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Full Version: Dismantling FZR Front Calipers
McRides :: NZ Motorcycling > General Biker Stuff > Mechanics > General Maintenance
Warr
I'd told Stephen to allow a few hours for this mission, so today turned out to be the appointed day.
In preparation we had dismantled the rear, polished the pistons and reassembled. The rear being just a 2 piston affair came apart easily and after the bleed was all sweet.

Today was no so easy
The front is 4 pistons each caliper, with a large and small piston.
Part of the dismantle process was to pump the pistons out to make things easier. This sort of worked to a point but the small pistons just seemed to be solid so the calipers came apart as they were.
We tried with compressed air to move the pistons but alas no movement, so was decided to enlist the help of a brake + clutch shop down the road. Left the bits with them and we returned an hour later to be told they couldnt move the pistons either smile.gif
So back home we measured up some spare Honda calipers I had but the FZR mounts were 100mm & the Honda were 80mm. Stephen phoned Bike Busters, they had some cailpers of a different year FZR and the mounts were 85mm.
So we carried on with what we had, Stephen proceeding to polish up the pistons we could get out.
I set my task to get out whatever pistons I could. It was smaller pistons that were the seized. There was a gallery between the 2 pistons and I searched around for something I could slot into the hole and lever the piston up.
Fortunately I had such item a set of bent screwdrivers where the smallest fitted. Yaaah
We figured if we could get one side working he would at least be mobile.
But with time and persuasion I managed to get all the pistons moving and out.
So a polish up and reassemble, then time for the bleeding.
With the pistons compressed home it took some time and patience to get the air out and pumping up.

The proof of time well spent was in the test drive after and Yes vast improvement.
Previously the brakes would come on in a rush and hard.
Now its even all the way making braking a lot more controlled smile.gif

An afternoon well spent!
Warr
I should add, We had opted not to replace the seals. OEM parts had been quoted at $200 for the set and from past experience so long as you dont disturb the seals they are all sweet after the pistons are polished and reassembled with some rubber grease.

Bleeding was achieved using a syringe and tube. Firstly by forcing brake fluid up from the bottom into the reservoir. This from both sides and then pumping from the lever till the pistons are up against the pads and disk. When pressured bleeding down and out via the bleed nipples.
EMFORAL
Good stuff. Im sure the seals should be alright since ya used grease smile.gif

Might have to overhall the CBR brakes sometime too smile.gif
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