i have an 1984 f250 diesel with a 6.9.i have replaced the rear main a couple of times. it keeps going out. the spring on the inside keeps falling off. i have since replaced the crank rods mains . and put a new rear main. it lasts about a month then the darn things starts leaking again. what do you all think?

 

Forgive me for asking a stupid question. I'm not trying to be funny or insult your intelligence. Are you putting the seal in with the spring to the inside of the engine? As I recall that rear seal was tricky to put on. We used to install the seal into the rear cover then, using an alignment tool which allowed the seal to be pushed on to the crank shaft without the seal lip catching on the crank as it passed the edge of the crank, along with guide pins (of course this was all done before the oil pan was on), the entire rear cover was installed. I've never replaced a rear seal as an aftermarket piece. Do they come with a plastic protector installed in them to aid in the installation? Also, does the crank have a wear ring on it? If so, you need to make sure that you have a seal that is designed to run WITH the wear ring (I believe they can be bought to run with the wear ring and without). If the seal lip is catching on the edge of the crank or the wear ring, that could be curling the lip up popping that spring out. Also, if your seal is designed to run with a wear ring and you don't have one, that could be a problem. And finally, don't forget to put some appropriate sealer on the flywheel bolt threads (we always used Permatex Avaition sealer) because those holes in the crank shaft are NOT blind holes. You may have to find someone who will let you use the seal alignment tool to get the thing properly installed.

 

yeah i put the spring on the inside. it does not have a wear ring on the crank. and the seal seams to be on there pretty snug.

 

Well, it sounds to me like you've done everything right but still you've got a problem (obviously). The rear cover has 2 small dowell pins that properly align it to the block. Make sure those pins are sticking through the cover and not pushed into the block (why they made those holes deep enough to allow that to happen is beyond me -- morons in the engineering department, no doubt). Also, if the crank has a groove in it where the seal rides you may want to get the seal that requires the wear ring and install it (use appropriate Locktite on it if you do). And, as a last resort, you may want to take it to a dealer that is trustworthy, that guarantees their work to have it installed. That way if it leaks it is their problem. Sorry I couldn't be more helpful.

 

thank you for your help.