I have an 1997 E300D. I recently replaced the brakes and rotors and decided to replace the old brake fluid. I bleed the brakes until the fluid was clear. I bled each brake however when I dive the car I need to pump the brakes to build up the required pressure to stop the car.

I have bled brakes before and never had this problem. The brake system worked fine before I replaced the parts and cant see how the master cylinder would go bad at this time.

Does anyone have any suggestions? Thanks

When bleeding brakes, be sure the rear compartment of the reservoir is full of fluid too. Make sure car is on level ground and reservoir full to the top and bleed again.

What do you mean rear compartment? I made sure the level never got low.

is the only way to go for an ABS car. Motive Products sells an excellent one for less than the equivalent of 30 minutes labor at a mechanic.

jmbeam, the master cylinder has front and rear chambers. Both must remain filled to ensure air doesn't get entrapped in the brake lines.

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Fred Hoelzle

There is no way I would let one side get low and not the other especially when the chambers are right next to each other, so that is definitely not a cause.

I used a cheap Harbor freight hand presser unit when I did the initial bleed. Thought it did a good job but still need to pump brakes to stop the vehicle.

The chambers are not connected other than at the top. A safety feature in case you lose one set of brakes, you'll at least you have the other.

jmbeam, the proper caliper bleeding sequence is RR, LR, RF, LF. If you bled the calipers in some other order you could have trapped air in the system resulting in a spongy feel to the brake pedal. It's also possible that if you had a helper press the brake pedal while you bled each caliper that the master cylinder was damaged inadvertently because the piston went beyond its normal travel range, or if the bleed fitting was not closed while the brake pedal was depressed air could have been sucked into the brake line(s). That's why it's best to use a pressure bleeder.

Recommend bleeding the system again before considering replacement of the master cylinder.

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Fred Hoelzle

I have the Motiv bleeder and used it on my '05 Ford Taurus. It worked fairly well, although I think I still have some air in the system as I replaced the rear calipers.

I plan on using the bleeder to change to the ATE Super Blue fluid in my '97 E300 as well.

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'97 E300
'99 E300