Blue cap caliper rebuild

[mantree91]

I picked up a full set of new calipers for my mk2. 2 right and one left blue cap calipers. Now my question is how do I rebuild them before I install them. I have seal kits coming for them and just need to know how to get them apart.

 

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[BlueSky]

I just googled "rebuid motorcycle caliper video" and got multiple video links. Give it a try.

[mantree91]

So there is no special considerations when rebuilding no monoblock brakes? Last brakes I changed seals in were a single piston caliper from a old cb750.

 

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[BlueSky]

My only suggestion is that if you use fine sandpaper to polish the cylinders, make sure you do it around the cylinder and not back and forth to help prevent seal leaks.

[mantree91]

My plan was scotch Brite pads but around as you suggested.

 

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[mantree91]

So I tried to get the pistons out but haven't been able to dose someone have a trick to get in there? My tape wrapped pliers just gouged the piston.

 

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[BlueSky]

I feel your pain. I tried to rebuild the calipers on my 66 GT Mustang way back when. they had two pistons per side. After that I decided not to rebuild any more. But, I think if I was doing it, I would put a plate or thin plywood where the pads were and use air pressure to blow them out. Rebuild one piston at a time. That is the way I plan to do it. But beware, it could be dangerous if a piston goes flying. There are members who have rebuilt them. Maybe they will chime it.

[cowpuc]

 

I have done as Sky suggested numerous times, just remove the line and hit em with air, works great. I have also just used hydraulic pressure and done so successfully, doing so will also drive in some fresh brake fluid in the process. Simply remove the master lid or plug and keep the res filled while working. Remove the,,, wait a second,, sounds like your starting with a replacement caliper? Pull the pads, get a good idea of how thick new pads would be and use that number/measurement to estimate how far to drive the pads out, fill the caliper with brake fluid, disconnect the line from the old caliper (or any master you choose to apply pressure) and attach it to the replacement caliper, do at quick bleed at the banjo connecter and tighten it, watch the master level carefully = keep fluid in it as you move the pistons out with the lever or pedal. Run the pistons out to no more than a new pads width = if you have a piston that sticks while the other piston(s) come freely outward = just hold the pistons with channel locks or c-clamps to keep them from coming out all the way past the pad width and then continue putting hydraulic pressure on the stuck piston. Usually you can now pull the pistons the rest of the way out, if not, work the pistons little by little with hydraulic pressure but do so in small increments,, patience is key.. Air is really nice cause of the less mess but hydraulic pressure has no compressability and of times those pistons really need the extra push of the hydraulics..

Any of that make sense?

[vzuden]

As long as you are disassembling for rebuild you use a grease gun. Plug the brake line inlet with a bolt of the correct thread. Open the bleeder screw and stick the grease gun on it and pump away. The grease will push the piston out. I usually use the brake system hydraulics as first choice and the more dangerous air pressure second but have used the grease gun too