Terrible front brake

[19Brendan81]

The front brake on my bike is shot. I flushed the system, filled with new fluid and then bled it properly. Then I installed brand new pads and cleaned up the disk and I can still roll the bike with the brakes on full. The lever is really firm, it doesn't pull in to the bars or anything. Has anyone had this problem before? Do you think its more likely to be a caliper issue or a master cylinder issue? Is it possible for the pistons in the caliper to bind or something???

 

[Dino Y]

Take the wheel out and check the pads if they come out while you press on the break if not then ther's probably something wrong with the caliper especialy If presure does comes out of the brake hose down to the caliper .

 

[John Cena]

The pads might need to wear in a little in order for them to make perfect even contact with the rotor.

 

[COMBEN]

Not too sure if you can do this on a KDX but you sure can on a KX-125 I had some years ago :coocoo:

.....it was possible to fit the brake disc between the piston and the rear of one of the pads and it looks correct...rather than between the pads...honestly, I did it!...crap brake performance but on the good side the pads last much longer!

well...you never know :nod:

 

[forbes]

i have heard that if the brake fluid is changed from dot 3 to dot 4 or the other way around, that the seals swell and need to be replaced. i don't know if that would make the problem that you are having but maybe someone else know's more about it.

 

[NM_KDX200]

I had poor front brakes on my KDX for years. While rebuilding the suspension this past winter, I started playing with the brakes and discovered that only one of the calipers was extending. Cleaned, lubed, polished and got the second caliper working. I went from having mushy front brakes to being able to do a stoppie.

 

[dirt bike dave]

On my '90 KDX 200 the front brake was horrible even after repeated flushings/bleedings and pad changes.

Bottom line was it still had air in the system, probably at the bend in the hose, and it wasn't getting bled out.

I removed the entire master cylinder/hose/caliper assemply and hung it on a wall for a few days, tapping the line with a screw driver every so often to dislodge the bubbles. Then I elevated the caliper and bled the system again off the bike. It worked!

 

[Green Hornet]

Brendan-How did you pull the fluid through the system (from MC to Caliper) I used the clear hose from catch bottle and used a medicine syringe (pulling out) to create a vacuum or you could suck on the end to pull the fluid through. Brake fluid tastes like crap with out a beer. Make sure you keep adding fluid to the mc whie doing this.

 

[pete fry]

I used a medical syringe to suck the fluid through works a treat.

 

[karlp]

Brendan described a firm lever, but no brakes.
Sounds like the brake line got kinked and split ion the inside of it.
No kidding, happened to me and I couldn't figure it out. They would bleed O.K., but with any pressure the brake line would squezze shut.

Karl

 

[19Brendan81]

Thanks for all the replies guys, I have been away a few days. Yeah I am pretty sure its not a bleeding issue, I am familiar with the spongy feel of air in a brake line and as I said my lever is rock solid. Ill do a test as per you described Dino to see if I can isolate something....it could be along the lines of what Karl or Forbes is describing. If that doesnt work I guess Ill do a full flush and bleed again as per Dirt Bike Daves instructions. If that still doesnt work I guess Ill just have to get over having brakes.

 

[KdxChode]

Brakes are overrated anyways...when in doubt 'Gas It'.

 

[Green Hornet]

Brakes are overrated anyways...when in doubt 'Gas It'.

THATS A PLAN :cool: