I need to change the brake fluid on my car. Do I empty the system first and then fill and bleed, or should I just introduce fresh fluid into the reservoir and bleed each calliper/cylinder until new fluid comes out?
|
|
I put a pressure bleeder on the reservoir, then work round each wheel releasing the screws one at a time into the traditional jar, until clear fluid runs out. That way there is no messing with re-bleeding to get out troublesome air-pockets, and you can do it in the most convenient sequence.
|
|
I empty the reservoir first (foul tasting stuff if you don't get the siphoning quite right).
|
|
|
|
To avoid mixing old and new fluid I empty the reservoir using a syringe,then fill with fresh and use pressure bleeder to run it through the brake pipes.Most chemists will sell a syringe barrell,without the needle,of course,get the largest they have.You may need to find a bit of tube to extend the nozzle,a bit of cable insulation does the job.
|
|
|
|
A pressure bleed kit will replace old fluid with new, but less fluid will be needed to be bled out if you draw some out of the reservoir.
Having done this a few times, few things to note: If you use a pressure bleed kit, pressurise it gently by blowing down tyre connecting valve to check for leaks in the pressure kit to reservoir cap. If there is a leak hitting it suddenly with 15 - 20 PSI may send fluid spraying everywhere!.
Surround reservoir with damp kitchen towel or rags just in case you spill any of the corrosive fluid.
Ideally wear gloves, you probably will get some fluid on your hands, if you do, don't touch the paintwork of the car.
Personally I find the pressure kits the best way to do this if you're doing it alone.
|
|
If you car has ABS don't go above 15 psi on the pressure bleeder.
|
Identifying the car would be a good idea as some newer ones require the use of a Vag-com or Snap on to turn on the ABS systems to get the fluid through. Regards Peter
Thanks Peter - edited into the subject line now !
|
It's a Mercedes A Class with ABS and ESP. I was a bit hesitant to drain it completely in case i got airlocks.
All the suggestions sound good - basically take out as much fluid from the reservoir as possible and the feed through fresh fluid.
Thanks a lot.
|
|
|
|
