Does anyone know if the Avid ‘caliper service kit’ come with pistons, and are juciy 3/5/7 pistons all the same?

How easy are they to fit and what does it involve?

the caliper service kit comes with new pistons and seals.
They are the same for all the juicy brakes.

Dont know how easy it is to fit new ones, only tried taking the pistons out. I had a caliper with very stuck pistons, i had to bleed the brakes and push them out that way, as none of the methods mentioned in manual worked, took them out and cleaned them, and never managed to get them back in, almost like the pistons had expanded.
Think fitting new ones should be fairly easy aslong as you make sure the seals are seated correctly.

Once the pistons are out it’s easy to get new ones in. Just remeber to put a bit of brake fluid around the seals before pushing them in and then bleed in the prescribed manner.

The difficult bit for me mirrored Mikkel’s experience – getting the blighters out.

Good luck

Hi, I recently had to fit new pistons on Juicy 7’s having cracked a piston whilst trying to push it back in to fit new pads. I was dubious about how easy this would be, but found it quite straightforward. The hardest part is rebleeding after fitting even with the Avid syringe bleed kit.

You have to take the two halves of the capliper apart. You then need a source of compressed air to force the pistons out. The manual recommends placing the caliper halves in a bag to catch the pistons – I didn’t do this and wish I had becuase when they pop they go with some force.

My tip is as follows – you will need a track pump. Then you need a means to connect this into the fluid cavity in the caliper body. I found taking one of my children’s felt tip pens and pulling out the back part which holds in the ink worked. Cut the ends off and place this in the track pump. Then force the other end into half of the caliper body. Assuming you’re working alone, hold the makeshift air line on place with one hand and pump with the other. The piston will soon come out as the pressure builds. One half (outboard I think) of the caliper will have a hole straight through both sides so you have to cover one side with you finger and press hard with the air line in the other side.

Getting the new pistons in is easy – just remove the old rubber O rings and fit the new ones in the piston kit, then lubricate these and the piston bodys – either user brake fluid or a little silcon lub spray.

Then reassemble, add fluid and bleed.

Good Luck

Neil

Do you need to pump like crazy or is a track pump a reliable enough fix if I fudge an adaptor?

I’ve found the technical manual and it mentions compressed air….

The track pump didn’t require much pumping at all – 2-3 strokes and they’ll pop right out. Key is to get your adapter widget to fit tightly in the caliper body hole.

BTW Edinburgh Bicycle Co had a good price on the pistons at 10 quid a pair (just pistons and the O rings) compared to about 25 quid from Chain Reaction (their’s had more O rings and bits). Took a while to get delivered but quite a price difference.

I had to break the pistons into tiny little bits to get them out. Tried a compressor but got nowhere.