Parking Brake Assembly - Flange Nut Finish

[Edgemontvillage]

I'll be re-installing the parking brake assembly on my 69 RS/Z project soon and in preparation was reviewing pre-tear down photos of the (2) flange nuts where they attach the assembly to the firewall, to confirm their finish. I thought the finish was manganese (dark) phosphate, consistent with the flange nuts used to attach the brake booster to the firewall, however from the photo below it appears the finish is instead gold dichromate / gold zinc. Can anyone confirm this?

[x66 714]

In Aug of 1969, they were phosphate but not dark. Kind of medium. Just cleaned mine. Almost at that point. Big wad of black goop on the bracket where it goes up to the inside of the firewall...Joe

[Edgemontvillage]

In Aug of 1969, they were phosphate but not dark. Kind of medium. Just cleaned mine. Almost at that point. Big wad of black goop on the bracket where it goes up to the inside of the firewall...Joe

Thanks for posting Joe, my Z is a February (Norwood) build so could be different.

[william]

Nut is p/n 1359887.

Also used to secure the hood bumper studs, front console mounting bracket, RS lower actuator bracket. Has several exhaust system applications. Probably furnished in several finishes.

[Edgemontvillage]

Nut is p/n 1359887.

Also used to secure the hood bumper studs, front console mounting bracket, RS lower actuator bracket. Has several exhaust system applications. Probably furnished in several finishes.

Thanks William.

[68camaroz28]

Nut is p/n 1359887.

Also used to secure the hood bumper studs, front console mounting bracket, RS lower actuator bracket. Has several exhaust system applications. Probably furnished in several finishes.

William, wouldn’t the part number print dictate finish requirements? That part number application seemed to be phosphate mostly Lloyd but can surely understand the question from the pic supplied.

[william]

In those, days it usually did. Not unusual to see more than one approved finish on an Engineering drawing. There is often more than one supplier; some have in-house capabilities. 

Finishes can be difficult to manage. When I worked in automotive supply chain, I had an assembly that consisted of two parts from different suppliers. Each was powder coated in satin black, made it through PPAP. When assembled, they didn't match. Chrome parts can surprise you; don't always match either.

[Edgemontvillage]

In those, days it usually did. Not unusual to see more than one approved finish on an Engineering drawing. There is often more than one supplier; some have in-house capabilities. 

Finishes can be difficult to manage. When I worked in automotive supply chain, I had an assembly that consisted of two parts from different suppliers. Each was powder coated in satin black, made it through PPAP. When assembled, they didn't match. Chrome parts can surprise you; don't always match either.

As so many fasteners on our cars are subject to points judging (Bowtie / Legends) and will attract a deduction if deemed "incorrect" as to finish or plating, I'm looking for feedback if gold dichromate / gold zinc is a typical finish or non-standard for this flange nut. I've not seen this fastener in other than manganese phosphate for the parking brake assembly.   

[william]

I have dismantled many '69s in my days and never saw 1359887 in anything other than phosphate. But your car was obviously built that way. I had the twin to your car, about 50 VINs later, and it had phosphate. They should place more emphasis on fasteners being physically correct since plating can vary, even from the same supplier.

Don't get me started on judging. Heard plenty of complaints. No one knows it all.

[69Z28-RS]

There are such varied anti-oxidation coatings/treatments used in the various fasteners on our early Camaros, it makes me wonder if GM had a simple anti-oxidation specification for their fasteners which allowed suppliers some options as to which to use.   Does anyone have any factual information in this regards?   If so, then that would explain why various anti-ox coatings are found on fasteners, even specific fasteners which were procured from multiple suppliers...

[william]

It is typically hours of salt fog/spray. In my experience, Engineering drawings will reference a company spec. The supplier will select a finish that meets the requirements. Very few automotive fasteners will also have an appearance requirement but my stuff did. Chrome and stainless went from 90 hours of spray to around 120. Resulted in some very expensive fasteners that few companies offer.

[68camaroz28]

In those, days it usually did. Not unusual to see more than one approved finish on an Engineering drawing. There is often more than one supplier; some have in-house capabilities. 

Finishes can be difficult to manage. When I worked in automotive supply chain, I had an assembly that consisted of two parts from different suppliers. Each was powder coated in satin black, made it through PPAP. When assembled, they didn't match. Chrome parts can surprise you; don't always match either.

As so many fasteners on our cars are subject to points judging (Bowtie / Legends) and will attract a deduction if deemed "incorrect" as to finish or plating, I'm looking for feedback if gold dichromate / gold zinc is a typical finish or non-standard for this flange nut. I've not seen this fastener in other than manganese phosphate for the parking brake assembly.   

Lioyd, here is an example, William noted where that part number fastener is used on hood bumper studs. I tend to believe those fasteners are phosphate and not the black looking manganese phosphate. I have that on our 68 and it received no demerits in 5000 point legend judging but either could be considered ok. Your point is well directed as the couple places where mine was somewhat different in fastener use and kept what I found, it got dinged. Lol

[x66 714]

Mine cleaned up perfectly. No refinishing required. I will see if I can take a good picture....Joe

[Mike S]

It is typically hours of salt fog/spray. In my experience, Engineering drawings will reference a company spec. The supplier will select a finish that meets the requirements. Very few automotive fasteners will also have an appearance requirement but my stuff did. Chrome and stainless went from 90 hours of spray to around 120. Resulted in some very expensive fasteners that few companies offer.

