rear main seal
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On The Tree
Joined: Mar 2012
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rear main seal So my rear main seal is bad. I have searched some but couldn't find anything. Is there any write ups on how to go about replacing this? Also is there any other modifications I would want to do while I am doing this? Thanks as always guys.
TECH Enthusiast
Joined: Feb 2007
Posts: 625
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From: Raleigh, NC
If your LS is older you should replace the oil bypass plug and the rear cover seal. The bypass plug changed sometime after 1998 or 1999 to keep it from pushing out and the engine losing oil pressure.
12639249 1 LS1 rear cover seal
12573460 1 LS1 barbell oil bypass plug
89060436 1 LS1 rear main seal
12639249 1 LS1 rear cover seal
12573460 1 LS1 barbell oil bypass plug
89060436 1 LS1 rear main seal
You can buy the rear cover assy. with a new seal already installed and it also comes with a new gasket and bolts for around $70.00 The rear seal and rear cover gasket runs you $60.00 I would get the complete assy. For only about $10 more
If you are not aligning the seal properly then your going to have leak issues.
Link below has a tool kit that will help and is not expensive IMHO. I have it on my to order list.
https://ls1tech.com/forums/generatio...one-these.html
Link below has a tool kit that will help and is not expensive IMHO. I have it on my to order list.
https://ls1tech.com/forums/generatio...one-these.html
the engine will have to be pulled, flexplate/flywheel removed, then reassemble..
You should do the " drop the engine attached to the k member" method, you disconnect the brake lines to the master cylinder that go to the rear wheels, and a few wires, and unbolt the k-member and lift the car off of it..
only takes an hour to do it, then youll have easy access to everything..
theres a write up with pics on how to drop the engine/k member if you search for it..
You should do the " drop the engine attached to the k member" method, you disconnect the brake lines to the master cylinder that go to the rear wheels, and a few wires, and unbolt the k-member and lift the car off of it..
only takes an hour to do it, then youll have easy access to everything..
theres a write up with pics on how to drop the engine/k member if you search for it..
TECH Enthusiast
Joined: Feb 2007
Posts: 625
Likes: 0
From: Raleigh, NC
I guess I don't see the point of the alignment tool. It looks nice and everything, but why not just put the rear main seal into the rear cover before positioning the cover onto the back of the block? That way the seal ensures the holes in the rear cover is concentric to the crank.
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the engine will have to be pulled, flexplate/flywheel removed, then reassemble..
You should do the " drop the engine attached to the k member" method, you disconnect the brake lines to the master cylinder that go to the rear wheels, and a few wires, and unbolt the k-member and lift the car off of it..
only takes an hour to do it, then youll have easy access to everything..
theres a write up with pics on how to drop the engine/k member if you search for it..
You should do the " drop the engine attached to the k member" method, you disconnect the brake lines to the master cylinder that go to the rear wheels, and a few wires, and unbolt the k-member and lift the car off of it..
only takes an hour to do it, then youll have easy access to everything..
theres a write up with pics on how to drop the engine/k member if you search for it..
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If it were Me I most likely would pull the trans to do the rear main seal and as long as apart probably the trans tq conv seal depending on how old it was and the trans dip-stick tube seal . Not sure where the prior poster was getting rear seal and cover gasket 4 $60 but I know at Advance auto parts the 2 together are like $30 and They are Federal Mogule which are the brand the factory gaskets and seals are at least some of the years of the LS based gen3 n 4's,,,at some point They changed gasket/seal vendors,,,,just not sure when and to what brand
Oh ya , as far as the alignment tool ,,,,,,,according to a repair manual You just measure the distance on each side of each of the covers to make them equal before tightening the bolts .
Oh ya , as far as the alignment tool ,,,,,,,according to a repair manual You just measure the distance on each side of each of the covers to make them equal before tightening the bolts .
Engine does NOT need to be pulled.
Remove trans, clutch (if manual) and flywheel. Remove seal and using the tools linked above or a block or wood if you want to risk it use a rubber hammer and hammer it in.
I would recommend the rear cover with the seal as well since it comes with everything and a new cover gasket. But that tool with help you line the cover back up when reassembling
Remove trans, clutch (if manual) and flywheel. Remove seal and using the tools linked above or a block or wood if you want to risk it use a rubber hammer and hammer it in.
I would recommend the rear cover with the seal as well since it comes with everything and a new cover gasket. But that tool with help you line the cover back up when reassembling
Let me rephrase, it's easier to replace if you "pull" the engine through the bottom using the drop the k member method..
I don't like the idea of pulling a tranny and doing everything under the car...
It's easier when you pull the k member, everything is easy access and you can do it alone with no help..
Tranny method requires 2 people
I don't like the idea of pulling a tranny and doing everything under the car...
It's easier when you pull the k member, everything is easy access and you can do it alone with no help..
Tranny method requires 2 people
Trans takes one person.. I can do it by myself easily.
Drop the trans.
I recommend a converter if you don't have one yet along with a flex plate.
Clutch if you are a manual with a speed bleeder.
Drop the trans.
I recommend a converter if you don't have one yet along with a flex plate.
Clutch if you are a manual with a speed bleeder.
If it were Me I most likely would pull the trans to do the rear main seal and as long as apart probably the trans tq conv seal depending on how old it was and the trans dip-stick tube seal . Not sure where the prior poster was getting rear seal and cover gasket 4 $60 but I know at Advance auto parts the 2 together are like $30 and They are Federal Mogule which are the brand the factory gaskets and seals are at least some of the years of the LS based gen3 n 4's,,,at some point They changed gasket/seal vendors,,,,just not sure when and to what brand
Oh ya , as far as the alignment tool ,,,,,,,according to a repair manual You just measure the distance on each side of each of the covers to make them equal before tightening the bolts .
Oh ya , as far as the alignment tool ,,,,,,,according to a repair manual You just measure the distance on each side of each of the covers to make them equal before tightening the bolts .
