the same rotors of the 907 (not full floating), while the 851/888 SP had the full floating rotors.
What do you mean?
Ciao

[Desmo_Demon]

The caliper pins that hold the pads in and the little springs were filthy on my bike. I cleaned everything and even scuffed the pads a little with some 600-grit sandpaper, but it doesn't seem to have made any difference with my bike.

[jomo]

I would be inclined to take the rotors to a macine shop or brake shop and get them machined. Very cheap and you will know they are OK.

[enzo906]

Hey Jomo

You live near by, do you know of a decent Machine shop or do I just take them to Repco?

[jomo]

Repco should do, or a brake and clutch place. I assume it only happens with the front brakes applied? On cars, the mechanics machine the front brakes when they shudder. If they still shudder they machine the front brakes again. Most don't seem to realise on a car your brakes are all linked and if the discs or drums are warped, you will still feel it through the pedal.

At least we can seperate that feeling on a bike. Unless one has linked brakes of course, something we never want on a sports bike!