T O P I C R E V I E W
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Droptop_50
Member # 12579
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posted
What are some reasons for a pilot bearing to go out in my 91 5.0
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*Als50*
Member # 6003
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posted
Wear & tear.
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Tom Renzo
Member # 13165
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posted
One of the biggest reasons is having the car in gear with the clutch in waiting for a traffic light.Also red line launches also wears out the bearing as well. If you do not do this the Pilot will live longer. I never do this because the main drive gear is not spinning in the pilot bearing wearing it out at stop lights and hard launches.. Also the clutch dust makes it's way in to the bearing and does a job on it. Most new bearings have a seal to prevent clutch dust from contaminating the bearing but it still gets in. Hope this explains it. [ 2014-05-08, 06:43 PM: Message edited by: Tom Renzo ]
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Blind
Member # 3052
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posted
quote: Originally posted by Tom Renzo: One of the biggest reasons is having the car in gear with the clutch in waiting for a traffic light.Also red line launches also wears out the bearing as well. If you do not do this the Pilot will live longer. I never do this because the main drive gear is spinning in the pilot bearing wearing it out at stop lights and hard launches.. Also the clutch dust makes it's way in to the bearing and does a job on it. Most new bearings have a seal to prevent clutch dust from contaminating the bearing but it still gets in. Hope this explains it.
doing that would wear the throw out bearing, not the pilot bearing.
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86_on_DA_machs
Member # 11083
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posted
quote: Originally posted by Blind: quote: Originally posted by Tom Renzo: One of the biggest reasons is having the car in gear with the clutch in waiting for a traffic light.Also red line launches also wears out the bearing as well. If you do not do this the Pilot will live longer. I never do this because the main drive gear is spinning in the pilot bearing wearing it out at stop lights and hard launches.. Also the clutch dust makes it's way in to the bearing and does a job on it. Most new bearings have a seal to prevent clutch dust from contaminating the bearing but it still gets in. Hope this explains it.
doing that would wear the throw out bearing, not the pilot bearing.
+1
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Tom Renzo
Member # 13165
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posted
So i guess having the engine running in gear with the clutch in does not spin the crankshaft where the pilot bearing is pressed in to. And the input shaft is not spinning, So pray tell then why would you need a pilot bearing????????? By the way i know it wears out the throw out as well,But that is not what he asked. He asked about the pilot bearing which is in the nose of the input shaft and it is used to center it as well as used when the input is not spinning and the engine is running. Another words at a light in gear with the clutch disengaged. I have changed hundreds of clutches in my life and i actually know how they work. [ 2014-05-08, 06:40 PM: Message edited by: Tom Renzo ]
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Blind
Member # 3052
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posted
quote: Originally posted by Tom Renzo: So i guess having the engine running in gear with the clutch in does not spin the crankshaft where the pilot bearing is pressed in to. And the input shaft is not spinning, So pray tell then why would you need a pilot bearing????????? Better think about it a little harder!!
the pilot bearing always spins on the input shaft, whether the clutch is engaged or not.
if the car is stopped the input shaft doesn't spin until the clutch is engaged in gear.
otherwise the input shaft is constantly spinning whenever the car is in gear and rear wheels are turning.
the throw out bearing is the only thing that is engaged and disengaged by the clutch pedal.
the pilot bearing just sits in the flywheel and lets the engine rotate around the input shaft at different speeds.
here's some extra question marks and exclamation points for you, if that helps.
?????????????? !!!!!!!!!!!!!! [ 2014-05-08, 06:45 PM: Message edited by: Blind ]
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Tom Renzo
Member # 13165
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posted
You are totally wrong as the transmission input shaft does not turn when the car is in gear and the clutch released and the car is stopped for a light . So there fore the car does not move and the nose of the tranny is in the crankshaft that is spinning on the pilot bearing. Simple better think about it a little further . Another words to make it even simpler the clutch does not spin either only the pressure plate and flywheel . That is how a clutch works. When gthe clutch is engaged the pilot does not do a thing but wait for the next shift or red light if the clutch is depressed and the tranny is in gear. Hope this explains it. [ 2014-05-08, 07:01 PM: Message edited by: Tom Renzo ]
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*Als50*
Member # 6003
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posted
Goddddammmmmitttttttt.......
