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Author
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Topic: Rear Main Leaks ??????
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ekbeanctr
Gearhead Posts: 733
From: Middlebury, IN USA
Registered: Dec 2000
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posted 09-19-2004 05:18 PM
   
Well, I thought my car was dripping oil because of the cheap ass chrome oil pan $49.95!! So I bought a Canton to replace it. Well after tearing the old one off, I see that the main leak is coming from the rear main seal. Why would a rear main seal start leaking after only about 1,000 miles?? I am going to go ahead and put in a new one from underneath and also new mains and rod bearings while it's off. Any tips or advice while I'm under there??------------------
Have a Wonderful Day
Red Fire Clearcoat 65 Fastback,
408W, Hooker Super Comps,4 Speed,
Versaille 9" Rear End,
Global West Front End
[email protected]
http://photo.starblvd.net/Ekbeanctr
http://mustangsandmore.50megs.com/ekbeanctr.html
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steve'66
Gearhead Posts: 9489
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 09-19-2004 05:56 PM
quote:
Originally posted by ekbeanctr:
and also new mains and rod bearings while it's off. Any tips or advice while I'm under there??
Yeah, Just one, don't make it harder than it has to be.  Do the bearings look bad? If they do after 1,000 miles, then you have other problems and the engine should come out. Otherwise leave the bearings alone and just change the seal.  SteveW
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SteveLaRiviere
Administrator Posts: 44935
From: Saco, Maine
Registered: May 99
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posted 09-19-2004 06:22 PM
Also, be sure the seal is oriented in the right direction. The lips should be pointed towards the center of the engine. Make sure you stagger the end gaps 1/4" from the block edge and use sealer at the ends.------------------
'70 Mustang Mach 1 351C 4V/FMX/3.25 Open
'70 Mustang Convertible 250 I6/3 speed/2.79 Open
'72 Mustang Sprint Hardtop 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
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ekbeanctr
Gearhead Posts: 733
From: Middlebury, IN USA
Registered: Dec 2000
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posted 09-19-2004 06:45 PM
The reason I was checking the bearings so closely is because: We ran the engine for about an hour on my engine stand. Good Oil Pressure, Etc. Then we put the engine in the car, re-used the same oil filter. Started the car, it ran for about 3-4 minutes before I noticed no oil pressure. We dicked around trying different gauges etc before we figured out the DAMN CARQUEST OIL FILTER was bad. The engine was turning over pretty hard by then. After changing filter oil pressure was good, about 60 at 2500 RPM, 35-40 at idle. After 2,000 miles about 45 at 2,500 RPM about 10 at idle !!  SO, I figure while changing the pan and rear seal, why not put in new bearings, just to make sure ??------------------
Have a Wonderful Day
Red Fire Clearcoat 65 Fastback,
408W, Hooker Super Comps,4 Speed,
Versaille 9" Rear End,
Global West Front End
[email protected]
http://photo.starblvd.net/Ekbeanctr
http://mustangsandmore.50megs.com/ekbeanctr.html
IP: Logged |
BLstangin
Gearhead Posts: 817
From: St. James, MN
Registered: Apr 2002
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posted 09-19-2004 06:59 PM
Yes, you shouldn't loose more than maybe 5lbs during break in, sounds like the bearings are going south. Another thing is that to loose that much pressure the mains have to be really worn, which lets the crank wobble and then the rear seal leaks.------------------
1970 coupe restored with the help of my dad. 306 with 600 holley, Weiand Stealth intake, headers, mme custom roller cam, harland sharp roller rockers, kb pistons, 10.3:1 compression ratio, pertonix ignitor 2 with matched coil, lakewood bellhousing, 4-speed toploader, and 2.79 open 8" rear. Soon to be 9" 3.50 trac-lok
1986 f-150, 5.0, factory towing package with original c-6 trans [This message has been edited by BLstangin (edited 09-19-2004).]
