Anyone have a suggestion for a pilot bushing rather than the needle bearing in my flywheel. Maybe a supplier. I have sworn off DAP. It looks like a weak design and I've seen pictures of input shafts chewed up after these have gone buggy. 

I don't have any suggestions for a pilot bearing / bushing, but I just wanted to pass on some information.   I had an OEM pilot bearing failure at 297,000 miles (original clutch).  The failure did some damage to the transmission input shaft pilot bearing surface.  I elected to not replace the input shaft and I used the LUK replacement clutch and flywheel which basically replicates the OEM assembly.  I also installed a needle type pilot bearing.   I am not recommending anything here; it is just what I decided to do.  I get to live with the consequences.  

 

Sometimes trying to get the maximum life out of everything is not the best decision.  As hind sight I should have just replaced my clutch at around 250,000 miles.   If I would have done that, the pilot bearing failure never would have occurred. 

 

The replacement clutch assembly, flywheel and needle type pilot bearing have since logged over 54,000 miles and the transmission / clutch operation is performing well at just over 350,000 miles on the original transmission.  I plan on doing a scheduled clutch replacement again when I approach between 150,000 - 200,000 miles on the new clutch.  Hopefully, the pilot bearing will last that long.  

 

In my case I think I could have had a pilot bearing failure with any type of pilot bearing with nearly 300,000 miles of operation, so I was not that concerned about using a needle type pilot bearing again.

 

- John

 

 

Thanks for the info Tractorman, I'm doing a complete rebuild on this engine and from the looks of it the transmission and clutch, they were rebuilt/replaced about 6K ago. I thought I saw something about an oversized bearing for this application. I don't like that the bearing uses the input shaft as the inner race. I would much rather see a hardened inner race as well as sealed to keep the debris out. It appears that on the last assembly they got a bit rough with it and damaged the edge of the bearing. Maybe hit it with the input shaft?

Just be sure I am hearing you right, the bearings are rolling on the input shaft with no race? That sounds pretty strange to me. My South Bernd has a bearing, but it is a sealed bearing with inner and outer races. I would hate to stab a tranny and try to not knock a needle out of place.

 

I have not had a pilot bearing failure, just a throw out bearing failure. My ECM failed at 240k and while I had it in a shop I had them replace the clutch. I figured after all those miles It had to be getting thin. I was surprised that it still had some life left in it but I feel I had gotten my moneys worth at that mileage.

Yep, that's how this one works. OD=1.000, ID=.750, so 1/8 wall on this bearing. That means the rollers are probably .093 or 3/32. That just seems like planned failure. 

I believe most clutches that come with flywheel use a larger sealed pilot ball bearing 

1 hour ago, Dieselfuture said:

I believe most clutches that come with flywheel use a larger sealed pilot ball bearing 

That was the case with my South Bend. 

 

2 hours ago, Dumb A said:

Yep, that's how this one works. OD=1.000, ID=.750, so 1/8 wall on this bearing. That means the rollers are probably .093 or 3/32. That just seems like planned failure.

That would explain it. I had pictured in my mind needle bearings like in a u joint cup. Dont think I would want to have the input shaft as the inner race.

Okay, here is some physics to consider. Pilot shaft diameter = .750 and the needle diameter = .093 so per every revolution of the pilot shaft the needle turns 8 times. (.750÷.093) that means at idle 800 rpm, you depress the clutch peddle, those needles are spinning a polite 6400 rpm. Toss a little heat, debris and frictional stress in the recipe and it becomes apparent the task we're asking this bearing to do. Pretty impressive they last as long as they do. This also supports my reasons for a bushing or larger ball bearing with larger balls (turning slower) and sealed to keep debris out. So what will it be??? A .500 caliber round through the side of the block or should I cut the truck in half with a large hacksaw??? 

Of course the last two questions are hypothetical.... Tractorman has it correct to what failure do we build these trucks? "I get to live with the consequences" but hopefully there is a lot of pleasure in-between failures.

1 hour ago, Dumb A said:

Okay, here is some physics to consider. Pilot shaft diameter = .750 and the needle diameter = .093 so per every revolution of the pilot shaft the needle turns 8 times. (.750÷.093) that means at idle 800 rpm, you depress the clutch peddle, those needles are spinning a polite 6400 rpm. Toss a little heat, debris and frictional stress in the recipe and it becomes apparent the task we're asking this bearing to do. Pretty impressive they last as long as they do.

 

You have made some good observations.  I really have nothing to back up what I am going say, but I think there might be more to the story.  I think there may be other factors that give the needle bearing a long life.  

 

1.   there is not a lot of weight resting on the needle bearing.  Most of the weight is supported by the transmission input shaft bearing.  (some gasoline powered engines do not even support the transmission input shaft on the flywheel side).

 

 2.  the pilot shaft end would ride on a thin film of lubricant which would allow for each bearing to slide while it rotated.  I could not imagine a needle bearing surviving at 6400 rpm.  I think they are rotating much slower - but I could be wrong about this.

 

From Wikipedia (the source for everything!) :  "Compared to ball bearings and ordinary roller bearings, needle bearings have a greater surface area in contact with the races, so they can support a greater load."

