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280 ZX 15/16 Master Cyl


FrankRizzo

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Does anyone remember Felix the Cat cartoon where the evil dude was a character  named "the Master Cylinder"???

 

Ff-mastercylinde_zps1mnbdwkd.png

 

Anyways...my next project is the brakes on the 620. I have 4 wheel disk but the PO left the 3/4" master cylinder in place with a questionable adjustable proportioning valve (with a gauge on it?!?!) for the rears. It's all covered in overspray so im down with replacing the whole thing. The problem is that the complete '79-81 ZX 15/16" master cylinder is made of unobtainium. No longer made, none on Rockauto. Google searches for Centric or Raybestos part numbers are mostly dead ends. Napa/ O'Reiley are dead ends too.

 

I think I have two options that I need opinions on. Silvermine motors has a 15/16 cylinder body with with no reservoirs and there are some on Rockauto.

http://www.silverminemotors.com/featured/15-16-upgraded-master-cylinder-for-240z-260z-280z

Does anyone have a good lead on brand new reservoirs for this? Remember, mine is covered in overspray and I just want/strongly prefer new stuff. Rockauto does not list the reservoirs separately for the ZX, Maxima, 810 - so not sure how put this together. Even if I could clean the 620's reservoirs, im not sure they fit on the ZX cylinder body...

 

Or should I just go for the 1" wilwood set up? It's about the same price and it includes the reservoirs (but needs thread converters for the brake lines. I know it will make the pedal harder, but at this point it is much easier to get. Does anyone know if the Wilwood has residual valve already installed for rear discs?

 

As I mentioned before. im going to try to get the ebrake working and the PO removed all of the cables, So I now have all the required cables to fab up, as well as new rear calipers with the cable brackets that are currently missing.

 

Finally - any recommendations on brake fluid? I have one tin of ATE super blue, but I dont think it enough to do the whole truck and it's like 5 years old.

And in the "while you are at it" theory; should I replace the booster whilst everything is apart. Me think so...

 

Thanks in advance!!!!!!!!!!

 

(6 sets of cables and two calipers - thankfully the Isuzu cables are on clearance on rockauto and were less than $20)

 

IMG_2718_zpsmpfu9amo.jpg

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Yes I remember the Master Cylinder and Crabby Appleton.

 

 

You have stock front 620 disc brakes? 15/16 is a bit large for this even with a booster. Try a 13/16" that's larger than the 3/4" maybe 7/8". Going so large won't make the brakes work

'better,' it will increase the effort though and the pedal will feel rock hard. Larger diameter = extra effort to get the same braking pressure..

 

All reservoirs seem to be the same diameter. They come in different shapes and some share a single top with a dual bottom..

 

Any DOT3 brake fluid will be fine. Must be from an unopened container.

 

Brake booster? don't fix what ain't broken.

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I'm with Mike on this one. Larger is not "better". I don't doubt that the Wilwood master bolted up nicely, but does it actually make the truck stop any quicker?

 

I do a lot of brake fine tuning here in my shop and I rarely find that a larger master works out without it's pitfalls. Unless you are also increasing the size of the booster, or need the extra volume for larger brake calipers, I would stick to the OEM size.

 

You need more leverage to push that large master. That leverage comes either from your foot, from increased pedal leverage (changing the pivot point of the pedal), or larger/more powerful booster.

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A larger master will move more fluid = shorter pedal travel to stop at the same pressures.  That's the key.  Less pedal stroke at the same pressures.  The pedal will feel more firm, but it will stop the same with less travel.  A smaller master will give you more pedal modulation, meaning with a longer stroke to stop at the same pressures, you have more control over braking - its not as immediate (slam the passenger's head on the dash less).  The opposite holds true for the wheel cylinders.  Larger acts slower (takes more fluid) while smaller responds faster at the same pressures (slam face).  I'd go for a 7/8" Wilwood.  260-6765 is only $58.  Doesn't look original but it should fit and work.  

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Im with ya.... but... I dont think youse guys read my p0st.  :blush:

 

I have the stock 3/4" master cyl on a 4 wheel disc set up. I need more volume to push the pistons...the pedal travel is far and sloppy I'd be MORE than happy to use an early 280ZX 15/16  MC, but they are not manufactured anymore and are currently made out of unobtainium.

 

So my choices are:

  1. Get the bare 15/16 master Cyl - but then I need to get the reservoirs someplace - unless anyone thinks/knows that the 620 reservoirs will fit on the ZX MC body, im not sure how to piece this togeter. The cylinders and caps are not sold separately that I can find? 
  2. Get the 1" Wilwood MC. I'm not looking for "bigger is better" but strictly that it is new and a quality piece and readily available and I seem to have limited options....

 

thanks for all your helps so far!!!

 

.

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.....  I'd go for a 7/8" Wilwood.  260-6765 is only $58.  Doesn't look original but it should fit and work.  

 

Holy sh!t. If this works, ima gonna name my kids after you!! w00t! thanks much!

