Probably the three words that nobody wants to hear....Rear Main Seal...

Ok well, I have a 1984 Ford F250 4x4 w/ 460 and it has an extremely small leak in the rear main seal. I know that these things are cheap but they are a b#@$% to replace. Has anyone ever replaced one on a 4-wheel drive vehicle? Do I need to drop the transfer case and transmission?

How much would a mechanic charge for something like this?

BTW, I really appreciate all the help that comes from you guys on the forum! This is definitely the best website out there!!!

 

Your left leg and your 1st born son! I was quoted $950 when my rear main went out on my F-250.

You don't need to drop the tranny or transfer case, but you will need to jack up the engine enough to drop the oil pan, loosen the main caps and fish out the 2 piece seal that's in there. With all the work you need to do, you might want to seriously consider just pulling the engine out and doing the work on an engine stand.

 

Ouch, big price for a little gasket!!! Is it really two pieces? If thats the case then your right, I wouldnt have to drop the transmission...

 

I can't guarantee that this will work for you, but it worked for me. Back in the early 80's I had a 68 F100 with a 360 that had a front and rear main seal leak, and I couldn't afford to fix it right. A friend told me to put a pint of brake fluid in the motor oil. I was very skepticle, but I did it and it completely stopped the leak. I drove the truck for several year afterwards, always adding a pint of brake fluid at each oil change. It never leaked again for as long as I drove it.

 

what? how wouldnt that not be good for the motor? cuz i have a front and rear main seal leaks as well.

 

no offense, but that brake fluid idea is probably one of the worst ideas i have ever heard of. every piece of rubber that the brake fluid comes in contact with will swell, and i just cannot see it being good for the lubrication of the engine. however, i can understand on a beater or something that doesnt get driven everyday, but for an everyday driver not a good idea.

 

You're right about the rubber swelling. That's what stops the leaks, it swells the seals. Yes, it was a beater, but it still worked for several years.

 

I most certainly believe you that it will work and did for you. I would probably do it also if it came down to doing a rear main seal in beater truck. I was by no means knocking you for doing it, believe me. It is probably brake fluid that is inside the those "engine rebuild in a can" gimmicks lol.

 

I've used some of the engine oil additives that claim to stop leaks and they worked for me. Especially in an old Chevy that had been unused for five or more years.

 

I believe it on the brake fluid trick. A lot of people don't know it but the active ingredient in most stop leak additives is basically brake fluid. It works and it doesn't seem to hurt anything. I have used black pepper to seal leaky radiators and small headgasket leaks. A couple old timer tricks that work!

 

Us old timers use what we've got, and sometimes it works.

 

I had to replace the oil pan in my 80 F100.I hated doing it.I had no choice but to jack the motor up and replace it.I've got an I6 and lining up the gasket and putting 26 bolts in isn't fun.I got it done though.It took two hours.And i had to drop the pan to fix the rear gasket again cuz it moved when i thought i had it.So i fixed that.And it's still leaking.So i'm just pouring a quart in every now and then.I gave up on it.I'm not keeping the motor anyways.But yea definitely take the motor out.It'll save ya the cursin and tired arms.

 

What will get you really upset, is after you replace the rear main, you still have the leak. There are many places that leak on the engine, and they look just like the rear main. A valve cover gasket leak, rear seal on the intake, oil pressure sensor on the rear of the engine, all look like rear main leaks when they run down behind the engine.

 

So that could be my problem?I need to check all those out..Thanks

 

I found the cheapest and easiest repair for my leaky pan/rear main seal. An old cafeteria tray and some cat litter!