Lower the crank to remove rear main rope seal?

Status
Not open for further replies.
Joined
Jan 26, 2014
Messages
25
Location
Germany
Hello,

I'm currently partly rebuilding the engine from my 1969 Thunderbird. The upper rear main seal is making trouble.
Lower was easy, because I just had to remove the cap and than could peel it off. The upper half won't come out at the moment. Easiest way would be to remove the crankshaft, but I want to avoid that.
Can I loosen the bearing caps in order to lower the crankshaft by an inch or two? I guess that would make things a lot easier.
Is there also a pin in the upper half just like the one in the main bearing cap?

As we're already talking about the crankshaft...what should I bear in mind if I remove it completely?

Thank you!
 
Last edited:
Or a sneaky pete, I know that tool, but I want to avoid buying something for that job.
 
I remember doing this once on a GM 2.8, well not very well I guess, as I don't remember how I did it. I don't recall using any special tool though. Maybe it was a metal shell and just the seal blew out...

I presume you can't just grab it with needle nose pliers? I wonder if you could make a tool out of an old half-seal, and push on one side, and grab on the other? Pop the spark plugs, and turn the crank by hand while pushing on the bad seal--maybe you can get lucky.

How does the bearing shell look in the main cap that you removed? If it's in lousy shape then I'd think to drop the crank and do the bottom end bearings. Maybe plastiguage at the moment, see what clearance you have.
 
Originally Posted By: OlDirty
I want to avoid buying something for that job.

I wonder how many times I have said that.


Originally Posted By: Chris142
I always loosen all the mains. No other way to get it in there.

Yeah.... rope seals are **tight**. I don't see it happening without lowering the crank.
 
On my Jeep 4.0 which uses a rubber, not rope seal, I had to loosen up all 7 main bearings to be able to get the old seal out and new seal in.

Be prepared for nasty smelling oil when you loosen up the crank bearings!
 
Originally Posted By: Linctex
Originally Posted By: OlDirty
I want to avoid buying something for that job.

I wonder how many times I have said that.


Originally Posted By: Chris142
I always loosen all the mains. No other way to get it in there.

Yeah.... rope seals are **tight**. I don't see it happening without lowering the crank.
That gives you a change to see if the bearings are worn.
 
Get a skinny screw, screw it into old seal so when you bump the starter over using a remote, pull gently on screw seal will come out, crankshaft rotation will help when pulling on seal. Have used this many times.

jerryg
 
After the rear main bearing cap is removed, just loosen the other cap bolts a couple of turns and pry the crankshaft down a fraction of an inch with a wooden dowel or something. Grab the upper part of the old rope seal with needle nose pliers and pull it out of the upper groove while a helper rotates the crankshaft in the direction it needs to go.

You need "Chinese Fingers" to get the upper rope in. Smear the new upper rope with petroleum jelly after the Chinese Finger contraption is fastened and pull it up and over the crank. Trimming and packing rope seals properly has almost become a lost art, but you have to get it right.
Are you rolling in new main bearings too with the crank in the car?

A two piece rubber replacement seal might be available too. You have to drive out the pointed pin in the lower cap to use them.
 
Status
Not open for further replies.
Back
Top