Front Main Seal/Cam Seal

[Bushman]

hey all,

so a while back i scored an '83 after receiving a ton of encouragement from the site. well, i finally got a good weekend to get some work done on it and my plan is to replace the front main seal and anything else along the way in that needs it (timing belt, etc.). my question is where does the front main seal live? i have the manual (available from the site, thanks) and no where does it really mention it. after doing a few searches on the site, i have a vague idea of where it is. the kicker was that Petros mentioned not to take the oil pump off, but rather to get under it with a thin screw driver and pry it out. knowing that just getting to work on things can help illuminate the picture, and i hope that this will be the case. but does anyone have any further suggestions on the process? i also read that replacing the cam seal is advisable as well. any advise there? i have all the gaskets and seals from a killer shop down the street that specializes in japanese engines, so i'm ready!
thanks for anything you might offer....

[dlb]

the front main seal is for the crankshaft. when you open the hood and look down between the radiator and the engine, you'll see the biggest, lowest pulley. that's the crankshaft pulley. the front main seal sits in the block behind that pulley.

do you have a big leak coming from the front main? if so, you should be able to see where it's coming from, but if it's not dripping i wouldn't bother replacing it. a bit of dampness or 'seapage' is normal and fine.

[Bushman]

yep, its got a pretty bad leak. when i bought it, the former owner had replaced the oil pan gasket only to have another leak start. at this point he gave up. no doubt the leak was a result from poor work done on it, but it afforded me a great steal of a price.
i am having a hard time seeing exactly where the leak stems from, but your description of location is pretty dead on. the stream is a constant pinhole size leak, and a cant think of anything else.
so today i am going to get into it and see whats up. once i get everything pulled i'll check back in. i am imagining it being a pretty simple, albeit methodical, tear down, but since i have never work on it before there remains a lot of unknowns.
thanks for the advice dlb.

[Petros]

the front main seal is actually not in the block, but on the oil pump housing that bolts to the front of the block. I thought I read a FSM proceedure that describs removing the the oil pump to replace it. Do not do that, it will compromise the pan gasket.

this is the one minute proceedure: drain and remove the radiator (gives you room to work); removing all the drive belts, and the pulley on the water pump (3-10mm bolts), remove the front cover, loosen and remove the cam timing belt. Now you have to break free the large bolt holding on the front pully, you will need a 17 or 19 mm socket (it varies year to year on bolt hex size), and a large breaker bar and a cheeter pipe on the end of it. the easiees way to hold the crank from turning was invented by another list member; remove front spark plug (or all of them, makes it easier to turn the crank), put number one cylinder before TDC in the direction of remove the bolt, and feed into the #1 spark plug hole a 18-24" length of soft cord and leave the end hanging out (so you can pull it out later), than turn the crank until it clamps down on the cord and stops it from turning. Make sure it is at TDC and not between strokes, that way the valves are closed and you dont risk bending them. break the front pulley bolt free and remove it. Usually some tapes with a soft mallet on the front pulley side to side will break it free and you can wiggle it out by hand, if it is really stuck you will need a puller (not hard to make one from a block of metal with two holes drilled in it to align with the front pulley side bolt holes, these take a 12mm socket). Once the front pulley is off you can remove the timing belt, and than you have to slide the lower timing belt gear off. Usually it just slipps off, but again sometimes goo depoisits or rust can make pulling off the dear difficult. You can carefully pry on it with two flat screwdrivers but be careful that you do not damage the aluminum oil pump housing that you have to pry agains. better to soak in ATF or other pentrating oil and heat it carefully with a heat gun, and than slide it off. under this front timing belt gear is the front seal, you have to get under it with a slim tool like a narrow screw driver and pull it out.

the front seal are a PIA to replace by themselves, but you are most of the way there when you replace the timing belt, so that is a good time to replace them. I use gasket sealer on the outside of the seal to help "glue" it into place, and put grease on the inside lip that rides against the inside flange of the front pulley. if the front pulley seal land is rusty or damaged, best to sand it out with 400 grit wet and dry paper. I usually use a plastic mallet to put the new seal in, but some have found a tool made from a short length of ABS plastic pipe a lot easier to drive the new seal home evenly with less risk of damaging the new seal.

the cam seal is easy, best way is to remove the cam sprocket (14 mm bolt), hold it from turning with a small pry tool through the spokes. remove the sprocket and than you will see the cam seal. you can either pry it out, or remove the front cam bearing cap to remove it.

