This question is for the experts here on the site...
I just recieved my rear main seal from Joblot Auto. I had spoken with them and requested a neoprene seal for my 1954 239 Y. I recieved the part with the number C1AZ-6321-C. The description was for "272,292 rear main seal model years 1954/64".
Are all the seals the same size? I'm kinda doughting it and does anyone have a parts number listing to check the above number for me before I take the truck apart for repair?
thanks, Ed

 

Ed, all Y-Block rear main seals are the same size except for the 312" which is larger.

 

my question is are they hard to replace? I need to do the one on my 239 Thanks Julie54

 

I just replaced the rear main seal in my 292 this past weekend and it went without TOO much of a hitch.

Key things to remember:
- Offset the seal a little in the block and retainer (3/8"). Not only is it a little more leak-free insurance, but it helps make lining up the lower retainer easier, as it will just slide together like a puzzle piece.
- Oil the lip of the seal so it doesn't burn up when you first start the motor.
- Let the engine drain overnight. You want to make sure all surfaces are CLEAN and oil free so the RTV will stick. Use Permatex RTV Ultra Black. That is some good stuff.
- Make sure you don't use too much RTV.
- Make sure you give the RTV time to dry.
- Don't over-torque bolts.
- The side seals can be a bitch, but take your time and try not to get frustrated. Remember that the nail goes on the retainer side (NOT block side).

If you are careful and patient, it should result in a leak-free seal; at least, that was my case. Good luck!

 

What matt2491 said. And please use the newer neoprene seals not the rope type.

 

The last time I did rope seals, RTV was not a reality... That being said, you may want to 'dry fit' the whole thing together at least one time. My memory says that the side seals are longer than the bearing cap, and need to be trimmed after installation. When I went to put the cap in, it was more than snug, and the side seals wanted to work their way down the groove as you push the cap into place. To make up for this, I put them into the bearing cap higher than their final position, and let them slide down a bit as I moved the cap into place. You want to know ahead of time how far they will protrude past the cap when they are in the right place. Measure their excess length, and compare when you do the final assembly.
Rope seals needed to be soaked in oil, then worked into the cap groove to get 'formed' into a seal. I used a large socket wrench to depress the rope into the groove and flatten the part that would ride on the crankshaft. Then use a chinese finger or other tool to pull the upper seal into place, while turning the crankshaft. Not fun. Then trim the upper seal, and make sure that no 'threads' went between the block and the cap. I would depress the ends of the upper 1/6" or so below the level of the block, and allow the lower seal to protrude into that cavity. Trim it a bit longer than the cap. Dry fit, trim, dry fit, trim,... yadda yadda. Ugh. Then to the final fit, making sure the side seals were in the right spot. Then trim them flush.
tom