Fixing the leaking rear main going to drop the oil pan/crossmember clearance issue?
 

Going to tackle the age old issue of a leaking rear main with a buddy of mine on my '68 GTO 400 w/TH400 - we plan on dropping the oil pan and lowering the crank just enough to r&r the seal...questions...

1) Will the oil pan clear the trans crossmember?
2) If not - suggestions?
3) Unbolt the trans, drop the drive shaft...anything else?

I'm installing a Viton BOP seal - the last two I did worked flawlessly.
I'm a bit reluctant to do this as my car runs so good....and if it ain't broke (other than an annoying oil leak) don't fix it!

Suggestions and/or pictures appreciated - thanks!

i can tell you that aint going to happen your not working on a chevy, the crank has to be removed to replace the roap seal on a pontiac, unless its pouring leave it alone, on the other hand, pull motor and detail engine and engine compartment fix all gaskets and seals be done w it,

Pull the engine.

Once you get halfway through trying to get the pan off you'll wish you had just yanked the engine in the first place.

If you use the BOP Viton seal, the instructions tell you how to replace it with the crank in place (for a 3" journal main). Getting the pan out of the way and removing the old seal is another story...

I concur with b-man - pull the engine.

Tried pan removal a few weeks ago on my 67 FB with engine installed. Even tho service manual gives instructions that it can be done, I couldn't get it off. I pulled the ripcord and yanked the engine out with much less frustraton.

I don't care for replacing rope seals with an engine on the stand. I can't imagine fighting with it while battling a crankshaft under a car.

I tried that 50 years ago or was it 49? Then I pulled the engine.

I pulled the pan and removed old rope seal, installed viton rear main on my 455 '75 trans am with engine in car. Wasn't fun but doable. Don't know on a gto though.

Very difficult without the Pontiac Tool that bolts on the timing cover along with using a 2-post hoist and a long 4x4.

My Uncle's mechanics did it several times on a F-Bird.

My Uncle told me to pull the engine on my GTO.

He was a very smart man and a Pontiac Dealer for 69 years so he saw it all.

Tom Vaught

Pulling the engine will be easier, than the other consequences...........

You know the best way and less aggravating is to aquire all your suspective needed parts and pull the engine/tranny combo as everyone agrees and at least pull trans and replace front seal,change engine mounts,while your pan is off to change rear main pull a couple of rod bearing caps,pull a main bearing or two and look at those,pull your oil pump and change the spring,take the heads off and.....oh sorry,..I forgot to say you might as well change the uni joints on the drive shalft and rear seal on the tranny and pull the pinion yoke and change the front rear-end housing seal and,.....always remember thats it's what you can feel satisfied with before you reverse the procedure and put it all back like it should!!

It can be done in car I have changed the seal in the car many times

CROSS MEMBER
 

:eek: It's not the trans cross member that's the problem,it's the cradle under the engine,that's the problem for clearence...:gag:yank the engine:2cents:

Pull the engine.

11 - 3 in favour of pulling the engine.....makes me rethink my options...

I do have a 2 post lift at work which will make things much easier.

I had the engine out a few years ago....reason I didn't do it then was because my thought process went something like this....

I need to pull the crank to replace the seal; if I pull the crank, I may as well rebuild the engine; if I rebuild the engine I may as well put in a stroker kit...

And.....she runs like an absolute champ....so the old "if it ain't (too) broke...." applies.

Thanks for the input - much appreciated.

YOU SAID MAYBE STROKE IT
 

:jumping: I love my stroked 400/462:usa2::focus:Attachment 314914

Which seal are you using as a replacement?

My two other builds (455 in my '66 LeMans & 400 in my '67 bird) both used the Viton BOP and they didn't leak.

I did this on my '67 2 years/4000 miles ago. Pull the engine. Very easy. And once it's out and on a stand, very easy to do the rear main seal without a total teardown. I pulled the mains and raised the crank at the rear, but didn't remove the crank from the engine. Checked the bearings, etc (77k on the rebuild at that time), all was fine, installed the BOP seal carefully with no issues. While I was at it, installed all new brass core plugs, timing cover gaskets, etc., and detailed the engine and engine bay. Actually, a pretty pleasant job. And, 2 years later, finally a dry undercarriage with NO oil leaks. I have a special tool that mounts to the timing cover to raise the engine so "in car" rear seals can be done, but I've BTDT, and it's several times the work of simply pulling the engine out of the car and doing it right.

There's more room on the second gen F bodies chassis than there is on a 68 A body to get the pan out, still no picnic, but a little easier. Pull the engine and it makes the job much easier, plus the engine will drip oil on your head for 2 days after you pull the pan. I've done it both ways and if I had to recommend to someone which way to do it, or do it myself again, I wouldn't even hesitate to pull the engine.

A little background on me, I made my living pulling wrenches for close to 40 years and when I worked for myself as well as flat rate in a dealership you find out the easiest/quickest way to do certain jobs. In your case pulling the engine will probably be quicker and with the engine on a stand your success rate at having a job that doesn't leak the first time goes up exponentially.