I just replaced the front calipers on my 123. I bought a pair of fully loaded ones from here. They came with new sensors which I installed properly (AFAIK). To bleed the brakes I used a thing called an eezbleed, a very poor man's pressure bleeding system. I bled all four calipers so as to flush the entire system. I took the car out for a spin to try and seat the pads. The brakes felt terrible, low pedal, lots of pulsation which was to be expected since the rotors were rusted from sitting for a couple of months. I brought the car up to 40 or so, hit the brakes firmly and did this a few times. The pedal still feels like crap and now the brake wear indicator lamp is lit. Parked with the engine running and pressing on the brake pedal it will slowly sink. The brakes are acting like there's air in them. Is there some shortcoming regarding the pressure bleed method? The fluid isn't dropping in the reservoir. What else might make the wear indicator lamp light up? The rotors aren't in the best condition, but they don't appear too thin and there not a big ridge on the outer edge like they get as they wear out. Any ideas what is happening here? Could I have bad re-builds? If I were loosing fluid I'd see it in the wheels right?
Can't believe I have to write in asking about a simple brake job. Very frustrating after two days in 90 degree sun :-(

low pedal is telling me you still have air in the system....I try to get about 10-20 low speed stops. Then let it cool down before hitting the highway...but oly if its feeling right first.

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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

the sinking pedal is due to a hydralic leak. it can be external at a caliper or its connection, anywhere in a brake line that is crimped and broken or rusted... or it could be an inernal leak in the master cyl. it also could just be air in the system. better check for leaks visually then bleed it again and be sure to start with the wheel furthest from the mc. if the pedal doesnt firm up then it must be an internal.

bleeding is tricky. perhaps i need to go through the proceedure... please ignore if i am talking down to you.

it takes two people. pump pedal with all bleeders shut off till it gets firm. the open a bleeder while the pumper holds pedal, pushing it to the floor. with the pedal on the floor never having let it rise, shut the bleeder. pump pedal again til it is hard. repeat. do this at each wheel til all the softness is gone from the pedal. it may take more than one turn at each wheel. if the fluid in the mc res is black and gunky, suck it out before adding new, then bleed it througn each wheel til it flows through the clear hose into a glass jar clean.

good luck

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

The true bleeding technique!!! I was hoping I could let my son avoid what I went through as a kid, "ok PUMP -------- HOLD" "ok PUMP ------ HOLD" for hours on end (or so it seemed). That's gong to have to be done since I am not trusting the results of using the alleged power bleeder. No visual leaks, no smell of fluid. I need to pull the wheels again ad see why the wear indicator lamp is lit. The brakes were OK just prior to this. One of the calipers heat shields disintegrated and the caliper it self locked on the disc. The rears were good, I didn't touch them except to bleed.
Back to it I guess.
Thanks.

did you replace the break lines with the calipers? sometims those old break line collapse internally causing the the caliper to freeze up.

Just loosen the rubbere hose on that frozen caliper. If you can then pry the pads back indeed the rubber hose has become a one way valve and requires replacement. If not it's the caliper.

I've been down the exact same road as you have.

I own an Eezibleed and find that it does a fine job for moving fluid through the lines slowly and with very little force. So, if any air gets trapped in the caliper at any point, the air won't be forced forward and out the bleeder.

So, what to do?

Firstly, the old method that Tom has ascribed will work, but it certainly is not necessary. I can bleed the brakes in 1/3 the time as compared to that procedure:

Get yourself a tall bottle (like a horseradish bottle) and fill it 1/3 full of brake fluid. Get a hose that fits the end of the bleeder screw. Shove hose on bleeder screw and open bleeder one full turn. Place other end of hose in bottle, below the level of the fluid, and stand bottle on driveway so it won't tip over.

Go back to driver's seat and press pedal slowly down and slowly release. Repeat 10 times.

Return to wheel. Carefully close bleeder screw by rotating hose. Keep opposite end in bottle. When screw is closed, remove hose and tighten bleeder screw.

Check reservoir to be sure fluid level remains above "min".

Repeat for second wheel (assuming you are only doing the front wheels).

This procedure is a one man procedure and is guaranteed to work as good as, or better than, the two man procedure. As an added plus, you are not jamming the bleeder screw against the stop 10 times.

Another tip: Use a different color brake fluid than what's in your system now. That way you know when the old stuff is all flushed out.

I used the "super blue" last time on my 240D. I could easily see when the old yellow stuff was gone and the new blue stuff was coming out.

- Patrick

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1982 240D. 198k, Marine Blue/Blue, 4 Speed, Crank Windows, No Sunroof, No Rust, No Oil Leaks
2001 TDI. 197k, Lagoon Blue/Black, 5 speed, Chip, G60/VR6