   Regarding the phosphate hardware, was the salt spray test done with our without the oil bath applied? One of the advantages of using a low cost phosphate application is the surface made an excellent base for an oil preservative. 

Mike

[KurtS]

I've looked at my original prints. They normally call out a plating, but often have an optional. Prints do not call out a corrosion spec - that's the job of the engineer, not the supplier.

[Edgemontvillage]

Lloyd, here is an example, William noted where that part number fastener is used on hood bumper studs. I tend to believe those fasteners are phosphate and not the black looking manganese phosphate. I have that on our 68 and it received no demerits in 5000 point legend judging but either could be considered ok. Your point is well directed as the couple places where mine was somewhat different in fastener use and kept what I found, it got dinged. Lol

Thanks for your thoughts on the subject Chick, I assume you mean zinc phosphate rather than manganese. Of interest, some of the fasteners I've restored including these in manganese phosphate come out closer to medium gray resembling zinc rather than manganese. Must be the alloy that is influencing the finish color. There have been a few small exceptions I've made in the process of my restoration where I've observed an original part that I'm convinced was factory installed such as these flange bolts, however when the finish or part isn't typical or normative I'm inclined to restore it to the accepted standard to avoid a challenge or deduction. Better safe. 

[68camaroz28]

Lloyd, here is an example, William noted where that part number fastener is used on hood bumper studs. I tend to believe those fasteners are phosphate and not the black looking manganese phosphate. I have that on our 68 and it received no demerits in 5000 point legend judging but either could be considered ok. Your point is well directed as the couple places where mine was somewhat different in fastener use and kept what I found, it got dinged. Lol

Thanks for your thoughts on the subject Chick, I assume you mean zinc phosphate rather than manganese. Of interest, some of the fasteners I've restored including these in manganese phosphate come out closer to medium gray resembling zinc rather than manganese. Must be the alloy that is influencing the finish color. There have been a few small exceptions I've made in the process of my restoration where I've observed an original part that I'm convinced was factory installed such as these flange bolts, however when the finish or part isn't typical or normative I'm inclined to restore it to the accepted standard to avoid a challenge or deduction. Better safe. 

Lloyd, I use two, the one dark manganese (very dark in color) and other is called gray phosphate which gives me that nice gray appearance found on many including what we are discussing. Do agree material and amount of time left in bath helps dictate the color.

[Edgemontvillage]

I was referencing the Palmetto brand whose phosphating solutions I use. They refer to their solutions as zinc (light-medium gray) and manganese (dark gray-charcoal) to distinguish them by gray scale. If you use a different brand they would likely use different names however to my knowledge there are only two types available.

[68camaroz28]

I was referencing the Palmetto brand whose phosphating solutions I use. They refer to their solutions as zinc (light-medium gray) and manganese (dark gray-charcoal) to distinguish them by gray scale. If you use a different brand they would likely use different names however to my knowledge there are only two types available.

Lol yes that is what I use, And was just calling it gray phosphate.

[169INDY]

^^^ That is the Good stuff!

[KurtS]

How fast do you use the solution? Would a pint last for a bunch of fasteners or is a quart a better amount?

[69Z28-RS]

I bought a quart of their light gray solution several years ago.  I've done at least 2 or 3 large batches of fasteners during that time and I still have nearly a half quart left.

[Edgemontvillage]

How fast do you use the solution? Would a pint last for a bunch of fasteners or is a quart a better amount?

Kurt, if you follow directions closely ensuring parts are well prepped, very clean and oil free, and don't allow the solution to overheat (boiling is the kiss of death) a few uses (heat cycles) are possible before the solution is depleted so you can get plenty (many hundreds) of fasteners treated with a quart of concentrate. I've found the solution's shelf life is about 18-24 months before it breaks down (solids appear) and it loses effectiveness. Others' experience likely varies.   

[68camaroz28]

How fast do you use the solution? Would a pint last for a bunch of fasteners or is a quart a better amount?

Lloyd hit the mark well Kurt and I was able to do all my original 68 screws, bolts and nuts with a quart of each and had some left over. You mix solution with distilled water and it can be used several times. I use a hot plate as it naturally keeps solution in the 180 to 200 degree desired range. Keys are glass beading parts just prior to phosphate process and then cleaning off after phosphate bath. Palmetto advises using WD-40 but I found dipping parts in mystery oil and lightly brushing with soft brush worked well. Search and several good threads have discussed process in detail.

[69Z28-RS]

I haven't seen any 'solids appearing' or breakdown in the phosphate solution when still unused in the original bottle (probably 7 or 8 yrs since purchased). 

I don't recall the dilution % specified off hand, but you add a certain amount to a larger amount of hot water (200 F) to use it.   Only rarely have I needed to 'reheat' an already used solution for later use, so I suppose when Lloyd talks about 'breakdown' that's what he's referring to.   I only mix up what I need for the prepared parts I have and after treating them I generally dispose of the used solution.

I have a gallon of WD 40 that I use to clean/seal the phosphate after phosphating; I do reuse the WD 40 bath I use, replenishing when necessary.

PS.  I purchased a 'set' of stainless steel 'pots' from Walmart fairly inexpensively, so I use the 'best' size pot for the amount of parts I'm doing.  I also use an inexpensive 1 burner hot plate for heating the water/solution.