Every time I put new pads in, I can't get the disk to go between them.
I usually let a little bit of fluid out. Is this the correct thing to do?
Yes
Not every time surely? Are you pushing the pistons back flush?
Before you remove the old pads, put a flat bladed screwdriver between them and twist so the pistons retract.
As above, push the pads back, I used the non-spiky end of an old but clean fork yesterday to push the rear pads/pistons back, after I discovered massive pad/rotor rub when re-fitting the rear wheel before an outdoor ride... Because I had accidentally pressed the rear brake lever a few times in the past month while on the direct drive turbo.
A few brake pumps as I headed off and modulation returned to a satisfactory level.
You have too much fluid in the system - bled with part worn brakes?
My Sram rival suffers this problem with aftermarket pads. I either file them down with a rasp or bench grinder, a PITA to get right and even then I usually just suffer them dragging until they wear sufficiently not to
I’ve chipped a piston using the screwdriver twist method, I use a decent plastic tyre lever now
I’ve chipped a piston using the screwdriver twist method
As they say above, stick the screwdriver between the old pads before you remove them not directly against the pistons
As above, you have overfilled the system when it was bled. With the old pads still in place, wedge them apart with a screwdriver and open the bleeder to make sure any extra fluid can escape. This should leave the system full, but with enough space for the pistons to fully retract when you need to fit new pads.
Leave the old pads in and push against them not the bare pistons with the screwdriver.
Metal tyre levers are better for pushing pistons back than a screwdriver. Use the blunted, angled end as there's no sharp edges and the bend gives you better access and leverage.
Every time I put new pads in, I can’t get the disk to go between them.
What do you mean by "every time" ? When did you last do a full bleed?
Given the weather why not do a full bleed and clean your pistons as well - even mineral oil need the fluid changing or it gets pretty dirty and will eventually cease the main piston.
I use one of the crap "XMAS gift" plastic tyre levers to push back pistons. Obviously easier with the bleed open at one end if it is sticking though used a closed spanner carefully when its been in my hand (like for undoing the bleed valve)
There is a Park tool piston cleaning video... get the calipers moving smoothly and evenly then put the bleed block in (or measure something to use)
Hopefully after that you just push them in within the reservoir space and don't need to keep playing with fluid levels..
Always push pistons back before putting in new pads, use a chisel or large flat screwdriver between the old pads, don't let a bit of fluid out, always push pistons back to bleed and stick spacer between pistons, if you don't have a spacer, make one with a few health lottery cards cut to size.
Remove old pads. Insert bleeding block into calipers. Bleed the brakes. Remove block. Insert new pads. (As noted above, be gentle with the pistons.)
This is first time swap with new bike.
When I say every time I mean with previous bikes. Yeah I do normally try to push apart the old pads but I still struggle when trying to get the wheel back in.
I use a plastic coated metal tyre lever if I'm doing it direct on pistons.
Wouldn't buy one just for that purpose though!
It's worth getting a bit of fluid on the pistons when the pads are out too, to help keep them moving freely.
Tools for pushing the pistons back are quite cheap and very satisfying to use..!
As above make sure the pistons have gone back flush
Done the front and the wheel went in OK with the screwdriver prising the old pads method. I think I had a few goes and made sure the pistons were right back.
It's rubbing slightly, should I ignore that or adjust the caliper?
Back one also done. Went in easily and no rubbing.
Yeah I do normally try to push apart the old pads but I still struggle when trying to get the wheel back in.
Every year my mam buys me a puncture repair kit ... (despite me being tubeless on everything but the DJ and having perfectly good tyre levers) ... I got a whole load of the cheap and nasty plastic tyre levers.. and the bent bit makes them ideal for pushing in pistons. Happy to pop a couple in the post if they go in a normal letter...
What brakes are they? I've also got a load of bleed blocks for Shimano 2 pots... if you are lacking?
Also ... if they are mineral oil don't wait too long to bleed... DOT more or less forces the issue but mineral oil will not adsorb water but it does get dirty and reviving after it sticks is way more work than a bleed every few months.
If you do a mini "bubble bleed" with part worn pads you will need to let a little bit of fluid out when you fit new pads.
Just undo the reservoir fill port a bit and tape a bit of rag to the brake and the push the pistons back fully.