Hi all,
 
I am looking at buying an SW20 NA 1992. The car has an issue with the brakes that I would really appreciate some help with.
 
When coming to a complete stop, or almost complete stop (i.e. down to 5km/h) the break pedal judders (i.e., shakes and vibrates rapidly and with force) quite a bit and there is a sort of grinding noise. The grinding noise almost sounds like when you go to shift without pushing in the clutch, although a little different. When braking while driving there is no noticeable issue with the brakes, it only happens when you slow right down, hence I do not think it is warped or damaged rotors. 
 
Does anyone have experience with this? I have not bought the car yet so I cant just take it to a mechanic to get checked out - which I will do first thing after purchasing it. I am mainly trying to get a sense for how much it could set me back to fix this.
 
Any advice is appreciate! Thanks!
 

Does it have ABS fitted ? Early ABS was not very wonderful. A sensor playing up or broken can cause a similar symptom. The system sees it as a wheel locking and triggers it's response. Hence the pedal pulses you are feeling.
Very difficult without being there. I wouldn't imagine it will be expensive to fix ?? Don't know though.

In your situation, for a quick check to see if it is the ABS (if it is fitted) simply disconnect the main ABS plug in the front trunk to disable. The ABS light should be on. 
If the problem goes away that would indicate it is the ABS operation.
 
With ABS problems the first thing to check would be each of the 4 wheel sensors for connectivity.
 
You can do that at the sensor plugs in the front trunk and the engine bay. 
I think they should each register + - 1000 ohms or so.
However, for a full ABS check you really need a service manual (can be downloaded free)
It will tell you how to use the self diagnosis system.