front brake problem

[DeanR]

My front brakes 'pulse' at Very Slow speed when stopping. It's kind of a bucking sensation. Very annoying. Would that be called pulsation? Don't think it was there the first couple times out this year. Did notice it last year but not, I think, all the time.
In looking thru past threads, there are no leaks, rotors are clean and not warped and the brake lever does not pulsate. Master cylinder kit put in last year just before I got the bike. Any thoughts? I would like smoooooth stops!
Thanks everyone.

[Snow]

It sounds like warped rotor(s) to me. Someone way back told me to check rotors with a pane of glass - just lay the glass flat on the rotor to get a good idea wether it is warped or not.

[pathfinder]

Sounds warped to me too.

[CMA1]

Special.... could it be a misalignment of the calipers on the fork mounts? They gotta' be lined-up straight, or they will 'hump' when hot.
Loosen the axle nut, check clearance on both sides, between the inner pad and rotor (on both sides) align then retorque axle nut.

[DeanR]

I only notice it when stopping. Don't know if speed just masks the affect or not. And it happens right from starting out with cold brakes to the end of a ride. Rotor runout checked out ok.
I don't know if it's any clue or not, but when I use the air compressor more brake dust blows out of one side than the other.

[randy]

Are the rotors contaminated with something like oil or are there rust or dirt spots?

My 81 SH did that and it was warped rotors, so bad that the lever pulsated, but only on hard fast stops.

[DeanR]

Still kind of stumped by my 'bucking' front brakes. I recently hit the rotors lightly with emory cloth and brakleen. It seemed to eliminate the pulsating for the next ride or two but becomes noticeable again quickly. I keep the rotors clean and blow out the whole area with air from time to time. The fact that it briefly goes away and that they measured out ok would seem to eliminate warpage possibility. Anybody have any other ideas?
Thanks.

[LoserShoes]

You might check and see if the pads are contaminated with oil or something. Surface them lightly on a piece of sandpaper on a sheet of glass to knock off the top layer. Good Luck.

Steve