Replacement engine rear main leak

PCV was replaced with new grommet in valve cover during motor rebuild so that should be good.

So had MLK-day off as a holiday but my son Bradley's busted fuel pressure damper on Sunday was a team effort and we replaced it. So that left the rear main had to happen on Monday. I started in earnest at 9 AM and was reconnecting the gear levers and trim by about 9:30 PM. Had to make a tool to adapt my floor jack to the t-case and used my Toyota bottle jack to get the t-case and transmission pitched correctly. Worked a charm and made the this a one man operation all through out.

Thus began a nice 12 hour stint in getting the seal carrier off the engine block and replaced with a newly pressed in rear main seal with which I used my Harbor Freight press and a nice big flat steel plate to normalize the insertion depth. I checked the new seal on the crank prior to pressing it into the carrier without the saver on it and it had plenty of springiness as I pushed it onto the crank's flange.

I tried 212 °F on the new seal saver and that wasn't going to work as it would cool off to quick and I was going to ruin it trying to push it on without a proper tool. So I skipped it and forged ahead.

Two drives to work and no oil today, fingers crossed, I think I nipped it in the bud so to speak. By removing the aluminum seal carrier casting from the block and getting that seal pressed in with the least amount of trauma might be the key to seal happiness after all!

Nice tip guys, I really appreciate the like mindedness in this threads content.

 

^^^so when you reinstall the seal carrier, how'd you assure no leaks at the oil pan? Just lots of RTV?

Nice work by the way!

The one I did is still leaking, but I think it's greatly reduced, and the oil pan "gasket" looked highly suspect, so high probability any remaining leaks are from there.

 

D60,
When I rebuilt the engine I literally glued the windage panel to the block with RightStuff gasket maker. Then I did the same with the oil pan to the windage panel and screwed them all together. So the seal carrier makes up part of the surface that is co-planer with the block. In removing the seal carrier I slipped a utility knife into the gasket maker and severed the joint. I had to twist the pair of M6 studs out of the seal carrier with a vice grip as I could not get it off the dowel pins that align it on the block and get it to come out of the windage panel and the oil pans sheet metal holes at an angle. So once that was done I was able to clean everything up and pried off the seal saver that I had pressed onto the crank shaft from my last attempt at solving this dilemma. The old seal was pried from the carrier and it had certainly left some markings on the seal savers surface.

With the seal carrier all spic and span I pressed in the new seal and used a nice hefty 4.00" x 4.00" x 1/4" thick steel plate to load the seal evenly as I pressed it in with my newest favorite tool. I greased up the crank shafts flange and filled the seal with grease inside the "V" that establishes the contact between the seal and the crank shaft.

With all of the 515 Loctite scraped from the carrier and the blocks mating surfaces all I had left to do was make sure the top of the windage panel was clean and ready for some RTV gasket maker. So I applied that to both surfaces on the seal carrier as it addresses both surfaces that are at right angles to each other on the block and windage panel. As I aligned it on the dowel pins I slid it onto to the crank shaft being careful not to roll or buckle that seals lip. While doing this I was worrying about the windage panel sealing to the carrier but I had applied a fairly liberal amount of the gasket maker RTV to the surfaces and the corners before I place it into position. I got a very nice satisfying squish from the block to carrier surfaces as I secured the M6 hex head screws and then followed up with two more M6 Hex head screw to bring the oil pan and windage panel snug up against the seal carrier. So I discarded the studs and used screws in the carrier at the bottom.

I have put 128 miles on the 4Runner this week in getting to work and back and so far the peep hole on the bottom of the bellhousing is still dry. I really think that taking the time to put the aluminum seal carrier on my Harbor Freight Press and using the steel plate are what won the day in getting that ruddy seal into the carrier in a correct fashion. Because the 4 inch square plate overlaps the seal carriers bore so that you cannot press the seal into the carrier too far. What is more using the press keeps the operation square and stops the seal from going in crooked which I think can ruin its general cross sectional geometry which may bugger its ability for the lip to properly contact the crank shaft and dynamically seal the engine as the crankshaft turns.

 

Yep the factory tool also won't go into the seal bore, but it's barely bigger so my fear was that you could still "tip" the tool and drive it unevenly. That's why I made the Al insert which forces the crank to keep the tool concentric, at which point it's nearly impossible to drive the seal anything but flush with the seal carrier.

