Help needed replacing rear brake pistons and seals

[Tigertriple]

Cant find any info in the how to threads so I'm looking for some advice on replacing the pistons and seals on the rear brake on my 06 Girly.

I've removed the pistons and have still to remove the seals. The brake was getting very seized up no matter how often it's overhauled. The pistons looked a bit scored and the seals feel a bit rough. It was very hard getting the pistons to move in and out by thumb pressure of a bit of wood to lever them.

The bores look okay apart from some crud that's sitting between the top and bottom seal.

My questions are,

1/what it the best way of getting this crud off without damaging the bores ?

2/Is there an easy way to install the new seals and pistons to avoid damaging them?

I've ordered all the bits I need so just need a bit of help before setting about it

 :D

I should add that this will be my first attempt at this so I don't want to fook it up  :shock:

[daveb]

when I worked on mine, I cleaned the pistons with metal polish to remove the crud and stuff.  I wiped the crud from between the seals will a soft cloth.
front set




Putting the seals in was a right pain, but patience was the key. the pistons I smeared clean brake fluid on them to act as a lube. they popped straight in with no fuss. under thumb pressure, remember to open up the bleed nipple before you push the pistons in, this will aid the removal of air, and back pressure. hence thumbs then will be able to push pistons in.

have you got a method for bleeding the brakes? if not a syringe and a tube. pull the fluid from the res into the syringe, its easy. remember to have a good seal on the bleed nipple

[Mustang]

any engine degreaser or brake cleaner in the spray cans will work , on reassembly put a liberal coating of brake fluid on the pistons bores and seals helps em slide together easier.
It's a pretty simple job actually .
you are putting in new brake pads too , right ?

[Tigertriple]

any engine degreaser or brake cleaner in the spray cans will work , on reassembly put a liberal coating of brake fluid on the pistons bores and seals helps em slide together easier.
It's a pretty simple job actually .
you are putting in new brake pads too , right ?

Wasn't planning on fitting new pads as the ones that are in have only covered about 1,000 miles. Should I fit new pads?

I'll use brake cleaner which I have and a soft cloth to clean the bores. As you say it's a simple job. Just want to make sure it's done right.  :D

[Tigertriple]

when I worked on mine, I cleaned the pistons with metal polish to remove the crud and stuff.  I wiped the crud from between the seals will a soft cloth.

Putting the seals in was a right pain, but patience was the key. the pistons I smeared clean brake fluid on them to act as a lube. they popped straight in with no fuss. under thumb pressure, remember to open up the bleed nipple before you push the pistons in, this will aid the removal of air, and back pressure. hence thumbs then will be able to push pistons in.

have you got a method for bleeding the brakes? if not a syringe and a tube. pull the fluid from the res into the syringe, its easy. remember to have a good seal on the bleed nipple

I've ordered speed bleed nipples so I'm hoping that bleeding the system should be fairly easy. Thanks for your help. :D

[PeteH]

Even with new seals and pistons I found that I could`nt press them in with my thumbs(probably a bit girly )

1- Nothing more than a used green kitchen scourer

2- Fit new seals and smear some clean brake fluid on them, now the tricky bit... make sure the pistons are square to the caliper and push home.. I used a small G clamp eventually.
After the first failed attempt I took the piston out and found the outer edge of the seal was cut away so removed the excess and then they went in ok`ish. All fine in the end :)

Hope this helps

[Mustang]

any engine degreaser or brake cleaner in the spray cans will work , on reassembly put a liberal coating of brake fluid on the pistons bores and seals helps em slide together easier.
It's a pretty simple job actually .
you are putting in new brake pads too , right ?

Wasn't planning on fitting new pads as the ones that are in have only covered about 1,000 miles. Should I fit new pads?

I'll use brake cleaner which I have and a soft cloth to clean the bores. As you say it's a simple job. Just want to make sure it's done right.  :D

I usually do but you can probably get away with the old pads just fine .

[NeilD]

I use a dental 'pick' to scrape all of the crud out of the grooves which the seals sit in... then a bit of red brake grease in there before fitting the seals

[Tigertriple]

Thanks for your help guys  :D

[cosmo]

I bleed brakes by putting a clear vinyl hose over the bleeder and running it upwards about 8-12 inches. Then I just pump slowly, watching to make sure the bubbles clear the bleeder before I let up for a second shot.

Never a soft pedal that way.

P.S. I also tie the lever hard towards the bar with a bungee cord. Leave it overnight, and have a super hard lever in the morn. Don't know how or why, just that it works.

Cosmo

[Sin_Tiger]

P.S. I also tie the lever hard towards the bar with a bungee cord. Leave it overnight, and have a super hard lever in the morn. Don't know how or why, just that it works.

Cosmo

Must try that, trouble with not getting hard enough these days