jbaron

MelWff

My guess would be 2 to 3 hours labor times the shop hourly rate.

lars

Recognized Flat Rate on that is 3 hours. Most shops around here are at about $100/hour, so you're looking at $300 plus parts (oil pan gasket and rear main seal), which will get you up close to $400.

Dynra Rockets

But that is an estimate. Actual will likely come in higher as a 40 year old seal could be problematic to get out. There are many past threads here where people struggle to get them out.

HeadsU.P.

I spent more time researching and reading all the horror stories about the job than actually changing the main rear seal. Not that bad of job. I found the worst part was scraping the old pan gasket off the block for a clean seal. Acetone helps here.
A few tips:
Buy a oil pan stud kit and never look back.
Use the new seal to force the old (upper) one out.
Clock the new seal gaps at 8 o clock & 2 o clock.
Use The Right Stuff (RTV) on the block. Let the gasket sit on the pan studs overnite with pan installed & only 3-6 nuts. Next day, remove pan, RTV the gasket, install pan, torque all nuts. These steps will prevent squeeze out (leaks) of RTV.

7T1vette

This is one of those items that a person can do for themselves....IF they have a basic tool set and a little bit of 'wrenching' experience.

Caution: If you can't afford the $400 sources and are looking for a "corner" mechanic, make sure that they have done this job before. It is not difficult; but if you just go at it 'blind' (zero knowledge on doing this job), the new seal can be damaged or just not seal.

If you decide to DIY, we can give you the important tips to watch out for.

HeadsU.P.

7T1 is correct. Its not hard if you have some ramps. If you just changed the oil, save it in a clean milk jug. You do not have to remove the starter. You don't even remove the oil filter. Two nuts on the idler arm drops the entire steering linkage a couple inches to clear the pan. Oil pump off, main cap off. Read instructions with the new seal.

Other Chevy Forums have great pictures of the seal exchange. Remember, you are forcing the top portion in only. The bottom seal is done on your work bench.
Try Google. SBC rear main seal install.

I don't know where others are coming up with 3 hr job. Must be 2 hrs of drinking beer, an hr of labor?

lvmyvt76

you could buy a lot of tools and beer for $400, jmo Find someone in a local corvette club to help you.

jbaron

Thanks everyone, I have access to a lift so maybe I'll give it a shot. I'm not sure yet but if I do I'll check-in for more info.

7T1vette

Good choice! You will learn things about your car in the process; and you can tell your 'buds' that you installed a rear main seal in your C3!!

Tips later {when you request them).

lars

If you do it yourself, here is another tip: Unbolt the idler arm from the frame.

Lars

Jebbysan

I was waiting for someone to say this!
You cannot really remove the pan without doing this......
It is really easy to tear up the seal with the sharp edge of the block. A small pointed nail file to knock the sharp edge off is more of a help than you think. Not filing the crap out of it mind you....but just to slightly chamfer the edge. I never have any luck with the "tongue" tab install tool while laying on my back. Also remember to stagger the parting line slightly.

Jebby

HeadsU.P.

Ah, see post #7. Someone mentioned the idler arm.

7T1vette

There are other specific tips on how to prevent damage to the new seal when installing it, and how to prevent leakage at the split between the two halves of the new seal.

Make sure that you purchase a seal made of Viton and from a good brand. This is something you only want to do ONCE! Research the process and the various seals available for that job on the internet. When performing the work, take your time and double check any action BEFORE you take it. If you have any doubt in the next step, use this Forum to ask questions.

drwet

Don't cheap out on the seal. There are good ones and there is junk.

Also upgrade to the one piece gasket and buy the gasket kit with the clips to hold the gasket and pan in place while you install the bolts. Can't imagine how we used to install a pan gasket in the car before those clips were invented.

HeadsU.P.

Thats why oil pan stud kits were born.

jbaron

I didn't think you could switch to a one piece seal because it was a different design from something I saw on the internet. Thanks

drwet

You are thinking of the rear main seal and you are correct. They are not interchangeable. I am talking about the pan gasket.

lars

Working "the line" at GM dealerships in the 70's, we used "Gorilla Snot" (aka, yellow 3M weatherstrip adhesive). It eliminated any "roll-backs" (aka, warranty returns), but Lord help the poor guy who had to remove the gasket the next time...

Lars