Miles

The FSM just says to replace the switch if it is defective. There is no latching device inside the switch, as in my 72 240Z switch , which would capture the piston and hold it. The springs at each end insure that the piston re-centers itself. I suppose that corrosion build up could cause the piston to freeze in the bore in which case the switch would be thrown away and replaced as per the FSM. Note if you take the switch apart and you tear a seal there are no new seals available from Nissan. You can bench test a switch by placing it in vise, attaching a volt meter to the electrical contact, and then push the piston in and out. The volt meter will turn on and off as the piston moves. Is the resetting of the pressure differential switch a Z car myth? Ancient Alien theorists would say yes. As per the guy with the boner hair on the History Channel.

Newzed My 72 240Z had the switch like the second picture (picture from FSM). Is the first picture the early or late model switch? With either switch the springs at each end recenter the piston. After reading many conflicting stories about the switch I removed mine and dissected it to see how it worked. Manually moving the piston against the spring and and then releasing it the piston returned to the center resting position. In the later Z cars (280ZX) the switch was replaced with level sensing master cylinder caps

The most likely scenario is that you allowed fluid to drain out of the MC tank for the front brakes. This will introduce air into the front brake lines making it impossible to bleed the front calipers. You will have to bench bleed the MC if this happened. This would be a good time to just replace it. The other scenario is that the MC was failing before the brake job and now the front part of the MC has failed. It has happened to me when I replaced the 240SX calipers on my 240Z. When I road tested the car after the brake job the MC let go. It happens. Now the infamous brake switch. All it does when the pressure drops in the front or rear brake circuit is that a spring loaded shuttle moves to the low pressure side blocking fluid flow to the"leak" and turning a red light on in the speedometer. That is it. The shuttle is spring loaded at each end and is self centering once you let off the brake pedal. There is no mechanism inside the switch to lock it one way or the other. Study the picture below. It is just a hydraulically operated light switch that moves when there is a pressure difference between the front and rear brake circuits. Hence "differential pressure safety switch". I replaced mine with a three way brass line connector years ago because I don't need a light to tell me that my brakes are failing. Do not gut the switch either as you will then tie the front and rear brakes together. There are no repair parts because Nissan built it as an expendable item in case the switch failed. So you either have air in the front circuit and or the MC has failed. There is nothing wrong with the brake booster unless you took the MC out and dropped the reaction disk inside the booster. That has a whole different set of symptoms. My 72 240Z had the switch as in the second picture. The second picture is from the FSM.

What are your plans for a parking brake? Search rotors by dimensions: http://www.bremboaftermarket.com/En/Car_Disc_Catalogue/Catalogue_Search.aspx?SearchMode=Size&IsResult=True&SearchDiameter=289,5&SearchTH=27&SearchMinTH=25,9&SearchA=57,1&SearchB=52&SearchC=4

Z Quip has been out of business for some time. You might be able to buy used Modern Motor Sports 240SX brackets from a Hybrid member or elsewhere and then get the 240SX calipers and correct 300ZX (11.4 in dia non turbo 1984) rotors and brake lines.

Does the caliper you have now look like the picture in the link below? http://forums.nicoclub.com/300zx-z32-rear-aluminum-calipers-brakes-t487499.html Most rear caliper swaps use Maxima, 280ZX (early/late) or 240SX parts. I have not seen mounting brackets recently for Z32 (300ZX) rear caliper swaps. You need to identify, conclusively, what mounting brackets you have and then get the correct parts. Post detailed pictures of each part that you have. Or you could just buy these: http://www.modern-motorsports.com/z-rear-disc-cnc-brake-brackets.html

Do you have an electrical schematic? If not look around Hybridz or do a google search and download a pdf copy of the schematic. Some members here have colorized the schematic making it easier to read. With a pdf copy of the schematic you will be able to enlarge it making the switch connections easier to read. See attachments. BE Body Electrical.pdf

My first brake mod was the Toyota 4x4 pickup caliper on stock rotors with stock drums. They worked fine. The reason I went to rear disk was the constant maintenance the drums required.

Brake line flaring tool: http://www.eastwood.com/professional-brake-tubing-flaring-tool.html Works.

My brake set up on my 240Z is similar to what you mentioned above: Toyota 4 piston front, 240SX rear, 1 inch Wilwood MC and 280Z booster. Originally I used a 280ZX mc but replaced it when it failed with the Wilwood 1 inch mc. I installed the 280Z booster to off set the heavier pedal caused by going to a larger diameter mc. It works! With the 280Z booster, the pedal is easy to modulate with minimum foot pressure. Now the facts: The popular 240Z brake swaps (Toyota, Maxima, 280ZX, 240SX) are not balanced front to rear. There is too much front brake bias. With the Toyota front and 240SX rear the ratio is 60% front and 40% rear. So performance suffers. There has been much debate about these brake "upgrades" so I took a year and did them all so I could see first hand how they perform. I experimented with a variety of front and rear pad materials as well. I found all of the various brake configurations to be overly front biased. Some of the racers will use high friction pads on the rear and then dial in the front-rear bias with a proportioning valve for various degrees of success. I tried it, but didn't like the idea for a daily driver.

Lots of posts in the brake section on stock brake line diameter.

Blob Concerning on-line upgrades advice: Trust, but verify. Been burned too many times. Looks like you have this about solved. Post some pictures when you are done.

No need to to wrap anything. Get rid of the stock starter and replace it with a Hitachi gear reduction or similar starter. Paste this into the search window: "Starter Heat Soak" http://www.oreillyauto.com/site/c/detail/HIT0/PSL100.oap?pt=N1643&ppt=C0376

discussed before here and other Z sites.

Well written post. I had a R200 with the same slop and replaced it. It helped, but every R200 I have used had a lot of slack and would clunk when shifting.

http://www.zcarparts.com/

A good fit would be under the Engine Components forum.

Note: all the original poster was suggesting was to have a dedicated place to post and search cooling system information.

I ordered a Ron Davis (RD) 24" x 19" radiator today. They are running about 10 weeks to deliver. Not a problem, but has anyone received a RD radiator in less than 10 weeks?

Just set it up the Cooling Forum like the other sub forums with a FAQ pinned to the top, move some informative threads form other forums into the Cooling sub forum and let it fill up with new posts. A first post like What Radiators are You Using, or post your cooling system would be a useful thread to list in the Cooling forum.

Agree. Just spent two days searching radiator threads.

I can relate. This link has lists of what calipers go with which rotors and brackets: http://forums.hybridz.org/index.php?app=core&module=search&do=search&andor_type=&sid=c97dfedf362bd0134fa39338154643b0&search_app_filters[forums][sortKey]=date&cType=topic&cId=39435&search_app_filters[forums][sortKey]=date&search_term=280zx&search_app=forums&st=25

By the time you are done with your car project you will understand the manual and you will be a better mechanic.

Does anybody know what the items in the pictures are and does anybody have any suggestions as to how i should attempt to problem solve from here? Answer: You need to download a Factory Service Manual (FSM) for your car. It will explain what all of the parts do. Search HybridZ for a FSM. Get a volt ohm meter and learn how to use it. Use the FSM and the schematic posted above and check each part of the ignition system until you find the problem. Running hot wires as a test is going to burn a wire or some component. Asking what this or that is every few hours is never going to help solve your problem. You need to study the FSM and the electrical schematic and methodically go through the car's electrical systems. People are going to be more inclined to help you if it appears that you have been doing your homework first. Study, analyze and then ask the question. Sometimes you just have to think real hard: "Thinking is the hardest work there is, which is the probable reason so few engage in it." -Henry Ford

Post some pictures of the parts.