Rear Main

[BadJoey]

My new rebuild engine is leaking at the rear main seal . I have maybe 200 miles on it . I lost about a quart in 90 miles today . Out of desperation I put something called Bar Leak in the oil today " it is suppose to soften up the seals and stop leaks " . Anyone know anything about this or am I kidding myself and the seal will have to be changed ?

[Oldschool]

Change the seal.....        

[Changin Gears]

Could have been intalled dry or backwards.

[71chally416]

Mine was leaking on the engine dyno so I changed it before putting the motor in the car. It's not hard to do.

[BadJoey]

Has anyone here ever changed the seal with the motor in the car ?If so :

I know I have to drop the drag link .

Guessing pick the motor up a little .

Do I have to drop the Tranny, Fly Wheel and clutch or can i just hold the clutch down . 

How do I get the old seal out without marking the crank ?

What about putting the new one in ? A friend told me there is a tool for that .

Maybe I should farm this out ? Maybe I should pull the motor and take it back where it was rebuild .

 

[72cudamaan]

First thing is to call the engine builder and see what he wants you to do. If he is reputable then he should take care of the problem. By the way, the oil leak sealer is for old seals. It is essentially brake fluid to swell the seal. Bad short term repair at best.

[quagmire]

  If for some reason you end up changing it yourself, it can definitely be done in the car.  Assumng this is a small block, you will need to drop the center link, oil pan, and oil pump.  You won't have to jack the motor at all if it is a stock pan, some aftermarket pans do not require it either. Big block should be even easier since it has a simpler oil pan and a separate seal cap.

Then remove the rear main cap, you may be able to push the top half of it out with a wooden or plastic pick or screwdriver.  Do not use metal and be careful about nicking the crank journal.  If it is real tight you can loosen the other main caps a bit to drop the crank ever so slightly to make it easier.

You can spin the new seal top half in without a special tool if you are careful.  The bottom half is obvious, but don't forget to put sealer on the flat surface of the cap on both sides of the rubber seal or you will have a leak.  Also make sure you don't install it backwards!

It really isn't that difficult, just take your time and don't forget the details like torqueing everything and putting oil on the lip portion of the seal that will contact the crank.  If you don't oil it there is a good chance it will get damaged from a dry start. 

[BadJoey]

I hate asking dumb questions but here goes . If the crank was turned in rebuilding is there such a thing as a oversize seal ?

[quagmire]

They only turn the journals that the bearings ride on, they won't do much more than scuff the seal surface, I've never heard of one.

[BadJoey]

Old seal is out . Piece of cake so far . In for 2 hours so far , new seal will be here tomorrow, Gaskets Thursday . Where the seal rides is knurled ,looked at a crank I have in the cellar and it's the same . I would had thought it would be a smooth surface ? I wish I could do the pitcher thing but I can't . That said if you think of the seal being shaped as a funnel The narrow end was inside the motor and the wide end was in the bell . Sound right ? Hoping the new seal has directions . You said to use sealer on the flat side ? The flat side of what ? The bottom of the seal that touches the motor is more round then flat . Anyone know the the torque for the seal cap .I'm going to talk to 2 motor guys tomorrow but I like as many opinions as I can get . If everyone agrees I feel better . I really appreciate the help . It was killing me seeing all the smoke from oil getting on the exhaust not to mention the mess and the fire hazard .THANKS AGAIN 

[BadJoey]

Stopped by a local , very successful mopar drag racers place on the way home . Seal was facing the right way (wide end in the motor). The knurling on the crank is because when these motors were build there was a rope type seal used and the angel of the knurling would push the oil back into the engine . The oil MAY have been leaking from the sides of the seal cap . If any of you guys have seen the way the new kits seal the sides of the cap what a joke . All the new side seal is (between the cap and block) , is some gasket sealer and 2 small pieces of pipe cleaner . Luckily I had a old cap off another motor in the cellar with the old style outside seals for between the motor and the cap . . My friend said by far that would be the way to go .Anyway the new seal is in the motor and if my pan gaskets get here tomorrow I hope to have it running tomorrow night . My fingers are crossed .

[BadJoey]

Just got home from a 15 mile ride . So far not a drop has leaked . If I knew it was this easy I would have changed it weeks ago . It took about 5 hours for my first time that didn't seem bad to me .