Ambush

After a few mishaps with the pressure brake bleeder leaking at the reservoir cap causing a mess I've reverted back to just using the pressure bleeder to apply pressure to the system and then topping up brake fluid directly in the reservoir between bleeding every wheel. That's working great and I've done so when bleeding the brakes on all my vehicles. But now I'm coming up on my first brake fluid change on the SL and I'm a bit afraid of the SBC bleeding process. I'll be using my Foxwell NT530 to run the SBC bleeding process but I wonder if anyone knows how much fluid the system will purge in every cycle - will it be enough if I top up the reservoir before every wheel bleed, run the bleeding cycle and then top up the reservoir again before proceeding to the next wheel? Or will the SBC bleed cycle purge so much fluid that I risk running getting air into the system unless I use the pressure bleeder to continously feed new fluid into the reservoir?

bbirdwell

"will it be enough if I top up the reservoir before every wheel bleed, run the bleeding cycle and then top up the reservoir again before proceeding to the next wheel?"
Yes. But check it every cycle.

"Or will the SBC bleed cycle purge so much fluid that I risk running getting air into the system unless I use the pressure bleeder to continously feed new fluid into the reservoir?"
No, so long as you ensure the reservoir is topped up every time and refill the fluid after every purge cycle.

If you have a helper, they can ensure the bleed line remains connected to the caliper while you observe the reservoir and control the bleed process with the diagnostic equipment. The pressure bleeder feeding new fluid into the reservoir would be nice but I had the same issues with mine that you had with yours. So...improvise, adapt, and overcome.