Brake cleaning/servicing and sticky pistons

[Amber Phoenix]

I've got a Fazer 600 with the standard Yammy blue spot calipers up front. It's been squeaking and squealing a lot lately when braking. Also my braking power doesn't seem quite what it used to be. So last night I took the calipers off and slowly pumped the pistons out to give them a clean. Of course I strategically shoved in a big spanner to stop the pistons coming out completely. Cleaning wise, Halfords only had some Muc-off brake cleaning spray, which used with an old tooth brush.

First question: is it normal when pumping the lever, for each piston to pump out in turn? i.e. first the one closest the hoses comes out, then once that pressed against the spanner another pumped out, then another and so on? Are they not all supposed to to come out at the same time-ish?

Pistons weren't in too bad shape, just a spot of corrosion at top edge nearest pads. But nowhere down enough to affect the seals.

Second question: Some pistons I was able to rotate to clean all around them. Others just wouldn't budge. And yes, it was the pistons that were last to move when pumping the lever. Does this sound like it could be jammed up deeper down, perhaps in need of a full strip down and new seals?

I have some Hel braided lines to fit, wondering if it makes sense to fit new piston seals whilst the system is drained.

Last question: the little curve plate that holds the pads in place has an arrow on it. When fitted is this supposed to point up or down?

Really beginning to wish I took some photos now...
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Beginner Biker Adventures Blog
Yamaha FZ6 S2 2007

[Taught2BCauti...]

You will always find on multi-piston calipers, that the piston that has the least resistance will move first until it can move no further - then the next piston with least resistance will move, and so on. This is normal.

Sounds like new seals would do no harm, but don't forget to clean out the grooves in the caliper that they sit in. Sometimes, you can get debris and rust building up there.

If you are changing brake lines, it would make sense to do it at this stage.

When you have brake components with arrows on them, they are meant to point in the direction of rotation of the wheel.
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[Fizzer Thou]

If your calipers look anything like this then it would be best to remove the pistons completely,rather than to just try and clean the pistons only

https://i666.photobucket.com/albums/vv23/WiNot_Rhencullen/Workshop/Picture383.jpg

By removing the seals you will be able to clean everything and to restore the braking efficiency back to normal

https://i666.photobucket.com/albums/vv23/WiNot_Rhencullen/Workshop/Picture382.jpg
https://i666.photobucket.com/albums/vv23/WiNot_Rhencullen/Workshop/Picture384.jpg

I did not replace the seals when I dismantled the calipers in the pics.Upon inspection they were still in good condition
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[Amber Phoenix]

Ah, mine weren't that bad. My pistons only had less than a mm of corrosion in a few odd spots on some pistons right near the tops. The rest of them came up nice a shiny.

A new set of seals aren't too much money, so I'll order some. If I'm going to go through hassle of stripping them right down, it doesn't seem worth not swapping them for sake of £15-20. Didn't realise a new set of pistons were so pricey though!
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Beginner Biker Adventures Blog
Yamaha FZ6 S2 2007

[bikenut]

don't forget the red rubber grease.......the alloy between the outer dust wiper seal ( rather than a total bellows type of dust seal ) and the hydraulic seal, this area usually corrodes and caused the pistons to be stiff........how black is the fluid in the master cylinder and does a jet of fluid spurt from the res floor when the caliper pistons are pushed home, by thumb pressure when serviced.

clamps and wood will help
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