I have basically taken posession of my fathers 1993 Cherokee Country as he no longer uses it for a tool hauler and never drives it anymore since I moved out a few years ago. In doing some routine maintenance I discovered that the rear diff was EXTREMELY low on oil. to the point that i could remove the rubber drain plug and stick my finger down there and come up dry. I tried to remove the cover to drain off any remaining old oil and refill it but for the life of me cannot remove the old rusty bolts. Penetrating oil and large ratchets have gotten me nowhere as i really dont want to snap any off. I dont want to heat the bolts with a torch as I'm afraid of cooking and destroying any remaining oil that wasnt wrecked by age. Any hints? I topped off the oil but would really like to clean out the crap that is surely in a 220k mile diff that has proabaly never seen an oil change in the last 8-10 years of its life.

P.S. Seafoam is amazing on old 4.0's The engine in this XJ used to idle real rough and got HORRID gas mileage but after a dose of seafoam (no smoke btw) and filling the rear diff the fuel mileage has almost doubled!

 

just keep soaking them with PB blaster a couple times a day and see if it helps, it usually does. it may have seized itself on there due to being hot and a lack of fluid

 

Put some PB blaster and then tap the bolts with something like a pry bar or a small metal hammer. The metal hammer will help to free up the seized corrosion and such. Only tap the bolts once though, and make sure it's a good, solid tap. Do this about once every 2 hours to each bolt and they'll free up.

Impact wrenches work great for that stuff if you have access to air tools.

 

what is seafoam?

 

try to tighten them a little
before you take them out

 

yeah what is this stuff, what does it do, and where can you get it???

 

Seafoam is a Carbon deposit remover. You disconnect the line going to your brake booster and add 1/3rd of a can then shut the motor off for 5 min and restart it. Most people end up smoking out the neighborhood with their exhaust but mine didnt smoke at all. It cleans out all the old gunk buildup in your engine and can seriously help. Google it and check youtube for some good seafoam smoking vids.

 

a lot of people will put seafoam in their gas tank to clean it out. personally, i run it through my throttle body. you can buy it at any auto parts store or hardware stores. it varies in price range from 7 to like 9$ a can.

 

Will seafoam remove congestion in the exhaust line?

 

I had the same problem with my XJ. I soaked the bolts twice a day for a week and then prayed every time I loosened one. It took some brute force but they broke loose. I imagine yours are a bit tighter but one thing I have learned about working on the XJ.....BRUTE force works!! If you have access to electrical pipe get a 1/2" piece of emt and slide it on your rachet for more leverage. Good luck!!

 

nice

 

I love google...

http://www.seafoamsales.com/motor-treatment/index.html

How to on youtube...