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Fastymz
Moderator Posts: 20708
From: Reno Nv USA M&M#1240
Registered: Apr 2001
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posted 09-19-2004 09:16 PM
Well that stinks, hope it was just a bad seal, or one that wasn't installed right. Maybe you should just pull the motor and rebuild it to put out alittle more HP.  ------------------
SCOOP "Half this game is ninety percent mental."
- Yogi Berra
65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc.
My Pics
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Strain Gang
Gearhead Posts: 225
From: Thor, Iowa
Registered: Mar 2003
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posted 09-19-2004 11:11 PM
I had a rear main take a dump after a couple hours of running this year. I lubed it up prior to installation, but after checking piston to valve clearance, getting the right length pushrods, and other things needed to check by turning engine over on the stand, it appeared to have lost the lube I put on. The result was a perfect black ring of rubber on the crank from a dry start up. I installed a fresh one with a LIBERAL amount Perfect Circle red lube and no more leak.. This is what happened to me, not saying it was your problem, HTH Steve.
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pendragon
Journeyman Posts: 9
From: Baytown Tx
Registered: Sep 2004
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posted 09-20-2004 08:38 AM
If you are going to change main and rod bearings, do yourself a favor and pull the motor. You won't believe how many times you will have to climb under the car if you don't! You will also be able to do a much better job.
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ekbeanctr
Gearhead Posts: 733
From: Middlebury, IN USA
Registered: Dec 2000
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posted 09-21-2004 09:08 PM
quote:
Originally posted by ekbeanctr:
The reason I was checking the bearings so closely is because: We ran the engine for about an hour on my engine stand. Good Oil Pressure, Etc. Then we put the engine in the car, re-used the same oil filter. Started the car, it ran for about 3-4 minutes before I noticed no oil pressure. We dicked around trying different gauges etc before we figured out the DAMN CARQUEST OIL FILTER was bad. The engine was turning over pretty hard by then. After changing filter oil pressure was good, about 60 at 2500 RPM, 35-40 at idle. After 2,000 miles about 45 at 2,500 RPM about 10 at idle !! SO, I figure while changing the pan and rear seal, why not put in new bearings, just to make sure ??
UPDATE
Sure Enough - Rear main bearing was showing bright copper all the way around it & also the thrust bearing was showing a lot of copper!!! Replaced all the rod bearings tonight. Would have replaced mains tonight except when we opened the box at the speed shop to check the mains, they were the wrong size, for a cleveland (Box clearly marked M144 for a 351W)  SO, now I have to wait another day for the right parts. It also looked like the rear main seal was messed up in 2 spots (Maybe it got hot when we ran it without oil). Anyway, I was glad to see something that would explain the lower oil pressure.Ernie ------------------
Have a Wonderful Day
Red Fire Clearcoat 65 Fastback,
408W, Hooker Super Comps,4 Speed,
Versaille 9" Rear End,
Global West Front End
[email protected]
http://photo.starblvd.net/Ekbeanctr
http://mustangsandmore.50megs.com/ekbeanctr.html
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steve'66
Gearhead Posts: 9489
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 09-21-2004 11:42 PM
Ernie,Change the oil every week or so until the oil and cut open filters looks like new. I had a main bearing go out early on the 408 and even though we pulled the motor, flushed everything and reground the crank, it took a long time to get the last of the bearing material out of the engine. That's why I voted for pulling the engine. Good luck with it, SteveW
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ekbeanctr
Gearhead Posts: 733
From: Middlebury, IN USA
Registered: Dec 2000
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posted 09-22-2004 12:46 PM
quote:
Originally posted by steve'66:
Ernie,Change the oil every week or so until the oil and cut open filters looks like new. I had a main bearing go out early on the 408 and even though we pulled the motor, flushed everything and reground the crank, it took a long time to get the last of the bearing material out of the engine. That's why I voted for pulling the engine. Good luck with it, SteveW
Steve, Thanks for the info, I will make sure and change it often until everything looks good. Ernie
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