morocco

My 2000 GS300 was making a series of screeching sounds on cold start and based on similar posts here, my own post, and the dealer's diagnosis, I had the master brake cylinder replaced with a remanufactured unit from eBay. Then we got the following codes: C1252 hydro-booster pump motor, C1256 Accumulator low pressure, and C1223 Abs control system malfunction. I think this is the point where my mechanic put back the original master cylinder, and as far as I know, he got no more codes.

The eBay seller sent a different accumulator and with that, the car made over 100 screeching sounds on cold start (compared to 10-30 before). Then the eBay seller sent a brand-new accumulator. So now with the new accumulator, a used motor, and my original master, the car *only* makes about 10 screeching sounds.

Question 1: I understand the whole unit is the MBC plus the brake booster, but where does the accumulator fit into all this, what is the motor, and how do those relate to the brake booster?

Question 2: Should I get another complete MBC unit from a different eBay seller? Or buy a new master cylinder (no brake booster = $1200)? Or buy a new 2001 complete unit for $2200?

And FWIW, the noise started exactly the day after the three A/C servos were replaced, which seems to be an amazing coincidence on a 17-year-old car.

Thanks for the help!