Jump to content
HybridZ
Elliott000

Late 71 z brake system changes. Installing new lines

Recommended Posts

Hey guys, I'm going to finally spray my engine bay and I'm ready to run new brake lines. I dug out the old junk from the pile and found that this system (I did not strip car) has 2 "switches" in it. Neither of these blocks have wiring so as far as I can tell there is no brake warning for the dash. I'm running all new lines from the MC, and need to decide what to use. Below are pics of the units, the one with no markings was first in line from mc to wheels. I will be installing a proportioning valve on the rear line but do I need to maintain these blocks? I'd prefer to not, I'd Sooner just run a pair of T's for front and rear and call it good. Does the one with the 2 F's do something to the front brakes wheel to wheel? Like a left/right balance.... Thanks guys

20201121_181913.jpg

20201121_181922.jpg

20201121_181941.jpg

Share this post


Link to post
Share on other sites

The unit with the brass electrical bullet connector on top is the brake malfunction warning switch....it's intended to detect an imbalance in pressure between the front and rear systems.  Someone must have removed the wire lead at some point.

 

The other unit is the OEM distribution block/proportioning valve.  If you're planning to install an aftermarket rear proportioning valve, you can either remove the OEM unit or gut it.  Since you're already planning to run new lines from the MC, may be best to just remove it....it will clean up the engine compartment and reduce the total potential points of failure/leaks.

 

If you decide to remove either (or both) of these; don't throw them out -- keep them and put them up for sale.  Folks are always looking for these for restoration projects, particularly on forums like ClassicZCars.com and "S30 Life" on FB.

Share this post


Link to post
Share on other sites

The one on the right is a proportioning valve which, according to Motorsport is first found on 73s and which is normally located on the fire wall. The proportioning valve for a 71 is located in the back by the differential.  On your 71 you should find the valve in the back connected to the T that splits the left and right brakes by an S shaped hardline.

Share this post


Link to post
Share on other sites

I used a 3-way splitter, too...similar to @Miles.  Crazy thing though -- I had a hard time finding one with deep enough threaded female ports...eventually found a supplier on eBay (from Latvia!) that had the one I needed.  Looks like they're still available if you can't source one locally.

 

https://www.ebay.com/i/264460358871?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=264460358871&targetid=934793862176&device=c&mktype=pla&googleloc=9008565&poi=&campaignid=10460107080&mkgroupid=106723174707&rlsatarget=pla-934793862176&abcId=2146001&merchantid=113613716&gclid=CjwKCAiA-_L9BRBQEiwA-bm5fsnFoomhpGU_ZHHRbK5CmpL-LxTRPXGb-dFDufeT6EE0ghXgev3c3xoCErwQAvD_BwE

 

WRT to your question regarding disc brakes on all 4 corners, you may need a larger bore MC (swapping reservoirs on your current 7/8 MC won't do anything.)  Depending on which disc setup you choose for the rear (and also if you're considering swapping in larger front disc setup), you typically will need to upgrade the MC to 15/16 or 1".  LOTS of good reading in the FAQs on this exact topic.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...