I have a 1974 260z which i just bought it has been stored in a garrage for 4 years and hasn't been started since i got it. It started fine and ran fine , a new fuel filter some fluids and seemed to run fine. Then the problems started, when I mash the brake petal the engine surges and when I put it in drive it shifts erratically. I'm sure its a vaccume leak, but I cannot find where can someone shed some light on this for me????

It sounds to me as though your master-vac (vaccum brake booster) diaphram is shot. When the diaphram gets old and cracks, it creates a vaccum leak...especially when you apply the brakes. They can be replaced but require some special tools. This happened on my 1970 240Z and I just purchased a new one.

If you're replacing, why not upgrade to the ZX m.c.? It has a larger bore, so you get more pressure.

thx

If you're replacing, why not upgrade to the ZX m.c.? It has a larger bore, so you get more pressure.

thx

jSTUDLY. when the vac. booster is leaking it effects the automatic as well . the auto has a vac. line that controls shifting so it all goes hand in hand. There are some, the privious post, that dont have a clue and give advise as though they did . I dont think he even knows what a booster is . In the past you could buy a kit to rebuild the booster , a simple thing to do, however I dont think they are available any longer. The boosters are but not the kits. They are year specific so when ordering be clear with the year and mention the automatic. Gary

Why do you disagree with 240Zx's suggestion, Beandip?

Why do you disagree with 240Zx's suggestion, Beandip?

Stop, Stop, you're killing me!!

Stop, Stop, you're killing me!!

YOU SEE WHAT I MEAN ! HELLO HELLO ANY BODY HOME ! :stupid: :stupid: :stupid:

As a clairification . I am not disagreing with 240ZX at all . The Vacum brake booster is what I am referring to in my origional post. What I am referring to with the statement '' some people dont have a clue'' is . The '' MEMBER '' comeing up with the off the wall unrelated comment of changing the master cylinder , which has absolutly nuthing to do with what this thread is about. :devious: :disappoin :stupid: LanceM gets it.

I know you were referring to the booster unit. I suggested the upgrade to the ZX unit, but I forgot to mention the master cylinder AND the booster both, BECAUSE:

When I do the brake booster, I replace both at the same time. It looks like Beandip and others only make reactive repairs, which means ONLY replacing the booster and using the same OLD worn-out master cylinder. This misunderstanding creates a problem.

Instead of presuming YOU have the only reasonable comments why don't you ask others to clarify their statement when you don't understand??:stupid:

LanceM gets it.

Don't Worry Gary, Lots of us get it

When I do the brake booster, I replace both at the same time. It looks like Beandip and others only make reactive repairs, which means ONLY replacing the booster and using the same OLD worn-out master cylinder.

Ok just to clarify this, so say when you replace a MC you also replace that OLD worn-out booster?? I mean one would follow the other from what you are saying right? What about rear wheel cylinders, they are as old as the MC more than likely, so we should change them too?

No wonder I only do "reactive" repairs, I couldn't afford to replace everything related to a failed componet just because I was there...

In any case you gotta stop, you're killing me

No. I only mean the Booster and the M.C, as those go together. If I was rebuilding the rear brakes I'd so the rear cylinders. You can do all the parts like you were suggesting, if you wish.