Stuck brake piston....

[pete]

Put a little bit of air pressure into the banjo bolt hole and place the brake fluid lubricated piston squarely over the dust boot. air pressure will cause the dust boot to go around the caliper piston allowing you push the caliper piston easily with your hand into it's bore (after removing the air pressure from the port) .

Man I wish I had've done that putting mine in!

I did the awkward lube up the piston, get the dust boot around the bottom, push it in and get the dust boot to pop into the recess on the top of the piston...

[Seana23]

Its not the dust boot thats the problem, its the seal inside the calliper... I just cant get the pistons past it!!! I've pushed pretty hard but it wont go down... Dont want to force it cos i may ruin the seal but dont seem to be able to get them in...
I dont understand how forcing air into the calliper will help me push the piston down??!
Please advise.

XXX

[pete]

Hmmm I had no problems with that bit... just made sure it was lubed with fluid and it slid down with some pressure.

If you get it on an angle it won't though...

[rustybronco]

Will the caliper piston fit into the bore w/out the seal in place? if it does and you have the correct piston seals, more than likely, you haven't cleaned out the groove well enough for the square cut seal to fit properly.

[chuck hahn]

Thats exactly why they came out so hard too. If you have removed the seal from the groove you should have seen a bunch of built up scale. The scale has to displace something, so the seal is forced tighter and tighter against the piston. Use a nut pick and get into all the bottom corners and get all that scale out. The seal will seat further into the groove thus allowing more space for the piston to reseat and operate poroperly when its all bled down . You can use the little wire brushes on a dremel to clean the grooves in just a few minutes..

[Seana23]

Ahha, ive not taken the seal out cos i thought it would be ok as it looks fine... Ill take them out and have a butchers at the groove...
Thanx for ya advise and patience...

XXXXXXXXXXXXXXXX

[rustybronco]

You really need to tear down and overhaul the complete brake system.

[Seana23]

Oh wise ones ov the West.....
One slipped back in once the groove was scraped out but one is still being a bit ov a mare....
Ill keep on scraping out the crap and see if it fits later...

Thanx all...
XXXXXXXXXXXX

[rustybronco]

Just because the o-ring groove is clean now, doesn't mean the o-ring isn't damaged or distorted because of the corrosion.

[Seana23]

Yes, yes, yes!!!
They went back in after following the fine advice i got off you lovlies!!!
Theyre back on, bled up and raring to go!!!
Just got to make the seat, solder up all the wiring blocks, fit various springs and clips, paint the tank and get it MOT'd. Not long now!!!
Thanx all.

Seana
XXXX

[rustybronco]

'Tis always a good feeling when all goes as it should. one step at a time babycakes!!!

[pete]

Nicely done

[claygs750e]

I would like to know the screwdriver cutting wheel method if anyone knows because I've tried everything else and the caliper isn't budging.