If anyone has replaced/installed the two-part rope seal in the rear main (without pulling the engine) with the tool that is made to hook into the old rope and pull it out and pull the new in thru, I would highly appreciate if you could share your experience doing it before I start.
Thanks.
I’ve done it many times on Chevys Pontiac and Oldsmobile usually it works sometimes to be turning the crank while pulling the old one out and the new one in. Also have the new one oiled.
When I worked at the Pontiac dealer if you did a rear main seal under warranty you replaced the lower rope and cut off pieces and packed into the upper half. No matter the job was usually a pain.
I have done it on both my 216s, successfully. I had the transmission pulled back and dropped the rear of the crankshaft by about 1/4”. I believe a good seal can only be achieved with all the main bearings adjusted to minimum clearance. I use the Lucas oil additive to lubricate the seal. I pulled it around with picture hanging wire. I recommend the Best seal.
Thank you!
Yeah I expect it to be a pain but I don’t mind that, I just want to do it right.
I like the idea of turning the crankshaft over to help it come out and help the new piece go in. Hopefully I can do it without separating and lowering the transmission or I might get in over my head. I guess I’ll find out.
I’ve got a tool they used to call a “Sneaky Pete” to hopefully help me grab the end of the old one and to pull it out and to pull the new one through.
Thanks again.
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I’m thinking of putting a dab of permatex gasket sealer on the ends where they join from top 1/2 to bottom 1/2 also.
If that’s a mistake please let me know not to do it.
I recommend an original GM seal. they are the best and can still be found. I always used permatex # 2 on the ends.
Based on your signature you might be working on a 1938 216. They do not have a rear main seal. They use a slinger to control oil going out the rear main bearing.
It is a 1938 Chevrolet 1/2 ton HC pickup.
Rusty is correct, there is no rear main seal in a 1938 engine, just an oil slinger.
Adjust the clearance and make sure the drain hole
is not plugged and that is all you can do.
I believe there was a thread about making a groove in the lower shell of the rear main to allow the pressure to drain to the front. If I am not mistaken there was a photo of the modification.
Okay thanks.
Does the engine have to be removed to adjust the clearance ?
Is it done by adding a shim or some other way?
Looks like it’s supposed to be not more than .002
Oh boy.
Now people are telling me there is no rear main rope seal on a 1938.
Gotta do something, pretty bad leak. Several drops a day.
If you do what is suggested in the above reference, you will have the best possible outcome. You don’t need to pull the motor, just drop the pan.
Several drops maybe a normal loss, Walmart sells pans to go under cars to collect minor leaks.
Dave
A 1938 Chevy that does not leak some fluid probably doesn't have enough fluid to lubricate properly. The are not like modern vehicles that almost don't leak.
Yep, the old saying is that if an old 216 isn't leaking oil it is probably out of oil! I have 3 old Chevys and they all leak oil. I just live with it. LOL
There is a possibility that when I pull the pan the rear pan gasket section is leaking.
Hopefully so.
That would be an easy fix.
The pan gasket is in 4 parts so -maybe.
Be sure to check out the oil pan gasket thread at the beginning of the 46-48 section. There is a way to do it correctly, wish I had known that the first time or two I did it.
Dave
to stop the no sealed engines from leaking and from the book"The Cast iron Wonder" I did the following with good results.
First remove cap to block shims to get the clearence down to .002"
Next using a hack saw blade cut a grove in the bearing babbitt from the center oil grove to the front of the lower bearing I did mine just off center,
This will reduce oi flow to the rear of the bearig.
I drove my 1939 cross contry at 65 MPH (3.73 gears) many miles with no leakage and no problems.
See the thread on proper oil pan gasket istallation as previously advised.
Also make sure breather pipe is not plugged-up
Your idea makes sense.
However When my engine was rebuilt they did not pour Babbitt but put in insert bearings.
It has been fine for many years but I’m not sure if it would weaken it if I cut a groove in it.
Maybe I could just make a small shallow cut and be okay since it would be only from the center forward and a little to one side.
I wouldn’t think it would take much of a groove to get the oil to go forward instead of leaking out the rear.
Thanks for the idea.
All crankshft bearings have a babbitt lining, insert or not including 2021 cars. The babbitt iis applied to the insert for all 6 cylinder Chevrolet engines.
Boy I wished I had read this about the rear oil rope seal replacement before I pulled the old one out. Got the tool , which I would not recommend , get a better one to save your hands, and seal from NAPA , the seal is a FEL PRO rope seal and it is way too large to get pulled through the top slot , I have rolled it and stretched it thinking it would thin down as it was played with , tried pulling it an got nothing done except a tool that broke an sliced my fingers. any ideas ?? I am feeling stupid right now an wonder will I have to loosen up the other main bearings to gain clearance or pull the motor out of the car to complete the job ? thanks for any good ideas Rick
Hi Stoker,
I assume you are working on a later engine that does have a rear main seal.
Replacing the upper half is always a difficult task. There is a trick that others have posted in Chat.
Using a small diameter non-metallic punch (plastic or wooden dowel) drive the exposed ends of the upper seal as far as you can up into the groove in the block. Then take short pieces of the old lower seal and drive them up into the space at the lower end of the upper groove. Keep doing that until you cannot install any more pieces. Then trim the ends flush with the block. The idea is that you can make the upper seal expand a little bit and fit tighter against the sealing surface on the crankshaft.
If there is a groove worn into that sealing surface I doubt if you will stop the leakage even with a new properly installed upper and lower rope seal.
If it were mine yes I would loosen all main bearings. There is a tool by KD that is made to remove and install the rope seal. Once installed I would then tighten the bearings to spec and follow the advise given above by Rusty 37.
Good morning , thought I would update my post, watched a Utube vidio an the guy recommended Best seal as the only way to go and after getting one I believe he was right. after fitting it into the bottom cap an using some silicon lube and a Leisle Sneaky Pete I got it installed. It is a big job no doubt about it. that Fel Pro seal is about twice the size of the Best seal and even stressing it out could not be made to fit., maybe it works well with the crank removed ?? Have not put the oil in yet ,but I am glad Its replaced as the old one crumbled as it was removed. thanks everyone for your thoughts and ideas. Rick