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Rear main seal issues

3K views 12 replies 6 participants last post by  19mach69 
#1 ·
My rear main seal was leaking bad. When I pulled the old one out I saw why. It was nearly missing a chunk in the rear. Its a 1 piece rope type seal. I go on summit and order a new one thats the ford racing 1 piece rubber type for a 1984 302. I am looking at the seal now and it doesn't look like its small enough to fit in the seal groove. Is this the wrong part?
 
#3 ·
Correct, early blocks that had a rope type seal must be replaced with a 2pc seal. The crank is not machined to accept the 1 pc which is installed from the transmission side of the crankshaft.

When replacing the rope seal with a new 2 piece seal, be sure to remove the little pointy pin found on the main cap. It is no longer needed and will ruin your new seal if you attempt to use it.
 
#4 ·
There is no pin, and also I pulled the seal which looks like rope apart. It was 1 piece. Not sure whats up, I'll hit the parts store and compare the old with the new ones they have available.
 
#5 ·
I suggest that you determine the year of your block. You will find the casting # in the area of the starter. Post it up and someone can tell you what year block and the appropriate seal needed.
 
#6 ·
It takes a 2 piece. All of the 1 piece seals are too big and won't fit into the groove. It had a crappy piece of rope in there. There is no pin. Its supposed to be a 1984 block out of an F-150. I'll get casting numbers tomorrow.
 
#8 ·
I guess I should have looked in the first post. If you truly have an 84' 302, it will have a 1 piece seal-nothing else was used in 84'. I don't know how a rope type got in there. I wonder what someone was trying to do. Again, verify the year of the block and maybe plan on posting a picture of what you have.

1 pc seals from NAPA, at least the desirable Teflon type, come with a little plastic installation sleeve that helps keep the rubber part of the seal from binding on the crank. Otherwise the seal will seem a little too large for the crank.

A 1 pc seal is installed from the rear of the crank, with the main bearing cap already torqued into place. The pan doesn't even need to be removed. It is NOT driven fully into the block, it only gets driven in until the rear is flush with the rear of the block casting.

_______________
Dennis

65' STANG, 3160 lbs

393W NA, 2.78 Toploader 4 Spd, 9" 3:70 Posi
Pro Comp Heads, Vic Jr. Intake, 750dp, 236/561 Solid Cam, 9.6CR, 1 3/4" Headers, Lakewood, Subframes, Caltracs



<font size=-1>[ This Message was edited by: dennis111 on 12/2/06 5:53pm ]</font>
 
#9 ·
If it does use the one piece seal be sure to lubricate the seal lip with oil or grease before you install it. A dry seal will burn up in a few minutes of use - long before there is enough oil splashed on it to lubricate it.
 
#10 ·
On 2006-12-03 04:24, PaulS1950 wrote:
If it does use the one piece seal be sure to lubricate the seal lip with oil or grease before you install it. A dry seal will burn up in a few minutes of use - long before there is enough oil splashed on it to lubricate it.
Correct for a normal rubber seal.

I must add that if the premium teflon type seal is used, it needs to be installed dry and the crank must also be dry. The teflon seal uses a coating that rubs onto the crank which helps the seal do its job.
 
#12 ·
On 2006-12-03 09:07, BRDVPRA wrote:
dennis111,
You mentioned removing the pin on the crank. Is it on the top or bottom of the crank? I need to replace mine, but don't want to get in over my head.
It is located on the main cap, so I guess you would call it the bottom side of the crank? Simply remove the cap and drive it out with a small punch--quite simple.

By the way, the rope seal hasn't been used for decades so it is rare to find one in an operational car. Most motors that originally came with the rope seal have long since been replace with the 2 pc design. I think the last rope seal that I installed was in the late 70's.
 
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