Cadmium vs. Zinc Plating

[x77-69z28]

Welcome back Jeff. Very sorry for your loss. My dad is gone 20 years already. He drove every car I ever owned. He was a cop for 40 years and never took a sick day. 2 weeks after working his last he died of a massive heart attack. Sounds like your dad had a wonderful life. The pic of him in his camaro is priceless!

[jeff68]

Thanks everyone for the warm welcome back.  I appreciate it.

When I asked Dad if he wanted to drive the car again, he said "I already drove it 160,000 miles, I think I know what it's like."  Then, he thought about it a little more and got into the driver's seat.  We had made a joint decision to replace the shifter with an old US-made NOS Hurst unit I found, and he wanted to see what it was like.  The car wasn't running.  Left hand on the wheel, right hand on the shifter, he was able to snick it through a couple of gears and said "Wow, that's nice ... maybe I'll try driving it..."  Then he tried pressing the clutch pedal and said "now I remember that clutch ..." and that was that.

[69Z28-RS]

   at 86, if we live that long, I doubt any of us will spend much time looking forward to our next drive and 'power shifting'...

[Dave69x33]

Steve at Brake Boosters just received my original brake booster, proportioning valve bracket, and master cylinder lid for the Zink Dichromate (Gold Iridite) plating, and my original front disc brake back plate spatter shields for Clear Zinc silver plating.  I was impressed that he calls you when he receives your shipment to discuss your parts and to ask you specific questions to verify exactly the work you want done.  He has been in this restoration business for a long time and knows what to look for and how to properly prep your parts before plating.  I was concerned about the prep as I had to sand and polish pits from the front cover of the brake booster and the PV bracket.  He will glass bead blast the polish parts so they do not have an incorrect mirror finish once they are plated.

Steve will sand and polish your pitted parts for an additional labor charge which may be worth it.  If you do not have experience with sanding and polish pits from parts, there is a bit of skilled and proper tools needed to prevent from damaging your original parts.  The process can also be labor intensive.

I'll post pics once I get the parts back.

Jerry MacNeish also does great work restoring these brake system componets.

Dave   

[janobyte]

Back from Brake Boosters, next to go out are the proportioning valve and metering block. Sort of interesting the difference between the R and L stamping. This is what was once under all the black tar and paint. Then hood release , z bar , hinges...

[janobyte]

My booster from CHP:

[sebastien]

looks good, Steve still has my booster. I'm looking forward to see it.

[janobyte]

Reminds me ,need to get a few items out to him next week.

[Sauron327]

The round valve under the MC is a metering/hold off valve, the proportioning valve is located on the subframe. There is then the distribution block. The hold-off valve can be rebuilt by a car owner and it is an easy job. Not sure if a rebuild kit is offered for the proportioning valve yet. This has been on this site before:
https://www.musclecarresearch.com/gm-3905525-rebuild

[68camaroz28]

The round valve under the MC is a metering/hold off valve, the proportioning valve is located on the subframe. There is then the distribution block. The hold-off valve can be rebuilt by a car owner and it is an easy job. Not sure if a rebuild kit is offered for the proportioning valve yet. This has been on this site before:
https://www.musclecarresearch.com/gm-3905525-rebuild

The metering/hold off valves nut is phosphate for a 68 (oh how I found that out LOL) as a reminder and maybe I've missed something but what prompted the coating on the three soft brake line clips as all originals I've looked at including mine were phosphate. Parts looking very nice!

[m22mike]

The round valve under the MC is a metering/hold off valve, the proportioning valve is located on the subframe. There is then the distribution block. The hold-off valve can be rebuilt by a car owner and it is an easy job. Not sure if a rebuild kit is offered for the proportioning valve yet. This has been on this site before:
https://www.musclecarresearch.com/gm-3905525-rebuild

Hard to find, but it is there.

https://www.musclecarresearch.com/2B091-Kit-2
https://www.musclecarresearch.com/valve-rebuild-kh-multi-prop

[janobyte]

Chic, actually spoke with Steve about that nut  in October.

Thought I may have seen some gold on the clips, which were entombed in tar. Honestly ,just my preference.

Hold off/metering sometimes refereed to as proportional valve:

What's called out as the proportional valve on the Drivers' side sub frame is not on my car. Rear brakes fed off a single line which extends into the engine compartment. From what I've read about this part it appeared in 67 , D/c'd on Norwood Camaro's mid 68, then reappeared.

The hold off valve does control/regulate pressure between the two systems allowing fronts to grab before rears ,as it should ( 75% braking in the front I believe was the number) A sort of early attempt at anti lock brakes to paraphrase an article I read awhile back.

Here is probably the reason for the alias. And the system worked....stopping never was an issue with my car.

All that aside ,parts going out to Brakeboosters next week because they look sooo good restored!

[janobyte]

Probably should start a different thread, but will theses different valves work together, and is there a correlation between nut size and sub frame valve? ( I should be mowing my yard)

I never had issues with the rears locking up ,of course I never drove it in the rain or snow ,so can't comment on performance in those conditions.

[Sauron327]

Valves and there purpose have been discussed here ad nauseum. The hold-pff valve does what it's name impies: it stops flow to the calipers until the valve reaches 30-40 PSI. It does not make the front discs operate before the rear drum brakes. Do a search on this site about the valves and all the data can be found.

[janobyte]

Valves and there purpose have been discussed here ad nauseum. The hold-pff valve does what it's name impies: it stops flow to the calipers until the valve reaches 30-40 PSI. It does not make the front discs operate before the rear drum brakes. Do a search on this site about the valves and all the data can be found.

Hey real sorry to set you off..