RedFive Posted October 23, 2005 Share Posted October 23, 2005 So I've had my '76 280z a few months. When I got it, brakes were pulling to the right a little bit and I hadn't had time to deal with it yet. Then today I was on the other end of town and at a stop light. The brakes were hissing a little bit, I noticed, and I was just playing with them while waiting for the light. Pumped them a couple times, listening to the sound...not much else. Light turns green and off I go...then the next time I go for the brakes they exhibit the following undesirable features suddenly: -very squishy -vibrating (felt like a gravely feeling, if that makes sense) -had to floor the pedal to get it to even try and stop I'm thinking the booster is dead, but I'd really like to not have to fork out cash for that right now. So before I go and spend money I'd like some second opinions. I did some searching and someone mentioned doing a test of pressing the pedal a few times with the car off -- it should harden up a little. I think maybe it did slightly. But then with a little pressure on the pedal, start the car and the pedal should drop away from your foor towards the floor -- didn't happen. I looked at the FSM troubleshooting section briefly, but...eh... anyways, any ideas? Quote Link to comment Share on other sites More sharing options...
rudypoochris Posted October 23, 2005 Share Posted October 23, 2005 Thats sounds like it could be it, did you check your brake fluid level and for any brake leaks at the calipers/mc? Quote Link to comment Share on other sites More sharing options...
RedFive Posted October 23, 2005 Author Share Posted October 23, 2005 Fluid level was fine. Didn't look for leaks. Will do so in the morning. I guess if I have to replace this thing...is there a better one I can replace it with? Quote Link to comment Share on other sites More sharing options...
rudypoochris Posted October 23, 2005 Share Posted October 23, 2005 Im under the impression that a booster is pretty much a booster. The thing is they are very expensive $$$ you will probably want to get one from a jy or ebay. Quote Link to comment Share on other sites More sharing options...
RedFive Posted October 24, 2005 Author Share Posted October 24, 2005 I thought I read somewhere that somebody was using a zx booster in their early model z....? I don't know. I just figure that if I'm going to replace it, I don't want to get el cheapo parts. I need to keep reminding myself that I'm a college student, haha! Quote Link to comment Share on other sites More sharing options...
BrandonsZ Posted October 26, 2005 Share Posted October 26, 2005 The booster would not exhibit the symptoms you indicated -very squishy [booster will make it squishy as opposed to not having one] -vibrating (felt like a gravely feeling, if that makes sense) [booster is all about pedal feel, if the pedal was vibrating maybe] -had to floor the pedal to get it to even try and stop [if the booster was bad, you wouldn't be able to floor the pedal if you ever had a car on a hill and you lose the booster the problem is not putting it to the floor, it's "how can I push hard enough to get it to the floor Iiiiiiiyyyeeeeeeeee...". So I think you have a caliper rpoblem, possibly warped rotors, possibly dragging pads making the rotors hot and fading them. Stop the car when it's hot and lift the front end if the wheels are hard to budge, then you've got a caliper problem, if the wheels move freely, take one off and check the pads, if the pads look good and the rotors are not scored, then it's ok. You might have a cracked pad, that would do it, or one that's gone completely. Quote Link to comment Share on other sites More sharing options...
RedFive Posted October 27, 2005 Author Share Posted October 27, 2005 I discovered this morning that the engine revs up when I press on the brakes. Is it still not the booster? I'll try what you suggested Brandon. Thanks. Quote Link to comment Share on other sites More sharing options...
olie05 Posted October 27, 2005 Share Posted October 27, 2005 Brandonsz, although your explenation sounds correct in theory, in my isolated experience, I had a very squishy pedal, that would stop the car rather normally to an extent, but after that "extent" was over, the car would not want to stop any faster. I found the problem to be a rust hole near the vacuum inlet on the brake booster. When I replaced it, the pedal felt harder, but you still had to push the pedal about half way without anything happening, even with a proper and thorough bleed. I know this second problem is with the brake master cylinder which I am replacing soon. Just remember, it could be a combination of both your booster or your master cylinder. Also, in my experience, any car that you pump the brakes on (with a booster), while the engine is running, will increase the RPM's. Quote Link to comment Share on other sites More sharing options...
BrandonsZ Posted October 27, 2005 Share Posted October 27, 2005 Brandonsz' date=' although your explenation sounds correct in theory, in my isolated experience, I had a very squishy pedal, that would stop the car rather normally to an extent, but after that "extent" was over, the car would not want to stop any faster. I found the problem to be a rust hole near the vacuum inlet on the brake booster. When I replaced it, the pedal felt harder, but you still had to push the pedal about half way without anything happening, even with a proper and thorough bleed. I know this second problem is with the brake master cylinder which I am replacing soon. Just remember, it could be a combination of both your booster or your master cylinder. Also, in my experience, any car that you pump the brakes on (with a booster), while the engine is running, will increase the RPM's.[/quote'] Booster causing idle to change is definately a leak having to do with the booster, but could be just the hose possibly. I think there is a booster problem now and maybe another problem somewhere else. Sounds fishy. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 27, 2005 Share Posted October 27, 2005 Gravely feeling is definitely something metal to metal in the brakes (either the pad lining or the shoe linings are gone). Can't pin it down any more than that, but you need to get the wheels off and find out what is grinding on what. Start with that, then adjust the rear brakes. Drums way out of adjustment will give a long pedal. Sounds like you need a booster too since you have a vacuum leak when you step on the brakes. Basically you're going to have to go through the whole system. Quote Link to comment Share on other sites More sharing options...
violacleff Posted October 28, 2005 Share Posted October 28, 2005 Hey my engine revs up also, and I just installed a brand new booster. Is this something to be worried about? Quote Link to comment Share on other sites More sharing options...
RedFive Posted November 2, 2005 Author Share Posted November 2, 2005 Yeah, nothing is grinding on anything. I knew this already because the vibration feeling is even when I'm stopped. I guess it's something to do with the booster. I checked the vacuum line...looks okay. Took off the front wheels and pads/calipers/etc all look in order. I'm kinda leaning towards the booster anyways, since the housing is all rusty (yet the rest of the car has no rust).... Quote Link to comment Share on other sites More sharing options...
BrandonsZ Posted November 2, 2005 Share Posted November 2, 2005 To be sure, just disconnect the booster, plug the line and see if the noise is still there. Your braking will be reduced and you'll have to push hard on the pedal so don't go racing when it's disconnected. Quote Link to comment Share on other sites More sharing options...
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