rizZO-6

So I started replacing the rear main seal today on my 69 and I'm having trouble getting the upper half out. I read that it could be tapped out with a screwdriver but all that seems to be doing is gouging it. The half that is in the cap was kinda tough getting out so if that's any indication I may be screwed. Any tips or advice is greatly appreciated!

keithl1967

don't use a screwdriver...if it slips, it can gouge the block or crank surface...
use a suitably sized punch with a blunt tip.

Also, if you can get someone to help, try having someone rotate the engine (make sure you pull all of the plugs, which will make rotating the motor way easier) as you tap the seal...once you get enough of it out on one side to grab it with pliers, continue rotating the engine, as you pull it out...

jacgillam

Yep, I replaced to rear main on my '57 chevy with a '78 sbc a few months ago and it was not difficult. I did use a punch to start it moving and a wooden dowel also so I could tap on it without scaring metal. When/if you get it started don't pull straight down, pull it around under the crankshaft. I should know this after years of pulling teeth! The rule was "to pull a tooth with curved roots, pull and elevate it in the direction to continue the arc of the roots". Good luck.

CanadaGrant

After a long time the seal can get stuck or sort of bond a bit to the block. I have had luck by inserting something thin and flat like an old oil dip stick between the block and the seal and push it up to the top on both sides to break the bond then use any of the above methods to remove the seal.

Dynra Rockets

I had to use the drywall/decking screw technique to get mine out. The course threads will screw it out. There are youtube videos.

rizZO-6

Thanks for the replies! I thought what CanadaGrant recommended sounded like a good idea. So I got a thin piece of metal and tried to slide it in there. But its not happening. Its so tight it wouldn't go. I could see a little bit of metal in the rear part of the seal so I got a punch and started tapping at the metal. This thing is not budging. Hopefully there is enough there that I can grab on to with long needle nose pliers. I should have known this wasn't going to come out based on how hard it was getting the other half out of the cap. I had to pull that piece out with pliers and it was still stuck to the cap. Its almost like it was glued in there. Not sure if its ever been replaced but it has GM 3767702 embossed on it.

7T1vette

There is no reason why you can't loosen the bearing caps a bit to get more clearance in the rear bearing journal. Loosen rear main bolts about 1 turn; loosen next cap about 3/4 turn; then 1/2 turn and then 1/4 turn. As you loosen more bearing caps, the crank will drop a bit and allow the removal of the old seal half. You should carefully inspect that area before you re-tighten the caps, checking for foreign material in that seal area or adhesive being used .

To re-tighten the caps, do so in reverse order of how you backed them off. Use a torque wrench to set bolt torques per GM specs. You could position the top half of the new seal in place before you re-tighten those bolts. Just don't "reposition" anything in the process.

terrys6t8roadster

I agree with 7T1vette, except I loosen them even more until you can see the crank drop slightly. It also gives more room between crank and bearing so you can pry the seal loose on both ends. Had the same situation with my 69 with the seal being stuck. Now that the main caps are loose, pop a couple off for bearing inspection. T

NeverTooOld

I have only replaced a couple of rear main seals over the years and I seem to recall using a screwdriver and a hammer to get it moving and then pried it out a little bit at a time using the same screwdriver; always being careful to not nick the crankshaft. I also remember my 1959 Chevy's 283" had a "rope" seal; something most of you have probably never heard of but all of the engines used them back in those days.

rizZO-6

Well I was looking forward to reporting back here tonight that I got the rest of the seal out but unfortunately that's not the case Is there anything else I need to do, loosen, disconnect or unbolt to get the crank to drop a little? I loosened the bolts as 7T1vette recommended but nothing dropped or moved. I even loosened them all another half a turn and still nothing. I can see the space between the bolt heads and bearing caps.

Also is it recommended to use anti-seize on the bolts or just torque them when I put this back together?

Thanks!

Dynra Rockets

The crank didn't drop because it is being held up in the front by belts and in the rear by the input shaft of the transmission. the only thing that worked for me was the deck screw method.

R

rizZO-6

I figured the shaft was the issue. He must have thought I had the transmission out already when he recommended doing that.

I don't know if I'm ballsy enough to try the deck screw method but its starting to look like my only option.

CanadaGrant

Since you have everything loose try the dipstick thing again only use your actual dipstick from your car instead of something metal that's similar in the garage. It has a rounded curve on the end and the edges are beveled up so it won't get caught or bind on the seal material.
If it still doesn't work you can drop the rear of the crankshaft slightly since it's already loose by using a floor jack with a piece of 2x4 or whatever up against the pan mating surface on one side at the rear to raise the rear of the block. That will drop the back of the crank slightly.
If that doesn't work, you might have to slack off on the bellhousing bolts to get the angle you need as that will allow the back of the crankshaft to angle down.

7T1vette

The bearing caps will hold the crank up, as long as you don't completely remove any bolts.

derekderek

The bearing caps have to be popped loose. They are still in place tight th the block. Unscrew the 2 bolts all the way. Pull the bolts down a bit. Wiggle bolts fore and aft. (Most of my chebby engines go in boats.) Now cap is free. Take main off. Chechnya bearing. Put it back and leave bolts 2-3 turns loose. Proceed to the next main cap. Did you try a flat punch just a bit smaller than the cross section of the seal?

silver74vette

I used the dipstick method, got it started between the block and the metal section and clamped some vise grips to the dipstick and tapped it in with a small hammer. Took some time but it worked. This was on a 69 427.

lionelhutz

If it's an auto then undo the torque converter and push it back from the crank.

Then, you likely have to pull the main caps down to let the crank drop since they are a tight fit into the block. Between the friction of the piston rings and the main caps all holding it in place, the crank would likely stay in place without any main bolts until it is pulled down.

sparky77

Go to the hardware store and get a putty knife that is real flexible,when you get home cut it down to about a 1/4 inch wide and leave it long . Sharpen the tip like a chisel ,than you can use the handle to tap it in between the seal and the block.If it gets hard to tap in pull it out and go in from the other side.Good luck. And I do remember rope seals.

rizZO-6

I had a major breakthrough this evening. I finally got the upper half of the seal out!! I ended up getting 10" long needle nose pliers. Pulled and pulled on the seal and it still was not coming out. Then I did what silver74vette did, used vice grips. But I didn't use my dipstick b/c I didn't want to damage it or have teeth marks on it from the vice grips. I had a similar thin narrow piece of metal that I used. Tapped it in with a hammer a few times. Pulled on it some more with the needle nose. Tapped on it some more. Eventually I pulled it out. Of course there is pieces still stuck to the metal just like when I pulled the half out of the cap. I have about 1" from each end of the seal that is stuck. Not sure how I will get that out. I was able to scrape some of it out but I can still see more up in there when I shine a light on it.

Thanks to everybody who chimed in on this with their ideas.

7t9l82

The Pistons and rods are going to hold the crank up a bit too, but I don't think you should be having such difficulty. Try threading a drywall screw in the end but use some sense get it in the middle and pull possible with someone else with a punch pushing on the other side. I've never had that much trouble with one .