Miles

Your MC is not pushing enough fluid under pressure. Take the MC off the car and bench bleed it. See post #3 in http://forums.hybridz.org/topic/109115-master-cylinder-bench-bleeding/?p=1020086 When you have the MC in a vice on the bench with the clear hose hooked up per the picture in the link above (post #3): Fill the tanks slowly so you do not create bubbles open both bleed screws. Make sure all fittings and hoses are air tight. Push the piston slowly so as not to create bubbles. If you see a lot of bubbles in the tank stop for 10 or 15 minutes and let the bubbles rise to the surface. Repeat until there are no bubbles. Be prepared to plug the output ports of the MC when you are ready to transfer the MC to the car otherwise fluid will leak out. At the car hook up the hard lines before placing the MC on the booster. Tighten the fittings finger tight. Once the MC is on the booster tighten the fittings the rest of the way. Resume bleeding the rear brakes. If there is still no fluid flowing while pumping the brake pedal then the MC is bad and you will need to replace it.

In order to be 100% sure all of the air is out, the piston must be pushed full stroke. On the car this can be accomplished by: Unbolt the MC from the booster, but leave the hard lines connected. Pull the MC out and away from the booster - the hard lines have enough flex to allow this. Attach clear plastic hoses to the bleeders and run into the tanks. Hold the hoses securely with clothes pins etc so they don't pop out and suck air. Open the bleeders and place a screw driver etc. up against the piston being careful not to scratch the bore. Push the piston slowly with the screw driver all the way until the piston bottoms out. Repeat until zero bubbles appear in the plastic hose. Note: sometimes air will enter around the hose where it is attached to the bleeder or around the threads of the bleeder giving the impression that there is still air in the MC and will also allow air to get sucked back into the MC. So make sure the hoses fit tight and just crack the bleeder enough to allow fluid flow. Speed bleeders insure that no air is leaking past the threads. I have been able to bleed a MC on the car with out unbolting it from the booster, but sometimes the only way to get all of the air out of the MC is to push the piston all the way until it stops as in bench bleeding.

Pac_Man In a situation like yours I prefer to eliminate the MC as a problem first then I know for certain that the MC builds pressure and can move fluid equally to each wheel. There two issues you may have to deal with: 1. air in the MC and 2. the MC leaking internally (pedal slowly sinks to the floor). So: Check for air Check that the MC holds pressure Go to the wheel cylinder: is it leaking? If so repair it. Bleed the system.

No, you don't need the car on an incline. There is most likely air in the rear section of the master cylinder. You will not be able to bleed the system with air in the MC. If you haven't done so, research how to bench bleed a master cylinder. If you do it off the car be sure all of the hoses and fittings you attach to the MC are air tight. After researching, make a logical check list of what you need to do starting with the MC.

The old finger trick.

Brake fluid eats paint down to the metal.

To check for fluid in the booster, you don't have to completely remove the master cylinder. There is enough flex in the hard lines connected at the bottom of the master cylinder that you can unbolt the master cylinder, pull it forward and then push it aside to look inside the booster for fluid. If there is no fluid then the leak is somewhere else in the brake system. If you remove the master cylinder completely you will have to bench bleed it before reinstalling it. Check the wheel cylinders and calipers for leaks first. Probably best after finding the leaks to take the car to a brake shop for any repairs.

If you allowed all of the fluid to drain out of the rear section then you will have air in the master cylinder which will require bench bleeding. Sometimes you can get the air out by bleeding the MC on the car by running a plastic hose from the bleed screw back into the tank. Even though the plastic tube is immersed in fluid in the tank air can still enter around the threads of the bleed screws. Have a helper open and close the bleed screw while you push the brake pedal. Just like bleeding the wheel cylinders. You can also install speed bleeders on the MC so you don't need a helper. If bleeding the MC in the car still does not result in a firm pedal, then you will have to remove the MC and bench bleed it. The procedure is documented in the brake forum. Don't allow the fluid to run out of the MC when reinstalling it in the car. Plug the output ports. To make mounting the MC easier, start the hard line fittings back into the MC before bolting it to the booster. In the future do not allow the tanks to empty out while working on the brake system. Fill the tanks and use a large rubber stopper or other means to plug the tank to create a vacuum so the fluid can not flow out. Secure the plug/stopper so it can not back out and leak air. You can also plug the ends of the brake lines to stop the flow of fluid. http://www.speedbleeder.com/ http://www.summitracing.com/parts/ear-280022erl?seid=srese1&gclid=CN2v8PrfksQCFYVqfgodGFYAcw

Did you allow all of the fluid to drain out of the master cylinder rear circuit while you had the wheel cylinder off?

