If you have the whole rear apart, you should be able to figure out if it makes a difference by measuring. The 66 Chassis manual doesn't mention anything about different lengths.
Both axle shafts are the same length. If one is longer,someone replaced it at some point in time. How much longer? 1/2” or so?
OH BOY, More posi units from BOP rears are ruined this way. God I can not tell you how many times we have seen this from customers goofing. Original Posi units (auburn) were 2 piece cone and side gear and if that axle is the 1/2" shorter on the 1967-1969 it kills the limited slip as it only engages 1/2 the system in the unit the cone gets spun on on e side and the spiders go round and round like an open. IN THIS case though you have a 1965 so it is short 29.25 axles on both sides. I would have to say someone stuck a longer 29.75 length axles in from a 67-69 rear which will be very close to the center crossshaft and even some times hit and bottom out on the center stuff in the posi etc. So your answer is 29.25 are your proper axle shaft length as long as you have a correct 1965 rear under the car BOTH are the SAME length. I would see what width rear you have first to see what your dealing with before seeing what axle shaft you have. (54.25 flange to flange or 55.25 flange to flange. ) reference picture how to measure this. (green is how to measure) You can also measure the most out side of backing plate to outside of backing plate lip edge to get the same number but you should remove the drum to do this. If you measure inside to inside you will get a 53.75 and a 54.75 reading on a tape measure as the drum brake backing plate curls out about a 1/2" on each side in to the drum lip edge to keep the water and debris from getting into the drum brake shoe area. FIRST THINGS FIRST always. Jim Mitschke J D Race
Thanks you guys. I will measure and make sure to get the right one. The longer one did seem to b about 1/2 inch longer
Those sealed bearings were known for failing,and if they did,it usually tore up the axle to where it was not reusable. It sounds like someone replaced it with a longer one from a 67-69 rear.
We use the same ball bearing sealed bearings for drag racing and even on the street. I will take them over the oiled bearing these days hands down 10 for 10. They have a life just like a old Honda Timing belt ...if you do not do the timing belt at 60k your doomed. Same with the Sealed axle bearings. change them when your supposed to your good. CV joints will die super fast the minute the rubber boot gets a hole in it and slings all its grease out too. EVERYthing has its kryptonite ... NOTHING lasts for ever. Right now the oiled bearings STINK. until these companies get the reproduction tapered bearings correct I will be running from them. WHICH may never happen Bring back the old Bower barrel type used in GM first design and I will think about coming back to the oiled bearing. EVEn Fords oiled tapered bearings we have had issues with. Jim J D Race
Jim, There is an eBay vendor selling the correct barrel style roller bearing,for the SET9 application,but I have not tried them. I do not know the manufacturer. As time went on,people didn’t think to check or service those sealed axle bearings,and when they went bad,it was too late.
Where do you measure the axle length from. I measured from where the studs go in and one is 29.25 and the other isn't even 29 inches. Thanks
You could run a tape measure through one of the aces holes on the wheel flange,and hook the tape on the hole. You would be starting the measurement from the face of the wheel flange. Then measure to the very end of the axle. The straighter the measurement,the more accurate of a reading you will get.
