Pinion Bearing Preload ?

AlexLTDLX · Nov 29, 2015

Hi Guys,

So I'm trying out some tall gears, and am using a solid spacer on the pinion. I've got two small issues: the preload is different when I check it clockwise (higher) vs counter clockwise. About 4 in-lbs difference.

Also, with the thinnest shim, I get around 5 in-lbs average preload. If I remove the shim, I get about 14 in-lbs counter clockwise and about 18 clockwise.

Is that too much for used bearings? This is a Ford 8.8 btw.

Thanks.

55chieftain · Nov 30, 2015

spec is 6 to 15 so should be ok for used bearings. dry bearings or wet? they should have some oil on them

AlexLTDLX · Nov 30, 2015

Yeah, I spent some time working gear lube into the bearings before putting them in (I cleaned them out thoroughly first). That 18 in-lbs doesn't offend you, then?

E.R. Racing · Nov 30, 2015

With the thin shim that you mention, after it's installed and torqued, take a hammer and tap the case where the two pinion bearing races are. Should loosen the preload some.

AlexLTDLX · Nov 30, 2015

That's a neat trick. I can also mill down the spacer .004" and run the thinnest shim to split the difference. What do you guys like for used bearings? I see the 6-14(15) recommendation in literature that 55cheiftan mentions and then amongst the shops, they tend to like looser - like closer to 6 in-lbs.

E.R. Racing · Nov 30, 2015

Well... it just sets the races. You should always do it when you put new races in the housing.

Used bearings probably around 5 or so.

AlexLTDLX · Dec 2, 2015

Ok. I'll mill about .002 off the spacer and run the shim. Thanks.

Pinion Bearing Preload ?

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