Brake Flush Question - PeachParts Mercedes-Benz Forum

tobybul · #1 08-26-2007, 10:27 PM

The post on the caliper removal got me wondering about how to flush a brake system. Always wondered how best to do that. I know how to bleed a brake line. I normally bleed from the bleeder valve by pumping the pedal. Is it basically the same procedure?

Since you are working on all (4) the brake circuits, how would I know that all the lines are flushed? Do you go by fluid color?

Will a fluid evacuator make the job easier? I am actually thinking about getting one not only for brake bleeding but also for engine and transmission oil changing. Only negative about the oil changing with an evac that I can think of is that it seems its not as effective in getting as much of the oil and particles out as draining it from the bottom. Would that thought be correct?

I believe there was a recent thread about fluid evacs....

toomany MBZ · #2 08-27-2007, 05:26 AM

Yes to flushing and bleeding. I've seen somewhere a product that pressurizes the MC and has a bunch of fluid too, so when you open the bleeder valve, there is pressure, no need to have someone pump and hold etc. I hear you are supposed to start at the furthest brake, and work your way forward. I did that on the CD, a bunch of cloudy fluid came out of the closest, left front, bleeder valve. Not too much elsewhere.

Shawn D. · #3 08-27-2007, 09:08 AM

Quote:

Originally Posted by toomany MBZ

Yes to flushing and bleeding. I've seen somewhere a product that pressurizes the MC and has a bunch of fluid too...

That's a pressure bleeder. I have a Motive and have very pleased with it.

vstech · #4 08-27-2007, 10:02 AM

Gravity works well with the 123 and 126 brakes. flushing is as simple as cleaning out the reservoir, filling with fresh fluid, keeping it full while you open the bleeders on each wheel and watch the fluid for color change.

tobybul · #5 08-27-2007, 10:34 AM

Quote:

Originally Posted by vstech

Gravity works well with the 123 and 126 brakes. flushing is as simple as cleaning out the reservoir, filling with fresh fluid, keeping it full while you open the bleeders on each wheel and watch the fluid for color change.

I wondering if gravity will effectively push out what any foreign matter....

vstech · #6 08-27-2007, 10:46 AM

Quote:

Originally Posted by tobybul

I wondering if gravity will effectively push out what any foreign matter....

most likely not. this is an ideal method to maintain brake fluid, not repair a damage system. if you have water and rust and corrosion, gravity will not fix it. but if you have no issues with your brakes and you are doing maintenance. Gravity bleeding works great with MB's.

rs899 · #7 08-27-2007, 12:16 PM

What I use to simplify my brake work is an old all-plastic pump sprayer. I took a cast-off Mercedes master cyl cap, put a hole through it and mounted the hose of the spayer on it. I fill the master cylinder with fluid, add 2 or 3 more pints to the sprayer , attach the cap with sprayer and pump it a few strokes to get maybe 10 PSI pressure in it. Then go around and bleed. Works great.

Rick

Stevo · #8 08-27-2007, 12:52 PM

Any kind if pressure bleeder is light years ahead of doing it the old, two person way. I have a "Speedy Bleeder" which gets its pressure from the L/F tire. You must be sure the two little "caps" on the master cylinder are not cracked or you get a B/F bath upon applying the pressure.

aklim · #9 08-27-2007, 12:56 PM

I suck out all the fluid from the reservoir. Longest line to shortest line flush, in that order. I make it a 2 man job. Open, down, close, up. Do it till the color is clear in the lines and I am satisfied that enough fluid has come out that everything is out.

toomany MBZ · #10 08-27-2007, 03:57 PM

Quote:

Originally Posted by Shawn D.

That's a pressure bleeder. I have a Motive and have very pleased with it.

I think that was it, which model do you have?

firemediceric · #11 08-27-2007, 04:38 PM

I first sucked the old fluid out of the reservoir with the Miti Vac and then when i refilled the reservoir with Valvoline Synthetic for DOT 3 & 4, I used the Miti Vac on the bleed screws until I saw clean fluid.

I started with the RR wheel, LR, RF and then LF always making sure the reservoir never went dry.