My front brake is spongey...no it`s not...yes it is.....

[Tarka]

I`ve fitted new HEL braided brakelines to my Kalahari 1100.
I`ve bled the system...from master cylinder to ABS,from ABS to calipers.
I`ve re-bled the system...and bled it again.

Sometimes the feel at the lever is fine...firm,almost heavy to squeeze but smooth and feeling constant when squeezed.
Sometimes the first squeeze produces a spongey feeling with low resistance until a second squeeze restores it.

When I got the wreckage of the bike from the Insurers the front brake was very spongy,and I saw that the master cylinder was almost empty.
I discovered that the banjo bolt was loose on the right hand caliper.

I`m now not too sure if I`ve got air trapped in the master cylinder piston seals....or if the seals are worn and need replacing.

I`ve changed master cylinder piston seals on my R80G/S,but haven`t touched the brakes on an 1100 before.

Any advice or comments ?

 

[ELIMINATOR]

Have you tried leaving the lever tied back overnight, allows air bubbles to rise to top. Not sure if this works on ABS system though?

 

[ianboydsnr]

sounds like the one of the pistons are retracting more than they should, possibly a warped disc

 

[Warthog]

If you have the time and money, I'd replace the seals: master cylinder and calipers. Also, I found that if you are having difficulties bleeding or suspect air to still be in the system, I hae used a big fat 50ml syringe full of Dot 4 and fed it into the system from the bleed nipple to fill from the bottom up and that has worked for me and the old air bubbles. Don't if you do that remember to check the fuid level in the master or you'll have a nice puddle of Dot 4 on you tank paint!!

 

[(RIP) Kaister]

caliper corroded behind the seal - pushes the seal out.

a good polish 'll sort it.

or just air in the system - keep bleeding - remove the caliper from the fork and raise it up.

or it really is the m/c seals - easy fix

 

[Noddy]

I have had the same on my 1100, found the fix by accident. I took out my front wheel to change the tyre and just left the calipers hanging for a few days before I put it all together again. Brake was perfect from then on.

I think straightening the hoses allowed the trapped air to rise up through the system.

 

[Tarka]

Cheers guys.....I`ll have the calipers off tomorrow to see if the pistons need a clean like MotoMartin suggests...so the calipers can be raised as high as possible then,Noddy.

Thanks to all.

 

[(RIP) Kaister]

I have had the same on my 1100, found the fix by accident. I took out my front wheel to change the tyre and just left the calipers hanging for a few days before I put it all together again. Brake was perfect from then on

nah - wouldn't happen - even the min bend radius of brake hose wouldn't trap air - so a slight bend / kink wouldn't.

more likely the pushing back of the pads as you pushed it over the disc - then pumped it a couple of times - dislodged trapped air in the caliper(s).

tarka - i knew you'd fall for the polish option .....

 

[cookie]

it can be an air bubble in a banjo bolt that may be dislodged when the caliper is moved.