440 REAR MAIN SEAL FIXED!!!!!!!!

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132068Dodge

132068Dodge

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I just wanted to post how well the Fastfishautoparts.com one piece rear main seal works. I have been wrestling with repairing rear main seal leaks ever since completion of my build last year. I ve used the two piece rubber design from Mopar and yes, they work well if everything is perfect!! The problem resides with the factory design and use of a loose fitting rear main seal retainer. I learned a couple of things which really help while installing it. The first thing is to mock up your retainer block and make sure the seal grooves line up and are concentric where the retainer meets the block. Fit your retainers bolts and make sure there is no contact from the bolt head or flange against the machined holes in the retainer itself. This will shift the retainer out of position as it did on my brand new 440 source piece. Going to return that piece of trash as soon as I can! Use a set of feeler gauges with equal spacing on each side of your retainer between the retainer and block to eliminate any twisting of the retainer as you torque the bolts. Many failures have occurred as a result of one or both halves of the two piece seal twisting/rotating slightly in the seal grooves as the retainer twists slightly out of position as it is tightened into position.
The Fastfish one piece rear main seal is expensive and yes, it works extremely well. It comes with excellent instructions. Combined with the above information and use of their seal, I have a bone dry rear main and have driven the car 200 miles in our lovely 110 degree Arizona heat. Several brutal heat cycles and not one drop of oil! I highly recommend their product despite the price tag. Worth every penny in my opinion!
 
Quick fix is to seal crankcase holes with tape, then use a different car's running engine PCV line to pull of vacuum on the leaking engine, and then put an extension tube on a tube of silicone rubber to get up to the rear main seal.
You will hear the hissing of air being pulled in at that point.
Add silicone, and the vacuum will pull it in.
Rotate the engine one turn slowly while adding the silicone rubber, and you will hear the leak stop. Let cure for normal time at whatever temperature.
I have used the vacuum trick several times, on my vehicles and others.
Only once on the crankshaft, but it worked completely and lasted for about 4 years, until I rebuilt the engine.
 
that fast fish 1 piece seal might be ok if crank is out on stand,but what about putting it in in the car with crank in,dart Thomas what silicone do you use
 
Gosh , that was about 1980 on the crankshaft seal, so it was probably plain blu permatex. Last time I did this was about 3 years ago on a neighbor's Honda which was spewing from a timing cover, and I used whatever was handy.
 
440outlawdart said:
that fast fish 1 piece seal might be ok if crank is out on stand,but what about putting it in in the car with crank in,dart Thomas what silicone do you use
Click to expand...
Yes, The fastfish part is designed to be installed with the motor out of the car and disassembled on an engine stand.
 
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