KDX weak frt brakes...

N

nectar

Member

Sep 11, 2002

175

0

• Mar 11, 2004

• #1

I've changed pads, rotors and bleed system using vac system and I still have weak frt brakes. I've done the search with no results. Is this an inherent problem with kdx's, btw mine's a 99 220 or can something be done. My 01 kx stops on a dime with very little work. Whereas the kdx, I gotta pump the thing to brake...they hold but not hardly at all....what should I do?

 

B

Braahp

~SPONSOR~

Jan 20, 2001

641

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• Mar 11, 2004

• #2

Something isn't right cause mine will stop on a dime.

 

G

G. Gearloose

Pigment of ur imagination

Jul 24, 2000

709

0

• Mar 11, 2004

• #3

Perhaps a warped rotor is causing the piston to retract, requiring pumping to stop.

 

C

cicone

Member

Sep 29, 2003

310

0

• Mar 11, 2004

• #4

Assuming you've done everything correctly and the rotor and caliper are in good working order, I would think some foreign substance must have got on the pads during the change. Sometimes you get some grease or brake fluid on them. Try soaking the rotor and pads repeatedly with brake contact cleaner. Also, if the last set of pads was allowed to go metal to metal the new pads may not seat well until they're ground into shape---could take a couple of rides with aggressive braking. Had to do that to with my '90.

 

T

Twiztid One

~SPONSOR~

Aug 19, 2003

312

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• Mar 11, 2004

• #5

mine was doing the same thing and it was a tweeked rotor , does it come and go ? if the lever goes all the way in mark the rotor with chalk at the brake pad and then rotate it and see if goes all the way in in a different spot .

 

7

70 marlin

Mi. Trail Riders

LIFETIME SPONSOR

Aug 15, 2000

2,960

2

• Mar 11, 2004

• #6

I feel its the front brake line expanding, maybe the seal in the master cylinder or a little of both. My 99 stops great. It’s the 96 that has sponge for front brakes.

 

L

levert

Member

Jan 29, 2002

90

0

• Mar 11, 2004

• #7

I have found these brakes extra sensitive to air.
I know this is a pain but take off the caliper and hang it from the ceiling above your master cylinder, coat hanger works great.Come back in an hour and do your bleed, hopefully you'll see bubbles.
Just curious, what fluid are you using?Make sure its right, don't accidently use 5.0.
Check that your front lever is fully releasing and not getting hung up on the bark busters.
If above fails clean everything. take it all apart and clean and assembly with appropriate grease.You might have gunk blocking the master or down in the caliper.
If all fails replace master cylinder piston.

Check the pads too and the seals, make sure there isn't fluid weeping from this area.
If you think this is hard ,try bleeding a new BMW with the evo brakes!
I'll bet you still have air in there, I have had lots of bikes and for some reason the KDX doesn't tolerate any air.We had the same problem and it was just a minute amount of air causing the spongy brake.
Good Luck, let us know what it was!

 

N

nectar

Member

Sep 11, 2002

175

0

• Mar 11, 2004

• Thread starter
• #8

Thanks for replys....I'll bleed again pulling caliper and hanging etc...tks again.

 

M

mbolton

Member

Mar 7, 2004

8

0

• Mar 11, 2004

• #9

Before you hang the caliper, try bleeding them in a cup of brake fluid. I just had to bleed my system a couple of weeks ago and really had a hard time removing the air. Just take a cup of brake fluid, attach a piece of tubing to your bleeder nipple and drop it into the brake fluid so as to suck back fluid instead of air on the release. Remove the cover to your master cylinder, loosen your bleeder and pump away! Just make sure that you don't suck air up top, run a few resevoirs through it, this not only totally removes the air, it really cleans the system too. Works like a champ every time!

 

C

canyncarvr

~SPONSOR~

Oct 14, 1999

4,005

0

• Mar 12, 2004

• #10

Why the hanging? Use your brake bleeder. Well, I assume 'vac system' to be a brake bleeder.

Your hoover won't work. ;)

There's an error somewhere.

Try pushing (the correct type) the fluid UP instead of sucking it DOWN.

 

L

levert

Member

Jan 29, 2002

90

0

• Mar 12, 2004

• #11

If you don't have a brake vac, hanging the brake caliper above the master cyclinder allows the bubbles to rise.
I know this seems extreme but before you rebuild a brake you may as well try something that is free.Even with a system that I swore was bleed by the next morning I did get some bubbles that had found there way up .
Some people claim that holding the brake lever on( with some rope) over night keeps the spool valve open to the resevoir , again allowing bubbles to escape up into the resevoir.

I know I did not mention it but I took it for granted that when bleeding you have the bleed line submerged in fluid to stop air from inadvertantly being sucked back in.


Good Luck

 

C

canyncarvr

~SPONSOR~

Oct 14, 1999

4,005

0

• Mar 12, 2004

• #12

I know why you would hang the thing. Asking 'why hang' isn't because I don't know why you might..but WHY would you waste your time doing that if you had a brake-vac that worked?

 

L

levert

Member

Jan 29, 2002

90

0

• Mar 15, 2004

• #13

If someone isn't having luck with a brake vac doing something that is free and easy to do might as well be tried.If the person feels its a waste of time they don't have to do it.

Good luck with the brakes!

 

D

dirt bike dave

Sponsoring Member

May 3, 2000

5,348

3

• Mar 15, 2004

• #14

When I bought my '90 KDX back in '91, the front brake was a weak spongey mess, and I bled it about a dozen times with little or no improvement. Hanging the hose on the wall and bleeding with the brakes off the bike worked like magic.