Easiest way to change rear main seal?
11-19-2008, 07:55 PM
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Easiest way to change rear main seal?
Yep, it's toast leaking really bad. Its a 85 Z28 with a 305 Carb. and 5 speed manual. From what I have read on this site it is a two piece I could be wrong though. I know with rear main seals that you have to pull the tranny out to change them. Except with the two piece you can do it with it in? Is this really possible and if it is wouldn't it be a B**** to do? Any solutions or Ideas?
11-19-2008, 09:32 PM
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Car: '87 IROC/'68 SS
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Re: Easiest way to change rear main seal?
There really is no easy way. It should be a two piece. Check the casting number behind the driver head to be sure. I'd pull it. You'll just torture yourself trying to do it in the car.
11-19-2008, 11:29 PM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
2-piece can be done without removing the transmission. You do have to drop the oil pan, though. The hard part is getting the block half of the seal around the crank.
Last edited by five7kid; 11-20-2008 at 01:07 PM.
11-20-2008, 01:30 PM
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Re: Easiest way to change rear main seal?
If it's an 85 block it's a 2 piece, they changed to a 1 piece in 86 or 87.
I have always done them with the engine in.
Take the oil pan down, pull the last main cap, and it's right their.
I haven't done one in a while, but if I remeber correctly I used the new seal to push the old one out.
Never did think it was very hard to do.
That's just me though.
I have always done them with the engine in.
Take the oil pan down, pull the last main cap, and it's right their.
I haven't done one in a while, but if I remeber correctly I used the new seal to push the old one out.
Never did think it was very hard to do.
That's just me though.
11-20-2008, 01:39 PM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
You can scrape the rubber off of the back side of the seal as you put it in if you aren't careful. Loosening the front four main caps can aid in that process by giving a little gap between the seal and crank. You might have to loosen the torque converter bolts to allow the crank to move down.
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11-20-2008, 02:23 PM
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Re: Easiest way to change rear main seal?
So just drop the oil pan and push out the old seal with the new one? Sounds easy enough. What are the Four Main Caps? I have little knowledge of any of this mechanics stuff. Oh and there shouldn't be a torque converter in it since its a Manual.
11-20-2008, 03:07 PM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Okay, missed the "5 speed" note.
You have to raise the engine off of the engine mounts to pull the pan. That's probably the hardest part of the whole operation.
Small block Chevy engines have 5 crank main bearings. The 2-piece rear main seal is built into the rear-most bearing cap. In order to get clearance between the crank and seal, you would have to at least loosen the front 4, assuming you needed to do that after removing the rear cap and trying to get the old seal out & new seal in.
You have to raise the engine off of the engine mounts to pull the pan. That's probably the hardest part of the whole operation.
Small block Chevy engines have 5 crank main bearings. The 2-piece rear main seal is built into the rear-most bearing cap. In order to get clearance between the crank and seal, you would have to at least loosen the front 4, assuming you needed to do that after removing the rear cap and trying to get the old seal out & new seal in.
11-20-2008, 03:21 PM
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Car: 1984 Z28 Hardtop
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Re: Easiest way to change rear main seal?
A replacement RMS often comes with a little thin plastic tab to slip between the block and the new seal while you slide it in to prevent this from happening. There are also tools you can get to help fish the seal around the crank.
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