A Good Reason Not to Blindly Follow the FSM

[mtbtim]

Hey Dudes and Dudettes,

As I've used my FSM over the last couple years, I've noticed discrepancies, mainly with torque specs. One page describing how to take something apart or put back together will show a bolt or nut with one torque spec and then you go to the master schematic page of the area of the truck you're working on and you'll see a totally different torque spec for the same bolt or nut.

This morning I was doing some research regarding dropping the transmission oil pan and I saw a torque spec for the transmission pan bolts that didn't make any sense. Since I know the bolts for the pan are fairly small, the 65 ft-lbf spec for these bolts seemed seriously excessive. I looked up conversions for the Newton-Meter and Kilogram Force-Centimeter values and they both converted to 65 in-lbf. 65 in-lbf is equal to 5.4 ft-lbf. The difference between 65 ft-lbf and 5.4 ft-lbf is pretty huge.

The point of this is you have to use your head and not blindly follow the FSM. If someone followed that spec, and they gradually tightened the bolts in a crossing pattern, they would have eventually snapped one off in the transmission and found themselves removing the pan, dealing with getting the broken bolt out and probably buying all new bolts because they were all over-torqued.

The FSM is still an invaluable resource for us DIY mechanics but you just have to be a little careful and question things when they don't seem to jive.

 

[97t4r81]

Good eye. Your video was awesome too

 

[I_bRAD]

Metric wins again!

 

[SFsquared]

Good looking out! Thanks for making us aware of this, as your advice is solid.

 

[T5RUNNER]

Another reason is that it sometimes makes jobs more complicated:

My wife's Rogue needed a blower motor. The FSM said I had to pull the whole HVAC assembly out through the engine compartment (and drain the coolant and refrigerant) to access it. But one peak under the dash revealed that there was a nice big cylindrical space SPECIFICALLY DESIGNED INTO the dash subframe to allow removal of the blower motor from inside the car. Ignoring the FSM saved me 5+ hours of labor and an AC recharge.

I just replaced the water pump on my Focus. The FSM says to drop the motor for access. But all that was needed was to pop off the crank pulley, which takes about 30 seconds. Again saved me hours.

I always wonder if they write it this way to pad billable hours for the shop, and all the mechanics use these tricks to majorly boost their pay.

 

[LittleCaesar]

Another reason is that it sometimes makes jobs more complicated:

My wife's Rogue needed a blower motor. The FSM said I had to pull the whole HVAC assembly out through the engine compartment (and drain the coolant and refrigerant) to access it. But one peak under the dash revealed that there was a nice big cylindrical space SPECIFICALLY DESIGNED INTO the dash subframe to allow removal of the blower motor from inside the car. Ignoring the FSM saved me 5+ hours of labor and an AC recharge.

I just replaced the water pump on my Focus. The FSM says to drop the motor for access. But all that was needed was to pop off the crank pulley, which takes about 30 seconds. Again saved me hours.

I always wonder if they write it this way to pad billable hours for the shop, and all the mechanics use these tricks to majorly boost their pay.

When my cousin was an ASE mechanic he hopped around a couple of shops. He said that they were many ways or procedures to cheat the time for a job to be completed. With some fellow techs that info could be shared but not always. On the flip side there are jobs that he would lose money on in order to get the job right (ask fellow member BlackCat concerning such).

I'd bet I could count the number of Toyota techs on one hand this year that will follow the FSM to the letter when removing the crank pulley for the 5vz for a timing belt job.

 

[nobb]

Good catch!

Auto manufacturers are huge bureacratic organizations. Manuals are written and checked by teams of engineers, but sometimes small details get missed. I wouldn't be surprised if it was one person's job (summer student? Lol) to go through an entire FSM and calculate torque specs for every bolt.

Without readily accessible TSBs outside of the dealership, there's almost no way for the typical hobbyist to get updates to the FSM as parts get supersceded or typos get caught.

I know of two places where the FSM is wrong: rear axle retainer positioning and the torque spec for the lower ball joint bolts.

 

[BlackCat914]

When my cousin was an ASE mechanic he hopped around a couple of shops. He said that they were many ways or procedures to cheat the time for a job to be completed. With some fellow techs that info could be shared but not always. On the flip side there are jobs that he would lose money on in order to get the job right (ask fellow member BlackCat concerning such).

