Brake Booster Question

[SimpleEnigma]

I have a '92 SE Coupe w/ no ABS or HICAS, and recently my brake pedal has become exceedingly squishy. not so that it touches the floor panel, but that i have to push very hard on the brake in order to get the car to stop...seems like the car just doesnt want to stop. I called a brake shop and asked, they said it could be that the brake booster is going bad, maybe due to the fact that brake fluid is extremely caustic and has worn out the diaphragms and rubber parts inside the booster.

so now here are my questions...1.) is this diagnosis an accurate possible problem or is he just BSing me and 2.) if it is the brake booster going bad, will the 300zx brake booster be a direct fitment since i am going to do the 300zx caliper upgrade anyway?

Also, the car has a weird vibration in 2nd gear b/w 20 and 30mph, only when engaged, a transmission shop says possible bad universal joint in driveshaft or lack of lube in univ-joint. Ideas?

[cdlong]

1) quite possible, an easy way to check for yourself; step on the brake a few times with the engine off and keep your foot on the brake with moderate pressure. then start the engine. if the pedal drops a little and gets easier to push the booster is still ok, or at least it's working a little. though it may be the cause of the problem. if it doesn't change at all or a very little bit, it's bad and needs to be replaced.

2) i don't know if the Z32 booster fits, but it isn't necessary. if you are going with Z32 calipers, the master cylinder is what you need to upgrade. don't bother with it, just get a 240sx booster.

[SimpleEnigma]

I just Check the booster, and all seems ok...

But maybe it was the Master Cylinder that the guy was talking about?

Anyway....if it is the MC the Z32 is direct fitment?