Recently tried to flush the brake fluid with a pressure bleeder. It uses a chain to hold a top on the fluid reservoir/expansion tank. That doens’t work at all well, didn’t hold well, brake fluid went everywhere.
On the other cars I look after there’s a screw on cap type that works really well with the pressure bleeder.
The reservoir that’s been on the car since building it was from Marlin, I don’t know what car it’s from but I can’t find an adapter for the pressure bleeder. So the next best thing was to change the tank for an OE BMW one that works with the bleeder.
The new part is from a 1972 BMW E21 BMW Part 34321112399 – ATE Part 03.3508-5851.3. It doesn’t come with a level sensor, for that I used a newer part from an E9X BMW part 34336774451. I had to modify the expansion take slightly to allow clearance for the sensor. It is about 0.5cm longer than there is room in the expansion tank, just meant chopping a small amount of the wall between the front/rear fluid chambers. There is a sensor specifically for the E21 tank 34321153157 but I wasn’t able to get one.
Removed this one, set it aside so the system remained closed while creating the mount for the new one.
Cut out an aluminium plate and added some riv nuts in the top to bolt the the tank to. Made sure the tank is level fron to back.
The rear bottom is the same mount as the old one, drilled a hole for the front riv nut.
Transferred the clutch and two pipes over from the old tank to the new one. Added some clips to be sure they’ll stay there under pressure.
Added a new plug on the end of the level sensor wire, this one is off ebay from an E46. Could figure out the part numbers for the plus so that was the easiest way to get one.
Clearance check for battery.
Battery back in, lots of clearance for the bonnet.
View through the louvers
Fluid change should be relatively clean and easy next time!