Idler pulleys, just some bearing observations

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whtbronco

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My 2004 Expedition with 5.4L developed a light engine speed vibration about a week ago. It's primarily noticeable in gear. Anyway, today I decided to check the pulleys and accessories. I didn't actually finish checking them, I checked the alternator and the 3 idler pulleys. Having found that both smooth idler pulleys felt ever so slightly rough and didn't sound right through my stethoscope I went to dealing with them. I should have finished checking things, but you know how it goes I got distracted by the first thing I found. Worse yet while these pulley bearings were not great, they were not likely the cause of the vibration.

I knew I had a new pulley in my attic so I grabbed that to replace the worst of the 2 smooth pulleys. I then decided I wanted to look inside the bearings. These are only 3 year old 41k mile Motorcraft pulleys. What I found was very little dark, chunky and burnt looking grease. For the heck of it I scraped out most of the grease and filled it in with Amsoil grease, it's all I had on hand and it felt much smoother. No real surprise since it was now full of grease. I then did the same thing to pulley the other Motorcraft pulley finding the same scenario. Well heck let's check the new Litens brand pulley. This time I found very little though nice clean silicone like grease. It was translucent white. I scraped out that grease and filled this one with Amsoil grease as well. The grease gun needle made getting some grease under the bearing cage very easy since there's a small gap around the perimeter and the needle allowed me to push some into that gap. Then filled it up. The rubber coated metal seal just pushes back in easily with fingers alone.

To get the rubber coated metal bearing seal out I used a flat head jewelers screw driver and it pretty much just popped out with minor pressure. I put the screwdriver perpendicular to the seal against the outside race and pushed down and kinda rolled the tip of the screwdriver to pull/push the seal out. There's nothing holding the seals in, they are just press fit. Then I used a pair of pliers to straighten out the seal again as all 3 of them bent slightly upon removal. None had damage to the rubber coating though.

One more observation. RockAuto says that Litens is the OE pulley manufacturer. I've had good luck with aftermarket products that RA lists as the OE manufacturer. While Litens might make the Motorcraft pulleys they are not entirely the same part. At least the bearing seal on the Motorcraft bearings says Litens and Canada. The Litens seal says NTN and China.

The worst part is yesterday the vibration was worse than it was before I started, LOL. Go figure. I can now feel it a little bit not in gear, but it's much more significant in gear moving or not. Anyway, this post is really just to share my findings on the pulley bearings. I did a bit of checking yesterday evening with my stethoscope again and am questioning the belt tensioner pulley. However, today I'll pull the belt off and fire it up to prove or rule out all the pulleys and accessories in 1 shot, like I should have done to start with.


Factory pulleys - 12yrs 186k miles
Motorcraft replacement pulleys - 3yrs 41k miles

I've installed 3 sets following the factory pulleys, none of the replacements lasted very long. In fact all 3 sets combined didn't last as long as the factory set. Maybe a lack of grease in the replacements is the reason.

Sorry no pics, I didn't have access to my wife's cell phone and I was too lazy to get the old DLSR camera out.
 
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whtbronco

whtbronco

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One more follow-up on this. I pulled the belt yesterday and had no vibration. Turns out the belt tensioner pulley was not so good. Best I could do in the time I had was pack it with grease and reassemble. It had virtually no grease in it and not a bit on the ball bearings. Vibration gone for about 90 miles and then slowly started to return as I had expected it would.

During this I got a call that my sons Ranger was not charging, 70 miles away. The stud for the alternator charge lead was broken and the fusible link had popped as well. This alternator, a reman from Advance, was installed in July.

This morning I ordered a replacement for the other 3 idler/tension pulleys. No reason to use Motorcraft for these again, they seem no better than Litens brand. All will be opened, cleaned and packed with Amsoil grease. Maybe they will last longer, we'll see.
 
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whtbronco

whtbronco

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Well I really didn't intend to update this thread again, but I found this very interesting and took some pics.

