A friend has a type "O" rear-end in his 56 Chevy. A local shop replaced all the bearings and seals. About 5,000+ miles later one of the sealed axle bearings went out; it actually broke. They replaced the bearing under warrantee but he was responsible for the labor cost$.

There was discussion with the mechanic about what caused the bearing failure. It was suggested the axle might be twisted. The mechanic also indicated when he cross referenced the bearing part number he could not find an Oldsmobile listing. Apparently when this shop originally replaced the axle bearing they went by the old bearing part number and not application. I think they could not ID the housing so the old part number was easiest. The sealed bearing they used is RW 507 CR.

I did some digging on my own and found the housing casting number is 402227. By matching this number on the internet found it was originally from a 1970 Oldsmobile A-body. The site also said this was the only year “type O” housings that used an open roller axle bearing lubricated by housing oil. I have nothing else to use for reference.

The fact that the internet site indicates open roller axle bearings is an issue. Is it possible the sealed bearing is an up-date that normally works or is there a mistake here? Could a sealed bearing be used in place of a open roller on this axle?

The 56 owner said when the bearing failed the car labored as if the brakes were being applied. This made me wonder if the mechanic’s suggestion of a twisted axle was really caused by the bearing failure. In other words, straight before bearing failure and twisted after.

This car is used for cruising, sometimes from state to state but now the owner is leery of the axle reliability.

Any ideas or suggestions?

Thanks……………..

Not sure what caused it without seeing it but you probably need the A9 oiled bearing for the 69-70.
Part's list- http://www.jdrace.com/Rear_ID/12bABodyOlds.htm

I'm not very familiar with the "O" axle. I just don't see very many of them around here. It's been many years sence the last one that I built. I will tell you that in the 9 inch Ford you can interchange the sealed ball bearing with the tapered roller bearing. If you use the selaed ball bearing then you must install an axle seal in the housing end. If you use the tapered roller bearing then you MUST remove the seal from the housing end. Otherwise they are a direct swap.

Are early (507CR) & late (A9) axle bearings interchangeable on all type O housing? Can one be used in place of the other?

Thank you for the site.........

From http://www.442.com/oldsfaq/ofdif.htm
The biggest weak spots in Olds rears are the wheel bearings and the availability of parts. Positive axle retention is good, but put in the new "updated" style wheel bearings for more strength.

Not really sure what that means but would seem the later A9 would be the one to use.