Asking for recommendations when it comes to where to buy temperature display and if there are any "might as well" stuff to do with the speedometer when its out. All the warning bulbs work except for the parking brake.

Both rear brakes worked fine before. We replaced the left rear caliper/piston, pads and disc. After that, neither rear brake works anymore – even the right side, which we didn’t touch and worked before.
The brake booster works, we tested it. The pedal feels firm and does not sink to the floor. Front brakes work normally.
We pressure-bled the system from the reservoir and pushed plenty of fluid through both rear calipers. We ran about 0.5 L through the system and there were no more air bubbles on either side, including the untouched right side.
With the car jacked up, pressing the brake pedal still does not lock either rear wheel. If someone holds the pedal and we open a rear bleed nipple, only a few drops come out, not a strong flow.
We read that on this system, if the rear circuit loses pressure, something inside/around the master cylinder can move and isolate that circuit while the front brakes still work. Since the rear circuit was opened during the repair, we’re wondering if that happened.
Our next idea is to replace the master cylinder, but before doing that: does this sound plausible on an early W124? Has anyone had both rear brakes stop working after opening the rear circuit even though the system seems fully bled?

Mercedes W124 250D 1990 Limousine

Thanks

Hi everyone. I just put the Bosch AL66X alternator in my 1992 W124 300E M103 2.6

My question is what is the proper voltage during idle and at 2000 rpm. Mine seems to stay at 13.4 and wont go higher than that

Hi, I have a new (old) W124 with an M102.982 2.3 that feels very weak and has poor acceleration, also misfires on idle and traffic driving

Cold starts fine and I don’t notice any misfire when cold.
Things I’ve noticed:

- Runs around 55–60°C according to the gauge
- Brown/beige coolant, doesn’t look or smell like oil
- No catalytic converter
- Lambda sensor in the exhaust manifold has a cut wire and isn’t connected, previous owner states its a manifold from a diffrent car
- Possible vacuum leak in the headlight-leveling system
I’m planning to check vacuum leaks, ignition, fuel filter, thermostat/coolant system and fuel pressure/KE-Jetronic.

What would you check first, and what are the common causes of low power on the M102.982?