PeachParts Mercedes-Benz Forum - Brake bleed - not very successful

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Quote:

Originally Posted by lupin..the..3rd (Post 2342466)

x2 on the Motive. Best tool for the job. Pressure bleeders do a far better job than vacuum bleeders, and are easier to use.

Tip: use a turkey baster or similar to suck all the old fluid out of the reservoir first, then fill the reservoir with clean new fluid, then go about your brake bleeding. The fluid in the reservoir will be more contaminated with moisture than the fluid in the rest of the system. Better to change it for new clean fluid before forcing it all the way through the system.

Precisely. Vacuum booster only provides mechanical assistance with pushing the brake pedal. It has absolutely zero affect on the brake fluid system. Therefore, there is no benefit to leaving the car running while you perform a brake bleed. Don't do it.

OK, so I found the new Motive unit was waiting for me in its box when I got home (from out of town) tonight. Jumped straight into it. As soon as I started pumping up the PSI, one of the little black caps on top of the BF reservoir started leaking from a fairly big crack in it. Do I have to buy the whole reservoir unit, or can I buy one of the small black caps (probably two)?

Simon

Quote:

Originally Posted by simonshearer (Post 2342648)

As soon as I started pumping up the PSI, one of the little black caps on top of the BF reservoir started leaking from a fairly big crack in it. Do I have to buy the whole reservoir unit, or can I buy one of the small black caps (probably two)?Simon

Black Protective caps:
A001 431 26 87 Girling
A000431 90 87 Teves

Motive mentions 10-15 PSI in their info I think. When you finally get to this you only need a couple pounds of pressure, 5 PSI works fine just a little slower. Too much pressure can pop the reservoir off the master cylinder of some cars.

I had the same issue: even after totally removing the bleeder no fluid would come out (and I was using a Motif power bleeder with 30psi). The bleeder port in the caliper was clogged. A piece of wire unclogged it and fluid started flowing out. If this is your case, I recommend you to do a complete overhaul of your calipers. You will be surprised on how much debris/corrosion you will find in there. I removed my calipers, pumped the pistons out with compressed air, and cleaned the pistons, bores and all passages. Surprisingly to me, I didn't need to replace any seals, it all went back with the original seals and I had no leaks.

Went to the dealer who had two replacement caps; cost about $12.

Hooked up the Motive bleeder and set the pressure at about 10psi.

Worked brilliantly!

I now have strong brakes again.

Thanks everyone!

Be diligent if you're going to pop the pistons out of your calipers to refurbish them. Some pistons, even though they're round, need to be oriented properly when you put them back in. I think there's even some Mercedes special tool/templates to assist in positioning them.

Quote:

Originally Posted by simonshearer (Post 2344312)

And, compared to the dealer, you paid for the Motive bleeder about 5 times over with one use!