Some people also replace the water pump, but it is easy to access after you remove the radiator anyway, so unless you suspect you need a water pump, I would leave it. they typically last about 100k miles. do not buy a re-manufactured water pump, they are junk. Get a new one from NAPA or other reliable sourse preferably made in Japan, and not made in any communist country.

Good luck. the first time you do this it can take all day, after some practice it can be done in about 2-3 hours (presuming nothing gets stuck!).

[Bushman]

Thanks Petros! coming with the info big time!

Well, had a hell of a time getting the pulley off. Do have one more question. Is the front seal a felt type gasket/seal that looks like an upside down "U"? The gasket set that I bought didnt contain it, so i bought one at the local, but its called a crankshaft seal. could this be the same, just under a different name?

Getting close....

[Bushman]

Nevermind about the last comment, i was trying to out smart myself again. I am now down to both the front main and cam seals. They are an absolute PIA to get off. So far all i have succeeded in doing is to scrape the top of the plastic ring off. Cant find the set if dental probes i use to have. Any suggestions?

[marlinh]

You need a hooked tool that is stronger than a dental pick to get behind the seal and pry it out. You can sometimes do it with a screwdriver. There are special tools, but you can drive a screwdriver along the edge of the crank or camshaft to get under the lip of the seal. You don't want to damage the shaft. If the seal is hardened and old you may need a small hammer to tap the tool behind the seal. Once you get underneath it pry the seal out towards you. If it breaks apart, no problem just position the screwdriver in another spot and try again. It will come out.

[Petros]

some people have had good luck by drilling a small hole in the metal rim of the seal and scewing in a small sheet metal screw. that gives you something to pry against. I have found a smallish screwdriver driven into it and lever it out usually works fine. You will damage it badly to get it out, but it is no good anyway. You can remove them so they can be reused, but that means getting behind it and tapping it out. Which means pulling off the oil pump (do not do that). just be careful installing the new seal so you do not damage it.

the cam seal is easy, with the valve cover off you can unbolt the front cam bearing cap (two 10mm bolts if I recall), and the seal will slip out. make sure you torque the cap back down to the factory spec, the bolts go into the aluminum head and it is easy to overtighten them and damge the threads. That would be bad.

[Jarf]

Don't know if this applies to our beloved Toyota's but back in my Suzy days, we would have all sorts of people complaining about the quality of the car cause they would leak oil everywhere, change this part and no sooner something else is leaking.
It is a rather common scenario and not really the fault of the car.

When the PCV system isn't functioning properly, crankcase pressure can build-up within the engine, it will build until it finds a way to release the pressure, whatever gasket is weakest will be the first to let go, after that it just becomes a chain reaction of the weakest link in the chain, until something major happens.

Usually starts with the valve cover gasket, then the upper cam seal, then the front main, if all those get fixed without dealing with the underlying problem it then usually blows out the rear main, at that point most people will just toss the car as they are sick of the routine and don't want to undertake a "major" repair,fearing that the cycle will just continue, which of course it will until properly addressed.
The failures would happen at any time of the year but most often in the winter when all the sludge inside the PCV system would freeze and totally block the system.
Any engine that burns oil is going to be suspect of having a contaminated pcv system as blow by will build up in the passageways and reduce the ability to breath.

It would be prudent to check your ventilation system, replace the valve and most importantly, clean out all the passages and ports and verify the engine is able to breath properly be especially mindful of the area within the valve cover that contains the steel mesh "filter" that is totally inaccessible (directly underneath where the valve installs).
While this can be a waste time and just as you say, incompetence of the PO's repairs, it is nice to know that you have done all you can to eliminate all the easy stuff that CAN cause major issues.

[terryismyride]

great advice here. Thanks Petros!

good to know I should try to clean the PCV system. Had to be a problem because there was some kind of janky repair done to hold the hose on (I accidently knocked it out one day, thus learning what a PCV valve was ) , but I replaced that and the hose. Should clean it out still!