Torque for steering gear cover bolts ?

[Wayne M.]

Can't find this value anywhere (Corvette Shop Manuals; supplements; Chev Shop manuals). I'm guessing at 25 ft.lbs; am I close ?

[John H.]

Re: Torque for steering gear cover bolts ?

Can't find this value anywhere (Corvette Shop Manuals; supplements; Chev Shop manuals). I'm guessing at 25 ft.lbs; am I close ?

Wayne -

Should be close - most 3/8"-16 bolts into cast iron are 25-30 ft-lbs.

[Jim S.]

Re: Torque for steering gear cover bolts ?

25 to 40 ft-lbs after head of bolt is seated against cover.

Jim

[Wayne M.]

Re: Torque for steering gear cover bolts ?

Thanks, guys -- strange that bolts that are to be R&R'ed as part of scheduled service operation, and are part of a safety component (steering), are not shown anywhere in Chev. documents, incl. shop, service, overhaul and owner manuals.

[Jim S.]

Re: Torque for steering gear cover bolts ?

The people that wrote the Chevrolet Service Manuals were pretty good at transfering torque specs from the AIM sheets and placing them in the Chassis Service Manuals (usually on a spread sheet.)

Torque specs for servicing a component that was shipped to the assembly plant (i.e. the assembly and reassembly of subassembly parts of a component) were usually provided by Saginaw in the form of a Saginaw generated component service manual. Whether or not the Chevrolet people used the Saginaw reference was up to them. The Chevrolet Service and Overhaul Manual usually had more component specs than the Chassis Service Manual.

My 1975 Chevrolet Overhaul Supplement has a more complete spec sheet for the manual gear (Specifications 21; Steering Section 9) but still doesn't list the side cover bolt specs.

BTW, I got the side cover bolt specs from the Saginaw assembly drawing. I think that those side cover bolts were unique in that they had a special thread. The note that described torquing those three bolts was very specific that the had of the bolt had to be fully seated before torquing to the 25 to 40 ft-lb spec.

"Bolt must assemble with 6-10 ft-lb turning torque & require 11-15 ft-lbs torque to seat bolt head. Final tightening torque to be 25-40 ft-lb after bolt head has been firmly seated."

Back in the 1970s and 80s, Oldsmobile Division was the lead division for steering within the General Motors car divisions. I suspect that their Service Manuals were probably the most complete for the steering area during that time.

Jim

[Joe L.]

Re: Torque for steering gear cover bolts ?

"Bolt must assemble with 6-10 ft-lb turning torque & require 11-15 ft-lbs torque to seat bolt head. Final tightening torque to be 25-40 ft-lb after bolt head has been firmly seated."

Jim

Jim-------


I'll bet this is exactly why there is no specification provided anywhere in the service and overhaul manuals. This represents a sort of "complicated" procedure compared to most bolt torquing specifications. During the period, most, if not all, torque specs were set up in tables rather than included in the procedural text. It would have been more difficult to tabulerize this kind of spec, even with footnote. So, the manual writers might just have decided to be safe and "leave it out". I've looked high-and-low myself in a variety of 63-82 Corvette service and overhaul manuals as well as other sources and I couldn't find a spec for these anywhere.

By the way, there are a few other notable cases of GM being "silent" on the torque specs for fasteners. The one that always comes to mind for me is the 68-82 front steering arm-to-steering knuckle bolts/nuts. These are critical fasteners and I've never been able to come up with a torque spec for them anywhere.

[Steve L.]

Re: Torque for steering gear cover bolts ?

I design cellphone radios located on towers. I very often specify this type of 3 stage torque sequence for the factory to insure that critical sealing covers are bolted down evenly. Otherwise they will power drive one bolt down to max torque and distorted the covers.

Same with removing covers. Un-torque it in stages. I've had cases where this wasn't followed. The last bolt couldn't be released because it held down the cover all by itself and surpassed the thread stresses. The threads collapse. The bolt has to be drilled out.

I don't think 3 stage torque sequence is odd. If anything, I'm surprised there isn't more of this on these cars. I always torque everything that has 2 or more bolts in sequence.

[Steve L.]

Re: Torque for steering gear cover bolts ?

Jim-------


By the way, there are a few other notable cases of GM being "silent" on the torque specs for fasteners. The one that always comes to mind for me is the 68-82 front steering arm-to-steering knuckle bolts/nuts. These are critical fasteners and I've never been able to come up with a torque spec for them anywhere.

Joe,
Do you have any idea what this torque should be. I'll be doing this particular one this wkend.

[Jim S.]

Re: Torque for steering gear cover bolts ?

I will bet you that the steering arms came to the assembly plant with the arms already bolted in place.

Jim

[Joe L.]

Re: Torque for steering gear cover bolts ?

I will bet you that the steering arms came to the assembly plant with the arms already bolted in place.

Jim

Jim------


Yes, they definitely did, and I would not expect to find torque values for these bolts/nuts in the AIMs. However, it's nowhere to be found in the service or overhaul manuals, either. I've checked numerous ones from 1968 to 1982 and could find it nowhere. I'm told that it may be in service manuals for C2 era cars but they used a different size bolt (7/16-20) versus 1/2-20 for C3.

There are many other fasteners that were part of assemblies used at St. Louis and, therefore, for which no torque specs are to be found in the AIMs. However, the vast majority of these do have torque specs to be found in the service or overhaul manuals. These steering arm bolts and the steering box cover bolts are not among them, though.

[Joe L.]

Re: Torque for steering gear cover bolts ?

Joe,
Do you have any idea what this torque should be. I'll be doing this particular one this wkend.

Steve------


I use a value of 95-100 lb/ft and I feel pretty confident that's within the original specification torque range. My GUESS is that the original range was probably something like 90-120 lb/ft.