Risks with purchasing 9inch off ebay and other questions

[SadbutTrue]

I've seen a lot of 57-59 9 inch rears on ebay, and being that I believe these are the only ones that bolt right into my car outside 65-66 K code rears (I believe these rears share dimensions with my rear, being 43 inch perch distance, 57.5 inch flange distance, and 52.5 backing plate distance... please correct me if I'm wrong here). Being that I need one, I was wondering...

I am wondering if there any risks that I should be aware of if I buy one of these rears... they usually look pretty beat, I wonder if there might be any ways in which they are simply "worn out," or if thats not a big concern with cases. Will any 28 spline third member fit into any 9 inch case and be able to use any 28 spline (8 inch or 9 inch) axles? I really don't want any compatibility problems. Anything else I should look out for? Thanks

 

[SandSprite]

The granada rear is supposed be close as well.

Any 9" pumkin will work.

If you get a big bearing rear, I don't think you can use the medium bearing axles. Pretty sure the inner race is a different size. The wagons and rancheros had the big bearings in '57-'59.

 

[Edbert]

No reason to look at big-bearing housings unless you want to run 31 or 35 spline axles.

28 spline axles are interchangeable between 8 and 9 inch diffs as long as their lenght is the same.

Buying off ebay is okay as long as the seller has a 95+% positive rate, in MY opinion, YMMV.

Be prepared (emotionaly and financially) to go completely through any used components you buy unelss they are sold as new.

All 9" diffs will bolt up to all 9" housings but check to make sure one of them has a drain plug.

Not all cast iron diff housings are the same, some are VERY strong others not so much.


...thats about it for now...unless you wanna get into the internals...

 

[Max Power]

I hear for strength that the W case from that era should be avoided. Something to do with nickel content in the metal. Also, the early models had the fill/drain plugs in the housing, the later models had the plugs in the carrier, so when mixing and matching, make sure you have a fill plug in one or the other. Nothing sadder than watching somebody spend hours on their diff only to find they can't fill it once assembled. Watching somebody fill their diff through an axle tube is a sorry sight indeed!

 

[vrooom]

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