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Droptop_50
Member # 12579
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posted
This means war lol
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SteveL
Member # 1241
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posted
Not to add to the flames on this one but it's worth checking the bell housing alignment and mounting. There are some special tools involved but the idea is to get the transmission opening at the back of the bell housing to be centered over the pilot bearing. Not having the transmission input shaft inline with the crankshaft puts a lot of stress on the pilot bearing. The transmission should not be offset or tilted with respect the the crankshaft (I want to see within 8 mils of center).
Unfortunately there isn't a real easy fix other than trying a different bell housing. Correcting a bell housing involves punching out and replacing the two alignment pins.
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Tom Renzo
Member # 13165
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posted
They make offset pins and a dial indicator is necessary for centering. years back this was an issue but normally with modern machining it is not an issue. This is of course if his setup is stock. But is the guy having numerous failures? He does not mention that? Maybe like i said he holds down the clutch in gear at stop lights.
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90GT510
Member # 9199
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posted
Would pilot bearings make a noise when had and go away when clutch is pushed in?
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Blow_U_In_Reverse
Member # 12298
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posted
quote: Originally posted by 90GT510: Would pilot bearings make a noise when had and go away when clutch is pushed in?
that would more than likely be the throw out bearing..
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Blind
Member # 3052
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posted
quote: Originally posted by Blow_U_In_Reverse: quote: Originally posted by 90GT510: Would pilot bearings make a noise when had and go away when clutch is pushed in?
that would more than likely be the throw out bearing..
because pushing in the clutch pedal has nothing to do with the pilot bearing
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Droptop_50
Member # 12579
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posted
And the winner is??? Lol
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Tom Renzo
Member # 13165
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posted
The original question was what causes wear on a pilot bearing. So it would have to have something spinning it to wear it out.Or an alignment issue. In theory!! So sitting @ a light with the clutch in and in gear is when the nose of the main drive is not spinning and the bearing is. Crank is turning main drive is not. Pilot is pressed in to the crank. With the clutch out the pilot does nothing but align the main drive gear so it runs true. So as for the Throw Out bearing it is put under load heavily with the clutch in but also has a slight pressure when the clutch is out. The throw out bearing in fact turns weather the clutch is in or out on modern hydrulic clutch cars because they are self centering and constant contact because of the hydraulics and some mechanical cable designs. Older cars do not have the throw out bearing riding the fingers by design. They pull off the fingers by the clutch linkage if adjusted properly with the clutch out. Hope this is the end of this.
LX i see you post 2.3 so if you have a 5 speeder in your car you will know first hand what a clutch chirp is. Reason being that car has an auto adjusting clutch and in fact has the dredid clutch chirp issues. The cable setup on that car also holds slight pressure on the throw out bearing and fingers.
Note a bad pilot bearing can do several things. It can cause gear clash noise and also clutch chatter on engagement. It can also cause vibrations and other nasty things. Remember it also centers the main drive gear in the tranny.
The throw out can also cause noise as it is also a bearing and is under heavy load at stop lights with the clutch in. OK!
@ 90 The pilot bearing can only make noise with the clutch in and the tranny in gear with the car stopped and the clutch in. That is the only time it is spinning other than between gear changes that can also make it make noise.
Years back when we only had oileite pilot bearings they would seize to the nose of the main drive at the track. reason being when the lights would come down our engines were at 8000 RPM's waiting for the tree and the bearing froze to the main drive. Race over!! [ 2014-05-12, 03:23 AM: Message edited by: Tom Renzo ]
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SacStangDriver
Member # 8304
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posted
.. [ 2014-05-14, 08:29 PM: Message edited by: SacStangDriver ]
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