Wilwood Proportion Valves are meant to be used on cars that have aftermarket brake systems. When you change your brakes the stock brake proportion valve is no longer useful since it was meant to bring the stock brake system into the correct bias. After you install aftermarket brakes your bias is not equal anymore. This proportion valve is meant to bring that bias back to a safe range. Installing this item is not hard, everything is completely bolt on. You do need to get two adapters so this unit can fit into your stock metric brake lines. Once this unit is installed you will have the power to change your brake bias to your specifications. I recommend this unit for anyone who has upgraded their brakes. Depending on what type of brakes you have your car might not be safe to drive since the front brakes might lock up way before the rear does or vise versa. This unit will fix that problem, and make your car much safer to drive. Install this adjustable proportion valve on the line that you want to reduce pressure to.
Ideal bias is when the front brakes lock up just before the rear brakes. If you installed brake upgrades and your rear was locking up before the front, install the adjustable valve on the rear. Then turn it down until the bias is perfect.
Metric to standard fittings: Nissan uses M10 x 1 thread with double flare inverted flare on brake components. These Wilwood proportion valves come in M 10 by 1.0 bubble flare size. You will need to buy our custom hard lines that have an inverted flare on one side and bubble flare on the other side to install the valve. You will also need one double female fitting to connect our custom Hardline to your original Hardline . If you would like 2 hardlines select to buy them when you place your order. See the drawing to see our recommended installation procedure for the adjustable valve. Every S30 Z car came with a self centering pressure differential switch that turns the brake warning light on. It is located on the frame rail . It does not change brake pressure so You do not need to uninstall it unless you want to. After the master cylinder and pressure differential switch you have a stock proportion valve. You will need to cancel this proportion valve out and install the adjustable prop valve in it's place. 1969-1973 240z's have the stock prop valve located over the rear differential. 1973.5-1978 280z's have the stock prop valve in the engine bay mounted on the fire wall near the brake booster. first picture of install is in a 240z, second picture is for 280z. you can install it a few different ways.
BMW E30 owners: You do not need the hardlines or double femail fittings to install this prop valve. It will bolt directly to your stock hardlines where your stock OEM prop valve is located.
Watch this how to install video for a 240Z.
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