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77 280z master cylinder check valve


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Quick question, my 280zx 15/16 master cylinder just went out on me and I have a spare 7/8 280z master cylinder that I can use. The question is, does the 7/8 have check valve in them, on both front and back? how do I take it out, because I already use a 17mm wrench and unbolt the bolt from underneath, and for some reason it isn't falling out. Btw, I have a rear 240sx rear disc brake conversion and toyota 4x4 front brakes.

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Yes the 7/8 240Z has a check valve in the rear port because the 240Z had drums on the rear. Note I have found check valves in the front port on some rebuilt MCs. So I always check the front and rear  MC ports  before installing the MC.

 

Do you mean the cone shaped seat for the pipe flange?  If so, the cone shaped part just sits in the MC and can become stuck in-place. Carefully use a small screw driver and pry around the cone's base. Or use a rod or small screw driver  that fits in the hole of the cone and gently move the cone from side to side.  Do not scratch or dent the cone where the flange seats or it will leak.  The cone usually just falls out after  some light prying. The check valve and spring should just fall out or use some needlenose pliers to pull the valve out.

 

There is a torque spec for the port fittitings. Look it up in the Haynes manual or in your factory service manual.

Edited by Miles
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I decide to ditch the 7/8 and just went ahead and order a wilwood master cylinder (260-8794) instead. I don't really get the part where they mention about adjusting booster pushrod. This is new to me and will be my first time attempting it. Is there a special tool needed to measure the rod length, plus how do you even adjust the pushrod out and in to get the right length for the wilwood master cylinder?

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Go to the brake section and enter "push rod" into the search window. There are many many posts, with pictures and methods for measuring the push rod.

 

Or just take it to a brake mechanic and have the MC installed

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Hey miles, does the push rod from the 79-80 280zx booster need to be adjust too, if i decide to put the wilwood master cylinder onto the booster? I remember seeing a post saying that if plan on using a 15/16 280zx master cylinder onto a 280z booster, the push rod will also need to be adjust. If I can put the wilwood master cylinder onto the 280zx booster without adjusting it then, I rather go with the 280zx because its much bigger. Inputs? 

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Hey miles, does the push rod from the 79-80 280zx booster need to be adjust too, if i decide to put the wilwood master cylinder onto the booster? I remember seeing a post saying that if plan on using a 15/16 280zx master cylinder onto a 280z booster, the push rod will also need to be adjust. If I can put the wilwood master cylinder onto the 280zx booster without adjusting it then, I rather go with the 280zx because its much bigger. Inputs? 

 

 

The stock 280Z pushrod works. Getting the measurement may take some creativity without the right tools (shown in the sticky: http://forums.hybridz.org/topic/102754-a-one-inch-diameter-brake-master-cylinder-for-the-s30-z-cars/). Find yourself a machinist's straightedge, a fine ruler, and Vernier calipers and you'll be golden.  

 

Mine measured pretty close, but not within the 0.3mm recommended. I tried to adjust the rod but it was complete seized. I figured I'd try to bolt it up anyways it performs flawlessly. The pedal is rather firm and threshold braking can be tricky without locking up the wheels, but I attribute that to the oversized m/c with stock disk and drums brakes (and high friction Hawk HP+ pads)

Edited by m1ghtymaxXx
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