I have had problems with "rebuilt" calipers new right out of the box. Especially with the Cardone and the cheap Napa house brand calipers. Problems with new out of the box calipers include: Piston would not retract into the bore. Piston seals leaked. Caliper filled with rust and debris that showed up while bleeding. Removing the bleed screw I was able to shake out rust flakes/powder. It happens. If after you have ruled out all other causes take the calipers back and buy Nugeon brand rebuilt calipers at Napa. Other stores may carry Nugeon as well. Unlike the Cardone and other cheap brands, Nugeon calipers are rebuilt in the USA (Stockton, Ca).

http://forums.hybridz.org/topic/97317-extended-wheel-studs/

So you didn't unplug and lights when cleaning the sockets?

My marker lights just had two pig tails with bullet connectors. One of them got flipped. As NewZed stated above, unplug all of the lights and reconnect until the fuse blows. My thought is you have a hot wire that got connected wrong when you reinstalled the lights.

Trouble shooting automotive electrical problems is a different skill mix compared to engineering. As a retired mechanical engineer I enjoy the hands-on problem solving.

Did you remove the marker lights? There are two wires connecting the marker lights. Did you reconnect the wires correctly? For example, on a 240Z rear marker light one wire is hot and the other wire is a ground. When I had my 240Z painted, the shop hooked up the right rear marker light backwards so each time I turned on the lights the fuse for the parking/marker/dash lights would blow. When things like this happen ask yourself what did I do to the car just before the fuse started blowing. Like retracing your steps to find lost keys.

Not with paltech. But I bought a set of SU carbs from Ztherapy when I discovered that the throttle shaft bushings were leaking. At that time (2004) a set of Ztherapy carbs ran about $600. If the throttle shafts had been air tight I would have just bought the Ztherapy rebuild kit. I see Paltech rebuilds SUs: http://www.paltech1.com/id4.html

Forgot to mention that. If the bushings are worn air will be sucked in around the throttle shaft creating a lean condition and make it impossible to properly adjust the mixture. Typical symptoms of leaking shaft bushings include rough idle, lean sag and backfiring through the carb. If the bushings are suspect you can spray carb cleaner etc. on the throttle shaft ends with the engine running and listen for the engine speeding up or smoothing out. Ztherapy fixed this problem by replacing the throttle shaft bushings with sealed bearings.

If you are new to SU carbs then you need to buy the "Just SUs" video at http://www.ztherapy.com/ After viewing this video you will be able to maintain, adjust and repair SU carbs. Ztherapy also carries parts for SU carbs. If you Google SU carb adjustment or SU repair you should get many how to work with SUs write ups by Z car owners. Also, search Hybridz and classiczcars.com as there are many posts on maintaining SU carbs. In addition to the video, download a pdf copy of the factory service manual (FSM) for your year Z from the Links forum. Look here too: http://atlanticz.ca/zclub/techtips/carbs/su/index.htm

See if you can Google a pdf copy of the 78 280Z schematic. The pdf is easier to read and you can enlarge it to better see the details. See AtlanticZ for some electrical schematics: http://atlanticz.ca/zclub/techtips/electrical.htm

Here is a thought.................. http://www.thezstore.com/page/TZS/PROD/11-3280

What year 240Z, 280Z, 280ZX. 300ZX?

Sometimes. There is no 'generalized" answer without knowing the specific brake configuration you are asking about. See Brake FAQs and the other posts in the brake section etc.

Once you watch the video you will understand why your carbs are not working when you move the throttle linkage. The linkage that you are pulling on the bottom of the carb is the choke which causes more fuel to enter the carb as long as you hold the choke open. On the other hand, the throttle linkage only opens a butterfly valve. That's it. Basically, fuel flow into the carb is controlled by the piston lifting a precision tapered needle up inside its tapered valve seat which allows more fuel to drip out of the bowel and get sucked in by high velocity air into the carb where it is mixed with the air forming the correct air-fuel mixture. Some refer to this as a "controlled drip". Mixture adjusters on the bottom of each carb determine the correct mixture. It is a bit long and complicated to explain how the SU carb, throttle and linkages work. The video explains the theory of operation along with tuning which is the best way to learn SUs. Or download SU instructions off the net.

If you are new to SU carbs then you need to buy the "Just SUs" video at http://www.ztherapy.com/ After viewing this video you will be able to maintain, adjust and repair SU carbs. Ztherapy also carries parts for SU carbs. Do you know about the mixture adjustment nuts on the bottom of each carb? If you Google SU carb adjustment or SU repair you should get some how to work with SUs write ups by Z car owners. Also, search Hybridz and classiczcars.com as there are many posts on maintaining SU carbs.

Take your time and buy the cleanest, rust free and unmolested Z you can find.