Front Brake Pad Replacement - PeachParts Mercedes-Benz Forum

tobybul · #1 04-25-2007, 11:50 PM

I replaced the pads on my 85D last summer but I seem to have forgotten how to spread the 2 pistons of the caliper. I'm planning th replace the 84D pads. If I recall, each piston can be pushed in without affecting the other?

compress ignite · #2 04-25-2007, 11:58 PM

If the pistons can be "retracted" individually without effecting the other , they
must be on completely different systems.

tobybul · #3 04-26-2007, 07:41 AM

Quote:

Originally Posted by compress ignite

If the pistons can be "retracted" individually without effecting the other , they
must be on completely different systems.

Can't imagine why they would be. I don't know that for a fact that they can be push in indivually. Thats why I'm asking. My Haynes manual only says put the new pads in. Does not discuss spreading the pistons apart

.

I realize the bleeder valve can be loosened to relieve the pressure but I was avoiding having to bleed the brakes. Maybe thats the only way to do it. I seem to recall thinking about replacing the blleder valves at the time so I must have gone thru this b4. Senior moment

dannym · #4 04-26-2007, 07:45 AM

Just do one pad at a time.
Keep the old pad in and use that to push the piston in with a screwdriver.

Danny

tobybul · #5 04-26-2007, 07:49 AM

Quote:

Originally Posted by dannym

Just do one pad at a time.
Keep the old pad in and use that to push the piston in with a screwdriver.

Danny

Or stick something in between both old pads and pry to spread them apart??? Its not a big deal. I'm sure I'll figure it out but I was wondering if there is a correct way of doing it. I need to replace pads soon.

t walgamuth · #6 04-26-2007, 08:48 AM

leave the caliper on the car. pry against the rotor. one at a time. the fluid will just push up in the res. be sure it is not full to begin with or it might run over.

tom w

SD Blue · #7 04-26-2007, 09:24 AM

I've always had great results with a C-clamp and squeezing against the outside of the caliper.

tobybul · #8 04-26-2007, 10:46 AM

Quote:

Originally Posted by SD Blue

I've always had great results with a C-clamp and squeezing against the outside of the caliper.

I usually use a c-clamp too but it may not be possible in this case since theres pistons on both sides which will get in the way of one end of the clamp.

I like the idea of leaving the caliper on while prying. At least its held down. Only challenge I foresee is sticking something in between the pad and the rotor. A wide chisel may be good for this since its sharp.

Brian Carlton · #9 04-26-2007, 11:37 AM

Quote:

Originally Posted by tobybul

I usually use a c-clamp too but it may not be possible in this case since theres pistons on both sides which will get in the way of one end of the clamp.

I like the idea of leaving the caliper on while prying. At least its held down. Only challenge I foresee is sticking something in between the pad and the rotor. A wide chisel may be good for this since its sharp.

Follow Tom's advice.

Leave the caliper on the vehicle. Leave the old pads in the caliper. Carefully pry the pad back and force the piston back into the cylinder. Don't pry from only one side........go back and forth.........so you don't jamb the piston.

The two pistons are on the same system. When you force one piston back into it's bore, the fluid will try to force the opposing piston inward. But, usually, it can't move due to insufficient force.........the fluid just climbs back to the m/c. With the caliper on the vehicle and the old pads in the caliper, it's not an issue.

tobybul · #10 04-27-2007, 08:28 PM

A lot of easier than I thought... like Brian said.... leave the caliper in-place.

I took off the sensors, spring clips and retainers. Then used vise grips on the old pads to compress the pistons. Also inserted a screw driver to shim other pad so other piston does not come out as I press other pad. Repeated a few times to fully compress each piston since you need room for the new pad.

Tip:

Do not unbolt the brake sensor bolt that holds it to the caliper. The bolt broke off when I was doing mine buz it was stuck pretty good. So, I had to drill and retap to get it back on.

As it turns out, there is no need to unbolt it. Just pop off the sensor connection.