So I bought four 12 oz bottles of BMW OEM brake fluid (part no. 81220142156) from the dealership for about $20 which is supposedly a low-viscosity brake fluid that our ABS and traction control systems need. I removed some of the Pentosin DOT4LV brake fluid I had in the reservoir from my failed attempt at flushing my system on Saturday. I filled up my pressure bleeder with all four bottles under the assumption I would make three to four passes around the car at each bleeder point. I ended up doing four cycles, in the following order: back passenger caliper, back driver caliper, clutch, front passenger caliper, front driver caliper. I didn't have any of the issues I had from Saturday so I think I successfully flushed and bled the system. Overall I liked the pressure bleeder system, it seemed to work well if you have excess brake fluid in there. I cleaned everything up, got it off the jack stands, took it for a spin, and everything seems to be in order.
Some notes:
- The BMW brake fluid is an almost lemon gatorade color compared to the amber Pentosin so it wasn't too difficult to discern when the lines were flushed to the new fluid.
- The clutch now feels lighter but also more sensitive. It's not night and day, but an improvement in my mind. Not sure how much is up to the SS brake line, the modified CDV, or low viscosity brake fluid.
- Overall the job would be much easier now if I had the experience, but even without any experience it wasn't too bad.
- Removing the wheels was a serious struggle. The wheel and the hub had basically rusted together on all four corners. I had to put my whole weight into pulling each one off. I put anti-seize compound on the hub and the wheel where they made contact so hopefully they'll be easier to get off next time around.
- While the wheels were off I weighed them. The rears, with Toyo Proxes T1 Sport tires (manufacturer claimed 26 lbs), weighed an average 53.4 lbs, so the rear wheels weigh about 27.4 lbs. The fronts, with Toyo Proxes T1R tires (manufacturer claimed 26 lbs), weighed an average 49.8 lbs, so the front wheels weigh about 25.8 lbs. That's why a set of Apex Arc-8s are on my list of mods, try and shed about 7-8 lbs per corner.
Pics:
BMW 12 oz bottle of brake fluid (I used four to be comfortable):
I remember reading somewhere that someone thought that the OEM brake lines had stainless steel weaving in them so there was no point to upgrading to SS lines. I decided to cut open one of my old ones. Looks like rubber and cloth/cord (like a tire) to me:
![]()