742 case front pinion bearing fit on pinion

[jdragster]

I have a 742 case 8.75" rear end. I wanted to put in new bearings and gears. When I took out the old pinion, the front bearing only needed a tap to be removed from the pinion. It was a Richmond Gear 4.57 gear set. The new Richmond 4.57 pinion has a .0015" press fit for the front bearing. Should the front bearing fit be this tight or should it be a snug fit that needs to be tapped onto the pinion shaft?

 

[oldkimmer]

That happens lots. Kim

 

[DC 340]

It needs to be pressed on. I don't remember any pinion bearing that could be tapped on. You can heat the bearing somewhat prior to install to ease installation. I remember heating the bearing to 200F for maybe 25 minutes and it made the press fit a smooth operation. Be prepared to press it off as well if the pinion depth/contact pattern etc. are not correct. I don't believe I ever got it right on the 1st attempt.

 

[413]

He is talking about the FRONT pinion bearing. That's the one right behind the pinion seal. It is not pressed on.

 

[perfacar]

usually new pinions are painted black, sand it off on both sufaces with 220 grit sand paper, the front bearing should slid on, i use a spray lube for it. after sanding surface, bearing should fit easier. thats way, i've done all my pinion bearings.

 

[RustyRatRod]

I would hone the bearing until it is a slip fit.

 

[john-9]

just built a nice 742 case with factory 2.93 gears and sure grip over the weekend and the front bearing was a light slip fit which is what you want when dealing with shims to set the pinion bearing preload. i have found this on most 8-3/4 factory gear sets for the 742 and 741 cases not so much for the 489 case which use a crush sleeve unless you convert to a solid spacer,, but the aftermarket gear sets usually are a press fit and i will polish the pinion gear at that area for a light slip fit , also do this for 9 inch Fords when using a solid spacer ,, this makes shim and solid spacer selection easier when changing out shims or spacers for correct preload. nothing to worry about unless the fit is really sloppy.

 

[RustyRatRod]

just built a nice 742 case with factory 2.93 gears and sure grip over the weekend and the front bearing was a light slip fit which is what you want when dealing with shims to set the pinion bearing preload. i have found this on most 8-3/4 factory gear sets for the 742 and 741 cases not so much for the 489 case which use a crush sleeve unless you convert to a solid spacer,, but the aftermarket gear sets usually are a press fit and i will polish the pinion gear at that area for a light slip fit , also do this for 9 inch Fords when using a solid spacer ,, this makes shim and solid spacer selection easier when changing out shims or spacers for correct preload. nothing to worry about unless the fit is really sloppy.

You mean like sloppy seconds?

 

[DC 340]

He is talking about the FRONT pinion bearing. That's the one right behind the pinion seal. It is not pressed on.

Gotcha. My bad. For some reason I was thinking of the rear bearing.

 

[perfacar]

i have tried to hone the bearings, they don't hone very well, too hard, i used my sunnen rod hone machine, also can't hold them either. when i did a few, only removed .0004 didn't register with a micrometer.

 

[jdragster]

He is talking about the FRONT pinion bearing. That's the one right behind the pinion seal. It is not pressed on.

That's what I thought. Actually found it today in the Dodge Charger Coronet and Dart Factory maintenance manual.

 

[jdragster]

Thank you all for your help. Richmond Gear is telling me that a .0015" press fit is normal. I said no.