Front brake fade

drikko

drikko

Hero member
Location
Orstralia
Was burning down Mt Mee the other day chasing a guy on a Buell and keeping up quite nicely behind the shower of sparks when the front brakes began to fade. I did replace the fluid a year ago and they feel firm when cold. My question is would, what feels like out of round, ie the pulsating be contributing to them heating up too quick?

What's the first steps in getting them to not pulsate, get Red to skim the discs? Just replace them? Can one convert them to floating discs without replacing the calipers? Can't afford new discs and calipers at the moment although I guess I could pinch them off the Beemer.....

Fortunately the back brake is excellent now with the copper sintered pads in it I was able to stop no problems then we hit the traffic lights where the front ones could cool down so didn't lose the Buell :)



 
Cosi said:
was the Buell running on one cylinder?  :P
Click to expand...

Get fucked

Cosi said:
was the lever still firm, or did it go soft?
Click to expand...

Was virtually back at the bars, quite frightening actually!

Will do Stefan, the pads are relatively new as well. Will buy a new bottle of oil and replace. Maybe there's some air in there still.
 
After changing the fluid,do what driving old cars has tought me,keep off them untill you need them.I see people keeping there brake lights on from the top of hills to the bottom.They need time to cool.
 
G'day Drikko,
The problem is that when you do a normal fluid bleed/replacement, you only replace the fluid in the lines, not the fluid behind the caliper pistons. To replace the fluid behind the pistons requires a bit of fiddling: the way I do it is to start with the normal bleed procedure until the new fluid comes out of the bleed hose, from this point I take the pads out and remove the calipers, now pump the brake to move the pistons out but not too far, next use a cable tie the hold the lever in to shut off the master cylinder, next step is to crack the bleed valve and force the pistons back into the calipers (you won't believe the crap that comes out), do this cycle a couple of times to remove all the shit fluid and then reassemble and finish off by doing a normal bleed.
Had the same problem with brake fade as you described; afterwards, all trace of fade had disapeared.

Hope this helps

Terry
 
How old are the brake hoses?
If original then I would replace them too.
As they age they can start to flex more under pressure.
 
If you've got warped discs (not really out of round - more out of flat) you would be better  replacing them, you wont believe the difference. 

If they're non floaters, you could skim them but you'll want someone good doing that. Set of new discs, pads and fluid will make  a big difference.

Warped discs, would contribute to overheating. Anything that makes the braking less efficient, means the the brakes have to work harder - therefore causing them further heart and fade. Pads oscillating back and forth, calipers and fork legs shuddering, trying to follow the contour ...well you get the picture

cheers Rob
 
Pulsating and fade are two different issues.
It sounds odd that one year old fluid will boil if you did bleed the system through, even if you didn?t do the pad retract trick. What pads are fitted?
A mate in the disc business advised me long ago that in most cases of "warped" discs sent in for skimming, it was in fact corrosion of the alloy carrier where the disc attaches to it that was the problem, and once this was tidied up the disc was in fact true. It is worth a look.
 
Drikko,

might be worth checking the front wheel bearings while you're at it. A bit of bearing wear can produce enough play to affect the brakes.

Cheers,

bazzee
 
G'day Cosi,
Wouldn't you have to split the calipers to remove the pistons?

Terry
 
yeah? youve already pulled the calliper and pads 2 more bolts n shes definetly squeaky clean with a bit of air

gets that brake dust / rust / shit off the piston outers also

 
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