brake booster's hissing at me, and killing idle.

[2sixTZombii]

So finally got done with the rear brakes, front struts(among other things) carb swapping and other odds and end, and decided I needed to test her out even just once around the block. I've driven it around the block before, but that was a week after first start, with no power(bad carbs), bad struts, and no back brakes. That was horrible and scary, this however was great! Runs a little rough yet, but pulled hard, steering felt really tight, and nice. Rear struts are still bad and there was alot of crashing and sqeaking back there, so that's next. Then came the brakes, they stopped me good, but I expected a little better, and when I hold them on idle drops about 250 rpms,and it actually killed the motor once, and I can hear hissing under the dash when holding the pedal, I had a friend hold them while I listened under the hood and I couldn't hear anything then, but in the car it's kinda loud. It seems like the boosting is really weak too. I am geussing the booster just needs replaced but, if there is some seal or something that could be causing this then I'd rather avoid the 150!! to buy one new. It's the type of thing I could live with for awhile but it's a pain at the stop sign or red light. Any advice or clues anyone? I also know where a 82 maxima is being parted out, I wonder if the booster is a bolt on?

[Mikes Z car]

One intrepid experimenter mentioned in a thread a few years ago that they fixed the hiss by spreading RTV on the rubber diaphragm in the master vac to seal cracks in the rubber that were leaking. I don't know if the fix lasted a long time. I also don't know if they put RTV over the whole diaphragm or just the places where it cracked. I would think you would want to put the RTV on the side of the diaphragm exposed to atmospheric pressure as opposed to the vacuum side. And with that, that is all I know.

The other thing is don't lose the reaction disk

Edited May 27, 2014 by Mikes Z car

[Kurbycar32]

I bought a brake booster at Orielly auto, I think it was around 100 bucks and looks way better in the engine compartment than the old one.

Our cars are clones, it seems every time you post something i have already had to deal with the exact same problem on my early 260..

[2sixTZombii]

Yeah the early 260s need to band together to keep track of how to fix their little quirks. I think I just need to replace it, ugh. It's always something, But she's getting close to the road, I actually took for a test spin this weekend, and she drove pretty nice, I kept it real close to home as I still need to get insurance. But I wanna finish my struts then take for some real driving.

[2sixTZombii]

Redid the master and booster yesterday. Finally it has brakes, moreover all the systems that I needed restored to properly drive are now functional. The suspension could certainly still use some more work but it's as good as most used cars. I took her for a little spin, and boy was it fun, I have driven it several times now but I could actually count on it this time, and I could actually drive it, drive it. Now I just need to do the floor pans, and the welder has me booked for the 5-6 of july to get it done.

[Kurbycar32]

Glad to hear you got it all working, keep that car rolling!