Hello Sgtb, it is my understanding according to the Haynes Repair Manual that one MUST remove the timing belt in order to access and replace the cam's oil seals, please see pictures attached for reference.
Now i have a question for you: I also have a tundra 2006 4WD with a 4.7 L. I am about to replace the timing belt also, Where did you set the crank shaft mark? on ZERO-TDC or past that mark on the white dot mark, also called the ATDC? I am enclosing two pictures herein so that you see what I am talking about.
Let me know if you need more info on the camshaft stuff, perhaps I could send you more pics and/or text info.
I am also attaching a section of a video of the timing belt replacement that I found in youtube, in there you'll see how he sets the crank shaft on the ATDC, as he calls it.
In this video go right to 3:25 to see what i am talking about. thanks again.
I did watch that video before hand. I'll have to go back and look at Haynes more closely, but I was thinking that the oil seal might be able to come out around the timing tube from the inside of the valve cover with the camshaft out of the way.... this is what I'm not sure of.
(EDIT: The Following discussion is dealing with Timing Belt R&R not cam seal)
To your question, Yes, you will want to set it #1cyl tdc and then go the "50 deg" or whatever the manual says so that the cams will not have any spring load on them. I didn't really understand what was going on with all the clockwise/counterclockwise 50deg stuff until after I only went to TDC (with all the marks lining up) and came back the next morning and saw one of the cams rotated out of TDC position... If I had done it all at one time I don't think it would matter, but since I had to tear down one day and leave it over night before I put the new belt back on- the driver side cam did turn back some due to the spring loading. I was able to hand turn everything back to TDC and don't think there was any damage - everything seems to be running ok, but it seems when I got it lined up and went then rested it at the ATDC mark (the T) mark there was no spring tension on it. That seems to be a neutral setting for the spring loaded variable timed valve cams. You'll just want to make sure you line it all up first and then mark it all with a sharpie or paint pen to make sure that nothing turns and it all goes back together in the proper places.
EDIT ****HOWEVER! The Haynes book does say to go clockwise for 2005 and counter clockwise for 2006... that still doesn't really make sense to me... SO PLEASE don't take my experience as the cold hard fact... **** I THINK that the T mark is where you want it based on my experience and the video - but that is opposite of what the Haynes (and Chilton btw - which is now also published by Haynes apparently) says for 2006 ****.
Also- a couple more side notes: (edit)
-I had a bit of a fight getting the belt over the passenger sprocket so I ended up loosing up both timing belt pulleys a bit for a little extra slack. then slipped on the belt, re-torqued the pulley bolts, check that all the marks were in place, and then pulled the tensioner pin.
- My timing belt looked like it could have gone much longer with no problems... it didn't show any signs of wear that I could tell... the water pump however had a lot of dried up pink gunk (like the video @ 4:19) coming out of the weep hole and all down in that pocket on the engine. So it was probably time to replace the water pump anyway (~110k miles)
- Also, the non tensioner timing belt pulley was a lot more "free" spinning than the replacement that came in the belt kit - so I went ahead and replaced all that stuff as well... used a toyota water pump and gates belts/pulley kit. don't remember the brand of tensioner, but i think the one I had was probably fine, but what's a bit of $45 insurance to just put in the new one... Went ahead and replaced spark plugs and radiator hoses as well - though they may have not really needed to be replaced.
***The hardest part of this job other than the time involved seems to generally be the crank bolt - unless you already have the tools.
(I had a problem getting one of the nuts off the AC bracket - it rounded off and I ended up having to nearly cut it off with a dremmel and cutting bit- but I think if I'd been careful and used a 6 point socket instead of a 12 pt and air tool to get it off that wouldn't have happened)
- I ended up with a 3/4in impact driver rated for like 1400 ftlb max torque (from harbor freight http://www.harborfreight.com/34-in-professional-air-impact-wrench-68423.html
) with an 30deg or so universal and an extension to get the impact driver to fit. (It was too long with 3/4 to 1/2in adapter and then the socket to fit between crank and A/C condenser.) My half inch impact was only rated for 250 max and as expected didn't budge the bolt. bigger impact broke it on second try after letting compressor build back up. I may have been able to break it using the chain wrench and a couple breaker bars with a cheater on the on, but didn't try it before trying the big impact driver... (don't tell harbor freight but I returned it afterwards- was like $240 on sale...):embarrassed3d:
- I used two of the cheap chain wrenches max diameter of one is 5 inches The actual pulley was a little over 6 I think... (EDIT: I measured the cut piece of drive belt at 19.25 in length to fit the pulley-- part of the 20 in length they list in the description is the head of the tool not really the whole chain)(http://www.harborfreight.com/20-inch-chain-wrench-97073.html
) from harbor freight on a 18in or so 1/2 inch breaker bar around the crank pulley (padded by one wrap of the old drive belt) to re-torque the crank bolt. The I used a small pin punch and socket and hammer to make one long chain to fit the pulley diameter. Adjusted the breaker bar to rest on a piece of 2x4 that I put between the breaker bar and the frame of the truck.
Don't mean to hijack my own thread...I should probably make the timing belt part it's own thread at this point... but here are 2 more things about timing belt replacement process:
For anyone else about to embark on this project... I found a nice way to check for the compression stroke when I did the belt on our honda van last fall - using a saltwater type fishing cork (the long triangular type - I believe it's called a popping cork or something). The plastic pin in the middle has a hole all the way through it so it almost whistles when on compression. It fits in the spark plug coil hole nicely. I heard of a guy who did something similar with duck call on a spark plug for finding TDC on piston aircraft engines.
And another EDIT... I keep thinking of things...
I did not disconnect the A/C compressor all the way. Just the wiring connector clip, the bracket in the way of the compressor to fan bracket bolts and the front two bolts. Worked fine - no need to take compressor all the way off as Haynes book recommended.