OEM disk bearing preload

[67GTFB]

Folks --

OK, reworking the stock disk rotors (67 GT 2+2) and bearings and the matter of "bearing preload" came up .... I did a search and didn't find any info on this subject (if I goofed, my bad), so I thought I'd ask this forum .... I've checked two (old) sources and both say (after proper packing, etc.) to torque up the bearing to around 15-20 ft-lbs (while rotating rotor), then back-off 1/2 turn and then re-torque to 10-15 ft-lbs .... the Timken site dicsusses preload and acknowledges that a "light preload" is optimal for bearing life -- but of course they cannot state what "light preload" means in terms of torque numbers .... too tight leads to rapid failure, while loose also leads to failure, but in less dramtic fashion .... my question is then, how are you guys setting the bearing preload if at all??? .... is "zero" (aka, finger tight) pretty good??? .... I followed the "procedure" but only ran the final torque up to around 8 ft-lbs as I have always been fearful of getting the bearing preload too tight .... any thoughts/comments appreciated ....

TIA,

67GTFB

 

[ultrastang]

While rotoating the disc/drum, torque the adjusting nut to 17-25 ft/lbs to seat the bearing. Back the adjusting nut off 1/2 turn, then retighten it to 10-15 in/lbs. Install the retainer and cotter pin.

CAREFUL: (second tightening procedure is in INCH pounds and NOT FOOT pounds)


www.ultrastang.com

 

[67GTFB]

ultrastang --

hey, thanks a ton for your post/info!! .... just the problem I was having with my old manual as it said second torquing was in ft-lbs, not the in-lbs you noted .... I recalled that from a long, long time ago, but lost the source .... I'll retorque accordingly .... 10-15 in-lbs is like 1-1.5 ft lbs -- dang near finger tight + a little .... fortunately I just installed the new rotor and haven't driven any .... thanks again for your prompt reply ....

67GTFB

 

[ultrastang]

No problem. Glad I could help.

--Steve

 

[thehueypilot]

Another method is to install the wheel but leave the wheel bearing center cap off. The wheel should be off the ground so you can rotate it freely. With the wheel bearing finger tight grab the tire top and bottom and pull and push on it so you can feel the play in the bearing and race. Slowly tighten until the play goes to zero. Put the cotter pin in and your done.

 

[67GTFB]

thanks for the tip .... more research on this indicates that "finger tight" (or zero end play as per "Huey") is the way to go .... I don't know why one source of mine said to final torque to 10-15 ft-libs .... perhaps a typo that could have been disastrous .... whew!! -- glad I checked ....