Front brake pulsing

[hurrican3p]

Hi,

Sometimes when I am coming to an abrupt slowdown to a stop I can feel my front brake sort of pulsing, sometime quite hard. Almost like the rotor is trying to wiggle a little but when clamped down upon.

Any throughts?

 

[Marthy]

Your rotor should be floater? Kind of self align. 2004... make sure you don't have any rust built up and the rotors move a bit.

 

[tosh23]

sounds like warped discs..check your bobbins

 

[FinalImpact]

Marthy, pretty sure the early ones only use a floating caliper, so if the caliper doesn't float any irregularities will be transmitted to the chassis.

As stated above, its very likely the rotor is bent or may even be hot spotted. Look for black or blue dark spots.

Raise the nose by placing weight on the seat or blocking the bike under the header.
Using a pen or other hard plastic item, rest it on the fork tube just touching the rotor. Spin the wheel and allow the rotor to push the object away. It should now maintain the same gap while being spun. If it doesn't, its likely bent. Repeat on the other side.

I'd pull the caliper off and confirm it slides in the brackets. It should move. Follow up with brake bleed. Do a search for this; but straight from the FSM is a process that works and takes no special tools. PM me if you need some insight as opinions vary on this.

Gotta run but I'll check back in.

 

[FinalImpact]

Drawing for 2004 seems to ^^ confirm. Also, the discs fits all years PN: 5VX-2581T-01-00.

As usual, your support is always welcome Marthy! :thumbup:

 

[TownsendsFJR1300]

Hi,

Sometimes when I am coming to an abrupt slowdown to a stop I can feel my front brake sort of pulsing, sometime quite hard. Almost like the rotor is trying to wiggle a little but when clamped down upon.

Any throughts?

The rotors are semi floaters (not like the race bikes that actually move).

As Randy posted, check the trueness of the rotors, I suspect one or both are warped. Per the 07 manual (its not listed in the 04-06 manual) deflection limit is 2-3mm, .0787"-.1181".

Also as pointed out (and regular maintainance), the calipers on your bike are hard mounted to the forks. Remove a bolt at a time and use BRAKE SPECIFIC GREASE (it doesn't fling, and is designed for high heats) after cleaning any hardened goo on the slider bolts. Don't be cheap with it..


[ame=http://www.amazon.com/Permatex-24110-Caliper-Brush-Top-Bottle/dp/B000HBNV6W]Amazon.com: Permatex 24110 Ultra Disc Brake Caliper Lube, 8 oz.: Automotive[/ame]


Not as likely, but should your rotors be straight, while the front tire is still in the air, check the wheel bearings. It'd be best to remove the front wheel and manually check them for any play..

 

[FinalImpact]

Something none of us mentioned: if the caliper doesn't float or the pistons are stuck and not moving easily, you can bend the rotor(s).

In the ideal situation you'll need a dial indicator to check run-out but in short, if you can see deflection in the surface, you need new rotors if you want the pulse to go away.

 

[hurrican3p]

thanks all. I (unfortunately) am not really experienced enough to perform some of these operations.

Esp. with something like the primary brake system.

I can do the super basics (oil, filters, batteries etc etc) only

 

[FinalImpact]

If you can lift the front end and free spin the wheel, you can perform the basic visual inspection checking for hot spots, checking for trueness using the crude method of resting an object on the fork leg and spinning the wheel as mentioned above. You need not take anything apart to perform this inspection.

 

[Motogiro]

Interesting. Just for clarification. Are you feeling pulsing in the brake lever itself or pulsing from the bike as it comes to a stop? If the pulsing is from the bike as it's stopping, one or both rotors may have gotten oil or some other contaminant on them. This can cause a glazed area on the rotor that translates to a pulsing sensation. I had this on my FZ6 after I was in a shop getting the bike dyno'd.
Sometimes this can easily be corrected by sanding the rotors, cleaning with acetone and replacing the pads.

I just replaced my pads (my SV1000s) with EBC HH pads and what a difference in braking!

 

[FinalImpact]

Interesting. Just for clarification. Are you feeling pulsing in the brake lever itself or pulsing from the bike as it comes to a stop? If the pulsing is from the bike as it's stopping, one or both rotors may have gotten oil or some other contaminant on them. This can cause a glazed area on the rotor that translates to a pulsing sensation. I had this on my FZ6 after I was in a shop getting the bike dyno'd.
Sometimes this can easily be corrected by sanding the rotors, cleaning with acetone and replacing the pads.

I just replaced my pads (my SV1000s) with EBC HH pads and what a difference in braking!

Your post made me think of this: a tire defect. How old are the tires??

Could be induced by damaged from the road or the sun (bikes under covers with exposed parts) or even some form of structural failure. While spinning tire, inspect it for trueness.
Example: watch the gap between the tire and fender. If it varies the ADDED LOAD OF BRAKING may allow you to feel it when its otherwise OK just rolling down the road....

 

[nsaP]

Like this?

[ame=http://www.youtube.com/watch?v=SjuJCNEWjqQ]bad brake shudder - YouTube[/ame]

That turned out to be jammed buttons. I used some wd40 and an alan wrench to free up the buttons and it hasn't happened since.

 

[Motogiro]

Your post made me think of this: a tire defect. How old are the tires??

Could be induced by damaged from the road or the sun (bikes under covers with exposed parts) or even some form of structural failure. While spinning tire, inspect it for trueness.
Example: watch the gap between the tire and fender. If it varies the ADDED LOAD OF BRAKING may allow you to feel it when its otherwise OK just rolling down the road....

For sure I never have old tires. Lol! When I swapped out the pads and cleaned the rotors I also wacked the rotor edges with a dead blow hammer and lubed the disk floaters. It was good to go.


Sent from Moto's Droid using Tapatalk 2 :mikebike:

 

[FinalImpact]

For sure I never have old tires. Lol! When I swapped out the pads and cleaned the rotors I also wacked the rotor edges with a dead blow hammer and lubed the disk floaters. It was good to go.


Sent from Moto's Droid using Tapatalk 2 :mikebike:

I think you used the wrong tool - supposed to use a 12lb maul to ensure a huge amount of deflection so as to destroy a good rotor even if it wasn't suspect of being warped! :rockon: :rof::rof::rof: