w124 / 250D Clicking noise and felt through brake pedal

[snoopy]

I have a clicking noise coming through the brake pedal at about 3 sec intervals and with a definite pattern. It clicks twice and I can feel a pulse through the brake pedal.

Upon inspection the noise appears to be coming from the part in the picture (bosch silver things). ABS is working and brakes are OK, perhaps a bit mushy but probably normal for this car.

Any ideas what this part does and whether it could be causing the clicking? Oh - and is the noise normal!?!

 

[EDZ649]

The part shown is the duovalve, nothing to do with your brakes. It to do with the heating system.

 

[krimat2005]

hi, this is duo valve, it opens and closes allowing hot water from the engine to the heat exchanger depending on what temp you set in the car ( if working correctly). and clicking noise is normal.