scraping noise after new clutch

[meatshieldchris]

I have a 1992 Ranger, 2.9L 4x4 manual with te M5OD. I just replaced the clutch, pilot bearing, rear main seal, throwout bearing, and flywheel. Now I've got a scraping noise (once per revolution of the engine type noise, confirmed by taking it to highway speed and letting it idle with the clutch in) when I have the clutch pedal pushed in, and occasionally when the clutch pedal is fully out, but in low gear and low rpm and I mash on the pedal. The latter doesn't happen all the time. The noise goes away when the clutch pedal is out, in gear or out of gear doesn't matter. Any ideas what it could be, before I do the way too much work to remove the transmission again?

 

[low_five]

man that really sounds like you got a bad throwout bearing.

 

[Big Jim M]

Yep!

man that really sounds like you got a bad throwout bearing.

That or it is installed improperly.
Big Jim

 

[meatshieldchris]

all I could see was that it snapped over the little nib at the top of the slave...anything else I needed to do? I could see how if the throwout bearing guide tube was spinning it would cause that noise...

 

[meatshieldchris]

I greased up the guide tube before installing the throwout bearing, is that a no-no?

 

[meatshieldchris]

hmm, not making the sound anymore. could it have been the clutch disc breaking in?

 

[meatshieldchris]

ach, it's back. managed to luck out and get under the truck, the noise is loudest with the stethiscope in the middle of the exposed section of the plate between the engine and transmission. I removed the transmission to look for more clues, and here's what I found:

Found a mark on the plate between the engine and transmission with fresh scrape marks on it. It looks like someone took a square hammer, and made a dent there. It's not a circular abrasion like you'd expect from the flywheel hitting it or something. The area of the flywheel behind of that section of the plate is smooth! there's no protrusions that could make that mark. In addition, when you rotate the motor, you can see that at all times, there's 1/4" of clearance between that spot and the flywheel. WTF!?

Center lower of the photo

Closeup

Other side

The dent is about 1/8" deep.

Any ideas? I'm at a total loss. There's nothing there to make that! The bolts don't even stick through the flywheel. Even if they did, they'd make circular scrapes with the radius of the bolt circle.

 

[Big Jim M]

Did you say AT TIMES? What the hell is that all about? The flywheel should rotate evenly without any WOBBLE.. I'd be taking it apart and giving it a good lookin at.
Big JIm

 

[meatshieldchris]

Did you say AT TIMES? What the hell is that all about? The flywheel should rotate evenly without any WOBBLE.. I'd be taking it apart and giving it a good lookin at.
Big JIm

agreed. starting to produce torque at part engagement (accelerating from a stop) it's the worst. Goes away when you let the clutch engage fully and you take your foot off the pedal. I caught it just right so I could slip under with a stethiscope, the knocking sound was definitely worst when the stethiscope was placed roughly where the mark is on the plate. I can turn the motor over by hand without it binding anywhere, or scraping, or anything visibly touching anything, so I don't know what's going on. I guess I'll have to take the clutch and flywheel off and have a look.

It's apart, there's no marks anywhere else other than the above pictures. There's not enough crank end play to make THAT much of a problem (it's in the neighborhood of 0.008"). The throwout bearing is still in good shape and engaged on the guide tube properly, it's not spinning on the guide tube.

I'm wondering if it's hitting somewhere and that mark is unrelated and was an old scar from something else.

Just because I can check easily with the transmission out right now, how much play should I have in the input shaft? And if the input shaft bearing was toast, I'd hear it worst with the stethiscope at the base of the bellhousing (furthest point on the bellhousing away from the engine) right?

 

[low_five]

what.... the..... ****.

 

[IMenriched]

inclined to agree that it might be an old battle scar....unrelated to this new noise

.0008 end play on the crankshaft....is not enough to make this noise....from the tranny.
but it is well out of spec....purhaps the noise is from the crank shaft (main bearings, center thrust )& is transmitting out the bell housing....just a thought

 

[holyford86]

when I installed my new clutch and flywheel I had the same problem with scraping on that plate when it was warm out and the engine was hot, I figured it was just hosed thrust mains and it eventually just went away

 

[meatshieldchris]

when I installed my new clutch and flywheel I had the same problem with scraping on that plate when it was warm out and the engine was hot, I figured it was just hosed thrust mains and it eventually just went away

that's interesting...it's definitely worse after the engine is hot.

 

[meatshieldchris]

inclined to agree that it might be an old battle scar....unrelated to this new noise

.0008 end play on the crankshaft....is not enough to make this noise....from the tranny.
but it is well out of spec....purhaps the noise is from the crank shaft (main bearings, center thrust )& is transmitting out the bell housing....just a thought

What is spec? My dial indicator is really poor, and I'm not sure the harmonic balancer is the right place to be checking, and I also had to have the indicator at an angle, so nothing was ideal about that measurement. I'll check again against the flywheel.

I noticed while I was under there that the pressure plate fingers looked slightly off center from the clutch disc center after I pulled the tranny. The clutch disc looked centered with the pilot. I'm gonna double check, but could an alignment problem with the pressure plate cause knocking/scraping noise when disengaging the clutch? If so, last time I did a clutch I didn't have to do anything with the pressure plate except bolt it up, so this would mean I got a bad pressure plate?

 

[meatshieldchris]

ok double checked end play right on the end of the crank, looks like I've got 0.006. What was the spec for that?

And I think the mystery is solved. I took the flywheel off, and there is a spot on my brand new rear main seal that's worn right to the metal. The rear main seal walked rearwards till it contacted the flywheel.

So, how do I prevent that? Did I not seat it far enough? How far do I push it? Till it stops?