I have 2 pics of the grooved idler pulley when new. One shows the pulley, backside of the seal and the 2 jewelers screwdrivers I used. The larger screwdriver I used to pull the seal out and remove most of the grease, the smaller one got in small spaces better for grease removal. The other pic is a close up to show the amount of grease in this one.

I also have 2 pics of the Motorcraft tensioner and pulley. Last weekend I had cleaned the old grease out, not much and it seemed burnt, and then greased it since I needed to run it another 350 miles or so. The pulley has 41k miles on it and it's a bit loose so it's been replaced. Here's what I found on the old pulley upon removal which is what I found so interesting and thought I'd share. One pic shows the tensioner as it came off with grease slung on it and inside the pulley. The other pic shows how much grease had been slung out.

It appears you can put too much grease in. On the replacements I installed today I filled them with grease and then wiped out enough to expose a bit of the bearings. So far that seems okay, but we'll find out over the next week.
 

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whtbronco

whtbronco

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So it appears that it wasn't really the amount of grease I had put into the pulley bearings that made it sling out. Instead it was because I has only wiped the seal seats, which must have left a very thin coating of grease allowing the seals to slide out a bit. After I carefully cleaned the seals and seal seats in the bearing with brake cleaner they have held the grease in just fine.
 

drankinatty

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Oh, so that's what those seal things are for ... :) This is a great thread. I'd replaced the pulleys and tensioner on my '05 at right about 200k. Not because of vibration, but due to a distinct little chirp. And it probably chirped for 10k before I got a "round toit". I've still got the set in a box in the garage. I bet when I open the seals I'll find exactly what you describe. I'm not complaining at 17-18 years of service and 200k. I've got about 40k on the new set, so far so good. Thanks for the write-up and the photos. If I find anything significant, I'll add a photo -- but then again, I doubt functional, but chirping, at the same age and same rough mileage as yours will turn up anything exciting or significant.
 

Expensedition

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I just came across this thread. I am not sure if anyone is looking here but I will update anyway.

First I am going back in time a little, and since I traded in my 2014 Expedition, I have no more images to show then the attached images below. I did make a video that I could post on YouTube.... maybe I will do that. I don't see an option to upload videos here.

Note: The stock pulleys from nearly any supplier are inferior. The bearings are complete trash. I bought brand new billet pulleys for my upgrade and pushed out the stock bearings which were a generic China brand and then I installed a much better SKF (possibly made in China but QC'd by SKF). You could easily tell the difference between the two bearings. And there was obvious visible difference between the stock FoMoCo pulley bearings and the SKF.

Anyway, bearings are typically a standard size and it is often easy to upgrade Any bearing, it is just the work to change them out that might stop you.

On these pulleys I also upgraded the snap ring to Stainless Steel.

If I find more images on this subject I will update this post.

By the way....my serpentine belt was near silent after the bearing upgrade.

V/r

SM
 

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whtbronco

whtbronco

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Wow those pulley's really look nice. Having a snap ring is sweet, should make swapping the bearing fairly easy.

Good bearings can make a major difference. I did briefly considered changing the bearings as the bearings in each pulley have too much play. With the original grease removed it was easy to feel and see. I had not considered looking for billet pulley's, they should have basically no runout.

Thanks, this is something to look into for a more permanent resolution.
 

Expensedition

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I used our press at the shop to change out the bearings. If you don't have an arbor press or hydraulic press, try using a large drill press and make something that you can chuck up that will be just under-size of the bearing outer race OD.

Just changing the bearings on the stock pulleys would make a difference, but I agree that the billet pulleys look awesome when you are done.

V/r

SM
 
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whtbronco

whtbronco

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Thankfully my neighbor has a 20 ton press. I just have to come up with the required bits to use it. Most of the time my various impact sockets work well. Even better I have the pulleys I recently removed.
 
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