A tale of two Z's - NA vs Turbo

[calZ]

I don't think I've ever seen a billet, CNC-machined backplate before. That's show car stuff

[MONZTER]

Finally finished both L&R of the new rear Backing plates for the NA car.  These are adapters that allow me to use a Z31 parking brake system and z31 rotor with Z32 aluminum 2 piston calipers and bolt it all on to a stock 240z strut.  Yep it all works.  For fun I took some pics of the machining steps to show what it took to make them from billet and finish them up.

 

This is the first operation that mills the side to mount all the parking brake shoes and hardware.  Comes out of a 8"x8.5"x2" thick piece of billet.

 

 

Some detail of the surface machining and stepover of the cutting tool to make for a smooth finish

 

 

After the first operation is complete the part needs to be flipped and held to machine the backside.  I made a simple fixture plate that held the part by registered with 3 mounting holes and a single center screw to hold it down.  This is the fixture plate.

 

 

And this is the part after the first OP held tot he fixture plate ready to machine the second OP

 

 

This is the part after the second aoperation is complete.  About 2 hours of run time.  You could go faster, but I wanted small step-over lines so it would not need any hand finishing

 

 

After washing it and prepping it for a Alodine finish, here is the part as machined

 

 

Final finish is a 5 second dip in the Alodine which gives it a goldish iridescent finish, then I sprayed it with a clear Cerakote to keep it looking good and easy cleaning

 

And this is the final part.  Next need to make a few small parts and the parking brake cable

 

 

 

 

 

[jhm]

That's some beautiful jewelry!!!  Really impressive work there.  👍👍

[MONZTER]

Here are some final assembly pics of the NA car Rear brakes.

 

I had to take the OEM Z31 backing plate and cut the spot rivets holding this parking brake cable guide on.  I then had to shorten it and weld on a new front mounting point.  I ground the welds all nice so it looked OEM and then replated it in Yellow Zink.  In the second picture you can see where I press fit in some stainless steel rivots, just sitting proud of the surface.  This is where the "feet" on the parking brake shoes hit, and a little dab of grease should keep them smooth and quiet without worry of wear on the aliminum

 

 

 

I next had to make a custom boss that will screw in to the new backing plate.  This is the pivot and load point for the parking brake shoes.  So I turned it out of 4140 steel, Yellow Zink plated it and threaded it into the backing plate with Red Loctite.

 

 

Then I could re-assemble the stub axle and companion flange.  These parts came out nice with a Zink plating on all the mating surfaces and powder-coating everywhere else.  They should stay nice for a while.

 

 

 

You can see the mounting bolts for the new backing pates.

 

 

This is what the caliper looks like mounted with the Z-31 rotor

 

 

Installed the parking brake shoes, springs, adjusters, ect.  All fit up just like OEM

 

 

 

Some final shots of the plates all assembled.  I think  they came out looking cool, kinda morphing from the struts hub shape to the mounting ears of the calipers.  The look will be very clean IMO

 

 

 

Edited September 28, 2023 by MONZTER

[MONZTER]

Been busy working on the body of the NA car.  Overall in really good original paint condition.  But of course the common areas still need to be replaces even in a low mile California car.  So I got busy cutting and welding.

 

The KF parts are really nice but I only want to replace as much metal as trulely needed, so instead of just replacing the entire part, I grafted in what I need to keep it as original as possible.  Here are some pics of the first dogleg

 

What is hiding inside you ask

 

 

Surprise

 

 

cut it all out

 

 

start fitting  rebuilding from the inside out as how it was originally done

 

 

 

 

 

 

 

Blast it all clean and start TIG welding

 

 

 

 

 

Edited April 18 by MONZTER

[MONZTER]

I dont want any filler, so I fit each part perfectly with a butt joint, dolly it out where possible, then grind it flat and smooth for an original fit.  before any welding I prime all parts on the back side and pinch points with weld-thru primer

 

the arc and inner rocker are new in this picture

 

 

then the rear of the rocker, putting back the spot welds in the OEM position

 

 

Some more primer to look super clean and blend in tot he original rocker which was perfect everywhere else

 

 

 

Finally fit the outer skin and tig it in small steps so no warping

 

 

Some more smoothing of the welds and original spotweld locations used

 

 

 

Just a small skim coat of filler on the upper weld seem, but making sure to leave all the factory spot welds to show through the paint.

 

Other side is the same, so on to the front fender next