Rear Main leaking, help?

davins130

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May 21, 2004

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Jun 4, 2007

#1

• Jun 4, 2007

• #1

I just replaced my lower manifold gaskets because i thought they were leaking again (blew after excessive boost in crankcase)..Anyways they are all sealed up, and after a degrease i found this morning that it is my rear main seal. Ive never replaced one before, and frankly dont even know what it is. Can anyone tell me what i need to do in order to replace this, and where i should get it from (dont want to get a cheap one and have it leak). Thanks!

 

Blackened302

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Jul 21, 2005

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South TX

Jun 4, 2007

#2

• Jun 4, 2007

• #2

just replaced mine during the engine swap w/ a felpro seal... it leaks.

took it the old one out w/ a screwdriver and tapped the new one in w/ a small 2x4. maybe that was the wrong way?

 

94 Cobra 5.0

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Sep 18, 2004

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Ft. Riley, KS

Jun 4, 2007

#3

• Jun 4, 2007

• #3

The rear main seal sits in the back of the motor. In order to access it you have to drop the transmission and take the flywheel and block plate off. once there as stated above, small screw driver and pry it out being very careful not to nick the crankshaft. tap the new one in and run with it. side note i have installed 2 in my car so far and they both have leaked.

 

Blackened302

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Jul 21, 2005

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Jun 4, 2007

#4

• Jun 4, 2007

• #4

see--that's what i mean... seems like they're bound to leak..

 

Black Stampede

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Sep 3, 2002

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Grand Rapids, MI

Jun 4, 2007

#5

• Jun 4, 2007

• #5

Mine leaked when I replaced it as well. Long story short, dont ever replace a rear main unless you really need to. For some reason my thinking was "hey its 10 yrs old might as well put the new one in that came with my gasket set". Stupid thought.

 

davins130

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#6

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mines an auto, so i just have to take off my flexplate then...dont have to drop the oil pan or anything? sounds a bit more simple then i thought, mine isnt leaking....its pouring like a faucet. Has anyone sucsessfully installed one w/o leaks?

 

SN95StangMan

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Jul 5, 2003

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Lynwood, CA

Jun 4, 2007

#7

• Jun 4, 2007

• #7

davins130 said:

mines an auto, so i just have to take off my flexplate then...dont have to drop the oil pan or anything? sounds a bit more simple then i thought, mine isnt leaking....its pouring like a faucet. Has anyone sucsessfully installed one w/o leaks?

Click to expand...

youre gonna have to drop the tranny, and everything else that is associated with doing that - d/s, exhaust, starter, tc, flexplate, etc.

oh, and the first time i dropped the tranny to change my TC, i didnt mess with the seal because it wasnt leaking. O course, with my luck, it started leaking a month later.

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

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Jun 4, 2007

#8

• Jun 4, 2007

• #8

Make totally sure the crankcase boost issue is fixed. When the crankcase gets pressurized, air looks for the next path of least resistance, which is often the RMS. Wouldnt it suck to do the seal and still have a leak because there's actually another issue?

It would be like having back pain so you limp. You wear out your shoes quickly because you drag a foot due to the limp. You buy new shoes but the new ones quickly get worn again. You're seeing the symptom (worn shoes or a RMS leak) and not the cause (back pain or crankcase pressure).

An alternative is a Teflon seal. They're a PITA to install but hold up decently IMHO.

Good luck bud.

 

davins130

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May 21, 2004

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Jun 5, 2007

#9

• Jun 5, 2007

• #9

i have taken care of the pcv problem, i had a decent sized post about it about a month ago and i think i have it all taken care of (still waiting on checkvalve to come from napa)...the worst part about taking my tranny out is taking off the exhaust ( rusty manifold/header bolts suck)

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

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Jun 5, 2007

#10

• Jun 5, 2007

• #10

PB the crap out of the exhaust bolts ahead of time. You can get partial access to the header/H connection with front wheels off [if needed]. Neverseize the crap out of stuff upon reinstallation.

Good luck.

 

True 5.0

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Sep 22, 2006

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Southeastern Wisconsin

Jun 5, 2007

#11

• Jun 5, 2007

• #11

HISSIN50 said:

An alternative is a Teflon seal. They're a PITA to install but hold up decently IMHO.

Click to expand...

+1

I installed a Teflon seal when I rebuilt my engine last year. Yes, they are a PITA to install but they last a long time. No matter what seal you use, make sure you install them with the smooth side facing out and the split side facing in. Also use some silicone grease to lube the seal wipers when installing. This will make it slide easier and help prevent folding back the inner wiper lip which will lead to leaks.

 

davins130

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May 21, 2004

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Jun 5, 2007

#12

• Jun 5, 2007

• #12

why is it so difficult to install a teflon seal? Anyways, is this a seal like a grease seal for wheel bearings (like that type of seal?)

 

True 5.0

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Sep 22, 2006

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Southeastern Wisconsin

Jun 5, 2007

#13

• Jun 5, 2007

• #13

The Teflon seals aren't as flexible as the rubber ones.