Mod Details
PremiumYes Difficulty
Mod ID1854
Creditevilution
For
Linkhttps://www.evilution.co.uk/mod/roadster-brake-master-cylinder.htm Copy to ClipboardThe brake master cylinder is what connects the movement of the brake pedal to the brakes of your car. It has the brake fluid reservoir sitting on top and it takes fluid from it and pushes it through 2 pipes into the ABS pump. From there, the pump splits the fluid into 4 pipes. 2 for the front brakes and 2 for the rear brakes.
Inside is a tandem cylinder that has multiple seals to stop the pressurised brake fluid from escaping or from not being pressurised at all.
If a rear seal fails, brake fluid can flow into the brake vacuum booster. You’ll loose the fluid, air will be introduced and you’ll lose the brakes.
If an internal seal fails, the movement of the cylinder won’t pressurise the fluid effectively so you have less brake power or none at all.
Location
To find it, open the bonnet and remove the front storage bucket. Disconnect the level sensor electrical connector. Remove the filler cap and suck out as much brake fluid as possible (not with your mouth you nob).
Place some paper towel underneath because some fluid will drip out. Using an 11mm spanner, disconnect the 2 brake pipes.
Shift the pipes out the way and pay attention to the…
…2x 13mm nuts that hold the brake master cylinder to the brake vacuum booster. Remove them and you’ll be able to slide the master cylinder away from the car.
Replacement
Apparently, smart don’t sell replacements any more. Great!
Thankfully, Nic C found a suitable replacement from another car. It also has an unexpected bonus side effect. I’ll get back to that later.