Pilot bearing noise?
03-10-14, 12:28 PM
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Pilot bearing noise?
What's up guys I have an 88 n/a series 4 with about 109k miles on it. I replaced the clutch with an oem/stage 1 exedy replacement I got off rock auto (came with clutch disc, pressure plate, TOB, and pilot bearing) about 2500 miles ago. Since then I've noticed a metallic spinning noise that comes and goes while in neutral without the clutch being pressed. I believe it's the pilot bearing. As soon as my foot touches the clutch even SLIGHTLY the noise goes away. What's the worst that can happen by driving the car this way?
I have a video on my phone of the noise but I can't post it on the forums unless I first upload to another site, so I'll try to do that later.
Also I should add that when I removed the old pilot bearing, it was actually a bushing. I replaced it with a bearing.
^^^ bushing vs bearing (not my picture)
Also my input shaft has been making noises since I've had the car the last 4 years so I don't think that's it. The input shaft becomes completely quiet as soon as the clutch is fully depressed.
I have a video on my phone of the noise but I can't post it on the forums unless I first upload to another site, so I'll try to do that later.
Also I should add that when I removed the old pilot bearing, it was actually a bushing. I replaced it with a bearing.
^^^ bushing vs bearing (not my picture)
Also my input shaft has been making noises since I've had the car the last 4 years so I don't think that's it. The input shaft becomes completely quiet as soon as the clutch is fully depressed.
03-10-14, 12:57 PM
#2
you have a dragging throwout bearing, not a faulty pilot bearing.
why the throwout? because the pilot only spins when you apply nearly full pressure to the clutch pedal, the throwout bearing is loaded as soon as the slack in the pedal travel is taken up.
be sure the pedal travel has the specified slack in it according to factory specs and hopefully that gets rid of the noise. if the bearing is lightly touching the fingers on the PP then you will get a light scraping sound. sometimes this also happens when you do not clean the throwout cone on the transmission thoroughly, the dried up old grease can make the throwout bearing movement sticky.
personally i think a bronze bushing would have been better to leave in there, i have never seen a supplier for them so i just use the roller bearings which tend to have a rather high failure rate.
why the throwout? because the pilot only spins when you apply nearly full pressure to the clutch pedal, the throwout bearing is loaded as soon as the slack in the pedal travel is taken up.
be sure the pedal travel has the specified slack in it according to factory specs and hopefully that gets rid of the noise. if the bearing is lightly touching the fingers on the PP then you will get a light scraping sound. sometimes this also happens when you do not clean the throwout cone on the transmission thoroughly, the dried up old grease can make the throwout bearing movement sticky.
personally i think a bronze bushing would have been better to leave in there, i have never seen a supplier for them so i just use the roller bearings which tend to have a rather high failure rate.
Last edited by RotaryEvolution; 03-10-14 at 01:01 PM.
03-11-14, 08:46 PM
#3
I can't hear my clutch or driveline while my car is on, but when I tore my engine down, I did have some throwout bearing wear on the pressure plate fingers. I do need a clutch anyway so I planned on replacing it when I rebuild. Would it be a better idea to use a bushing instead? I have access to Navy-quality brass and have the tools to mill it and shape it. Would it be okay to make a bushing to fit instead of using the pilot bearing and seal?
03-11-14, 08:50 PM
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It was a nice day in NYC today so I had my windows down and have noticed a odd noise coming from the trans area while letting off in 1st gear. Kind of like a bov flutter. I tried adjusting my clutch and it made no difference. I do believe you were right about it being the TOB. should I replace with an oem one from mazda?
03-11-14, 10:53 PM
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I just got a TOB from Mazda and they don't seem as rugged as the Federal Mogul bearings.
In fact I didn't use the NEW OEM throw out because my old one was in good shape and looked to be a better design.The face of the Federal Mogul bearing where it contacts the clutch plate is more rigid.
The OEM is like a thin ring.
I hear that the 1st gen TOB are more sturdy though...(what I heard,not what I have seen,so take that at not 100% on that info)
In fact I didn't use the NEW OEM throw out because my old one was in good shape and looked to be a better design.The face of the Federal Mogul bearing where it contacts the clutch plate is more rigid.
The OEM is like a thin ring.
I hear that the 1st gen TOB are more sturdy though...(what I heard,not what I have seen,so take that at not 100% on that info)
03-12-14, 11:10 AM
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It's a disc clutch.
My old clutch didn't make any noises like this and looked the same. Swapped it out because it began to chatter and slip terribly
^^^ old clutch. New one was identical but had 4 springs instead I believe
My old clutch didn't make any noises like this and looked the same. Swapped it out because it began to chatter and slip terribly
^^^ old clutch. New one was identical but had 4 springs instead I believe
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