Brake Proportioning Valve

[CDL1542]

My 240z has hard brake lines connected to the stock brake proportioning valve below the master cylinder. There is fluid seeping from around these hard lines even though the nuts on the proportioning valve are cranked down tight. I'm going to be upgrading my master cylinder to install 4 piston calipers which I've had on hand for a while and can not seem to find somewhere to purchase a new proportioning valve (which I believe is the issue). Thank you for your help and any comments or thoughts would be greatly appreciated!

[Kurbycar32]

I'd bet that if you disassemble, clean and reassemble that valve seals up nice and tight.  Don't forget to clean up the threads on both sides of the connection.

[EuroDat]

I dismantled mine and tried to find replacement cup, but had no luck finding any. Did find the o-ring seals. In the end I cleaned all the parts in the proportioning valve and the brake switch, changed the o-rings and reasembled them.

Here is a link to the thread with photos. I also did the brake switch and they are both still leak free.

http://www.classiczcars.com/topic/45461-parts-for-oem-np-valve-and-brake-indicator-switch-unit/

Chas

[Mike W]

Are you just changing the fronts to 4 caliper pistons or are you also going discs in the rear as well?  If you are planning for discs in the rear you will have to find an alternative to the stock proportioning valve and use one that will give you some adjustability so you can get the front / rear bias correct.  I just got done doing this and came up with a pretty clever way to add a small adjustable proportioning valve in pretty much the same location as the OEM one.

 

If you are not planning on discs for the rear you can likely get away with the fixed stock valve.  If you need a replacement for yours, I do not believe they are available any longer, but I have a used one that I will not likely have use for any longer and could work something out with you.

 

Let me know.

 

Mike.

[Zed Head]

It's usually the hard lines that need replacing.  They work-harden when compressed and don't take the proper set on later re-assemblies.  They can even crack.  The seat in the valve just needs to be smooth and gouge-free.  You could probably get straight lines at the local parts store and bend them to fit.