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Old 06-15-2013, 01:42 PM
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Hydraulic throwout bearing issues..

I have a Howe Hydraulic throwout bearing #82870 and am utilizing a Centerforce Chevy pressure plate. The throwout bearing measures 2.375 and when I do all the measurements of the bellhousing to the pressure plate fingers it seems that my throwout bearing is 3 tenths of an inch to tall....If I install it it will be pressing the fingers on the pressure plate which Im assuming is not what you want.. Does anyone know of a hydraulic throwout bearing that is not as tall? The GM stock one seems to measure the same.

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Old 09-06-2013, 05:46 PM
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Anyone have suggestions? Should I look into a block to bellhousing spacer?

My clutch will not engage as a result, the measurements I just took show that the throwout bearing fully closed is preloading the fingers on my clutch about .20 or around 3/16ths which is enough to release the clutch engagement ever so slightly. I have a Howe racing thowout bearing and compared it to the stock GM and it is the same size. I need to move the transmission away from the bellhousing or bellhousing away from the motor since i can not get a smaller throwout bearing.
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Old 09-06-2013, 07:57 PM
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No one? Anyone? Help please...
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Old 09-06-2013, 09:53 PM
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First off, have you talked to the folks at Howe about this? Spacing the bell housing or transmission away to remove this preload will cause issues with the pilot bearing engagement, I've never heard of anyone doing this. Talk to Howe.
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Old 09-06-2013, 10:30 PM
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Originally Posted by evolvo View Post
First off, have you talked to the folks at Howe about this? Spacing the bell housing or transmission away to remove this preload will cause issues with the pilot bearing engagement, I've never heard of anyone doing this. Talk to Howe.

I have been on the phone with Centerforce, but every time I try contacting Howe, they are already closed. Do you really think a .25 spacer will make the difference with the pilot bearing and spline engagement?
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Old 09-08-2013, 04:55 AM
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Have you or anyone put any shims behind the bearing? push the bearing out from the back with your thumbs and check.
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Old 09-08-2013, 07:56 AM
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Originally Posted by WickedFast1 View Post
Have you or anyone put any shims behind the bearing? push the bearing out from the back with your thumbs and check.
Thats just the thing I dont need shims,its too long as it is. fully compressed it is 2 tenths too long , meaning it is already compressing the fingers of the pressure plate 2 tenths in resting state, no clutch pedal needed.
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Old 09-08-2013, 08:59 AM
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The first thing I would do is to verify that I have the right part for the application. Then if so I would make myself available to talk to the manufacturer about the problem. Unless so stated in the instructions that came with your throwout bearing that you have to modify your components I'll bet you that you have the wrong part. If you needed a spacet to make it work, they'd probably sell that also.

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Old 09-08-2013, 01:01 PM
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The first thing I would do is to verify that I have the right part for the application. Then if so I would make myself available to talk to the manufacturer about the problem. Unless so stated in the instructions that came with your throwout bearing that you have to modify your components I'll bet you that you have the wrong part. If you needed a spacet to make it work, they'd probably sell that also.

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How's racing sells 3 throwout bearings. 1 for a small race clutch, 1 for an OEM style clutch with a Saginaw, Muncie or Jerico style trans and one for a T56.
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Old 09-08-2013, 01:44 PM
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Talk to them and tell them your set up.

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Old 09-08-2013, 05:12 PM
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Originally Posted by boothboy View Post
Talk to them and tell them your set up.

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Will do, but the only solution I see is to space the tranny back about .25-.35. I just experimented with some washers as a temporary spacer for fitting purposes. I placed them in between the tranny and bellhousing for a total of about .30 clearance and it seems like it will function properly. I am able to see the throwout bearing expand and retract as the clutch pedal is depressed. Tomorrow I need to install the shifter and linkage and see if it holds. If it holds then my .25 spacer I ordered from Lakewood industries, should do the trick.
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Old 09-09-2013, 06:43 AM
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I measured an old TO bearing for a racing clutch thats sitting on my toolbox and it too measures about 2 3/4 OA height. I think you have the wrong TO bearing assembly.
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Old 09-09-2013, 08:23 AM
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Originally Posted by lmsport View Post
I measured an old TO bearing for a racing clutch thats sitting on my toolbox and it too measures about 2 3/4 OA height. I think you have the wrong TO bearing assembly.
Mine is not a racing clutch. The clutch that was originally in there was a 7.25" clutch with a bolt on style TO bearing from Quartermaster. I since went to a 11" oem style street clutch with a standard flywheel. Howe makes 3 TO bearings, 1 being for race clutch applicatications and it is a bolt on style. The other 2 are slip on style TO bearings, one (82870) measures 1.688 the other for the T56 (82876)tranny measures 1.512.

Even if I switched I only pick up 175 thousandths. I need just over 200 thousandths to not preload the clutch fingers. I talked to Howe, they have heard of shimming the tranny so as long as I have enough engagement on the thrust bearing input shaft.

I dont know why my set up is off by so much, I can only assume the centerforce clutch is the issue.

Also if yout TO bearing is 2.750 your still 150 thousandths larger than my installed set up..
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Old 09-09-2013, 08:43 AM
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A lot of my A-Sedan customers have had this issue. Its the tolerance stack up from the flywheel, clutch and Hyd unit itself. There's no magic fix as there are too many variables.

Maybe the T56 unit and less spacers? You want to make sure you have adequate pilot bushing engagement AND that all this switching around doesn't knock the bellhousing/trans alignment off. The Total Indicated Runout (TIR) should be .005 or less for a race application. You could go up a little bit from that; but, any more than .009 is probably asking for trouble.
You may want a longer bushing. Our off the shelf Oilite ones are 1.094 OD, .590 ID and .750" L. We've made some that are 1.00" L and 1.250" L. If you get a new bushing, check it with the magnetic tip on an electricians screwdriver or something similar. A GOOD sintered bronze bushing will NOT be magnetic; make sure you check the OD and the ID as well
Don't get discouraged; you've almost got this.

Last edited by AutoGear; 09-09-2013 at 08:51 AM.
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Old 09-09-2013, 01:21 PM
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I spoke with How's as well as Center force today and none of us could come up with a reason as to why I was missing clearance. Center force assumed it was the flywheel off spec so I pulled the bell housing and measured it while I was on the phone with them. We concluded that the flywheel was fine and I would need to space the trans back some, but could not figure out why my specs were off to begin with. I'm beginning to suspect the Jerico TO bearing retainer shaft is too thick.
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