Rear Main Seal Advice

4barrel · 04-15-2007, 11:59 PM

I'm building a street/strip 347 from a production 302 roller block with a Coast High Performance kit. I'm thinking the block is a later 5.0 piece, so it should get a 1 piece seal, right? I'm just wondering what brand and material is the rear main seal you guys use or recommend.

USMC302 · 04-16-2007, 04:30 PM

Fel-pro and Mr gasket sell both the 2 pieces and 1 pieces just to name a couple.

~The Jester~ · 04-17-2007, 07:27 AM

If it's a later block, it's gonna be a 1 piece which seals WAY better. It's metal coated in a rubber polymer, typical round seal. Spring goes towards the oil. USMC nailed it, go FelPro or Mr. Gasket. You can get a FelPro at your local Autozone, Advance, etc etc.

If you do find out you need a 2 piece, DO NOT put the gaps in line with the block/oil pan flange. Rotate it almost 45* so the seams are up in the block, and down in the oil pan.

4barrel · 04-17-2007, 11:39 AM

I also hear NAPA Teflon rear seals are good, but I think the two you fellers listed sounds like more reputable names. Thanks for the help.

sleeperstang · 04-23-2007, 09:52 AM

Did you really mean 45*, Jester? If it is, that's a bit of advice I've been wanting to hear. I've replaced the main seal twice in the last year, and the leak doesn't seem to go away. I don't line up the two pieces witht he flange, but I only offset it between 10*-15*. If that's the case, I may need to go under the car again, because I just did that deal 4 weeks ago, and it seems I have the drip still.

Dark_5.0 · 04-24-2007, 02:59 PM

Everytime someone tells me that their rear main seal is leaking I find a valve cover leak.

04-15-2007, 11:59 PM	#1
4barrel Mustang Rookie Join Date: Apr 2005 Location: Lexington Kentucky Posts: 98	Rear Main Seal Advice I'm building a street/strip 347 from a production 302 roller block with a Coast High Performance kit. I'm thinking the block is a later 5.0 piece, so it should get a 1 piece seal, right? I'm just wondering what brand and material is the rear main seal you guys use or recommend. __________________ 1989 Mustang GT aka Hailey http://www.cardomain.com/ride/822269

04-16-2007, 04:30 PM	#2
USMC302 Registered Member Join Date: Apr 2001 Location: Gallatin, Tn Posts: 1,326	Re: Rear Main Seal Advice Fel-pro and Mr gasket sell both the 2 pieces and 1 pieces just to name a couple. __________________

04-17-2007, 07:27 AM	#3
~The Jester~ Rat Killer Join Date: Aug 2002 Location: Cold ass Ohio Posts: 1,143	Re: Rear Main Seal Advice If it's a later block, it's gonna be a 1 piece which seals WAY better. It's metal coated in a rubber polymer, typical round seal. Spring goes towards the oil. USMC nailed it, go FelPro or Mr. Gasket. You can get a FelPro at your local Autozone, Advance, etc etc. If you do find out you need a 2 piece, DO NOT put the gaps in line with the block/oil pan flange. Rotate it almost 45* so the seams are up in the block, and down in the oil pan. __________________ d-Con Racing "Nothing fancy, just 347 inches of RAT POISON!" MICE need not apply.....

04-17-2007, 11:39 AM	#4
4barrel Mustang Rookie Join Date: Apr 2005 Location: Lexington Kentucky Posts: 98	Re: Rear Main Seal Advice I also hear NAPA Teflon rear seals are good, but I think the two you fellers listed sounds like more reputable names. Thanks for the help. __________________ 1989 Mustang GT aka Hailey http://www.cardomain.com/ride/822269

04-23-2007, 09:52 AM	#5
sleeperstang Registered Member Join Date: Jun 2001 Location: Lynwood, CA, U.S.A. Posts: 82	Re: Rear Main Seal Advice Did you really mean 45, Jester? If it is, that's a bit of advice I've been wanting to hear. I've replaced the main seal twice in the last year, and the leak doesn't seem to go away. I don't line up the two pieces witht he flange, but I only offset it between 10-15. If that's the case, I may need to go under the car again, because I just did that deal 4 weeks ago, and it seems I have the drip still. __________________ 65 Mustang Coupe...Comp Cams 262 Xtreme Energy, T-5 conversion, Romac Balancer, 620 Front Springs-4.5 Mid-eye rear springs.......work in progress Last edited by sleeperstang; 04-23-2007 at 11:40 PM..*

04-24-2007, 02:59 PM	#6
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	Re: Rear Main Seal Advice Everytime someone tells me that their rear main seal is leaking I find a valve cover leak. __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

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