hy im having a nightmare with my ajp front brake on montesa 4rt ive gone to change the pistons and seals but i cant get them in without damaging the seals ive fully cleaned the caliper and used brake fluid as lube but just no luck ive never had this prob before ,i bought 3 kits each costing

Sorry I can't help but have the same problem with a 315 front brake. It was just about OK before I put in new seals and pistons, now it's useless. I've tried bleeding forward and backwards, and there doesn't seem to be any air.

I'd be interested in any advice as well.

Sorry I can't help but have the same problem with a 315 front brake. It was just about OK before I put in new seals and pistons, now it's useless. I've tried bleeding forward and backwards, and there doesn't seem to be any air.

I'd be interested in any advice as well.

i got a easybleed kit that connects to a tyre and modified it to fit bike and that bleeds bike perfect well worth

I use an easy bleed kit as well and haven't had any problems in the past (other than getting fluid everywhere when I use too much pressure or it isn't sealed correctly). After your post I'm wondering if the seals aren't seated properly. So any advice on the correct way to ensure that the seals are in properly would be great.

I use an easy bleed kit as well and haven't had any problems in the past (other than getting fluid everywhere when I use too much pressure or it isn't sealed correctly). After your post I'm wondering if the seals aren't seated properly. So any advice on the correct way to ensure that the seals are in properly would be great.

basicly pop the pistons out and take the seals out without damaging them and the grove they sit in make sure there perfectly clean and no scaws or scuffs then replace back in thats the only way then wen bleeding keep the pads out and check the pistons for leaks if not its just traped air .

Is the problem getting the seals to go in without cutting them on the cylinder edges? if so why not make up a tool like a piston ring clamp, sorry if I got wrong impression of your troubles, it seems the other replies here refer to not being able to prime behind the pistons with brake fluid;.. I suppose the trick ther would be to only just engage the pistons (all in like that and then ease them in to fully prime the void behind the pistons.

Is the problem getting the seals to go in without cutting them on the cylinder edges? if so why not make up a tool like a piston ring clamp, sorry if I got wrong impression of your troubles, it seems the other replies here refer to not being able to prime behind the pistons with brake fluid;.. I suppose the trick ther would be to only just engage the pistons (all in like that and then ease them in to fully prime the void behind the pistons.

hy no my problem is i can put the seals in neatly but when i put the pistons in they just wont go past the seals ive used brake fluid for lube but still no good

You can bevel the edge of the piston with emery paper. Assuming you installed the seals facing the proper direction, you should be able to lube the seals and the piston with brake fluid, and then push the piston in. Use a C-clamp rather than brute force, as the c-clamp lets you do it nice and steady while controlling alignment.

Here is what I do to help start the bleeding process:

1) Unscrew the brake line from the caliper.

2) Make sure piston is sticking about half-way out of the bore.

3) Fill caliper with brake fluid via the brake line hole (where the banjo bolt screws in).

Syringe with needle works well for this, as it allows you to stick the needle all the way into

the bore and fill it with fluid.

4) Push piston into the bore until brake fluid starts to overflow from the brake line hole.

5) Screw in the brake line.

6) Bleed as usual.