I picked up some Valvoline synthetic DOT 3 and 4 brake fluid today and I'm planning to bleed out the fluid on my MCS this weekend. I don't plan on flushing out the entire system. Since after bleeding each caliper, I have to top off the master cylinder, I'm worried about mixing the new fluid w/ the existing in there already. Is there a problem of mixing the new brake fluid w/ the existing fluid in the MCS? thanks

 

There is no problem mixing the fluid with what you have. That said I try to take out most of what is in the reservoir before I start. I use a plastic hypodermic but a baster will do if you don't want to ever use it again for food.

It's not a hard job.

Rich

 

one more thing, do you know how many bottles I would need?

 

I bled my O2 MCS last month, used almost a whole 32oz botle of Valvoline. Of course, your method might differ from mine but if you don't get too carried away a single bottle ought to be enough.

 

Yeah, that's a bit much. I can do mine with one bottle of ATE superblue with plenty to spare with a pressure bleeder, and those bottles are much smaller than 32 ounces.

On the other hand, once you open a bottle of brake fluid it's probably best to discard any that's leftover anyway (unless you're using it in the near future); over time, once the seal on the can is broken, it can pick up water, which is a no-no for brake fluid, so if you're using a whole bottle it's not like you're wasting anything.

 

I use an old turkey baster to suck the old fluid out of the master cylinder before starting. It saves time bleeding.

 

To flush the whole system should take less than one bottle. If just bleeding the brakes it will take very little fluid.

 

I think you could do brakes only with 1 pint, but it's safer to buy two (and it's cheap stuff). I did the brakes and clutch this weekend and used about 1.5 pint bottles, being very thorough and making sure I was getting good clean fluid at each bleed point.

 

Thats one of the benefits of using Ate brake fluid. You can alternate between Superblue and 200 (amber in color) so you know when you have a good flush without wasting fluid. One bottle should be enough.