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1980 280z proportioning valve ???


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Hey guys, im doing a disc brake swap on a 521 and plan on using the 280zx M/C... saw one in my local parts yard an 80.. the M/C had 15/16 stamped on the side of it.. Ive only heard people talking about 280zx M/C's with a 7/8 bore..... anyway.... I need a portioning valve, and I figure one off of the 280z will be as good as any... anybody give me a hint where its located...

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Are you using Fineline's kit? Mike used a wilwood proportioning valve to dial it in perfectly. Check the brake section Fineline has a write-up on his rear disk conversion and has answers questions. He sells front and rear bracket's so does Beebani.

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My manual with a supplement for the 280 shows it mounted just to the passenger side of the M/C and booster, on the firewall. It will have four (4) brake lines connected to it. If you find something with brake lines and an electrical wire on it, that's the pressure differential switch and not what you want.

 

Just a reminder, if you are not using a booster, switching to a larger diameter M/C will require more peddle effort and the peddle will not travel as far.

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yeah I bought Finelines.. and Im thinking about the Wilwood.. what are they 40 bucks?? Its probably what im going for, but im a cheap bastard and Im considering going back to get the M/C at the salvage instead of buying one new, and my logic is im there tearing out one used part, while im there get the portioning valve....blah blah blah, but ill buy the wilwood probably when its said and done...

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My manual with a supplement for the 280 shows it mounted just to the passenger side of the M/C and booster, on the firewall. It will have four (4) brake lines connected to it. If you find something with brake lines and an electrical wire on it, that's the pressure differential switch and not what you want.

 

Just a reminder, if you are not using a booster, switching to a larger diameter M/C will require more peddle effort and the peddle will not travel as far.

 

Ias i understand it since the calipers require more volume to operate i will need the larger bore to keep it from being spongy...

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Ias i understand it since the calipers require more volume to operate i will need the larger bore to keep it from being spongy...

 

 

Yeah the single resivor master isn't going to be enough for disks. As for the amount of master you will need I wouldn't know that. I ran my 620 with no booster for a few weeks when I first got the ka running. It was kinda stiff but I'm used to manual breaks. Its the only boosted rig I got, unless you count turbo's :D

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It is not a proportioning valve. The balance is designed into the piston bore sizes, master cylinder, etc. What you are seeing is a distribution block with a differential pressure switch to light the brake warning light on a huge differential pressure between the front and rear brake circuit.

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It is not a proportioning valve. The balance is designed into the piston bore sizes, master cylinder, etc. What you are seeing is a distribution block with a differential pressure switch to light the brake warning light on a huge differential pressure between the front and rear brake circuit.

 

Have you taken the Z master apart? When I first got my rusty car I was having a hell of a time with the breaks. Thanks to Hainz I finally got a good master (stock). I at one time had my stock 510 master apart next to a "new" zx master, the zx master has a spring in-between the two pistons.... So I guess that is what is different about the proportioning in a zx master. My idea was to fit the zx check valves into my stock bad master. I can't remember if it worked, I had so many hours in those dam breaks.

 

 

I really want to know what all the break crap under my 620 is.... Maybe I should bust out the manual :D

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