Topic: 67 9" axle paint

[Bossbill]

I found some obscure paint marking while cleaning up parts of my 67 Shelby 9".
This may well apply to other cars so I thought I'd post some pics.

When Sterling Plant builds the rear axle they, too, use paint marks to help their line workers assemble the rear end.
You've probably seen the paint marks on the end of the axles (seen when the wheels are off) but it appears the color used there is also used in a few other places.

First two pics show an axle that I was cleaning up prior to restoration. It features a identifying paint mark on the end and the same color on the end of the axle going into the differential ring gear case.
Interestingly, the differential ring gear case itself also features the same paint mark.

I believe I also found this color as an "O" on the outside of the main case near the pinion support. I'm unsure about this last one, but it is the only mark on the exterior of the main case that matches, color-wise.

This color coding makes it easy for the line worker to identify all the same color coded items, pull them from the racks by color and install them.

[Bob Gaines]

The yellow mark on the center section was typical for 67 9 inch. It was put on after fill plug was tightened  possibly as a indication that it was tight. Because of the way the center section was in the fixture the yellow paint had a tendency to run off of the plug and down hill leaving a trail.

[Bossbill]

A lot of the pics I've seen of 9 inchers has the yellow paint dripping down, as if the axle is installed in the car with the pinion snout facing forward.
Here (see pic in previous post), the paint has dripped down as if the pinion were pointing straight up.

The outer cast iron housing was painted -- I think dipped -- before any machining was done. The machining removed paint from the mating cap surfaces to name but one surface, but all machined areas show evidence of paint first. The front of the pinion support really shows the machine marks done after paint.

While I was cleaning the outer differential housing I pulled the plug (shown here all cleaned up) out and thought about its finish. The plug could not have been painted red as machining was required for it to be threaded in, so it stays as a zinc plug.
The plug had some sort of sealant on the threads. It looks like red permatex, but I'm not sure.
After the permatex it appears the yellow paint was applied to show an inspector it was filled and/or  torqued.

[J_Speegle]

Focusing just on 67 9" applications.....

A lot of the pics I've seen of 9 inchers has the yellow paint dripping down, as if the axle is installed in the car with the pinion snout facing forward.
Here (see pic in previous post), the paint has dripped down as if the pinion were pointing straight up.

Not sure of where your referring to - depending on year and application there are often many yellow marks in different locations. We often find on later cars (specific applications) a large daub at the top of the case but as mentioned there are often others. Owners/builders will borrow marks so it would be wise IMHO not to trust what you see on restored cars 

Of course its not uncommon to find what appears to just be drips from a brush on the face of the thifd member - just the worker trying to be quick and in turn a bit sloppy

The outer cast iron housing was painted -- I think dipped -- before any machining was done. The machining removed paint from the mating cap surfaces to name but one surface, but all machined areas show evidence of paint first. The front of the pinion support really shows the machine marks done after paint.

Never seen a drip or pooling of the epoxy sealer coat so can't confirm that but yes there was full coverage prior to the machining

I believe I also found this color as an "O" on the outside of the main case near the pinion support. I'm unsure about this last one, but it is the only mark on the exterior of the main case that matches, color-wise.

I have about 30 examples with the white O in the same location as your picture - sometimes it was applied with a much wider brush and in a couple of cases just a roundish blob or daub. This mark likely confirmed an operation or process since it not design to identify a specific worker or inspector like some of the others

The plug had some sort of sealant on the threads. It looks like red permatex, but I'm not sure.
After the permatex it appears the yellow paint was applied to show an inspector it was filled and/or  torqued.

Have found yellowish sealant on the threads I've found through the years

As far as what each mark means (as far as daubs) the yellow daub by the later filler could be to indicate that the rear end was filled, plug tightened or carrier nuts torque or one of a number of things. In general IMHO what is most important is to reproduce what is found truthfully - knowing what they may have been for is secondary

[bullitt68]

A lot of the pics I've seen of 9 inchers has the yellow paint dripping down, as if the axle is installed in the car with the pinion snout facing forward.
Here (see pic in previous post), the paint has dripped down as if the pinion were pointing straight up.

The outer cast iron housing was painted -- I think dipped -- before any machining was done. The machining removed paint from the mating cap surfaces to name but one surface, but all machined areas show evidence of paint first. The front of the pinion support really shows the machine marks done after paint.

While I was cleaning the outer differential housing I pulled the plug (shown here all cleaned up) out and thought about its finish. The plug could not have been painted red as machining was required for it to be threaded in, so it stays as a zinc plug.
The plug had some sort of sealant on the threads. It looks like red permatex, but I'm not sure.
After the permatex it appears the yellow paint was applied to show an inspector it was filled and/or  torqued.

That might explain my previous post where I was asking why my drain plug did not take the phostphate very well. Good to know that the filler plug should be zinc plated instead of phosphated.

[mtinkham]

When do we think the diff oil was added - before or after application of the yellow paint? If before, what orientation was the differential in - snout horizontal or vertical?

I am accustomed to verify a full differential by checking the level in the as-used orientation - snout horizontal.

However, the factory probably metered-in the correct volume of diff oil, so orientation probably didn't matter.

[Bossbill]

I was searching for a linkage on the paint and I'll take it on the chin for the white "O".

[conjecture]
Perhaps Sterling, as a Ford facility, simply used broadcast sheets and the colors on the axle and differential ring gear carrier were on the sheet. That makes more sense.[/conjecture]

With respect to the yellow drip, I was referring to this picture:

The drip pattern here looks as if the pinion nut were facing up, based on the pooling. Other pictures I've seen show the pooling pattern as if the pinion nut were facing the transmission.

[J_Speegle]

Here is another example and maybe a bit more similar to others I have pictures of and have seen. Not that yours should be reproduced any differently that you found and documented it. Guys were just sloppy and focused on getting the job done - and quickly

For those viewing this the plug is not red oxide but just rusty - yes those two can look similar   from the right angle and in a picture

[Bossbill]

Here is another example and maybe a bit more similar to others I have pictures of and have seen. Not that yours should be reproduced any differently that you found and documented it. Guys were just sloppy and focused on getting the job done - and quickly

For those viewing this the plug is not red oxide but just rusty - yes those two can look similar   from the right angle and in a picture

While it's fun to try and figure out how each plant or sub-assembly did their job what I emphasized in Jeff's reply really is the point, isn't it?
Put back what you found if you are certain of its originality.
Don't use paint marks from other cars, plants or years unless you can somehow verify it's appropriate for your car. If you are not sure, don't add the mark!

[Bob Gaines]

While it's fun to try and figure out how each plant or sub-assembly did their job what I emphasized in Jeff's reply really is the point, isn't it?
Put back what you found if you are certain of its originality.
Don't use paint marks from other cars, plants or years unless you can somehow verify it's appropriate for your car. If you are not sure, don't add the mark!

I important note is to document the original paint mark with a picture so that if there is a question about it you have provenience to show why you did it the way you did. That is if you are in concours competition. Of course that documentation needs to be with the car when it is judged . Otherwise just have records so that you can show others.