Topic: Parking brake parts - 65

[J_Speegle]

This subject has come up a number of times. My personal hands-on experience has been mostly (for 65) with San Jose cars and I've never found the rod or the equalizer in a dichromate finish. Now with that said most that I come in contact with are fairly dirty or oily. And I think we can all agree that the dichromate part of Zinc dichromate is a weak finish that does not hold up well over time. With that said if they were originally zinc dichrommate we would expect to at least see the remains of the zinc coating since this holds up much better over time

I have always done them as bare steel since that is what I've seen or concluded based on what I saw when cleaning them.












Given the pictures from 65 San Jose cars about I would think the best we could to is compare other parts in those pictures where we agree the finishes are than compare those to the parts in question.





I have seen Mikes examples and have additional pictures of 65 Dearborn that appear to be zinc dichromate

Not sure if this may be a different supplier detail or something else at this point in time - but that is why there is a discusion

[CharlesTurner]

Wish I would have taken pics of the ones I removed from the San Jose cars I've disassembled/restored.  Once I started seeing gold on the equalizer bracket and threaded shaft back years ago, it was something I thought was common knowledge.

The gold plating is relatively thin on these parts, so it is going to be hard to see.  On the threaded shafts, there have been ones where the only place I found gold was on the threads where the locking nut was.

[J_Speegle]

Wish I would have taken pics of the ones I removed from the San Jose cars I've disassembled/restored.  Once I started seeing gold on the equalizer bracket and threaded shaft back years ago, it was something I thought was common knowledge.

Have had the same experience (seeing something that I thought was commonly accepted) a number of times in discussions.  Good thing IMHO is if it is something that is common we should be able to come up with examples since we will likely be on the look out following this discussion

BTW I believe the picture of just the equalizer above that I posted is from one of your SJ cars

In any case just part of the process and working together we should be able to come up with some facts/findings

[Bob Gaines]

Wish I would have taken pics of the ones I removed from the San Jose cars I've disassembled/restored.  Once I started seeing gold on the equalizer bracket and threaded shaft back years ago, it was something I thought was common knowledge.

The gold plating is relatively thin on these parts, so it is going to be hard to see.  On the threaded shafts, there have been ones where the only place I found gold was on the threads where the locking nut was.

As you have said the zinc yellow/gold chromate is thin however the zinc silver plating underneath is typically thicker. As you know the part has to have a zinc plating so that the the zinc yellow/gold chromate has something to stick to. The gold may disappear and wear off quickly the silver underneath not so much. It will but it takes much longer. The absence of any evidence of the zinc silver on the parts I have observed in even the hidden places is what helps me formulate my opinion of bare metal on the SJ parts I have studied. For instance still zinc silver on adjusting nut but no plating on the threaded rod.The zinc gold adds a longer corrosion resistance (salt spray rating). Logically the zinc plating on the nut would wear off before all evidence on the threaded rod with both zinc gold and zinc silver plating would wear off (your example).  Just explaining the reason for my SJ part finish opinion .     

[CharlesTurner]

BTW I believe the picture of just the equalizer above that I posted is from one of your SJ cars

Yes, I recognized it, but not a good reference of what I was seeing.  I was so confident I had seen it across all the plants that I stopped looking and automatically put the parts in the zinc dichromate pile for re-plating.

As for the zinc plating underneath, it just depends what environment/conditions the parts are exposed to.  Usually if the gold is gone, the zinc base has started to break down also.

[ChrisV289]

I don't know if these help or not. This is on an Oct 64 SJ car.  Did the best I could right now to clean up the area but the car isn't jacked up and it is a little toasty in the garage.

[J_Speegle]

I don't know if these help or not. This is on an Oct 64 SJ car.  Did the best I could right now to clean up the area but the car isn't jacked up and it is a little toasty in the garage.

In your pictures - without a good wipe down the threaded shaft, adjusting nut and equalizer all appear to have the same look

[CharlesTurner]

Mineral spirits with a soft brush would be best to clean with as it normally won't remove any plating.

From your pics, the equalizer bracket shows signs of dichromate plating.

[ChrisV289]

So was able to wipe down this part and there appears to be yellow on this piece. Not a lot left though.

[ChrisV289]

Cleaned this piece up. In certain angles I can see like a rainbow finish so to speak but it is very faint. I don't think it was ever zinc dichromate based on what I can see

[MustangAndFairlane1867]

Thank you for those pictures.  Nice piece.  I found one with a similar finish and it's now on the car.  Thanks again!

[J_Speegle]

Cleaned this piece up. In certain angles I can see like a rainbow finish so to speak but it is very faint...........

The rainbow effect would be characteristic of zinc dichromate. Though as mentioned the dichromate part of the finish holds up poorly over time, gets thin or goes way completely with time and exposure

Think you may have confirmed what the finish after 50 years is not fully showing

[Bob Gaines]

 I have always seen those parts plated as a service part. Many service parts were plated or painted so they would not rust on the shelf and not look bad when sold to a customer. The same part on the assemblyline may or may not be plated or painted depending on the part. With that said I have found the majority of brake parts being discussed on otherwise unmolested cars as bare steel.  This is not to say some of the assemblyline parts could not be plated but at the very least some of the pieces were of the bare steel variety because of my observations .