U-Joint Bolt Torque

[Allen N.]

I have looked in the 1970 AIM, and it shows a u-bolt with 2 nuts holding the u-joint on the half shaft to the differential. My big block has a u-bolt cap with 2 bolts. Does anyone know the proper torque for these bolts?

Thanks,
Allen

[Gary R.]

Re: U-oint Bolt Torque

Allen,
I believe off the top of my head the HD cap torque was 35-40 but you should be able to find it in the AIM- look in the back in the options page, should show the HD axle and the torque

[Allen N.]

Re: U-oint Bolt Torque

Thanks Gary,

I just skimmed thru all the options pages and did not find it. I'll look again tomorrow.

[Gary R.]

Re: U-oint Bolt Torque

Hi Allen
I went over my 69 AIM and the page is listed as v-8 engine 427 rear wheel driveshaft but it is the 1/2 shaft. I was close with my call on the torque- it is listed as 40-50 ft/lb but there is no mention of cap fitment, that would be interesting to see what the original spec was. I had an original gm blueprint of the axles someone gave me last year. I wanted to see if it had that spec as well as some others on it but it was late so I left it on the coffee table at home, intending to look it over the next evening. Well as fate is, I came home last year and all the Xmas decorations were up at home- looked great, then I sat down to look at the print and it was gone. I suspect "well wishers" cleaned up and tossed out the trash, including all the papers on the coffee table. The trash was picked up that same day.

[Richard M.]

Re: U-Joint Bolt Torque

In my 1967 AIM under L36 Sheet A12, which is the 427CI rear wheel half shafts....

It shows the bolts for the U-Joint caps torque is 40-50 lbs/ft.

1970 AIM RPO LS5 454CI may show similar.

Rich
PS Gary we typed at the same time.

[Gary B.]

Re: U-oint Bolt Torque

AIM shows the nuts and u-bolts have a torque of 12-16 lbs-ft. The caps and bolts show 12-17 lbs-ft. These should not be over-tightened, as it will crush the u-joint caps, reduce the clearance in the bearings and cause premature failure.
Gary Bosselman

[Allen N.]

Re: U-Joint Bolt Torque

Thanks to everyone for the responses.

Gary Ramadei sent me UPC L36 Sheet B7 from the 1969 AIM, and it shows 40-50 lbs-ft for the drive shaft u-joint cap bolts.

I still cannot find this page in the 1970 AIM. If someone finds this sheet in their 1970 AIM, please let me know the UPC and sheet number.

Thanks,
Allen

[Jim D.]

Re: U-Joint Bolt Torque

Are the bolts for a 1970 big blocks different than for 1965 big blocks? My 65 has it's original 3/8 X 16 grade 5 bolts which according to the industry standard should be torqued to 23 ft. lbs. lubed or 28 ft. lbs. dry. Even grade 8 bolts are only torqued to 33 ft. lbs. lubed & 39 ft. lbs. dry.

[Gary R.]

Re: U-Joint Bolt Torque

All the "HD" axles used 3/8-16 threads, all the AIM I have seen have been 40-50 ft/lb for the caps but about 15 for U-bolts axles. I share the same concern on the fit of the cap. When I fit a steel cap to the housing to replace a stock cast cap I set the "rock" to 001" so I know when I torque the 1/2-13's to 100 ft/lb the race isn't going to spin and the bearings isn't going to burn up.

[Gary B.]

Re: U-Joint Bolt Torque

[Gary R.]

Re: U-Joint Bolt Torque

Gary that sure is interesting, we both have different spec's. I have a 72 & 75 AIM at home now I want to see what those state.

[Allen N.]

Re: U-Joint Bolt Torque

Thanks Gary,

I had found 1970 sheet above, but it is for a ubolt with nuts. I cannot find a sheet like the 1972 sheet above in the 1970 AIM, but the parts I removed from my car are the cap and bolts like the 1972 AIM sheet.

At this point I am still somewhat confused, but I think I will use a drop of Loctite 242 and torque to 35 lbs-ft.

Thanks,
Allen

[Gary B.]

Re: U-Joint Bolt Torque

My 1970 AIM does not have the sheet the 1972 sheet I posted. I don't have a 71 AIM. Really need to buy one someday.

I suspect, maybe, just maybe, GM found they had a warranty problem with high of torque??? Low u-joint life?

I think a lighter torque and a drop of Locktite is a good idea. would ensure a longer u-joint life.

Gary B