Pulley Seal Replacement - Step by Step for dummies

[NeedSpace]

Why replace the Pully seal?

If you have oil leaks down the front of your engine (closest to the bumper). In the pic below, you will see the top red circle has oil coming down and landing on the cross over pipe. The dent in the pipe was not causing the leak.



Do I have to drop the engine to fix this?

No, others have done this replacement with the engine still in place. I had the engine out for other repairs.

Getting started

Put the car in 5th gear (if still in the car) or lock the crankshaft in place with something like this. They sell tools to do this, but coming up with your own solutions is more fun. Make sure you have disconnected the battery if it is still in the car.



Get access to pulley

Remove crossmember (engine mount) and remove the pulley shroud. The shroud was slightly difficult to get one bolt out. My craftsman sockets were too deep. I had a cheap asian tool set where one of the sockets was shallow and that did the trick. Sorry about the orientation of the pic. Loosen the alternator fan belt bolt and remove the fan belt.



Time to remove the pulley. You don't have to line anything up as there is no way to put the pulley back in the wrong place. Therefore the timing marks will remain in the correct place. I used a long socket to remove the pulley.



It'll be hard to get this bolt to budge. I used a long pipe (probably too long) to get the bolt moving. But this worked like a charm.



Do some cleaning

Given how long it has probably been since this has seen the light of day, do some cleaning before taking out the seal. The pic below shows the before pic. I use engine degreaser, but there are a lot options. You will use a lot of paper towels so have a trashbin handy. I also used an old paintbrush to get into some of the hard to reach areas.



Removing the old cruddy seal

This is harder than you would think. The procedure is same as the flywheel seal so you can search for that online as well. I used self-drilling screws on either side of the seal. Notice I also tried the top but that didn't work.



With a vicegrip on one or both of the screws, I leveraged a long screwdriver in place until the seal started to give way. You can use a screwdriver as well but be EXTREMELY careful not to scratch the case...otherwise you might make more leaks! Ta dah, it's out! Clean the heck out of the opening left by the seal with clean paper towels and degreaser. Should be shiny and clean! Check for wear on the shaft, if not perfectly smooth you may need to put a sleeve on it.

[NeedSpace]

Installing the new seal

Purchase the right seal. I have read many posts about the pulley seal part number 999-113-290-41-M30. Most claim that Elring is the best; you can purchase that through Pelican. Make sure seal is clean and free of imperfections. Lube the inner opening of seal with some oil and place seal back in case. Some use Curil-T to help avoid future leaks, however, it is an option from what I have read.

A number of people bought tools to evenly coax seal into opening. Others got PVC pipes to do this. I took a full roll of gorilla tape and placed it over the opening. It fit perfectly and honestly, the softer material I thought would be less likely to damage the new seal. Slowly I tapped it in with a rubber mallet until flush.



Putting it back together

Clean the pully while out. Then install. Note the pin on the back of the pulley. Line that up with the hole on the shaft. Then tighten the the pulley bolt.



Put back on the shroud and crossmember. Before putting back on the shroud and the crossmember, clean, sand off rust and paint with gloss black. Consider powder coating. I am not ready to put the engine back together as I have a number of things left to do. There are a number of posts on powder coating. You can do it yourself or send it off to a local shop to have it done.

Good luck!

[gazzerr]

Great job! Thanks for the write up.

[rwest]

Great write up, thanks, I may need to do mine soon.

[mreid]

Well done!

One other point, anytime you have a part with a machined surface that rides on a seal, carefully inspect it for wear. Overtime, the surface can become worn or grooved and no matter how careful you are it will leak. For most parts, thin stainless sleeves are available that can be pressed over the sealing surface making it good as new.

[sugarwood]

Would offset wrenches be helpful for the tight space? Instead of a socket?
http://www.harborfreight.com/8-piece-metric-offset-box-wrench-set-32042.html

[sugarwood]

Does someone have a moment to explain what we are even looking at?

I understand the basics of an engine top end (valves, cylinders, pistons, etc)
and the bottom end (cam pushes the valves, piston -> connecting rod -> crankshaft)

Never did understand what bearings are, and why they get spun...

But, what is this round thing end the front of the engine?
What is this connected to? Why is there a seal in the first place?

