Flaking Paint Inside Differential

[JoeCA]

I am working on the restoration of my 1960 BT7 and started on the rear axle yesterday. The rear axle has three main problems - a leaking seal on the left side, a leak on the carrier:housing gasket and a pinion seal leak.

Anyway, I removed the carrier and found that the inside of the differential is painted. I have never seen this before on a differential. For the most part, the paint appears solid, but was peeling in a few spots. I cleaned up the loose spots of paint, but I wonder what others have done with confronting this issue.

The rear axle has a lot of areas that appear difficult to clean. It seems to me that stripping off all the paint has a potential to deposit more contaminants in the differential than just cleaning up the loose spots and letting it be.

Interested in your opinion/experiences.

Thanks...Joe

 

[vette]

Joe, I agree with you that it does seem disconcerting. Having said that I think that unless there were large quantities of the stuff coming off that it probably wouldn't hurt anything. Again having said that and since I am so anal about everything I would remove ALL of it. I would use a paint remover, scrape and use small picks and scrapping tools to remove every bit of it that I could in all the crevices, etc. I would not use any sand paper for fear of the grit not getting completely cleaned out. Anything can be cleaned with enough attention. Just set your mind to it and get it done. Then clean and slush with copious amounts of soap and water then spray with something like WD 40 to preserve from rust till you are ready to assemble. Good Luck.

 

[roscoe]

I can't imagine anyone using unsuitable paint to coat the inside of any type of gearbox. There is another possibility and that is Glyptal coating. Glyptal is most commonly red but it is available in black. Using it properly relies, as all painting does, on meticulous preparation and I have seen it flake for lack of that. It does fill the pores of castings and supposedly allows oil to circulate better. Even with that being assumed to be true, I am not an enthusiastic promoter. I doubt oil circulation is much of an issue for our pumpkins or if Glyptal coating is called out fot them.

 

[John Turney]

I've recently had my 62-yo rear axle open, and it had some paint inside it. Looks original. I would leave it alone. There are too many blind spots in the casing to do a complete cleaning, and paint is soft compared with steel.

 

[Michael Oritt]

I would vote for getting the paint and peelings out of the axle tube. If you are at the point where the third member is out of the housing it should not be difficult to apply strippers to remove the paint and to flush the axle tube well both from the center and the ends. The interior of the center section and axle tube is essentially a sealed environment (despite the breather valve) and I cannot envision a situation where the interior is going to corrode/rust unless the car is submerged, in which case you have bigger and more substantial issues.

 

[JoeCA]

Thank you for your input.

John, I agree...this paint (glyptal?) looks original. It's really only painted in the carrier housing (pumpkin) section as far as I can tell.

From an access point of view, the carrier housing section is accessible...it's actually the axle tubes that are not...and that is what I am afraid of contaminating and not being able to properly clean. I have no plans to repaint this area.

I will think on it a bit before proceeding. I've found when I run into road blocks, it is best to mull over the solutions space for a bit. There are plenty of things to work on.

I appreciate the replies.

Joe

 

[dancrim]

The reason for this "paint", most likely Glyptal is to keep the lubricant from weeping through the
iron pumpkin. It is used on extensively on aluminum blocks to keep the outside free from oil
and the dirt that collects on it. This is why you see "pumpkins " covered with sludge.
Not a real bad thing, as it preserves the outside.