I'd bet I could count the number of Toyota techs on one hand this year that will follow the FSM to the letter when removing the crank pulley for the 5vz for a timing belt job.

I can't speak for Toyota, but with Infiniti, I can say that probably 90% of jobs can be done easier/quicker than what the FSM states by simply following common sense. I really only use our FSM's for torque specs. Other than that, they're kinda dumb.

 

[cfranck1]

I know of two places where the FSM is wrong: rear axle retainer positioning and the torque spec for the lower ball joint bolts.

Don't forget the fluid capacity of the transmission!!

Drain and Refill - 2.1qts? WTH?

 

[thegipper]

Don't forget the fluid capacity of the transmission!!

Drain and Refill - 2.1qts? WTH?

I noticed that too, who the hell came up with those numbers? Not even close...

 

[zoombyu86]

The digital fsm I use has the correct specs but I agree, don't just blindly follow.

 

[GunnIT]

Came in looking for the Flying Spaghetti Monster, instead there is now a bookmark and writing in my service manual.:clap2:

 

[AntleredRuin]

I find with torque specs, unless it is on a moving part, getting it till it's good and tight by hand, then one extra whack/yank will get you pretty much right on. I don't even torque drain bolts anymore. Too many threads about stripping them, and I've never had a leak yet.
Also, I never use an impact driver for bolts/nuts that need to be torqued.

Sent from my VS980 4G using Tapatalk

 

[Kbuch1]

"Also, I never use an impact driver for bolts/nuts that need to be torqued."


That's Sound Advise!!

 

[ShooterMcGavin]

Metric wins again!

This can't be stressed enough. Sticking with SAE is stupid.

 

[mtbtim]

I find with torque specs, unless it is on a moving part, getting it till it's good and tight by hand, then one extra whack/yank will get you pretty much right on. I don't even torque drain bolts anymore. Too many threads about stripping them, and I've never had a leak yet.
Also, I never use an impact driver for bolts/nuts that need to be torqued.

Sent from my VS980 4G using Tapatalk

This year is the first time in my life I've owned a torque wrench and now I own three. It's a handy tool, but like you, I still tighten nuts and bolts without a torque wrench all the time. I recently changed the engine oil, trans fluid, transfer case fluid and both differentials and didn't bother with the torque specs because I learned early on in my life how to tighten bolts and nuts without stripping them. I've done 100's of oil changes in my life and haven't torqued a single drain plug. But, for some of the things I've done on my truck like the the Lower Ball Joints, Steering Rack Bushings and Valve Cover Gasket Replacement, torquing to spec does give me some piece of mind that I did it right.

I like the impact gun for taking things apart. I don't use it for putting things back together other than to get lug nuts cinched up snug before I torque them to spec.

 

[AntleredRuin]

This year is the first time in my life I've owned a torque wrench and now I own three. It's a handy tool, but like you, I still tighten nuts and bolts without a torque wrench all the time. I recently changed the engine oil, trans fluid, transfer case fluid and both differentials and didn't bother with the torque specs because I learned early on in my life how to tighten bolts and nuts without stripping them. I've done 100's of oil changes in my life and haven't torqued a single drain plug. But, for some of the things I've done on my truck like the the Lower Ball Joints, Steering Rack Bushings and Valve Cover Gasket Replacement, torquing to spec does give me some piece of mind that I did it right.

I like the impact gun for taking things apart. I don't use it for putting things back together other than to get lug nuts cinched up snug before I torque them to spec.

Haha and I don't even torque my lugnuts. I just give it a good amount of 'umph' with a cross bar. I probably should but have never had a problem. I just make sure to slowly tighten in a cross pattern. I'm always amazed when I see people with wobbly wheels that are due to tightening a wheel crooked.

Sent from my VS980 4G using Tapatalk

 

[mtbtim]

Haha and I don't even torque my lugnuts. I just give it a good amount of 'umph' with a cross bar. I probably should but have never had a problem. I just make sure to slowly tighten in a cross pattern. I'm always amazed when I see people with wobbly wheels that are due to tightening a wheel crooked.

Sent from my VS980 4G using Tapatalk

I never torqued them before either. Just used the lug nut wrench and body weight to get them tight. But, since I have a big bad ass torque wrench now, I figured I'd get some use out of it.