:thumbup:   :w00t:  :thumbup:

 

$54 on Amazon - Prime. If it does not fit, at least I can return it. I'll check boltspacing when I get home!

https://www.amazon.com/Wilwood-260-6765-Bore-Master-Cylinder/dp/B003XVJOD2

 

 

 

Not going for stock look at all - that ship sailed a long time ago...

Kinda hard to see in this pic, but the rear line goes into a proportioning valve, with a 0-3000 psi gauge on it and the fittings have teflon tape on them....the whole set up gotta go. 

 

EDIT: Shoot. That ^ master cyl is only single circuit...

:bye:

 

 

wir_zpsgew5mt5k.jpg

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Here are 3 options in 7/8 dual.  Sorry I missed that the other wasn't a dual.  

260-9439

260-14241-P

261-14249-P

You can go here to check bolt pattern, but I bet they're all the same:

http://www.wilwood.com/MasterCylinders/MasterCylinderLanding.aspx

Now if you want cheap, you can go steel instead of Wilwood and start digging through a Bendix or Wagner catalog (online?).  

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Thankx again!  I saw those..kinda spendy... but an option. I think at that point I'd use the same 1" that Hobo used.

 

Inquiring minds are wondering....how hard is it to replace the residual valve on a stock '77-78 280z MC? It's 7/8" but it is set up for disc/drum...seems like a possible good option if it can be changed. I saw several posts by Mikey where he messed with the residual valves. Can it be done? Maybe buy the rebuild kit for the ZX master cyl and use the valve?

 

http://www.partsgeek.com/catalog/1978/nissan/280z/brake/brake_master_cylinder.html

 

.

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The mushy/long pedal is from the brake shoes being out of adjustment.  Adjust, pump the pedal, adjust again at all 4 corners until you have light to moderate drag.  If its still mushy, bleed again.  

Willwood makes a 10 psi residual valve that mounts in the brake line and its better than the ones in the master.  I believe all the Willwood masters are set up for discs.  Truth is - it doesn't much matter when the wheel cylinders are as small as ours, as long as the pedal stroke is long enough to fill the wheel cylinders, which it is.  Disc brakes get a 2 psi residual valve, drum get 10 psi. 

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The mushy/long pedal is from the brake shoes being out of adjustment. Adjust, pump the pedal, adjust again at all 4 corners until you have light to moderate drag. If its still mushy, bleed again.

Willwood makes a 10 psi residual valve that mounts in the brake line and its better than the ones in the master. I believe all the Willwood masters are set up for discs. Truth is - it doesn't much matter when the wheel cylinders are as small as ours, as long as the pedal stroke is long enough to fill the wheel cylinders, which it is. Disc brakes get a 2 psi residual valve, drum get 10 psi.

all around disk. No shoes to adjust
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He says it at the beginning of the paragraph

 

Im with ya.... but... I dont think youse guys read my p0st. :blush:

 

I have the stock 3/4" master cyl on a 4 wheel disc set up. I need more volume to push the pistons...the pedal travel is far and sloppy I'd be MORE than happy to use an early 280ZX 15/16 MC, but they are not manufactured anymore and are currently made out of unobtainium.

 

So my choices are:

  • Get the bare 15/16 master Cyl - but then I need to get the reservoirs someplace - unless anyone thinks/knows that the 620 reservoirs will fit on the ZX MC body, im not sure how to piece this togeter. The cylinders and caps are not sold separately that I can find?
  • Get the 1" Wilwood MC. I'm not looking for "bigger is better" but strictly that it is new and a quality piece and readily available and I seem to have limited options....

thanks for all your helps so far!!!

 

.

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I didn't catch the part about adding rear discs. Either way, I'd try the stock master first.

 

One thing I absolutely detest about the Wilwood masters is the screw down lid. Not all of them have this, but checking the fluid becomes a real pain with the screw down lid. I saw, in one of my hotrod magazines, that someone is producing a lid for those Wilwood masters that has removable caps. Great idea.

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Update: In case anyone is googling 280ZX 1979 to 1981 master cylinder 15/16 replacement like I did for several hours...

 

Here's what ima gonna do

 

Arizona Z manufactures the early ZX 15/16" master cylinder because they were discontinued, $129 shipped. I called Dave at Az Z today and from his description it seems perfect - made for 4 disks w/no residual valves. This guy knows a whole bunch about Datsun brakes...I ordered it today.

 

Scroll about 3/4 down this page:

http://www.arizonazcar.com/brake.html

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I got one recently from oreilly's. The stock reservoir should fit too although I plan on getting new ones from tilton. It was about 7-8 bucks a reservoir when i checked. 

 

http://www.oreillyauto.com/site/c/detail/OBH3/111837/01292.oap?year=1979&make=Nissan&model=280ZX&vi=1209293&ck=Search_master+cylinder_01292_1209293_3629&keyword=master+cylinder&pt=01292&ppt=C0066 

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