Was trying to drain, clean and refill the rear diff last night at 2 A.M. Eleven of the twelve bolts broke free just fine. Last one (always!) wouldn't budge. Socket jumped a tooth slightly rounding the bold head. The how-to I was using spec'd them as using a 1/2" or 13mm socket. 13mm was sloppy - 1/2 inch was ok, but 15/32 would have been good - if I'd had one. No rust to speak of.

Thank the Lord we didn't crack the seal on the case before we broke all the bolts free.

We re-torqued all but the one we couldn't break, and checked for leaks an hour later - slightly wet at the bottom - not even enough to drip. Haven't checked it yet this morning (50 miles trip home), but my guess is that the seal will hold for at least a couple of days.

Gonna start with that bad bolt next time so it isn't the only one carying the preasure. Don't want to heat it too much - is metal fatuge an issue there? Gonna soak it with Deep Creep the day before too.

Q1: Good ideas for breaking that last bolt free? Any tools? The "As seen on TV" wrenches that grabb in the middle of the facet?

Q2: The how-to I have on the rear diff fluid change suggests not adding the friction mod first. Instead, add it at the end, a bit at a time until you get the desired slip behavior. How do you add the friction mod once the rear diff is full? Use a turkey baster to remove some fluid, then add friction mod? Or slightly underfil the diff for the limitted slip tests - then top off after you are comfortable with the slip behavior.

Q3: Why doesn't my friend have a lift so that I didn't have to spend my day on my back doing all these maintenance items?

Q4: Forget that, why don't I have a lift!?!?

Q5: Why is the sky blue?

Thanks all!

 

I only use 6 point sockets for difficult bolts and make sure to determine it is metric or english. Then use a 6 point not a 12 point socket.

The sky is blue because the short spectrum light from the sun passes through the atomsphere and thereby showing only the blue until the sun is low on the horizon, then the long waves in the red spectrum will be pronounced therefore red skies if there are no clouds.

Your friend doesn't have a lift because you haven't bought him one yet.

Add the special lub in exact amounts specified usually one container / differential, then just fill up with oil using a special tool for about $4.00 from Autozone on a qt. container.

Jim

 

The blue color of the sky is caused by the scattering of sunlight off the molecules of the atmosphere. This scattering, called Rayleigh scattering, is more effective at short wavelengths (the blue end of the visible spectrum). Therefore the light scattered down to the earth at a large angle with respect to the direction of the sun's light is predominantly in the blue end of the spectrum.

An interesting read: http://math.ucr.edu/home/baez/physic.../blue_sky.html

 

bigger hammer!!

no seriously try tapping the bolt head a few 10 -20 times may break loose the grunge
save heat for last may change temper of bolt and will increase bolt diameter till it cools down competely. 6point socket and after that pipe wrench/ vise grips, then drill it out and tap and buy new bolt.
if it works don't mess with it . if its broke, fix it. if you can't fix it f8$%it up so bad no one else can fix and make you look bad!

 

I've had good luck using an impact wrench when bolts were stuck and I was afraid of breaking them. It is also possible that during assembly or at a previous service the bolt was crossthreaded or something in which case betontheturtle pretty much sums it up.

Jim

 

Get some PB Blaster, and spray it down 2-3 times a day till you get to taking it out. You cant overdue it. Just a qucik shot around the head is all you need a 1-2 sec blast. Impact would be nice with the CORRECT size socket. Get the tightest socket you can on there, and if you dont have an impact you steady even pressure on it with a pipe for extra leverage. If your really hitting it hard and its still not tunring, get the torck and heat he housiung around the bolt. If it still wont turn, sell the truck. Or just drill and tap, but i leave the drill/tap as an absolute final positively last resort, in fact, iive never had to do it yet! Just keep playing with it, its a bolt, its not rusty, it will come out.

 

Believe it or not I did use a 6 point! I couldn't believe it slipped. Only thing I can guess is that it was a slightly smaller head that the others - maybe replaced with differnt size in the past.

Lots of good suggestions - thanks! I also just got a "spiral" extractor that should ensure a good bite.

 

vettdvr and monsta, you guys crack me up. lol..

 

Well, he asked. I didn't even see vettdrv's response!

 

Got to have fun,, yes I have fought with stuck bolts worst was an 79 Caddy with broken head bolt from factory.

Always trying to help and hope others have a little humor.

vettdvr

 

You can remove all the bolts that come out then pry the cover loose.After you break the seal loose just wiggle the cover left to right slightly and the bolt should break loose. Go to the dealer and buy a new one don't reuse it.

 

I think after reading this thread it would be a good idea to already have some from your dealer before tackling this job.