PeachParts Mercedes-Benz Forum - Brake bleed on 95 E420... questions

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Brake bleed on 95 E420... questions

1) Do I need to remove the tires to get to each bleed nipple or just raise the tires to get access?

2) Where is exactly the bleed nipple located and how does it look like? Is it covered with some special cap?

3) Do I need special wrench, or can I use a box wrench and what size?

4) I am planning to use the Motive Power bleed unit. How much pressure do I pump it to draw the brake fluid, I read somewhere 30 PSI, is that correct?

5) What brand of brake fluid shall I use? Dealer parts dept guy said any DOT4 will do, is that the case? I thought MB recommends a particular brand?

Thanks

Re: Brake bleed on 95 E420... questions

I have 92 400E and that should be identical
brake bleeders to your '95. My comments
preceeded by *

Quote:

Originally posted by Joseph_H
1) Do I need to remove the tires to get to each bleed nipple or just raise the tires to get access?

*No. It makes it a little easier if the tires
*are off. I had mine off as I was working
*on the brakes. Make sure car is level
*i.e. do not have rear jacked up and front
*down...either all four on the ground or
*all four at the same height above ground.
*This will (hopefully) prevent air bubbles *from getting trapped in weird places in your *brake lines.
*Bleed sequence
*Passenger Side Rear
*Driver Side Rear
*Passenger Side Front
*Driver Side Front

*You can choose to bleed the ABS
*contraption and that I believe that
*procedure is documented in the E-Class *Owner's Bible by Stu Ritter (your local *Barnes & Noble should have it)

*I did not bleed the ABS unit and have
*not detected any untoward issues.

2) Where is exactly the bleed nipple located and how does it look like? Is it covered with some special cap?

*The nipple is easy to find if you peak behind each wheel assembly and should have
*small black rubber cap on it.
3) Do I need special wrench, or can I use a box wrench and what size?
*I used regular box wrench...If I recall *correctly it was an 8 mm...but this was
*4 months ago so do not hold me to it.
*Again, easy to check.CAUTION: Do not overtighten those bleed screws when you are done.

4) I am planning to use the Motive Power bleed unit. How much pressure do I pump it to draw the brake fluid, I read somewhere 30 PSI, is that correct?

*That is what I used...I kept it 20psi seemed *to do the trick. Your mileage may vary.

5) What brand of brake fluid shall I use? Dealer parts dept guy said any DOT4 will do, is that the case? I thought MB recommends a particular brand?

*I used Valvoline Synpower Dot 4...I am sure
*there is a plethora of opinion on what to use. I use this stuff in all of my cars.

Good Luck!

Thanks

Re: Brake bleed on 95 E420... questions

2) Where is exactly the bleed nipple located and how does it look like? Is it covered with some special cap?

They should be obvious. They may or may not still have a rubber cap on them.

3) Do I need special wrench, or can I use a box wrench and what size?

Box wrench would be fine. Have some lengths of clear hose to direct the old fluid. Be gentle with the bleed screws.

glenmore
1991 300CE

Well, let me add my comments. I just did this last week on my '95 E300D. I STRONGLY suggest removing the wheels - one at a time. In fact, I'd say it's a practical requirement, especially if you have not done this before.

Bleeder nipples are notorious for being stuck - i.e. hard to loosen. I don't know where you live, but unless the car is a garage queen in Arizona you could have problems getting them loose with a plain wrench. They are soft material and EASY to round off. I strongly suggest (again) you get a "flare nut" wrench for this. This is like a box end wrench, only it's a 6 point with a gap in it. You don't want to break off a bleeder, ask me how I know. It is cheap insurance to have a good wrench. A set of 3 are not that expensive at Sears.

Also, even with a good quality wrench, the nipples may not want to break loose. I put my propane torch on them and heat them up some (not red hot) then chill them with an ice cube a few times to thermal cycle them, also you probably should soak them with penetrating oil a few days ahead of time. Those steps should make them easy to break free.

I used 20 psi on my Motive Power bleeder, and you can follow Stu Ritter's procedure for the ABS, as the other poster said. You will probably use about 2 liters or so of brake fluid - that's the minimum I would have on hand.

Good luck - you'll feel satisfied when you're done - getting that nasty brown stuff out of the lines!

Rgds,
Chris W.

The bleeder valves are 9mm wrench size.