There is brake fluid leak in my 93 bonnie at the back of the master cylinder, where the master cylinder and brake booster meet. the bark booster is wet. Not very serious though, I top barke fluid up once during last six month.

What should I do ? Keep an eye on it and top brake fluid up as needed (safe ? )
or have it fixed ?

How much would it cost to fix it, do I need to replace the booster as well ?

Thanks

Just the master cylinder. I had the same problem with my car.

It would be worth it to just replace the M/C The last thing you want is that leak getting alot worse or air getting into the lines. Price one out at Autozone, they arent to hard to change out and install.

Right; I had to do mine last summer for exactly the same problem.

It was pretty easy to do. The biggest problem turned out to be the two roll pins that attach the reservoir to the top of the master cylinder. (You usually re-use the existing plastic reservoir; only the master cylinder itself is replaced.) They're a really tight fit and you have to knock them through and out with a small punch. Mine were kind of rusty on the ends, so I had to press them through from the side with the least amount of rust, in order to avoid splitting the retainer holes that pass through the bottom of the reservoir. Other than that, it was pretty straightforward to do.

I had the same problem. The piston seal in the back of the master cylinder is blown. Its a simple 30 minute fix. I paid like $58 dollars for the new cylinder. When you change it make sure to bench bleed the cylinder.

must be a thing with 93'* I had to replace mine about 2 months ago. It is an easy fix. definatelly be sure to bench bleed the master cylinder