Main Bearing install HELP!....Please...

[mike78]

Okay, rookie question. Installing new main bearings, standard size. I already figured out that I screwed up by breaking all of the caps free, and I think I shifted the crank -- I now Know one at a time, and will never forget! Here is the hang up, all of the uppers installed smoothly except for second one from the front. I have tried tapping the whole crank with a dead blow, tried hooking the bearing and rolling it in, and tried tapping the bearing in with a wooden handle. All I have accomplished is bending the bearing (very slightly) and got it to go only (at most) an inch in. Right now all of the main bearing caps are loose. Do I need another new bearing? Advice....?

Rookie question number 2: How the heck do I get the upper rear main seal out?

Third and final question -- assuming that I don't explode my car, If I ever get the new bearing in, what sequence should the caps be tightened in?

 

[dmoody]

Been a while since I put the bottom end of an engine together... if you bent the bearing it should absolutely be replaced. Also if you haven't done so already you should have the crank checked to make sure it doesn't have any wear on the journals. I don't remember much about the upper rear main seal. I think I used silicone sealant around where it meets the oil pan in the rear. As for the caps have you tried a book on small block Fords?

d

 

[Wart]

Your trying to replace the bearings with the engine in the car? Doing this on an engine stand and don't want to pull the entire engine apart?

??

I'm assuming hte engines in the car.

You have to drop all the mains at once to get clearance to R&R the bearing upper.

The rear main seal upper. You need the back of the crank down about as far as you can get it. Loosen #1 about one turn to keep the crank from damaging the front seal then loosen #2 - 4 a couple turns. Pull #5. Pull the crank from the block and move it as far from the exposed part of hte seal as possable. Now you should be able to grip the exposed seal with a pait of needle nose and pull it from the block ...... LMAO!!

THat's how it's suppose to work. Except it can be a bear to get a grip on the rope, and the rope tends to fray. You need to break the exposed end of the seal loose from the block while pulling on the seal, the rest of the seal should follow. If the end gets torn up so badly you can't get a grip on it you need to get an aggressive screw, screw it into the seal and try to pull the seal out that way.

I have done the in-car rear seal replacement, it is not fun.

Far as tightening sequence? Draw the mains to the block evenly and seat. Then torgue them. Remember to set the thrust bearing (#3).

 

[mike78]

I have the engine on a stand, was re-assembling the top end, and figured I'd replace the rear main while it was out -- pulled the bearing cap and then noticed the copper -- the front bearing looked great when I was trying to figure out weather or not to rebuild, was almost done when I found the rear bearing bad, so I was advised to switch 'em all if I switched any.

set the thrust bearing? huh? more advice needed here please?

If I get the rear main seal out, any tricks to reinstall?

 

[Wart]

You noticce how #3 wrapped around the cap? THat's the thrust bearing. That's the bearing that locates the crank forwrd/ aft. It's alsxo the bearing the crank pushes against with a clutch car. The back of the cap half has to be 'flush' or 'level' with the back of the block half.

This is typically set by #3 being just snug then tapping the cap to the rear to make sure the cap is further rear than the block half, then tapping the crank to the front till the crank seats against the block half. The cap needs to be tight enough so it doesn't jump further than flush on the last hit before the crank hits the block half, but it needs to be loose enough to move, but it needs to be tight enough to not shift when #3 main is tightened.

I don't know how critical this is with a automatic. With an auto the crank just sort of floats. Fasilure to set the thrust bearing with a manual can be devistating to the bearing and crank. Unless the back of #3 is flush the clutch spring tension and thus the crank is only pushing on half the thrust surface but mostly damage is caused because the jutting bearing scrapes oil from the crank.

Your doing this on an engine stand?? Hell, I've done this with the engine in the car. Want to talk about a frigging night mare!! Fact, when I saw your post I was trasported back to the first time I did this in a car and started getting the shakes. It was not fun.

Since you have this on a stand, if I were you, I would pull all the caps, the chain cover and chain and jack the crank. Be careful not to pull an oil ring from the bore. You should be able to get enough clearance to do a finger wipe ont he bearing journals to make sure there isn't contamination. Getting the rope seal out under these circumstances should be a cake walk. The secret is to get the end your pulling on away from the V it's set in. Do Not Push as it forces the rope into the V. If this isn't the rope seal the idea is the same, it needs broken loose, it won't pull or slide straight out, sort of.

If your mains are worn I would also check the rod bearings.

 

[mike78]

new rod bearings are sitting on the roof, and the car is an auto, thanx for advice. any suprises for the rods? I know to put everything back the same way, and I will only do one at a time....
As for doing this work in the car -- you are braver than I.

 

[Wart]

new rod bearings are sitting on the roof, and the car is an auto, thanx for advice. any suprises for the rods? I know to put everything back the same way, and I will only do one at a time....

No surprises.

Keep it clean, use plenty of assembly lube (I don't know if it's possable to use too much lube), don't ding the crank with the rod bolts (fuel line), and rotate the crank in stead of moving the piston. Re-check EVERY fasteners torque before installing the pan (actually , check torque before installing the oil pump. The pump can get in the way).

As for doing this work in the car -- you are braver than I.

The first time it was do it in the car, or pull the 351M out of a fully loaded '76 T-Bird. One way or the other it was going to be a PITA.

 

[itsaMustangtoo]

new rod bearings are sitting on the roof, and the car is an auto, thanx for advice. any suprises for the rods? I know to put everything back the same way, and I will only do one at a time....
As for doing this work in the car -- you are braver than I.

I have done in car replacements as well as in car crank replacements. All my experience came as I am sure yours will if you replace the rod bearings. If ,as you mentioned, the crank bearing was showing copper, I am sure the rod bearings are in the same condition. Just replacing them, they are sure to spin. It is just a matter of time before you have a knock. Why not pull the crank have a shop a least check it. That way we can all sleep better at night