 

I do think that contamination is the downfall of the needle type pilot bearing.

 

Anyway, just some thoughts.

 

- John

 

That style of bearing has been in use for years, most failures are due to the grease drying out or contamination due to the open design.

 

One thing to remember is that the pilot bearing is only "being a bearing" when the clutch pedal is depressed. Once the pedal is released and the clutch grabs, the needles are stationary. 

So, yes the bearing needles individually would see high rpm, however it is for intermittent short bursts unless you keep the clutch pedal pressed down at a stop light. But once you get moving, they would slow down until the clutch is released and therefore becomes stationary. I think this is part of the reason that they last so long. 

 

Another thing, semi-float axles use the same design of bearing for the axle shaft, so its not uncommon.

This is for the 2nd gen Ram 1500 Chrysler 9.25 rear axle, the bearing is located just in from the axle flange.. Chrysler 9.25" Rear Axle Bearing and Seal kit (10048) (lowrangeoffroad.com) Personally never had a problem with that bearing but its lubed a bit more than a pilot bearing (used to have a 2001 ram 1500)

 

Finally, I would agree with  @Tractorman in that there isn't very much weight being applied to the pilot bearing, if any. The straightness and weight is supported by the input shaft bearing of the transmission.

 

If you are intent on a sealed bearing, South Bend and Valair sell a sealed ball bearing replacement, HOWEVER, unless you buy their flywheel/clutch, you have to machine your flywheel to accept it. 

I would agree with both of the statements above That bearing does not deal with a lot of load and minimal time under any load. But I dont like the bearing in the @Dumb A picture. That one just seems prone to failure. I have had both a Valair and a South Ben in mine and they both came with a sealed ball bearing for the input shaft.  

All of you have brought up good information and I believe history the most. When Tractorman says he has 297 K on a needle pilot bearing before it failed, that's real... I also believe Tractorman is correct in saying any bearing may have failed at 297 K. That said I also believe that low load and intermittent demand, as all of you have stated are the reasons for longevity of this bearing. I think we all agree that contamination is the biggest reason for failure. Now the failure question, when this needle bearing fails while riding on the input shaft it will likely gall the input shaft due to needle breakage. Whereas a ball bearing with inner and outer races may afford you some warning prior to eating up the input shaft. Dragging the input shaft between shifts or bearing noise with clutch depressed may tip you off. This is why I'm interested in getting away from the needle bearing. I priced a flywheel with the sealed ball bearing for 297 and that seems like the best way forward and less expensive then replacing an input shaft down the road. It's been educational talking with all of you, thanks for your input and years of experience with these trucks, it's very helpful!!!

4 hours ago, Dumb A said:

I priced a flywheel with the sealed ball bearing for 297 and that seems like the best way forward and less expensive then replacing an input shaft down the road.

 

I think that is a good way to go.  I think the sealed ball bearing will keep out contamination better because it has its own seal and sealing surface.  My replacement needle bearing has a seal on both ends, but its ability to seal is largely determined by the surface condition of the input shaft which is no longer in good condition on my truck.

 

5 hours ago, Dumb A said:

Whereas a ball bearing with inner and outer races may afford you some warning prior to eating up the input shaft

 

I would not count on that.  In my instance I was driving in a rural area about ten miles from my destination when I noticed a subtle change in the way the transmission was shifting - no noises at all.  At the next stop sign, I could not select any gear from neutral.  I had to shut the engine off, select first gear and then restart the engine to get moving again.  The rest of the trip I just floated the gears and did California stops.  However, I needed to make a left turn across two very busy lanes of a four lane road to a place of business.  So, while I was waiting for an opportunity to turn, I had the transmission in first gear, clutch pedal depressed with engine idling - something I normally never do.   I knew it was going to be a couple of minutes before I would be able to turn.  About a minute later there was a muffled screech (barely audible) that lasted about 1/4 of a second (that was when the needle bearings left their home).  I am certain that was when the input shaft damage occurred.  The good news was that the transmission was instantly back to shifting normal again because the pesky pilot bearing left the premises, which made parking the truck easy and the trip back home much less stressful.  Who needs a pilot bearing anyway!!

  

I think the sealed ball bearing will a good choice for you, but what is more important (I learned this the hard way) is to schedule a clutch replacement at a specific mileage, not run it until you have problems.

 

- John

I've used both clutches supplied by DAP... Valair Dual disc (early version) in my 2002 Dodge. Now I've bought the Valiar Dual Disc Quiet towing clutch which is also awesome design and better than my 2002 clutch. Then before that I've bought the South Bend Con OFE through DAP. All came with seal ball bearings for the pilot shaft. 

 

Even the clutch I did in @Jthor 1995 7.3L Ford Powerstoke came with the old school needle bearing from NAPA. Previous flywheel the dual mass spring broke and the pilot bearing was fine just drying out on lube. The clutch still had some life yet but since the flywheel upgrade to a 13 inch so did the pressure plate and friction disc. All new there and butter smooth! 

 

Oh just a heads up 95 Ford F-350 manual transmission should have ATF in it. Surprise some got smart like me and ditched the ATF and put in quality GL-4 lube!