Hello All
I am new here
Recently I bought a 1984 230CE and everything works normally

The car is usually run on short 20 mins trips in the city with typical city traffic and returns 6km/litre. Quite understandable for city mode

A strange problem occured whenever I drive on highway speeds, the front brakes would start to lock up graually even only 10mins but not in the city.
The front calipers rebuilt with new seals, new hoses, Textar pads, Vac hose and master cylinder replaced to no avail. Rear brakes checked OK
Tried driving with servo disconnected, problem still return with front brakes binding, although at a later part of the drive (20mins )

The brake pedal travel would be shorten indicating binding problem arising.
Now I drive with my left foot tapping and checking the pedal travel. once the pedal travel is reduced, and the car feels heavy, I would accelerate to reduce the vac pressure, and tapping the pedal till the vac is exhausted, then the car frees up, the pedal travel is normal i.e. one and half inch of travel.

I was asked to replace the servo unit but am not convinced. also we have no new parts available here.

Q: Anyone here who have experienced this unusual fault?

Thankyou for taking time to read and share your thoughts

William
230CE W123