Tips and procedure to removing and installing a BB rear main seal?
jim larson said
Jan 4, 2011
I plan to replace my rear main seal. I just removed the oil pump and rear main.
How do I go about this? Thanks.
Dave Seitz said
Jan 4, 2011
Have John Delke come over and spend about 2 hours tweeking the pan rails and cleaning everything and let him install it. He was very anal about how he did it and appears alergic to RTV but the engines do not leak from his work when done.
John D said
Jan 4, 2011
Har Har Har... you a funny guy..
It's true though, my assemblies don't leak.
I don't remember, is it a rope seal or 2-piece rubber?
jim larson said
Jan 4, 2011
2 piece rubber. I read the infrormation in the 66 service manual. It seems pretty straight forth. But sometimes I miss something. What do you clean with? Book says you don't have to loosen any mains except the rear. Just wonder if you should loosen the other ones. What I should look for regarding bearing wear, misc signs. Thanks.
Lost in the 60s said
Jan 5, 2011
jim larson wrote:
2 piece rubber. I read the infrormation in the 66 service manual. It seems pretty straight forth. But sometimes I miss something. What do you clean with? Book says you don't have to loosen any mains except the rear. Just wonder if you should loosen the other ones. What I should look for regarding bearing wear, misc signs. Thanks.
ABSOLUTELTY loosen ALL the mains, in fact the BEST procedure is to remove the crank, but I doubt you want to go thru all that. Sliding the new seal around the block groove can shave rubber off the sides from sharp edges and it will leak just like you didn't change a thing. I would use a wood wedge to hold the crank elevated a 1/4" at the rear to allow positioning the new seal without any sliding force and then seat it with the weight of the crank. I also clock the 2 piece seams at 2 and 8 o'clock so they are not on the same plane as the block/cap seam to help eliminate a potential leak there. If there is a lot of sludge/crap in the seal groove of the block, you really should remove the crank for cleaning. Any debris in that groove is a potential leak.
The bearing has a coating the color of aluminum over the main shell. If it is worn thru the aluminum color into a copper tone, it may be out of service. You would need to check actual clearnace with plasti-gauge to know for sure. If in doubt, post a clear pic for the engine guys to analyze...
SShink said
Jan 5, 2011
Agree with everything Mitch said except all I've done is remove the REAR main bearing cap.
I did this on a 396 a couple of years ago, and did ruin the first half seal when I caught the edge of the seal on the edge of the block and it did cut it when sliding it in the groove.
The seals will come with a thin plastic sheet cut out to fit the groove width so that you don't slice it. After I figured that out... it worked fine the second time.
Clocking the edges is important. I think the instructions said to put a dab of RTV on the seal edge so that it sealed to the other edge before you 'clock' them.
Just take your time sliding it in and it will be fine. Retorque the bearing cap and it's all good.
jim larson said
Jan 5, 2011
Thanks guys. Ordered the parts this morning, so so sure what you mean on the thin plastic sheet. Is that removed after you install the seal. How will I know if I cut the seal on the edge of the block?
Don't really want to take the other mains off and lifting the crank . Worried about getting the crank back down in place, as I have never done this before.
I will take a photo of the bearing and post tomorrow; but see no signs of copper.
SShink said
Jan 5, 2011
jim larson wrote:
Thanks guys. Ordered the parts this morning, so so sure what you mean on the thin plastic sheet. Is that removed after you install the seal. How will I know if I cut the seal on the edge of the block?
Jim, the thin plastic guide is about 1/2" wide with a 1/8" wide tip on it that you insert into the groove as you are sliding the seal in. This protects the seal from the sharp edge of the block groove. You remove the guide after the seal has been slid in. There should be instructions with the seal that show you this. I'm sure you'll figure it out.
Lost in the 60s said
Jan 6, 2011
jim larson wrote:Thanks guys. Ordered the parts this morning, so so sure what you mean on the thin plastic sheet. Is that removed after you install the seal. How will I know if I cut the seal on the edge of the block?
Don't really want to take the other mains off and lifting the crank . Worried about getting the crank back down in place, as I have never done this before.
I will take a photo of the bearing and post tomorrow; but see no signs of copper. Jim, if you want, I'll run down and help you with this when you get the parts. Prefer a week day as neither of us seems to have a job... I have all the tools to git 'r done.
jim larson said
Jan 6, 2011
Lost in the 60s wrote:
jim larson wrote:Thanks guys. Ordered the parts this morning, so so sure what you mean on the thin plastic sheet. Is that removed after you install the seal. How will I know if I cut the seal on the edge of the block?
Don't really want to take the other mains off and lifting the crank . Worried about getting the crank back down in place, as I have never done this before.
I will take a photo of the bearing and post tomorrow; but see no signs of copper. Jim, if you want, I'll run down and help you with this when you get the parts. Prefer a week day as neither of us seems to have a job... I have all the tools to git 'r done.
Great Offer, Thanks. All the parts shipped out yesterday, except the head gaskets. I have not ordered yet, because I haven't deceided on a thickness, brand, or diameter. Any suggestions? Engine is bored at 4.155; and a napa store 3 blocks away.
My wife is in FL and returns next Tuesday @ 4:30 pm. I was hoping to contact you and see if it was OK to stop by and see your project, if that would be OK.
And yes, no job, retired; and any day or time would work for me. I think the bearings are OK; but will post a few pictures in the general discussion area.
Chris R said
Jan 6, 2011
I would suggest getting Fel-Pro headgaskets. The kind that have the blue meterial on each side. Nice product.
SShink said
Jan 9, 2011
Jim, I'm making the parts order list for my 402 and here is a pic of the rear main seal and plastic tool I was trying to describe (the tool is on the right and is made out of a flat sheet of thin plastic):
-- Edited by SShink on Sunday 9th of January 2011 0404 PM
-- Edited by SShink on Sunday 9th of January 2011 0423 PM
jim larson said
Jan 9, 2011
Thanks Stan, I will probably have help with this assembly.
How do I go about this? Thanks.
It's true though, my assemblies don't leak.
I don't remember, is it a rope seal or 2-piece rubber?
I did this on a 396 a couple of years ago, and did ruin the first half seal when I caught the edge of the seal on the edge of the block and it did cut it when sliding it in the groove.
The seals will come with a thin plastic sheet cut out to fit the groove width so that you don't slice it. After I figured that out... it worked fine the second time.
Clocking the edges is important. I think the instructions said to put a dab of RTV on the seal edge so that it sealed to the other edge before you 'clock' them.
Just take your time sliding it in and it will be fine. Retorque the bearing cap and it's all good.
My wife is in FL and returns next Tuesday @ 4:30 pm. I was hoping to contact you and see if it was OK to stop by and see your project, if that would be OK.
And yes, no job, retired; and any day or time would work for me. I think the bearings are OK; but will post a few pictures in the general discussion area.
Jim, I'm making the parts order list for my 402 and here is a pic of the rear main seal and plastic tool I was trying to describe (the tool is on the right and is made out of a flat sheet of thin plastic):
-- Edited by SShink on Sunday 9th of January 2011 0404 PM
-- Edited by SShink on Sunday 9th of January 2011 04