frcc16 Posted August 29, 2017 Report Posted August 29, 2017 My rear main seal has an annoying leak and I would like to replace it. The first thing I noticed is that the bell housing of the fluid drive is blocking access to the seal halves. This same bell housing appears to extend underneath the rear drive train support (and may be held in place by the two rear motor mounts. Does anyone have experience with removing the fluid drive bell housing? What are the tricks, if any? Do I need to remove the two rear motor/transmission mounts in order to remove the housing? Thanks! Greg Quote
Merle Coggins Posted August 29, 2017 Report Posted August 29, 2017 You posted this on the truck forum. You may get a better reply if it is moved to the car side. However, I don't believe you should have to remove the bellhousing to access the rear main seal, but you may need to remove the FD itself to access the upper half of the rear dust seal. Isn't the oil seal in the rear main bearing cap? So you would need to drop the oil pan to access that. Quote
frcc16 Posted August 29, 2017 Author Report Posted August 29, 2017 Yes, I realized my mistake as soon as I posted but I couldn't delete it. I reposted on the correct forum. I have removed the oil pan. The lower half of the seal is butted right up against the bell housing front. It appears like there isn't enough room to even begin to back out the bolts that hold the seal in place! Greg Quote
NiftyFifty Posted August 29, 2017 Report Posted August 29, 2017 Doing the two piece seal in the vehicle is close to impossible, but apparently is do-able, but I know when I went to fix mine this spring, it's 10x more work then I was willing to do with the timeline and area I had to do it in. The manual is useless in this case, at least for the trucks. Quote
frcc16 Posted August 29, 2017 Author Report Posted August 29, 2017 Thanks! I'm usually pretty brave but I'm really on the fence with regards to handing this job off to my vintage car shop!! And these posts just may have shoved me over to the other side!! I only have my home garage stall and jack stands. It may be a bit more than I can handle alone... I may end up breaking more than I fix!!! Quote
John-T-53 Posted August 29, 2017 Report Posted August 29, 2017 (edited) Rear main seal replacement is tricky. I'd pull the motor, mainly because I'm sick of laying on the ground. You'd have to unbolt the transmission and remove the bellhousing and flywheel for proper access. You have to remove the timing chain so that the crank can be moved down for clearance. The good news is that you can leave the connecting rods bolted in place, and the pistons will all slide down in their cylinders. Trick is not to move the crank to the point of the rings snapping out! This is at least for a two-piece modern seal. You need to take these steps so that the seal can be properly glued into place. Without sealant, it's a waste of time. Also, I'm Not sure about a rope seal, that's a different animal. See pics below for a recent rear main seal replacement on a 251. Edited August 29, 2017 by John-T-53 2 Quote
John-T-53 Posted August 29, 2017 Report Posted August 29, 2017 (edited) . Edited August 30, 2017 by John-T-53 Quote
frcc16 Posted August 30, 2017 Author Report Posted August 30, 2017 Yea... this job is really over my head! I just don't have the resources to do it right! Thanks for all the input from everyone! Greg Quote
John-T-53 Posted August 30, 2017 Report Posted August 30, 2017 (edited) Interesting, I see the "like" meter has changed. Thanks for the little heart, Don! Haha! Edited August 30, 2017 by John-T-53 1 Quote
John-T-53 Posted August 30, 2017 Report Posted August 30, 2017 11 hours ago, frcc16 said: Yea... this job is really over my head! I just don't have the resources to do it right! Thanks for all the input from everyone! Greg How bad is the leak? Do you know what type of seal is in there currently? If rubber, perhaps some ATP-205 additive might help. And / or, "high mileage" type of oil. Unfortunately, the rear main seals on these motors like to leak, even when new and with a polished crank. Often, you will see corrosion pits on the crank surface which a new seal won't fix. See photo below, above the thrust collar. Pits. Quote
Don Coatney Posted August 30, 2017 Report Posted August 30, 2017 6 minutes ago, John-T-53 said: Interesting, I see the "like" meter has changed. Thanks for the little heart, Don! Haha! Does not indicate we have anything going on. But with this latest upgrade there is no way to make a "LIKE" without that stupid heart thing appearing. So forget the little heart! I like your posting but hot that much. This upgrade feature should change! GTK are you listening???? 2 1 Quote
DJ194950 Posted August 30, 2017 Report Posted August 30, 2017 Oh, Don you are so sentimental about the past! No name! 2 Quote
frcc16 Posted August 31, 2017 Author Report Posted August 31, 2017 If I drive the car for like 10-15 miles and park it overnight, it will leak less than 2 tablespoons of oil. Quote
NiftyFifty Posted August 31, 2017 Report Posted August 31, 2017 Oils cheap, and lots of cardboard in the world for the garage floor! Lol i changed the bottom half of my seal and got away with that...you could get lucky too if that where the leak is from. I cleaned my engine really well with brake clean around the rear, then took the inspection cover off and got the truck hot and up on some engine stands..I couldnt see oil coming out that high so I cleaned it again and replaced the bottom 1/2. Fixed that leak....now my front seal is leaking Quote
Don Coatney Posted August 31, 2017 Report Posted August 31, 2017 I have owned several Mopar flathead engines over the years and everyone marked there territory sooner or later. Quote
darenfroe Posted July 25, 2018 Report Posted July 25, 2018 I love the comment about marking their territory. Mine leaks small around the rear, but it sprung a leak around the oil pan plug boss. I welded it up and will reinstall tomorrow. Quote
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