As I continue to try and improve my car I always try to learn more. I have a 1972 142 with a b20f engine. On the door jam it says it was built in November of 1971. I have a chiltons manuel that covers a bunch of years and models of volvo and I also have a haynes manuel. I am trying to learn about replacing the rear oil seal (it leaks). In the haynes manuel it only shows the replacement with the engine out and disasembled. My engine is still in and I don't want to remove it. In the chilton manuel it shows it replaced with the engine in but since it covers so many models and years it is a bit confusing. The replacement one I got from Schmucks is rubber and a I read that they are felt in many things. What is the correct one. Also on some parts sites they show a fuel pump relay that says was installed in cars built starting january 1972. So as always any help is appreciated I want to keep the 140 on the road I love it and it really is only getting broke in a 170,000 miles.