1. It probably does not have ABS, very few 84's have ABS. In fact, I believe that it was not available until '85, but I am not sure. If you have ABS, it is unmistakeable. You will have a large box in the engine bay that says ABS on the cover and brake lines going from the master cylinder to the ABS control. Also, there will be an ABS light in the instrument panel set of lights under the gauges.

2. Check to see if you have an original vacuum pump (no screws on the cover plate). If so, then replace it with the new one. You may have a bad vacuum pump which can cause your problems.

3. The master cylinder is different for the 123 than the 201, so you cannot interchange these. I have never replaced a master cylinder on either the 123, the 126 or the 201 (I carefully bleed the system often).

4. Lastly, check to see if there is a leak in any brake line. Sounds funny, but I had a leak in the line going to the back end. The leak was caused by rust that had initiated at the place that the line exits from under the plastic underbelly panels.

__________________
Jovan

'84 (11/83) 190D 2.2 5-Speed; Silver/Blue; Motor No. 00354, 402k mi (340+kmi mine)

'89 Porsche 911 Turbo Coupe; Black/Black; 53kmi
'05 BMW 530i 6-Speed; 302kmi
'19 Range Rover; 30kmi