Author Topic: Soft front brake.. (Read 4124 times)

todius · « **on:** October 14, 2005, 05:36:36 PM »

The front brake lever on my Bandit 4 is pretty soft compared to most every other bike I have come across. I have bled the brake several times with new fluid and even zip tied the front brake lever tight for several days to try to force out any air/water that may have infiltrated the system, but it remains soft.

By soft I mean if I grab the lever at the outer edge (most leverage), I can squeeze the lever all the way to the grip. I figure I may need to rebuild the master cylinder and/or replace the brake lines, but I read a review at some point which mentioned the B4 had a soft front brake.

So is this just normal or do I need to go through my master cyl rebuild and new lines?

jcmjrt · « **Reply #1 on:** October 14, 2005, 07:34:46 PM »

Being able to squeeze the lever all the way to the grip isn't normal.

Sometimes air can get caught in the bolt just outside the mastercylinder. Tapping it/tilting it can sometimes free air.

Racerruss-ducati · « **Reply #2 on:** October 14, 2005, 09:41:31 PM »

I just went through this with my B4. I had to disconnect the brake line while installing a set of clip ons. I bled the brake and got out no air, but it still was mushy. What I found was that the angle of the master cylinder on the bars allows an air bubble to be trapped (like jcmjrt said). I took off the master cylinder and tilted it so the top cover was level with the earth in front to back tilt and the brake lever was slightly "uphill" to the master cylinder. I pumped the brake a couple of times and a bit of air came up through the hole in the bottom of the resevoir. Presto, solid brakes again. Give it a try.

If that doesn't fix it, you might try the same technique with the solid brake line connector mounted under the bottom triple clamp.

If the lever feels like it getting solid part way through the stroke, but keeps going down with constant pressure, it may be the master cylinder needs a rebuild. Brake lines will definately not help this condition nor with anything you can do to the caliper. Brake lines will give a more solid feel when everything is right, but what you are describing is not "right".

Good luck!!!

b4cruz · « **Reply #3 on:** October 15, 2005, 12:08:19 AM »

yeah I hate bleeding my brakes
you gotta have it level on the center stand
and make sure you don't knock the handle bars
then you gotta wach the level its so small
I wind up having to repeat it over and over

i'm too clumsy with stuff like that though

gsxr400 racer · « **Reply #4 on:** October 15, 2005, 12:48:59 AM »

Let me explain something called reverse bleeding:

todius · « **Reply #5 on:** October 15, 2005, 02:14:32 AM »

Quote from: "gsxr400 racer"

Let me explain something called reverse bleeding:
Take a small peice of hose and a clean bottle filled half way with your favorite brake fluid
Run the hose from the bleeder to the bottle with the fluid in it
Open the bleeder with the hose in it
Pump away (no need to close the bleeder between pumps)
VIOLA! No air leaks!

Yeah, this is the method I used... I ran a full bottle of fluid out and had no air coming out when I closed it back up, but the lever was still soft.

I'll try all the other suggestions. Gotta have a bubble trapped somewhere. It does Not get hard and slowly compress to the lever under constant pressure, so the master cylinder doesn't seem to be leaking. It's just relatively soft.. bike stops fine. Don't have to pump them if I sit at a light or anything. Probably don't have the extra reserve braking power for emergency stops, though.

billybandit · « **Reply #6 on:** October 15, 2005, 05:04:31 AM »

Don't get DOT4 anywhere it's not designated!!!

Yeah I noticed my Bandit 250 has always had spongey front brake. Had a new EBC disc, Goodridge hoses, bled hundreds of times, master cylinder's fine, it's just slightly spongey

gsxr400 racer · « **Reply #7 on:** October 15, 2005, 10:56:49 AM »

dont you mean dot5 , dot 3-4 are the same. once you've bleed thatthat way now pull in lever and crack open the master cylinder that should fix it right up ! if not got find a master from a gsxr 600-1100 and put that on the one with the little resivor bottle youll love that!