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1938 Wheel Bolt Torque


EmTee
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I've been servicing the front & rear wheel bearings on my '38 Century.  The good news is I have 3/4 completed, but I'm wondering what the specified torque is for the wheel bolts.  I've sifted through the shop manual, but couldn't find anything for the wheel bolts.  I used my 4-way wrench to tighten them to what 'felt right' and determined with my torque wrench that they were about 80 ft-lbs, so that's where they are now.  Several of them were really tight when I removed them, requiring my breaker bar to loosen them.  I don't ant the wheels to come off, but I also don't want to mess-up the threads in the hub/flange.  I know that someone here will have the answer - thanks!

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I think you are right on. 1938 is pretty early for torque wrenches and torque specs. It may be best to find a newer model that uses the same hardware if you want to know for sure. If I remember correctly it usually winds up about 60 on smaller fasteners (6 lug Chevys and the like). and about 80 on the bigger ones (like a 5 lug Buick). In 1938, they would have just tightened it up. Heck, they still would have in 1988 on an American car with drum brakes.

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On 1/25/2022 at 3:48 AM, 37_Roadmaster_C said:

I am fairly certain my 37 Roadmaster has 9/16 Fine thread bolts

I confirmed this ^^^ on my Century; they're also 9/16 fine thread bolts.  I always clean the threads (if they look dirty) and apply a little oil to the threads.  I have also used anti-seize on occasion; particularly around the hub on alloy wheels.  The salt used here in the winter will seep in between the wheel and the hub flange and corrosion will bind the wheel to the hub flange...

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My 37 had the exact same failure with the same wheel. This happened in the early 50's when the car was my dads college car. He told the story of the wheel coming off in Seattle when he was attending the U of W. The wheel was trapped in the wheel well and actually caused some body damage as the rear quarter was lifted. It caved in the body just above the quarter and also twisted the body alignment on the frame.  The strange thing was that it did not damage the brake drum. Go figure...

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Good question,, infact  Robin story  re the 37 Roadmaster  this  reminded me back in   Sacramento 

about 1992--4  one of my Buick Club friends from  Sacramento  owned a  beautiful 41 Roadmaster

and on a trip to  a Buick National  exactly the same  wheel came off,  and a true story  ,the wheel   came of and

went past him on the freeway--as his Buick came  to a crutching stop ,Older members will remember  him,  Ken  Schmidt,  he  past away  years back.

But what i say is  EmTee--is  correct torque to   80 is correct,  i would be ---82-83--, when i do my cars i use 

one drop of three in one oil on the start of the thread,  and of course with  a 5 wheel lug nut, start  at every second

nut at about 10 ft ib,  going around  every second nut until you get to  82 ft ib.

Using one drop of thin oil   spreads the oil along the thread and enables the nut to get a true  smooth reading .

 

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13 hours ago, Wayne R said:

...exactly the same  wheel came off...

 

I may be missing something, but which wheel specifically are you and 37_Roadmaster_C referring to?  Note that I see damage to the backing plate and marks on the outer edge of the drum on my car that suggests the left-rear tire came off sometime after its restoration...

 

As I said at the start, I used my 'calibrated arms' together with my 4-way wrench to initially tighten the wheel bolts.  I then used my torque wrench and incrementally increased the setting to determine that what 'felt good' to me was about 70 ~ 75 ft-lbs.  I rounded that up to 80 ft-lbs and torqued the bolts to that value.  The table that Brian posted refers specifically to 1/2" wheel bolts, so I'm inclined to stick with 80 ft-lbs for the 9/16" bolts used on my Century.

 

Lastly, since the topic is wheel bolts, a final word of caution: A couple of my original bolts had some 'flattened' threads that increased the effort needed to turn them, so I ordered four new bolts from CARS.  I used a couple of them when I re-installed one of the rear tires after finishing my axle bearing/seal replacement.  Before lowering the jack I spun the wheel by hand to check the brake adjustment.  The wheel turned about 60* before stopping with a 'clink'.  Puzzled, I then turned the wheel in the opposite direction and it eventually stopped in the same way.  It felt as though something was binding in either the brake or the differential.  Since both rear wheels were raised, I spun the other wheel with no issue.  I then went back to the problem wheel and removed the tire.  With the tire off, I was able to turn the drum 360* without binding.  Long story short is I compared the new bolts to the old ones and the new ones from CARS were anywhere from 1/8" to 1/4" longer.  The longest bolt was just long enough to strike the parking brake equalizer rod between the two shoes, just below the wheel cylinder.  I reinstalled the drum and tire using the original; bolts and confirmed there was no interference.  I will likely swap a couple of the bolts from a front wheel to the back to replace the damaged ones and use the new bolts only up front, where there's nothing to cause interference.

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Going on -- with this a little further with this subject,    torque is very important---here is an example,

Porsche are critical ,   on a 911  example 1972 correct   torque   factory spec  is--96 ft - ibs---130 nm.

here is a photo of  a spare lug bolt from  my  72  911---, it might surprise  members here ,  yes they are made  from ALLOY.

When you pick one up it is as light as  a small 1/4 inch bolt.

Also  the factory lug wrench is designed and  made the correct length, for  an average adult,  to use 

and  tighten  the lug nut  with average strength ,.

My Buick wrench is 19 inches long, my daughters corolla is 12 inches long, medium size cars are about  14 inches long.

Yes  tire  shops are the worst bad boyes, some could not care less and tighten  them so tight,  that its hard to remove 

especially for a woman driver. 

P1100569.JPG

P1100570.JPG

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3 hours ago, 37_Roadmaster_C said:

We are referring to the left rear (Driver side rear) wheel as shown in Marks picture.

Ah - the picture didn't show up in my browser until I clicked the link and opened it in another window.  Now I'm on the same page!  Yes, it's really interesting that there have been 3 occurrences with the same wheel (left rear).  I know I'll be periodically checking torque on my wheel bolts this summer...  ;)

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5 hours ago, Matt Harwood said:

Good thing you gave it a spin instead of just putting it on the ground and going for a drive!

Yeah, but I'll admit that my heart stopped briefly when it happened because I thought I had discovered a problem with the differential (which I had just buttoned-up after removing and replacing the axle bearings).  When the blood started flowing again I walked around to the passenger side and spun that tire without issue.  That's when I decided to remove the tire and try again.  When I removed the LR drum there wasn't anything immediately amiss, until I spotted a shiny spot on the equalizer rod.  That's when I lined-up all of the wheel bolts on the bench and noticed the length discrepancy.

 

I could have easily missed this until eventually backing out of the garage, except that adjusting the rear brakes was such a headache (particularly the parking brake adjustment) that I felt I better check one final time...  :huh:

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22 hours ago, Wayne R said:

  one of my Buick Club friends from  Sacramento  owned a  beautiful 41 Roadmaster

and on a trip to  a Buick National  exactly the same  wheel came off,  and a true story  ,the wheel   came of and

went past him on the freeway--as his Buick came  to a crutching stop ,Older members will remember  him,  Ken  Schmidt,  he  past away  years back.

 

I recall this and his wife had a really funny poem about the experience at the awards banquet.

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Thank you  Brian,---i am getting   a bit old now ---but i thought i was correct.

Incase members remember ---Ken  was owner operator  of  Buick Bonnery ---Buick dismantler--in Sacramemto.

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