Brembo 05's with seized pistons

[Jotaman]

Hello collective,
I have a set of 05 Brembo's with 5 out of the 6 featuring seized pistons, i would normally heat up the caliper and freeze the piston and try to pop, but would love a revised methodology.

Peter
ps: don't tell, but they are off a Guzzi

 

[sfcpiet]

Either fit a grease nipple or use an altered bleed nipple to attach a grease gun and pump 'em out.  Results in quite a mess, but works every time! 

piet

 

[Dellortoman]

I use heat on the caliper while feeding compressed air into the brake line. Usually works, but be ready with a piece of rag in your hand to catch the hot piston when it pops out like a champagne cork 

With really stubborn pistons, you can prize them out with a screwdriver under the lip on the edge of the piston. It doesn't matter if you fuck the piston because you'll be replacing it anyway if it's seized that bad. But protect the caliper with something where you lean against it with the screwdriver.

Last resort: Grab the edge of the piston with a pair of vice grips and wangle it around while heating the caliper. It's like pulling teeth so helps if you have some dentistry skills.  Again, the piston will be scrap, but you'll rescue the caliper.

 

[Haggis]

Pushing the piston in (to initially break the hold of the oxides and shit) is often easier than pulling. Counter intuitive, but can loosen things up to make the next steps easier. Obviously clean exposed piston surface to avoid dragging more crud into the bore.

Warming the assembly and then cooling the piston with freeze spay has also worked for me.

Good luck.

P

 

[breganzane]

My first action is usually to split the caliper, hold it piston side down on some soft wood and wrapped in a rag, and use air pressure.  It usually works.  The piston comes out with considerable velocity, my Dad once badly cut his finger with one so keep them clear.  Shooting the piston out against a close/solid/forgiving surface limits the carnage, and the rag catches the spray of fluid and crud that comes with it.

On really stuck calipers, and without a suitable grease nipple handy I've sometimes fitted the assembled caliper up to a master cylinder on the bench and bled it up, then used the hydraulic action to free up the first piston then held it back with a clamp to do the other one.  A bit tedious but it works when air does not and doesn't damage anything.  As PaulH pointed out, pushing it in first often helps but sometimes only jams it more.

This thread reminds me I should get an M10x1 grease nipple and stick it in my brake parts box, it is surely a quicker and easier method although a mess to clean up.

 

[Haggis]

Good point Steve. I'll qualify my note for posterity ... 

Pushing the piston in a very small amount (to initially break the hold of the oxides and shit) is often easier than pulling. Counter intuitive, but can loosen things up to make the next steps easier. Obviously clean exposed piston surface to avoid dragging more crud into the bore.

Warming the assembly and then cooling the piston with freeze spay has also worked for me.

Good luck.

P

 

[breganzane]

Good point Steve. I'll qualify my note for posterity ... 

(cheers)  It always pays to read the fine print! 

 

[Ventodue]

... be ready with a piece of rag in your hand to catch the hot piston when it pops out like a champagne cork 

Stuff that, Cam.  I fire the blessed things into a bucket stuffed full of rags ... 

 

[Jotaman]

Many thanks for the wisdom: I am off a hunting for M10 and M6 grease nipples, will let you know how messy it gets.

Peter

 

[Mactriple]

Doesn't hurt to put the halves into an ultrasonic cleaner then soaking the pistons over night with crc before having a go with compressed air.
Ian

 

[LJ-2]

soaked overnight in diesel first.

 

[Ernesto]

I use brake piston pliers. Don't cost a fortune on fleabay.
A liitle heat and trying to turn the piston with changing
directions clockwise/anticlockwise.
As soon as it can be turned, the evil piston has surrendered
and you can get it out by turning and at the same time pulling.
hth
Ernesto

 

[CLEMTOG]

nah
Piet is right
grease nipple and a big side lever grease gun every time for me, messy? it certainly is, but so, so good at what you are trying to achieve.
CLEM

 

[Jotaman]

Messy - clearly you fella's have not pressure washed old facades: the grease nipple methodology worked a treat - many thanks thanks Piet - one and all.

In celebration even fitted a 25yr old NOS set of conti replica's i had in (greasy) storage - Thank you Mr Pipe Masters and pinched the 28mm Dell's of the race bike (she's getting Mik flat slides)

Happy days

Peter