Front Brake Calipers.........

[DragonRider]

Are all MK II front calipers the same from 86-93? I finally got my front brakes hooked up to work together, but It still gives me the same amount of braking, virtually none, I am thinking the right one is bad, when I pump them up to bleed them I get good flow from the left when I bleed it, but when I bleed the right one after pumping them up again, just dribbles from the bleeder. If I let it sit for a while the brake lever has no pressure at all, have to pump them up to get any feel but the lever still goes to the handlebar. I am thinking the right caliper is leaking down, but I cant find any leaks anywhere. I have someone offering calipers from an 86 or 87 but I want to make sure they are the same before I get them. Any help here would be greatly appreciated.

[Squeeze]

Sounds pretty much like you're in Need of a Rebuild of the Master Cylinder at first.

[MiCarl]

I agree.

[lsutley]

The front calipers sets are the same. The left calipers are different than the right. The piston diameters are smaller on the left. I don't believe the left front gets as much use as the right when in the normal linked setup. My left front was a bugger to disassemble as the pistons were really stuck. Wedging blocks of wood between piston faces and using a grease gun for pressure finally freed the units. Had to replace a couple pistons that were pitted badly. The right was not nearly the trouble.

 

If you have de-linked the front and rear calipers there should be a noticeable difference in the front stopping power. I did the whole shoot'n match last winter. Installed skydock17's de-linking kit, completely rebuilt the calipers and installed new EBC pads. The "bite" is now much improved and I would do it again without hesitation.

 

Both calipers will push fluid with the same gusto when working properly. I did have have issues with the master cylinder pumping up properly when the lines and calipers were full of air. Speed bleeders were some of the problem as one was bad and would allow air to reenter the caliper during each cycle.

 

I replaced the faulty bleeder and still no luck. Rebuilt the master cylinder and no luck. Was about to shoot myself for getting involved in the mess. Came down a day or two later and the brake lever was stiff and was able to bleed everything without further problems and have had no troubles since. The tiny hole in the bore of the master cylinder that vents into the reservoir may have been plugged or some tiny bubbles may have been in the wine. I have heard some say that a rubber band holding lever over night works to vent bubbles from the system.

 

I can't explain the process but the time sitting seemed to do the trick for whatever reason. The final result was almost worth the extra gray hairs. Well if I had any hair.

[DragonRider]

Just found a set of R1's at a good price so they are on the way.............

[lsutley]

If you find a source of the tool to remove the pistons from the R1's, please don't keep it a secret. I have a set for my winter projects and would like to disassemble and rebuild.