I'm having a hard time diagnosing the cause of my bad brakes and clunky transmission.

First the brakes: stock '88 GXL (4 piston)

They have always been pretty bad (very soft, not alot of power behind them) but i just assumed they needed to be bled. So about a month ago a got some Cork Sport SS lines installed and had all the fluid replaced, professionally. But still they felt like crap, so I had them bled one more time for good measure. But still, crap.

So now I'm thinking its the master cylinder.



Next question: how are my clutch hydraulics related to my brake hydraulics (if at all)? Do they run off the same Master Cylinder or anything like that?

The reason i ask is because my transmission is in baaad shape, especially when cold. I have a really hard time shifting into second (both downshifting and up). I really have to force it and bump it into gear. Also first gear is IMPOSSIBLE to get into at any speed over 2mph and without double clutching.

Normally you'd think "Oh, bad syncros" but the problem gets much better after i warm up the transmission (though, first is still hopeless). Now the reason i think it ISN'T just bad syncros is because after its warm, im not moving, and i shift veeeery slowly i can feel the gears grinding, as if the clutch isn't full disengaged. Which makes me think the hydraulics aren't too good. Does that sound logical??

I'm not too sure on how all the hydraulics work, so I'm trying to stay as logical as possible without assuming its this or that.


I know its a long post but I want to be as detailed as I can. Any input is greatly appreciated, I'd like to learn as much as possible before i go looking for parts i don't need lol

 

I have always approached repairing the hydraulics as a one-time, replace everything deal.
Rebuild the calipers, replace lines/hoses. rebuild/replace MC, new fluid and pads.
Rotors as necessary...but they're pretty cheap, so replace.
It's actually cheaper in the long run since you don't suffer through multiple rebleeds.
Bite the bullet one time and you're good for years to come.

In your case, you could have sticky pistons in the calipers, bad pads, bad MC or even (less likely) a bad vacuum booster or a combination of them all.

The clutch and brake hydraulics share no components.
Make sure your shifter bushings are in good shape and then drain and refill the tranny using a good quality gear lube...I've used both Redline and Royal Purple synthetics to good effect.
If the problem persists, replacing the entire clutch hydraulic system is pretty cheap (@$125, including hose) and really easy to do.

 

A new brake master cylinder fixed my soft brake problem.

 

hmm, i guess I'll replace the MC, everything else seems fine though. Good, pads, rotors lines etc