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Discussion Starter #1
I have been searching for a good article on how to replace the rear main seal in a 68 with the engine in the car. Does anyone know of any?
 

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Not that I know of.

Did the rear main in my 69 not too long ago, in the car.
351W, 4-speed, PS

Put the cat up on 4 jack stands for working room.
Drained the oil and remove the oil filter.
Coolant is up to you. I drained it to take the lower hose off and then flush and fill.
Took the front tires off.
Dropped the steering center link down by taking the passenger side idler off the frame and taking the control valve loose from the pitman arm.
Did NOT disconnect the power steering hoses.
Unbolted the cross member and took it off of the car.
Put plastic down on the floor under the front of the car.
Removed the oil pan bolts and carefully popped it loose from the block.
Sat it on the floor under the engine and took the oli pump off.

Let it sit and drip for the night!

Wiped everything down and pulled the pan out.
Carefully broke all the main bolts loose.
Backed them all out about 1/4 turn.
Took the rear main cap bolts out and wiggled the cap off.
Using a thin punch, I tapped on one side of the seal in the block to push it out.
After having issues getting the seal to move, I used a bigger hammer and a bit more force - the seal spun out as planned.
Oiled the crank edge of the new seal half and spun it up into place, leaving about 1/4" sticking out on one side.
Oiled the crank edge of the other half of the new seal and put it in the cap, leaving one end out to "mate" with the other seal.
A touch of Black RTV on the exposed ends of the seals and put the cap on, being carefull to get the ends in the grooves.
Spun the main bolts up into place and snugged them down to get the cap to seat in place.

Let the blood get back into my fingers and arms!

Using the sequence and specs in the manual (or Chiltons), torque the main bolts down.
Check all the main bolts torque for good measure.
Cleaned up the oil pump and pan.
Bolted the oil pump back in place with a new gasket, making sure to get the shaft aligned.
New gasket sealed on the oil pan and the pan goes back in, geting all the bolts in and finger tight.
Tighten down the oil pan, being carefull not to over tighten them and keep them evenly tightened (pain in the butt).
Reinstall the cross member.
Bolt the steering center link back into place on both ends.
Make sure the drain plug is in the oil pan and tight.
Remove plastic from the floor and clean up any messes.
Look for any wet/oil spots on the pan/block/bell housing.
Make sure the bottom of the engine is clean/dry.

Put the tires back on.
Take the Cat off of the jack stands.
Put on a new oil filter and put 5 quarts of fresh oil in.
If coolant was drained, close petcock, install hoses and check clamps.
Refill with a 50/50 mix of anitfreeze and water.
Check for any water/oil drips under the car.

Start the Cat and let it warm up.
Keep an eye on the antifreeze level and add as needed.
Check under the Cat for signs of oil leaks.

If everything went well, there will be no oil leaks.

My oil pan was seeping a bit, but a re-tightening of the pan bolts stopped that leak.
My rear main has been dry ever since.

Good Luck!
 

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Sticky note this one! LOL Add: Consume beer for job well done:.... ;>) The key to oil pans and valve covers is not to overtighten them or you will have leaks....follow sequence correctly too.
 

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I *think* that the original was a rope seal, and it is held by a nail/pin that is in the rear main cap in the pan seal groove and goes through the main cap and into the crank seal. If using an aftermarket or replacement rubber seal, make sure you knock that pin out of the maincap first!
 

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Discussion Starter #5
Cougarkid, that's good info. For some reason I thought the trans had to be way from the block. What bites for me is I replaced my oil pan a month ago and had the car on jacks, oil drained and oil pump off, and power steering out of the way. I have some idea of what I'm in for.
 

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Yep, I feel your pain!

This rear main replacement was on the engine I COMPLETELY rebuilt about 6000 miles ago, top to bottom.
You just never know about the rear main seal.

I did this twice on a 4WD Jeep Cherokee I had before. Once for the pan and then again for the rear main and, of course, pan. Only 2 weeks in between. Jacking the front axel away from the frame/pan was the most fun! Then the leak moved upward to the oil filter adadter. Fixed that and it finally quit leaking oil.

The Pin in the main cap was already out of mine. I rebuilt this engine after I got the Cat and it had been re-sealed (poorly) before.
Actually, I added a touch of Black RTV where the pin "was", since it was nicked up from the previous removal job.

I did my rear main replacement with the tranny still bolted to the bell housing/block.

You can do it!
 

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Discussion Starter #7
Yeah my engine completly rebuilt 5 or 6 thousand mile ago too.
I have a 1970 371W block, how do I know if it is a two peice or one peice seal? Also, I use full synthetic oil, does that make difference with the seal? Which is the best? I really don't want to have to do this
 

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jimk127,
SBFs got the one-piece rear seal some time in the mid '80s, IIRC... So your '70 block would definitely be a two-piece seal casting. Yet another reason why I shop for later blocks for my 351W-based engine builds...

Synthetic vs dino oils shouldn't make any difference.
 

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