Author Topic: 1970 9" rear axle housing yellow paint  (Read 331 times)

Offline 1970 Snake

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1970 9" rear axle housing yellow paint
« on: December 03, 2017, 11:46:31 PM »
So I am a bit confused, as I have see several people say the yellow paint marking on the rear axle housing flange of a 1970 mustang is on the drivers side, and have seen a resent magazine article where Bob Perkins has detail a 1970 Boss 429 rear axle and he has put the yellow paint on the driver side. But when stripping the dirt and rust off my axle housing the yellow paint is definitely on the passenger side flange and area. Would like comments on this as I am going to apply the yellow paint to the passenger side as original to my car axle and want to make sure this is also correct.
« Last Edit: December 06, 2017, 03:09:20 PM by J_Speegle »

Offline J_Speegle

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Re: 1970 rear axle housing yellow paint
« Reply #1 on: December 04, 2017, 02:24:32 AM »
Have original examples of that yellow mark on either end of the rear end housing during 69-70 production side apparently it does not indicate direction of installation but something else. In any case document and reproduce what you find IMHO
Jeff Speegle

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Offline specialed

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Re: 1970 rear axle housing yellow paint
« Reply #2 on: December 04, 2017, 10:03:32 AM »
we have a original car in shop now with the yellow on passenger side & seen many that way.

Offline bgp429

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Re: 1970 rear axle housing yellow paint
« Reply #3 on: December 04, 2017, 11:06:11 AM »
So I am a bit confused, as I have see several people say the yellow paint marking on the rear axle housing flange of a 1970 mustang is on the drivers side, and have seen a resent magazine article where Bob Perkins has detail a 1970 Boss 429 rear axle and he has put the yellow paint on the driver side. But when stripping the dirt and rust off my axle housing the yellow paint is definitely on the passenger side flange and area. Would like comments on this as I am going to apply the yellow paint to the passenger side as original to my car axle and want to make sure this is also correct.

Do you know where you saw the article? I need to restore a B9 rear end next summer. Thanks

Offline J_Speegle

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Re: 1970 rear axle housing yellow paint
« Reply #4 on: December 04, 2017, 02:56:55 PM »
Do you know where you saw the article? I need to restore a B9 rear end next summer. Thanks

Did your car not have any marks on it when you disassembled?  The subject discussed here is a prefect example of why you don't want to copy someone elses marks since they are not always/often the same. Your rear end was likely more similar to another 9" non Boss 429 built around the same time than a random Boss 429 rear end that you don't know anything about.

Plus no telling what more we may uncover or learn in the next six months ;)

Jeff Speegle

Anything worth doing is worth doing concours ;)

Offline bgp429

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Re: 1970 rear axle housing yellow paint
« Reply #5 on: December 04, 2017, 05:01:56 PM »
Not going to randomly copy another diff. Mine has been bead blasted many years ago so all marks are gone. I think the rear end is one of the only drive train parts that might be similar to a regular production HP car.

Offline J_Speegle

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Re: 1970 rear axle housing yellow paint
« Reply #6 on: December 04, 2017, 05:18:45 PM »
On transmissions (any top loader from the same period) as well as rear ends you can find and identify some basic patterns and details that seem to be repeated over and over again that IMHO are normally "safe" or reliable to reproduce once all the more important details are addressed. Things like font style, general location, some colors and inspector/assemblers markings for example.  Same workers and plants assembled these for tens of thousands of cars or more.  May be able to help as you approach these sorts of tasks
Jeff Speegle

Anything worth doing is worth doing concours ;)

Offline bgp429

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Re: 1970 rear axle housing yellow paint
« Reply #7 on: December 04, 2017, 11:04:06 PM »
Appreciate the help. Next year when I start on it will post the request.

Offline Armond

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Re: 1970 rear axle housing yellow paint
« Reply #8 on: December 05, 2017, 01:13:46 AM »
I believe it indicated a 31 spline housing and what side the yellow was applied,  was determined on what end the housing was standing on. That is what I have always believed.
MCA#31064
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Offline J_Speegle

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Re: 1970 rear axle housing yellow paint
« Reply #9 on: December 05, 2017, 02:49:17 PM »
Here are a couple of examples. Most of them I've seen or found appear to have been applied when the rearend was level (as installed) or on end with the paint applied to the end on the down side. But then there are examples where it appears the were applied on the top end of the housing while standing/held with the other end downward. Or could just be the results of using or or less paint on the brush when it was applied. 





Jeff Speegle

Anything worth doing is worth doing concours ;)

Offline specialed

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Re: 1970 rear axle housing yellow paint
« Reply #10 on: December 06, 2017, 11:48:35 AM »
The 69 Dearborn gt500 Shelby  we had in shop last month was exactly like jeffs last pic with the yellow runs on the rh side & it was june built.

Offline 1970 Snake

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Re: 1970 9" rear axle housing yellow paint
« Reply #11 on: December 08, 2017, 11:29:52 PM »
Lots of great comments guys thanks, Jeff, I will proceed with yellow painting the passenger side as planned. I can't really tell the extent of the yellow paint as the original housing was quit rusty, so think I should paint with the housing standing on that end and do some of the flange and about 1.5" of the housing tube, much like Bob did on the Boss 429 housing.

Offline J_Speegle

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Re: 1970 9" rear axle housing yellow paint
« Reply #12 on: December 08, 2017, 11:45:51 PM »
Lots of great comments guys thanks, Jeff, I will proceed with yellow painting the passenger side as planned. I can't really tell the extent of the yellow paint as the original housing was quit rusty, so think I should paint with the housing standing on that end and do some of the flange and about 1.5" of the housing tube, much like Bob did on the Boss 429 housing.

Your call since you'll be answering any questions about the mark if asked and you'll need to provide what you found and why you choose what you did.

The tread has provided you with a number of options - but basically fairly similar to one another not familiar with the article you mentioned hopefully its a fairly recent one
Jeff Speegle

Anything worth doing is worth doing concours ;)

Offline 1970 Snake

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Re: 1970 9" rear axle housing yellow paint
« Reply #13 on: December 12, 2017, 02:37:16 AM »
I found the article googling, its a Mustang Monthly/Mustang 360 article not sure of the date,  title was "Detailing and Restoring the Mustang 9-inch Rear Axle", its and excellent article for details on restoring a 69/70 9". Regarding my painting the PS flange yellow, you can see it on the picture I attached when I started this thread, that's my axle and its definitely yellow on the PS and is why I am going forward with that. Another question I have is if the PS has the yellow flange would the paper axle tag also go on that side under the inner U bolt or would it still be on the DS of the axle?