Throwout Bearing??? - ZR-1 Net Registry Forums

cadillac531 · 05-29-2015

Armed with my new fuel pumps and tires, I took the Beast for a little trip out of town last weekend. She ran like a champ, through the rain, and up the hills and mountains with the AC on and the cruise on, it pulled down 23.2 mpg. I was pretty happy, as this makes the ZR my most fuel efficient vehicle

Anyway, when I left my folks' house to come back home, the trans made a high pitched bearing-like sound just as the clutch engaged. It did it as I would engage reverse and as I would engage first. I took it around the block before heading on back, and when everything warmed up, the sound went away and didn't come back.

I started the car again today and it gave me the same sounds, I rocked the car front and back with the clutch and after the third time of doing this, the sound stopped and the clutch engaged quietly like usual.

Can anyone describe to me the sound a throwout bearing makes? The trans shifts fine, and there are not any other audible sounds other than the ones a ZF usually makes.

Thanks.

QB93Z · 05-29-2015

The sound you describe could be the pilot bearing. It is sometimes hard to differentiate between pilot bearing and throw out bearing noise.

In my most recent experience, the pilot bearing gave the symptoms you have. The noise would go away after the first few clutch operations. A bad throw out bearing doesn't usually get quieter.

Either way, the transmission and clutch need to be removed.

Jim

GOLDCYLON · 05-29-2015

#2 on the pilot bearing. Throw out bearing noise does not go away. Kinda like fidanza flywheel noise that only goes away when you enguage the clutch or while cruising

cadillac531 · 05-29-2015

Thanks for the replies guys. I will drop the trans and get this all fixed up.

XfireZ51 · 05-29-2015

Use the brass bearing, not the needle bearing pilot. Fewer parts to go bad.

cadillac531 · 05-29-2015

Quote:

Originally Posted by XfireZ51

Use the brass bearing, not the needle bearing pilot. Fewer parts to go bad.

Thanks for the reply. In a previous post I found, Mark Haibeck suggested this pilot bearing gm pn14061685 saying it won't come loose. Do you happen to have a part number for the brass one you suggest?

Thanks.

WVZR-1 · 05-30-2015

Quote:

Originally Posted by cadillac531

Thanks for the reply. In a previous post I found, Mark Haibeck suggested this pilot bearing gm pn14061685 saying it won't come loose. Do you happen to have a part number for the brass one you suggest?

Thanks.

if you prefer an "impregnated BRONZE" insert you'll just need to ask for one from most vendors. GM # for the original "bushing type" for the LT5 is/was 10125896. Use an impregnated insert "dry" as it comes out of the box. The GM is also "fluted". Jim at PowerTorque I believe still keeps this.

Removal of the old is NOT accomplished using the old grease compression method some are accustomed to doing. If it's a "FOR HIRE" clutch job make sure you mention this ..................

cadillac531 · 05-30-2015

Quote:

Originally Posted by WVZR-1

if you prefer an "impregnated BRONZE" insert you'll just need to ask for one from most vendors. GM # for the original "bushing type" for the LT5 is/was 10125896. Use an impregnated insert "dry" as it comes out of the box. The GM is also "fluted". Jim at PowerTorque I believe still keeps this.

Removal of the old is NOT accomplished using the old grease compression method some are accustomed to doing. If it's a "FOR HIRE" clutch job make sure you mention this ..................

Thank you for the info. Is there a special way to remove the old one? Slide hammer?

WVZR-1 · 05-30-2015

Quote:

Originally Posted by cadillac531

Thank you for the info. Is there a special way to remove the old one? Slide hammer?

Slide hammer/KNOCKER does very well .............

cadillac531 · 05-30-2015

Can anyone tell me what causes a pilot bearing to go bad? I can understand a higher mileage car having this issue, but I've only got 33k miles on it. Can these go bad from lack of use?

