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I need to replace the rear pads on my Avid Elixir 1 caliper but I'm having trouble getting the pistons back into the caliper.
As it is, I can fit the pads but there is not gap between them at all.
I don't think the pistons are stuck/seized as they move under pressure but once that pressure is released the pistons start creeping out again.
Any suggestions please?
Thanks.
Use a plastic tyre lever to reset the pistons in the caliper, with the pads out.
PS. use a bit of vegetable based grease on the sides of the pistons, think it's the teflon stuff you shouldn't use as bad for the brake seals.
use silicone grease from a plumbing supply house. i got some last month to sort my Hopes and it cost £8 for a pot for life....
Thanks folks. I've got some silicone grease so I'll give that a try. I suppose, logically thinking, the pistons must be gripping the seals as I push them back into the caliper body.
You may have too much fluid in the master cylinder to allow them to go back. I have had it in the past when I have bled with a half worn set of pads and they wont return enough to accept new pads. The quick cure on mine was to release the top cap screws enough that a little fluid spills out when you push the pistons back in. The proper cure is to re-bleed.
An option if they are just stiff is to re-install the old pads and use a flat headed screwdriver or similar to lever them back open.
If they are that badly stuck though I would look at stripping, cleaning, replacing seals if necessary and rebuilding using silicon grease on the seals.
Out of interest, why silicone grease and not red rubber grease? My brakes are Avids which use Dot 4 and I've always been taught that you should only use red rubber grease on piston seals.
Happy to be corrected as always.
Many people don't understand how hydraulic brakes work.
The pistons don't move through the seals when you apply the brakes. If they did, what spring is there in the system with sufficient power to push them back? What happens is that on the first squeeze of the brake the pistons do slip through the seals, which are a very very tight fit indeed to resist the hydraulic pressure, then they settle back away from the disc as the seal flexes back to its resting shape. Operating the brake just distorts the seals although over time the pistons do creep through by tiny amounts as the pads wear.
This is why old, hardened seals give problems.