I Had some over the weekend – the offside front piston had started sticking in the week so I replaced the seals and cleaned the surface corrosion off the piston. I had just finished bleeding the brakes when I stamped on the pedal to test for firmness and the rear line split near the ‘U’ bends before the steel pipe joins the flexible pipe. Luckily it happened on the drive and not down a hill. Thinking back I remember an advisory on the last MOT but it looks like they’ve corroded much quicker than expected. So – if your E46 rear brake lines are corroded I have put together a quick guide. I checked the opposite side and sure enough it was also starting to go – so if one side has gone, the other won’t be far off – replace both.
Options for replacement:
- The lines can be replaced by new ones from BMW. Both join under the drivers footwell somewhere.
- Make your own lines from copper / copper nickel and join onto the original steel pipes with unions.
I went for option 2 – mainly because I could get all the parts and BMW didn’t have stock on the day I needed them. I’m not sure what other floor panels need to be removed to gain access to the unions as I put my joins just before the pipes turn up to go above the fuel tank. More »