[NeedSpace]

Originally Posted by mreid

Well done!

One other point, anytime you have a part with a machined surface that rides on a seal, carefully inspect it for wear. Overtime, the surface can become worn or grooved and no matter how careful you are it will leak. For most parts, thin stainless sleeves are available that can be pressed over the sealing surface making it good as new.

Oh excellent point! I'll add that above. Thanks.

[NeedSpace]

Originally Posted by sugarwood

Would offset wrenches be helpful for the tight space? Instead of a socket?
8 Piece Metric Offset Box Wrench Set

I don't think so, the bolt is recessed about an inch. I couldn't get my box wrenches in there, but mine weren't as angled as much as yours.

[boyt911sc]

Originally Posted by sugarwood

Does someone have a moment to explain what we are even looking at?

I understand the basics of an engine top end (valves, cylinders, pistons, etc)
and the bottom end (cam pushes the valves, piston -> connecting rod -> crankshaft)

Never did understand what bearings are, and why they get spun...

But, what is this round thing end the front of the engine?
What is this connected to? Why is there a seal in the first place?

Sugar,

The round thing at the end of the crankshaft is the crank pulley. Behind it is the nose bearing. Attached below is the picture of a partially disassembled 3.0 liter SC engine. At the end of the crankshaft (right side) is the old nose bearing.




If you look very closely at the picture below, you will find seven (7) bright spots on the crankshaft that sit on the crankacase halve's saddle/s where the bearings are located. The 8th saddle is where the nose bearing is sitting.


Below is the new nose aluminum bearing installed.

Get your self a copy of Wayne's engine rebuilding book and will help you easily understand the detail engine components.

Tony

[sugarwood]

Tony, thanks for the primer!

So, the crankshaft sits on those semi-circular saddles?
That is where the bearings are?
Why can't the shiny crankshaft just sit directly on the engine case semi-circular saddles?
Why does there need to be a semi-circular bearing in between? What is holding the bearing in place?

The green dot is where the nose bearing sits?
Oil is all inside this case, so it can leak out of the front, since the entire crankshaft needs to rotate.
Why can't you just close the engine so there is no way for oil to leak out of the spinning nose bearing area?
Is it because the nose bearing needs to sit on a saddle?
Why not just close the entire engine after the nose bearing?

And in the 2nd photo, the oil leaks out of the inner red area? (Look closely at the added red line)

[shoooo32]

This is a great fix for a crankshaft seal leak. Unfortunately, most leak where the case halves meet the nose bearing. Ask me how I know...

[Luccia at Pelican Parts]

This is some great stuff! Might I suggest you submit this for our tech article library? You already have all the info and steps done so it should be pretty easy. Info on it here: Enthusiast Tech Article Submissions - Pelican Parts.

[KTL]

Originally Posted by shoooo32

This is a great fix for a crankshaft seal leak. Unfortunately, most leak where the case halves meet the nose bearing. Ask me how I know...

Yep on this comment. I didn't want to poo poo the job of replacing the seal because it was well done. But unfortunately often times people mistake a leak in this area as being the crankshaft/pulley seal, when in fact it's the #8 main bearing housing that is leaking due to a failed o-ring.

I highlighted the o-ring groove in green below.





A belt-and-suspenders trick to guard against leakage when the o-ring degrades is to put a THIN layer of case sealant around the bearing housing, further into the engine beyond the o-ring. Treating this area with sealant helps prevent the oil from sneaking past the o-ring because the case itself is the source of the oil.

Plus it's actual pressurized oil, not just splashed oil. It's pressurized here because there's an internal passage drilled in the case at this location. The passage not only feeds the #8 main bearing housing with oil, but also internally feeds the crankshaft. The internal feed to the crankshaft is necessary to direct oil to the connecting rod bearings.

[NeedSpace]

Originally Posted by KTL

Yep on this comment. I didn't want to poo poo the job of replacing the seal because it was well done. But unfortunately often times people mistake a leak in this area as being the crankshaft/pulley seal, when in fact it's the #8 main bearing housing that is leaking due to a failed o-ring.

I highlighted the o-ring groove in green below.





