04 R1150 RT ABS Brake Bleed Question

[sundance71]

Hello Folks,

I just rebuilt my brake system (new lines, pistons, seals, rotors, pads). There is still some old fluid in the master cylinders and ABS pump but the calipers are empty. I read the PDF by Dana Hager and Charles Gilman.

With the new pads and rotors, the pistons are pretty much all the way in the calipers. Is this close enough or do I still need to pull them off and use the wood blocks?

Thanks
Chris

 

[52184]

There are two main reasons for retracting pistons on a bleed job. One, to assure that no, or minimal, old fluid is retained in the caliper, and two, to reduce the chance of air bubbles being trapped in the caliper and yielding spongy brakes and failed ABS tests. With new pistons and seals and empty lines you shouldn’t have major concerns with fluid but possibly a greater chance of trapping a small amount of air in the caliper. Removing and blocking the calipers is a bit of a pain, but not as much as tracking down and rectifying a failed ABS bleed test at the end of the procedure.

Best,
DeVern

 

[sundance71]

Thanks DeVern.

Looks like I will be cutting some wood blocks.

Best
Chris