I just changed my front brake pads and rotors. on an slk 230 1998. I pumped them about 15 times, then went for a ride. I don't think they are grabbing. after i seated the piston when putting in the new pads... is there something I missed?

New pads aren't fully effective until the "fur" is worn off the surface. This doesn't take long.

You did clean all the cosmoline off the new rotors didn't you?

You may also need to bleed some air out if you opened the bleeder valve or brake line at any point.

I'm not sure exactly what calipers you have, but I expect the newer "floating" type -- make SURE the little "ears" (springs" are under the sliding portion and not sticking up out of the slot, and that the outer pad is seated correctly in the caliper. If it is sitting sideways with one end out of the carrier, you won't have much in the way of brakes!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

No I didn't clean all the cosmoline off the new rotors. How do I do that. what should I use? what is cosmoline? I think the pads are seated correctly.

Cosmoline is a grease-like substance that is applied to the rotors to prevent rust. Brake cleaner is a good thing to remove it with. You will need to clean the pads also. Otherwise, you will have "greased" brakes. Not a good thing.

A couple cans of brake parts cleaner. I think you can do this with the rotors on the car, although I've never done it that way (I clean them first), but you will have to remove the pads and spray all the cosmoline off the face of the pads.

Spray the cleaner over the friction area of the disk and let it run off, then repeat. Wipe with paper towels. Make SURE you get it all off the back side of the rotors.

It will EVENTUALLY all burn away, but the brakes will never work properly.

In the future, flush off the cosmoline just before you mount the rotors, only take a minute or two. On the rears, don't forget the parking brake drum surface on the inside!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

thanks everyone, I will try it.

if your rotors are OEM I don't think there is cosmoline on them.

did you put the 5mm set screw back on the rotor?

how did you press the piston back into the caliper?

torque the caliper bracket mounting bracket to 85 lbf
guide pin bolts to 15 lbf

is the brake pedal firming up?

Thanks for your response....yes the peddle is firming up, I put the caliper bracket mounting bracket to at least 85 lbf
but I am not sure about the guide pin bolts to 15 lbf, I just tightend ...do you think they could be too tight?

If you were to be a little more discriptive about what you feel when saying not grabbing.
On wet pavement how does the ABS kick in?
When you pressed the piston back into the caliper, you had the top off the brake reservoir, did you check brake fluid level? too much fluid?
If you did the guide pin bolts to around 15lbf by just feel that should be sufficient.

Had you opened the bleeder nubs at any of the calipers?

what make were the rotors and pads?

with the car turned off, when you pump up the brake pedal to make it firm, what happens when keeping your foot depressed when you turn on the engine?

And how did you press the piston back into the caliper? the piston rubber seals weren't deformed?

just trying to hit everything that coud be wrong

I will drive it tommorow and see how it goes. I didn't open the bleeder nubs or open the brake fluid resivoir. I will check the level of the brake fluid. I just cleaned the rotors with brake cleaner. I will try the abs, in the snow.. I used a clamp to put the piston into the caliper and the rubber seals are ok. I will let u know more soon. thanks for your help.