Brake System Question
 

Pertaining to my 1988 190e 2.3 8v without ABS .

I rebuilt my calipers, installed new Brembo discs front and rear, new pads front and rear (oem), new lines, new hoses, and new brake fluid Pentosin Dot 4.

The problem is that I have to use a lot of pressure to stop the car. What can I do to check my system? Also, I'm wondering how I can know if my power brake booster is functioning properly and if master cylinder needs to be rebuilt or not. Another thing that I'm wondering is if there is air in the hydraulic system, could that be thew reason why I'm experiencing this problem.

Thanks in advance.

philipminion,

When you appy the brakes is the pedal "hard" or "soft" and how much travel do you go through?

Air would tend to let you push the pedal further to compress the air, making the feel more on the soft or spongy side.

It is also possible the new discs came with a preservative that is interfering with your pad/disc ability to convert kinetic energy to heat, and until it wears off you will have a less effective braking system. I think you are supposed to clean them (the discs) off when you install them.

If you get the chance, call the outfit that sold the discs to you and ask them if they ship with a preservative. Since most discs are made of non-corrosion resistant steels, it is not uncommon to coat them with something to prevent them from degrading in storage or shipping. Like wet brakes, until the material is removed, it acts like a lubricant, making your foot push harder to get an acceptable response.

If you cannot "burn" the stuff off by driving around with the brake applied lightly, you will probably have to take the calipers off to wash the stuff off so you do not contaminate the pads.

Based on what you wrote that is about the best I can do, hope it helps, and good luck. Jim

New Brake Discs
 

Sorry to say, but if you had preservative on the rotors it will have ruined your pads.

Had it myself quite a few years ago.

After I was advised to clean the rotors off I reused the same pads and ended up cleaning the rotors a second time and fitting new pads.

By the way the best thing to clean them off is paraffin (kerosene) as it is VERY slightly abrasive. It will really get into the machining marks.
Then give a final clean using petrol to get rid of any residuals.

Don't forget the edges and the hub.

Mike Stone

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JimSmith
 

Thanks Jim

When I apply the brakes the pedal feels hard and requires some strength to stop the car. I'm actually going to go out for a road test again and think about how the pedal feels to be sure. After reading your post, I feel like I'm not sure. I'll confirm and repost.

The discs were cleaned prior to installation, because they did have that preservative that your talking about and it was also mentioned on the instruction sheet that came with them.

Mike Stone
 

The discs were cleaned prior to installation, because they did have that preservative that your talking about and it was also mentioned on the instruction sheet that came with them.So I did clean them thoroughly before I installed them.