05-29-2015	#1
cadillac531 Join Date: Jul 2005 Posts: 243	Throwout Bearing??? Armed with my new fuel pumps and tires, I took the Beast for a little trip out of town last weekend. She ran like a champ, through the rain, and up the hills and mountains with the AC on and the cruise on, it pulled down 23.2 mpg. I was pretty happy, as this makes the ZR my most fuel efficient vehicle Anyway, when I left my folks' house to come back home, the trans made a high pitched bearing-like sound just as the clutch engaged. It did it as I would engage reverse and as I would engage first. I took it around the block before heading on back, and when everything warmed up, the sound went away and didn't come back. I started the car again today and it gave me the same sounds, I rocked the car front and back with the clutch and after the third time of doing this, the sound stopped and the clutch engaged quietly like usual. Can anyone describe to me the sound a throwout bearing makes? The trans shifts fine, and there are not any other audible sounds other than the ones a ZF usually makes. Thanks. __________________ Constantine Registry Founding Member #0235 1991 Corvette ZR-1 -- Stock, 94 ZR-1 exhaust system, muffler delete. 1956 Chevrolet Belair -- Pro Street, 531ci Cadillac, 8-71 Blower, 8pt roll bar, built TH-400, 9" rear, 1,100 HP -- Street Car. https://www.youtube.com/watch?v=z8y4cwcvK0s 1968 Mustang "Pegasus" -- Zeeker Chassis, 584ci Dart Block, Brodix Big Brodies, 2-1150 Dominators, FTI 'Glide, 1168 hp, best ET & Trap(holding back) 8.57@159 -- 7.9X -- 1/4 mile car. 1970 Chevelle -- 468ci, TKO600, shaved and smoothed everything.

05-29-2015	#3
GOLDCYLON Join Date: May 2007 Location: Peoria, AZ Posts: 9,155	Re: Throwout Bearing??? #2 on the pilot bearing. Throw out bearing noise does not go away. Kinda like fidanza flywheel noise that only goes away when you enguage the clutch or while cruising __________________ GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V

05-29-2015	#4
cadillac531 Join Date: Jul 2005 Posts: 243	Re: Throwout Bearing??? Thanks for the replies guys. I will drop the trans and get this all fixed up. __________________ Constantine Registry Founding Member #0235 1991 Corvette ZR-1 -- Stock, 94 ZR-1 exhaust system, muffler delete. 1956 Chevrolet Belair -- Pro Street, 531ci Cadillac, 8-71 Blower, 8pt roll bar, built TH-400, 9" rear, 1,100 HP -- Street Car. https://www.youtube.com/watch?v=z8y4cwcvK0s 1968 Mustang "Pegasus" -- Zeeker Chassis, 584ci Dart Block, Brodix Big Brodies, 2-1150 Dominators, FTI 'Glide, 1168 hp, best ET & Trap(holding back) 8.57@159 -- 7.9X -- 1/4 mile car. 1970 Chevelle -- 468ci, TKO600, shaved and smoothed everything.

05-29-2015	#5
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,708	Re: Throwout Bearing??? Use the brass bearing, not the needle bearing pilot. Fewer parts to go bad. __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX

05-30-2015	#10
cadillac531 Join Date: Jul 2005 Posts: 243	Re: Throwout Bearing??? Can anyone tell me what causes a pilot bearing to go bad? I can understand a higher mileage car having this issue, but I've only got 33k miles on it. Can these go bad from lack of use? __________________ Constantine Registry Founding Member #0235 1991 Corvette ZR-1 -- Stock, 94 ZR-1 exhaust system, muffler delete. 1956 Chevrolet Belair -- Pro Street, 531ci Cadillac, 8-71 Blower, 8pt roll bar, built TH-400, 9" rear, 1,100 HP -- Street Car. https://www.youtube.com/watch?v=z8y4cwcvK0s 1968 Mustang "Pegasus" -- Zeeker Chassis, 584ci Dart Block, Brodix Big Brodies, 2-1150 Dominators, FTI 'Glide, 1168 hp, best ET & Trap(holding back) 8.57@159 -- 7.9X -- 1/4 mile car. 1970 Chevelle -- 468ci, TKO600, shaved and smoothed everything.

05-29-2015	#2
QB93Z Join Date: May 2007 Location: Westminster, Maryland Posts: 3,689	Re: Throwout Bearing??? The sound you describe could be the pilot bearing. It is sometimes hard to differentiate between pilot bearing and throw out bearing noise. In my most recent experience, the pilot bearing gave the symptoms you have. The noise would go away after the first few clutch operations. A bad throw out bearing doesn't usually get quieter. Either way, the transmission and clutch need to be removed. Jim __________________ If it isn't fun, you aren't doing it right! 1990 Black ZR-1 - sold 1993 Quasar Blue ZR-1 1994 Competition Yellow ZR-1 1995 Dark Purple ZR-1 Maryland State Coordinator WAZOO Member