More than one way to skin a cat I suppose

 

What are the odds your second attempt was successful because the seal carrier was leaking? I'm wondering if this is an often overlooked aspect of the RMS job? IOW I'm wondering if the seal itself is often blamed when in fact it's the factory sealant on the carrier breaking down?

Just a theory....thoughts?

 

D60,
Sure is a possibility that the Loctite 515 I used to set the carrier to the block may have failed when I rebuilt the motor. The seal went into the carrier with a lot less trauma using my press than when I hammered it into the carrier with my mallet while it was on the engine as the the first time I replaced it after the original engine rebuild seal did not work as expected. Or so I thought and to your point it might have been the 515 not working out as expected all along? Also the seal saver I used was very suspect and am glad I was able to remove it and not bugger up the crank shafts surface. I was really expecting that removing the carrier from the oil pan and windage tray panel was going to give me a non-sealing junction after I cut the RightStuff between the carrier and the windage tray's surfaces. Swapping out the studs for machine screws I think helped with getting the carrier back onto the motor and also helped with making sure I got a good blurb or sealant to extrude everywhere when drew the fasteners tight.

I just checked the bellhousing at work this morning and still dry, yay! Perhaps using the grey silicone gasket compound on the carrier this time around has indeed solved what I thought was the darn seal not sealing. Sure is nice not being that guy leaving oil stains everywhere I park the 4Runner now that it is sealed up and no more mess all over the undercarriage either. This is the sort of thing I am more accustomed to with Toyota ownership, by and large no oil leaks!

 

Well now you've got me all paranoid....I just bought a bunch of Ultra Black to reseal this motor....I've got time to let it cure for 24 hours after install... I wonder if this is sufficient?

 

I always like the RightStuff gasket maker that comes in a cheese-wiz can with nozzle. The stuff is good for everything: gasoline, oil, antifreeze, ATF and air. Some limits with trying to use on the exhaust but that's about the only thing I can think of that would be a no go for this stuff. The Ultra Black is good goop too but it does not have the immediate use capability like RightStuff claims. Fleet Mechanics swear by RightStuff.

 

Well my saga also seems concluded after pulling the trans a 2nd time and sealing the carrier plate in which the RMS rides. In my case the problem was apparent as there was a paper gasket there missing huge pieces.

The only reason I didn't pull the carrier the first time was that I'm not a Toyota expert and most write-ups online (at least that I found) say to not pull the plate or you'll just cause more work for yourself.

However I would posit the following argument: if you're in that deep to do an RMS job you absolutely SHOULD yank the carrier plate and re-seal it. To do any less is only doing half the job because you effectively have two seals that could leak right there: the RMS itself and the plate in which the RMS resides.

Some write-ups say to only pull the plate if it's leaking but I honestly don't know how you could differentiate which is leaking without starting the engine and watching....which becomes problematic with no flex plate or flywheel installed

 

Also if you have credible reason to believe the oil pan gasket leaking, now's the time to just address that, too.

It does increase the scope of the job considerably but not as much as you'd think. The front diff drops out with basically just 3 bolts and the crossmember has 4. Some say removing the crossmember affects alignment and indeed I do think the frame spread A TOUCH when I unbolted this one....but truthfully I don't see how it could have affected camber more than MAYBE 1/2 degree per side....so, negligible.

With the front diff removed access to just everything is more of a joy and getting at the starter is a breeze.

If you opt for this do the following:
-remove front diff
-remove oil pan and windage tray (grab a new gasket for oil pump to block interface)
-remove trans and RMS carrier
-replace RMS and re-seal plate
-reinstall windage tray and oil pan
-reinstall trans and bolt up starter now
-reinstall front diff

If you drive out the studs for the CV shafts it makes the job easy to R&R front diff. I actually turned down the "splined" portion of the studs -- there's no reason they have to be press fit and they have a hex head just like a bolt so holding them during installation is NO problem

 

This is a great thread, I’ve bookmarked it. It’s an issue we’re all going to face sooner or later.

 

It's completely tangential but if one is going to remove the front diff (to drop the oil pan) this is what I used to drive out the studs on the inner CV flanges.

It's a crude air hammer attachment I made YEARS ago for just such things. It's just got a basic counterbore so you can set it over a stud or bolt and not walk off. Each stud popped out readily with just one or two "baps" of the air hammer.

It does bugger the threads a bit but I ran 'em thru an M12x1.25 die to clean them up. No problems on any of the twelve. Still, I guess running my own machine/fab shop makes things easier.....

