Thread: Master Cylinder Cap

i've heard big arguments over wheither to remove your master cylindar cap when changing your brake pads....what do u guys think? i think it should be removed for the purpose that when u put pressure on the rotors using a screw-driver to loosen the calipar that your putting more pressure on the seals than they're designed...

any other opnions???

I do not remove the cap anymore when I am pressing the brakes back into the caliper. I did this once a couple years ago. I was going to bleed the brakes lines at the same time, so I didn't remove the cap for the pressure aspect, just getting ready to bleed. But with the cap off, as I pressed the pistons back into the calipers, the force from the fluid coming back through the lines and into the master cylinder made fluid shoot out of the reservoir like a water fountain. It got all over my hood, firewall, inner fenders, and whatever else was under there. It sucks.

So my advice is to leave the cap on till you are done installing the brakes.

But one other thing you might want to consider is removing some fluid from the reservoir before you press them back in. I have also had a friends car where the garage must have checked his fluids, saw his brake fluid was a on the low side, and filled it up. I didn't realize this, and as we were pressing the pistons back into the calipers, the master cylinder overflowed from the excess brake fluid the shop added.

So I also advise to watch the level as you are doing this.

lol seems u have had some bad mis-haps doing that

Originally Posted by offroadfury6

lol seems u have had some bad mis-haps doing that

Whenever you work on a car, things don't always go right. You have to live and learn. I have had so many things not go the way I expected. But you can't let them get to you. Just know to do something different next time.

I used to leave the cap on, now I remove the cap, and suck out a little fluid with my syringe sucker, makes it a whole lot easier to press the caliper pistons back in with little to no effort since your now not fighting a sealed pressurized system by leaving the cap on.

Each it their own.

Work smart, not hard.

~F~