400ex Brake Question

[Just-Tri-It]

On my 400ex, it has developed a brake fluid leak on the left hand side of the caliper where the cable hooks up and the bolt goes in. It has a black rubber boot on that side and when I press on the brake, the fluid runs out around the boot. I think the snow may have frozen them up and when I pressed on the pedal it may have blown a rubber seal on the inside or something. I haven't worked on 400ex brakes before and was looking for insight to possible cause of the leak and repair solution before I tear it down and try to figure it out. I included a standard pic of a caliper below. At the bottom of the black boot is where the fluid leaks out, or streams out if you press hard on the brake.
Thanks

[bugler30]

I know this is a old post, but that is the part the e-brake normally attatches to which looks like the cable has been removed. Cure the problem by taking those two bolts out and replace the the e-brake assembly with a block of plate. Can be had at almost any ATV shop for ~10 bucks.

[falloutboy]

also, there are a couple o-rings that are supposed to keep fluid from coming out of the caliper where the shaft for the parking brake comes out. These could be worn out

#26 and 27

[Mosh]

The part that is causing the leak is number 27 in that pic.
To replace that requires a caliper rebuild, sometimes with a new piston, and you might as well rebuild the slides.
It is a PITA job to do, and honestly, by time you go through all that work and spend the $50-70 bucks on the parts to do the job right, you are better off to buy a new caliper.
A new caliper with Bracket and all hardware can be bought for $115 ready to go, with new pads also.
The only reason you would want to do this (rebuild) job is if the caliper is no longer available and you have no other choice.
For a 400ex caliper, it is just easier to replace it.


The stock E brake linkage is what causes water and mud to get in there and ruin the piston seals.
Whatever you do, ditch that system.

[jason85atc250r]

For a 400ex you could also do the cr80 caliper swap i posted about in the mad scientist section. you can get one from a 08 or newer bike for $40 or less on EBAY