 

Here's what the rear of the engine looks like with seal carrier plate removed. You can see the alignment dowels lower left and right.

Also note the flange on the exhaust near top of bellhousing -- if you're still running the factory crossover pipe. This flange will fight you when it comes to getting a socket on the upper LH bolt for bellhousing. Once trans is out I reco taking an all-sixteenths or Vise Grips and bending the flange back and up a bit - you'll be glad you did!

The 3.0 has a reputation for leaking rear mains and "failed" RMS jobs - I still maintain most of this is due to people not re-sealing the rear main carrier plate.

That said, I'm not a Toyota expert so if anyone wants to disagree, I proclaim No Contest and defer to your judgment

edit: note front diff gone, oil pan gone. Sure makes it easier to walk "through" when the vehicle is on a lift. May not matter so much on the ground, not sure

 

Hi fellas,

Thank you all for the information. I've been chasing an oil leak around for a few months and could use your help. This summer I bought a 1993 T100 with the 3VZE and R150F. Blown HG, clutch was toast, leaks everywhere - the whole 9 yards. I replaced the HG, had the heads resurfaced, and replaced every seal and gasket I could touch while I was in there. Truck is running well now, but since the rebuild I've had a persistent leak at the rear of the engine. Here's the rundown. The back of my heads are dry. Valve cover gaskets are new, cam covers are new. I am confident there is no oil coming from the top of the engine. I have replaced the rear main twice now - once with a Toyota genuine seal and once with NAPA brand. I've pulled the seal carrier and resealed it with Permatex RightStuff. Last week I resealed the oil pan and windage tray to the block with Permatex UltraBlack (let cure for 48h). To install the seals, I lightly coat the outside with grease, pack the lip with grease, and tap them into place with a piece of wood. They have appeared to be seated well to me. I've done one seal with the carrier in the truck, and one with the carrier removed (on the bench). I have not tried any seal savers because the crank surface looks to be in good shape. Still, I have a pretty healthy drip. Once I park the truck, a pancake size puddle appears within minutes. Oil appears to be coming from the rear main area, dripping out between the clutch cover and bellhousing. Two things I have not done yet: replaced the PCV or oil cooler o-ring. I figure I should take care of these things, but I don't suspect they are the cause of my leak. Any advice you may have would be greatly appreciated.

Thanks,
Brendan

 

Are you sure it is not comming from those blasted pucks at the back or the cam shafts. You have to use Right Stuff on them and put them in the head fist and then install the cam bearing cap over the top of it with 515 on the sealing surfaces with the head. Pushing them into the head doesn't work.

 

Hi Andrew, thanks for getting back to me. If it is coming from the pucks, I can't see any traces. I installed them in a similar manner to what you've described except with Toyota black RTV on both the puck and cam cap to head interfaces. I did this when I installed the cams back into the heads.

 

That's good on the pucks. Then if the RM seal doesn't go into the carrier really flat and parallel to the face of the carrier it will warp during insertion and it will leak. Hammering with mallet will bugger it for sure. The only success I have had was to get a harbor freight shop press and use some thick steel plates from IMS to load the seal evenly as I pushed it into the carrier. That was my final and third attempt at getting the ruddy thing to not leak after installation. +30K miles and dry bell housing to date. Blue Feld Pro cam cover seals seem the best so far on those glass filled plastic composite covers. But bond the gasket into the groove in the covers with right stuff and leave the seal to head surface clean and dry of any oil residue. So far that is seeming to last the longest before they weep.

 

Thanks for your help, Andrew. My leak has mysteriously stopped (or at least slowed to an occasional drip). The only things I could imagine that happened are maybe I had the seal lip folded and it corrected itself? Or maybe some of the grease I packed the seal with has stopped the leak? I don't suppose it could have been residual from before the replacement, but you never know. I hope this isn't indicative of another issue. There's still oil in the truck so I'm not touching it!

 

hoag3,
Glad my love affair with my own 3.0 has had some practical application. Christ's second commandment is to love your neighbor as yourself. So, it is a joy to make my 4Runner the best it can be as they carry so much negativity in reputation. Your love affair with your 3.0 makes for this forum and critical mass in swapping experiences. So, Merry Christmas to you and your loved ones and know the best two days in your life are the day you were born and the day you realise what it is Christ intends for you to do in this life.
Cheerio,
AP