Rear Brake seals on K4

Rebuit my rear caliper and put in new dust seal and also the main seal but after less than 700 miles rear pads had worn down to nothing. The caliper and piston are in good condition no pitting or corrosion i suspect that i might have put the main brake seal in around the wrong way causing binding but cannot find any info anywhere on the correct placement of seal i read that the seal is wedge shaped but mine looks square also i can see inside the caliper that the gap that holds the main seal in place is angled slightly which is confusing me. I have an old Haynes curvy manual that doesnt really explain in detail.

Cheers

any ideas on what could cause binding on my rear disk other than knackered seals, anybody?

incorrectly adjusted lever (if they are adjustable)

too much brake fluid ?

warped brake disc

incorrectly mounted brake disc

incorrect wheel alignment.

not sure what way round the seals go in the SV

Originally Posted by bikageboy

incorrectly adjusted lever (if they are adjustable)

too much brake fluid ?

warped brake disc

incorrectly mounted brake disc

incorrect wheel alignment.

not sure what way round the seals go in the SV

I'd say one of these too.

Probably the wheel alignment. I cant imagine anyone braking hard enough to warp a rear disc

im guessing the disk isnt warped because i would feel a pulsating through the rear brake lever.

the rear wheel alignment i have checked.

i have also kept within the maximun fluid level.

can someone explain what is it that makes the pads return after you have used the brakes?

thanks for the help.

[Sid Squid]

I'd guess that, as you have stripped the hydraulic section of the caliper, that the problem lies with the pins upon which the caliper moves. If these fail to slide smoothly, and they commonly do, the brake will not free off correctly.
The brake isn't retracted exactly, but the piston - assuming there's no drag - is returned a dab by the brake seal reforming when the hydraulic pressure is removed from it - brake seals are an example of pressure backed seals, they only fully seal when the brake pressure is applied to them, otherwise the piston could not advance through the seal as the pads wear.

Originally Posted by Sid Squid

I'd guess that, as you have stripped the hydraulic section of the caliper, that the problem lies with the pins upon which the caliper moves. If these fail to slide smoothly, and they commonly do, the brake will not free off correctly.
The brake isn't retracted exactly, but the piston - assuming there's no drag - is returned a dab by the brake seal reforming when the hydraulic pressure is removed from it - brake seals are an example of pressure backed seals, they only fully seal when the brake pressure is applied to them, otherwise the piston could not advance through the seal as the pads wear.

It all slides smoothly, so i decided to remove the caliper with the hose still connected i took the caliper off by removing the two bolts pushed the piston all the way back in and then held the caliper in my left hand and then pumped the brake lever with my right hand, as i was pumping the lever i could see the piston travel out and then retract back in a little as you stated it would, this was working fine until the two pads touched and then the piston stopped retracting as the pads came into contact.
I then slid a flat spanner between the pads and repeated the same thing again, the pads gripped the spanner pretty tightly even after i had released the brake lever, this is obviously why my pads are wearing out super fast.

Im starting to think that it could be just that i havent bled the caliper enough and i need a bleeding kit other than that im totally stumped.

the helps been much appreicated thanks.