When I got my 500SL over a year ago I replaced the 43 year old brake hoses for braided hoses but after I installed the new (HEL) hose I could not bleed the rear brake. The brake master, a replica PS12 with integrated reservoir was seized and the piston would not release no matter what. I always use Castrol Dot 5.1 brake fluid in all my cars and bikes. These replica brembos cannot be disassembled as they are pressed together. After looking endlessley for a rebuildable original I decided to buy another replica PS12. I think Officine08 and Stein-Dinse sell the same unit. Before I install this new MC I would like to know if anybody has experienced the same thing and if it can be caused by using DOT 5.1?
The ones from stein are PS15 castings but bored PS12 so the "nose" of the casting is a little longer than the original PS12. I have sold dozens of these and never had a problem. stick to Dot 4 on these old brembo parts for the sake of the master cylinder and the caliper seals. I doubt 5.1 would cause a problem but its not really needed in these old brake systems as i doubt you are boiling the fluid with the back brake
