Im doing the Rear Main right now...Questions

Where do I put the RTV on the rear main?

Thanks
Chris

You don't. Soak the seal halves in clean oil for about 10 minutes before you put them in (longer is better) and slip them into place. Torque to spec.

If you look carefully, there is just a touch of protrusion all around that forces the seal ends against each other - that is what seals the ends. This also assures a 360* seal.

Make sure you put the seal in the right way 'round (sharp lip torward front of engine, gradual slope to rear) so it won't leak, make sure everything's clean, and make sure your crankshaft isn't "grooved" where the seal rides (rare on these things, but it can happen) and put it all together.

If it makes you feel better, I've done three of these on 242 engines and I've NEVER used RTV. These aren't Chevvies or Fords - they'll seal the first time!

5-90

You can always double check with John at Auburn Car Repair.

I know he puts a little dab of RTV at the ends where they meet the pan just to ensure a leak free installation. We've done a couple recently and they always turn out nice.

I used engine assembly lube. went right in the rfirst time (1st time done in 180k and 14 years)

Hey, I'm starting a slow leak from my rear main seal. How long did it take you to do this? What was your general set-up as far as tools, equipment, and location? Thanks for the help! :repair:

I guess I should dig out that writeup I did a fwe years ago...

It's really a simple job, doable with hand tools and without major disassembly. It helps if you're already lifted, but if you can jack up the front end and let the front axle (for 4WD) get to "full droop" you'll have room to pull the oil sump.

You'll need a socket wrench and sockets - the oil sump uses two sizes (7/16" and 1/2" for the 1/4" and 5/16" bolts,) a 3/4" socket for the main bolts (as I recall) and tools to remove the starter as well as the inspection/cover plate for the lower bellhousing. With luck and care, that's all you'll have to pull out. I don't have the P/N handy for the one-piece sump gasket, but I've heard good things about it (haven't used one myself.) You can also for the later oil sump gasket - I think that's the OEM application for it (somehwere past 1996.) It should fit all oil sumps on the 242. You'll also want a lightweight shop hammer (one pound or less) and a small brass punch or rod (about 1/8",) as well as a fairly hefty soft mallet (2# or so,) and a torque wrench to reinstall. Have some RTV - especially if you use the 4-part gasket - and some engine assembly lube. If you've noticed a drop in oil pressure, you way want to have a micrometer handy (2-3") to measure the crankpin journals for new bearings. This is about a three-beer driveway job if you jump in and get it done. Time things so you can soak the new seal halves in clean engine oil for a minimum of 10 minutes before installation.

Disconnect negative battery cable and remove starter (doing so gives you some very useful wiggle room!) Jack up the front of the vehicle and allow the axle to droop (for 4WD - if you are lifted under 3", suspend the vehicle with the front tyres just off the ground. At 3" or more, you'll be able to ease the oil sump out easily - I did.)

Remove the inspection plate on the lower bellhousing, drain the engine oil. Remove the oil sump pan (there's something like 30 bolts on the thing - take your time and make sure you have them all.) If it's the original factory seal, it's going to be a little sticky - a soft mallet (rubber, wood, rawhide, nylon) applied gently against the side of the pan can help break it loose.

Slip the oil sump pan toward the rear of the vehicle. It should slip out right underneath the transmission.

NOTE - Check the oil pickup screen for any trapped debris. Now is also a good time to give the oil sump a thorough cleaning!

Remove the rear main bearing cap, and get your brass rod/punch and small hammer. Clean around the mating surface for the main cap and look for the ends of the upper seal half. Place the rod against the seal and push - if it doesn't slip out, tap with the hammer. Once you have enough sticking out the other side to grab, pull it out with pliers. It's got a rigid core, so it will be easy to handle - and the "Sneaky Pete" tool for the old-style "rope" seals won't work! Prise the lower seal half out of the main cap with a scrwedriver or similar - it has "ears," so you don't need to work right at the seal interface.

Take a moment to inspect the sealing surface on the crankshaft for grooving - if it's still smooth, you're good to go! (Grooving is rare with XJ's, but not unheard of. If the seal face is grooved, you'll be doing a bit more work than you planned....)

Take out the new upper seal half (without ears) and orient it so that the seal lip will point into the engine case (with the sloped side of the seal toward the rear.) Start the end of the seal into the hole, and push it into place with finger pressure only (that's all you should need!) Install the lower seal half into the rear main cap, coat the bearing shell with assembly lubricant, and put the cap in place. Clean the bolts and install - torque bolts to 40 pound-feet, then 80 pound-feet.

Install the oil sump. I have found it helpful to install about eight small studs - four in each long rail - to hold things in place while I wrestle with the pan. A good size is about 1/4"-20x1-1/4" long, but you can get a set of SBChevvy valve cover studs and you'll be all set. Make sure you get studs for "stamped" valve covers rather than "cast" - the studs for cast covers are too long and will get in your way. Space the studs out, and don't install any on the timing cover! Apply your sealer of choice to the gasket and press it into place over the studs (which will help keep things from "walking.") Guide the sump pan onto the studs and place nuts - place all bolts. Torque the 1/4" sump bolts and studs to NOT MORE THAN 120 pound-inches/10 pound-feet, and the 5/16" bolts to NOT MORE THAN 156 pound-inches/about 12.5 pound-feet. Torquing beyond these values typically results in a crushed gasket and you'll be doing the job again. For best results, use LocTite 518 "Gasket Eliminator" sealant with your gasket.

Install starter and bellhousing inspection/access plate.

Reconnect negative battery cable and lower vehicle.

Refill engine oil - it's not a bad idea to put on a new filter as well...

Allow minimum of 8 hours for sealant to cure before operating vehicle (mandatory with LT518 - but the stuff WORKS!)

NOTES -
It is not usually necessary to remove more than the rear main bearing cap. In the (rare) event that you can't get the seal out, you can remove the next cap forward - remember to coat the bearing with assembly lube if you do, before you reinstall it.

This job is a lot easier if you're lifted 3" or more - it gives you enough space to remove the oil sump without jacking. It can be done on a stocker by jacking up the vehicle and letting the axle droop, tho.

It is NOT necessary to put any sealer on the rear main cap or seal. I never have, everything's still running fine in the bottom end.

It is NOT necessary to remove the transmission, clutch, or torque converter to do this job. No reason to do extra work...

Consider it MANDATORY to use brass tools when working near the crankshaft. No-thing can ruin your fun more than scraping, scuffing, or scoring the crankshaft journal and wrecking something important. Brass is cheap, crankshafts are not.

I really think the studs help - they've helped me. It's worth the extra minute or so of install time to put them in - it will save 5-10 minutes of wrestling with a gasket, and it makes it easier to keep everything in place with one hand while you reach for bolts with the other. Retain the studs in the block with LocTite 242, or equivalent.

It may or may not be necessary to detach the exhaust downpipe from the header collector. If you do (or while you're down there,) replace the nuts with brass - 3/8" coarse thread. You're going to have to disconnect the damn thing sooner or later - save yourself a headache when you do!

One of these days I'll find/do a real writeup on this job...

5-90

5-90 Hey thanks for the information. Gives me the idea I might be able to do this myself instead of taking it to the shop! dn