New Front Brake Discs and Pads - Braking results in a pulsing / shudder when stopping

dakarDude

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Hi All,

First off, I'm a total newbie at bike mechanics, I've had a go at a few things on my bikes now, and for the most part, I'm happy with what I've done myself.

Last night, I got the front wheel off my 525EXC. I then fitted new EBC front pads and a new brake disc and managed to fit the magnetic sensor to the new disc and got it aligned OK.

So, all good so far.

I then remounted the front wheel and before locking it all down fully, dropped the bike off the stand to ensure the forks settled as per the handbook instructions.

Tightened everything up (I dont have a 1/2" torque wrench just yet, its due in the mail today), I tightened it up as tight as fook as I could minus the torque wrench. I plan to get it to 40Nm tonight.

Then, took it for a light spin to check all was well.

This is when I found the brakes are much better, BUT.... When I grab the front brake to stop, it smoothly begins the braking OK, then for the last say 10-15 feet, the front of the bike and brakes "pulsate" or shudder before I come to a halt.

Its quite pronounced!

Note the pads are brand spanking EBC's, no wear at all.

The brake disc is not warped, its out the box only last night from new and I inspected it and its good.

What the hell is causing the shudder / pulsing of the brakes? Is it that I need to torque it up fully? Can it be air in the fluid system somewhere?

Any help would be good.

Thanks all. :thumb2
 
40Nm isnt tight as fook, but anyway...
Loosen and retighten once you get the wrench but check The disc's seated on the hub properly.
If it's pulsing, it's likely the disc's not seated correctly or it's warped.
Did you clean (degrease) the disc before fitting?

Easy to diagnose when it's in front of you and very easy to check run-out with a dial gauge if you have one and know how.
But I'd suggest you get the wheel off the ground, slowly rotate it and have a close look at any side to side movement there.
All the best!
 
40Nm isnt tight as fook, but anyway...
Loosen and retighten once you get the wrench but check The disc's seated on the hub properly.
If it's pulsing, it's likely the disc's not seated correctly or it's warped.
Did you clean (degrease) the disc before fitting?

Easy to diagnose when it's in front of you and very easy to check run-out with a dial gauge if you have one and know how.
But I'd suggest you get the wheel off the ground, slowly rotate it and have a close look at any side to side movement there.
All the best!


Cheers for the reply.

40Nm - agreed, its light compared to other bikes, but thats what the manual says to torque to.

Will loosen everything tonight and take a good look at the potential warping, I can't see it though, its brand new out of the packet just last night. It also went down flat on a flat surface.

Then I'll torque it up as per handbook and take a test ride.

I'm hearing ScotBrite does a good job of cleaning discs.

Will post back findings / fix.
 
OK sorted it - its the new brake disc.

Went back to the old one and its smooth as a baby's arse.

Sending the disc back.
 
Hi Timpo,

Not really any name on it - the knackered one has "KKF" on it.

I got sent a replacement by the EBay seller last Friday, just fitted it tonight, its spot on. New one doesn't have a manufacturers name on it either.

:thumb2
 


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