Front brakes - piston fell out

[HarryHornby]

Hi All,

You've not had a good laugh at my expense for a fair while now, so I thought I had best try some DITY on the bike.

Front brakes were squeaking so thought I would give them a clean, like, surely even I can't foc that up.... WRONG!!  ha ha

Cleaned one calliper, pads were a little low so ordered some new ones (SBS 634HS, incase you ask).

All going well, on to next calliper.  Pads out, bit of a clean.  One piston not moving so well so pumped out a little.  kept pushing other calliper pistons back as they kept moving too (remember the pads are still out) and then a tiny knock and the sound of running liquid.  FFS, a piston on the 2nd side has popped out as a result of me pushing the other ones back in.

No, I've not been here before.  So, am I ok to pop the piston back in (might as well give it a proper clean while it's out).  Do I need to worry or do they go back in ok?  And now I'm guessing I'm in the realms of having to refill the brake lines and bleed when the new pads arrive?  ARSE!!!!!!  Why does nothing ever go to plan with me??  LOL

[Grahamm]

You have to take the pistons out to check/ replace the seals, so you might as well do that anyway as you're already half way there

But, yes, providing everything is clean, you can just put the piston back in.

And, yes, you'd need to top up the brake fluid (or replace it if it's more than a couple of years old) and bleed the system.

[HarryHornby]

Cheers Grahamm,

I had a stuck bleed valve and thought a half hour tidy up was going to turn into a new calliper after it snaps. But 3 days of penetrating oil, some percussive maintenance and a socket got it shifted in the end :-)  PHEW!!

[HarryHornby]

So, I've put everything back, put in new pads, copper slip and red rubber grease on all the right bits. Took the bike out to bed them in, and still squeaking on the final bite, as I stop. Any ideas, guys?

[Grahamm]

Did you check the discs?

Also what sort of pads were they? Cheap ones can squeak more than quality ones.

They may just need bedding in. Try some gentle braking before you go full pressure on them.

[fazersharp]

At least you didn't snap the bleed nipple, that would of been an even bigger job.

[HarryHornby]

At least you didn't snap the bleed nipple, that would of been an even bigger job.

been there, done that, bought a new calliper LOL

[darrsi]

Don't be alarmed, because if you still have OEM discs they'll probably be okay, but your choice of pads on the front triggered something in my currently not so good brain, so i tried to find the history on here which didn't appear to be available, then had a look at my own service history notes that i keep for reference and i'd written that my aftermarket discs didn't have a good relationship with SBS pads on the front of my bike and were very noticeably wearing the discs after as little as 6 months so i changed them immediately for Galfer G-1054 ones again that barely touch the metal at all.
It'll be down to the two components being a good match for each other, but if you are not using OEM discs then i would suggest watching out for any wearing that may be happening much faster than you're used to.
On the flip side i have used Ceramic SBS pads on the rear wheel for a few years now and they have always worked just fine with very little dust caused and seem to play nicely with that aftermarket disc, but unfortunately i never wrote down which brand the disc was at the time of fitting. Next time i'm near the bike i'll see if the brand is visible.

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I don't even know where i got mine from, as i've had them for a long time, but get yourself some small G-Clamps.
Three will be enough to hold three pistons in place while you gently pump the brake lever a little bit to move the fourth piston out for cleaning.

As you are quite obviously very well aware of now you only need to pump it out until you see about 3mm of clean piston then you can stop and use brake cleaner with a tooth brush to clean everything up then put some Red Rubber Grease on the exposed outers of each piston before pushing them back in to refit the pads.

I do this process once or twice a year, but if you do quite a bit of mileage or you're an all weather/winter rider then a before/after winter clean up is a good idea.

Another very quick and easy but very effective thing to do is to pull out the pad pins, clean them with stainless wool, then use a very light coating of copper grease on the pins before putting them back into place without having to remove anything else. Just the lightest coating possible, don't start heaving it on.
This simple bit of cleaning not only takes just a few minutes to do but it helps the brake pads slide comfortably sideways like they should be able to do at all times. If the pads can't slide freely this can cause them to get stuck in one position which in turn will lead to some unwanted brake issues, like seizing, disc wear or much quicker pad wear, for example.