A belt-and-suspenders trick to guard against leakage when the o-ring degrades is to put a THIN layer of case sealant around the bearing housing, further into the engine beyond the o-ring. Treating this area with sealant helps prevent the oil from sneaking past the o-ring because the case itself is the source of the oil.

Plus it's actual pressurized oil, not just splashed oil. It's pressurized here because there's an internal passage drilled in the case at this location. The passage not only feeds the #8 main bearing housing with oil, but also internally feeds the crankshaft. The internal feed to the crankshaft is necessary to direct oil to the connecting rod bearings.

Wow, that would be a bummer. Can this be replaced without splitting the case? I think probably not, eh? Thanks for the feedback! We'll see in a few weeks if you are right! No offense, I hope you are dead wrong but the pessimist in me is eager to find out!

[boyt911sc]

Originally Posted by NeedSpace

Wow, that would be a bummer. Can this be replaced without splitting the case? I think probably not, eh? Thanks for the feedback! We'll see in a few weeks if you are right! No offense, I hope you are dead wrong but the pessimist in me is eager to find out!

NeedSpace,

The nose bearing could not be removed or replaced without splitting the crankcase. Aside from being clamped by the crankcase/s housing, the nose bearing is being kept in place by a dowel or pin from rotating or sliding out.



The 'pin' is located on the crankcase side for 4-5-6 cylinders. Shown above is the hole for the pin.


Tony

[sugarwood]

Damn, this hallowed 911 engine sometimes needs to be split open just for a $1 o-ring?

[Rawknees'Turbo]

Originally Posted by sugarwood

Tony, thanks for the primer!

So, the crankshaft sits on those semi-circular saddles?
That is where the bearings are?
Why can't the shiny crankshaft just sit directly on the engine case semi-circular saddles?
Why does there need to be a semi-circular bearing in between? What is holding the bearing in place?

The case is not made of a material that is tough enough to withstand the spinning, twisting and thrust forces of the crankshaft (combustion forces supplied to it by way of the pistons and connecting rods), and in addition, having removable bearings means that the case does not need to be scrapped at given intervals (simply replace the bearings instead).

The bearings are actually full circular (one half of each circle is on each half of the vertically split engine case), and are held in place by a precision friction fit.

Originally Posted by sugarwood

The green dot is where the nose bearing sits?
Oil is all inside this case, so it can leak out of the front, since the entire crankshaft needs to rotate.
Why can't you just close the engine so there is no way for oil to leak out of the spinning nose bearing area?
Is it because the nose bearing needs to sit on a saddle?
Why not just close the entire engine after the nose bearing?

The engine cannot be closed on that end as the external crank pulley needs to be there (the drive boss for it is actually the tip of the crankshaft), and it can't be closed on the other end as that is the drive side for the flywheel/gearbox input shaft, etc.

Originally Posted by sugarwood

Damn, this hallowed 911 engine sometimes needs to be split open just for a $1 o-ring?

Yes, that is one of several, very dumb design flaws.

Originally Posted by sugarwood

I understand the basics of an engine top end (valves, cylinders, pistons, etc)
and the bottom end (cam pushes the valves, piston -> connecting rod -> crankshaft)

Never did understand what bearings are, and why they get spun...

On a 911 engine (overhead camshaft design), the cam is part of the "top end" - on a pushrod engine (like aircooled VW, many American V8s, etc) it is part of the "bottom end" - cam is in the case, driven by a gear or chain from the crank, and pushrods from the cam lifters actuate the valves.

Crank or rod bearings get "spun" when they are deformed by wear, heat, oil starvation, etc. and actually move from their mount positions and get quickly torn to pieces by the component they are supporting (crank, rods, etc). Also, when the bearing shell moves a little bit, it often fully, or partially, blocks the oil passage hole for that bearing, and as you can imagine, full carnage follows.

[KTL]

Can it be fixed w/out splitting the case? Yep. Some choose a ring placed around the #8 bearing housing (the bearing housing actually sticks out of the case, although most people tend to think the part that sticks out is integral to the engine case itself) and some choose to goop up the area with epoxy. I know from experience that the epoxy is a real headache for the next guy who has to deal with that engine case!

Successful #8 Bearing Oil Leak Fix

[KTL]

This is also a pretty good link Leaking #8 Bearing Seal