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Discussion Starter #1
I'm FU**ING PISSED. I was torquing down my rear diff to sub frame bolts and set my snap on wrench to 125 ft lbs, As I was torquing it would get close to the torque, then keep going, it felt odd, but not overly tight. Finally I checked up at the top of the bolt, and the whole area around the bolt and the bolt itself is sunk down 1/4" in a bent bowl down into the sub frame. I feel like now I'll need to get another one...it just never fails with these cars, go to fix one thing, destroy another.
 

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Can't blame the car in this instance, that's WAY too much torque.
What is the recommended torque for that location?

Edit: N/M, Thanks Ian.

Hell, Hammer it back and add a washer to distribute the load.
 

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Discussion Starter #5
What is the recommended torque for that location?

Edit: N/M, Thanks Ian.

Hell, Hammer it back and add a washer to distribute the load.
I wish it were that simple, the member it bolts to is a box, so you cant get underneath to hammer it out
 

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1994 Cougar XR7 DOHC/5-Speed
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Ford spec is 100-155 ft lbs. check your service manual.
I think you're mixing up newton meters with foot pounds, and your spec is still wrong

And for anyone interested in frame specs, my disc manual says:

Description Nm Lb-Ft
Front Sub-Frame-to-Body Through Bolts 97-132 72-97
Stabilizer Bar Links-to-Front Wheel Spindle Retainers 55-75 41-55
Lower Arm Inner Pivots-to-Front Sub-Frame Retainers 125-170 92-125
Front Suspension Lower Arm Struts-to-Front Suspension Lower Arm Retainers 120-160 89-118
Front Spring and Shock-to-Front Suspension Lower Arm Retainers 140-195 103-144
Rear Sub-Frame-Body-Insulator Retaining Bolts 98-132 72-97
Rear Sub-Frame Stabilizer Bracket Retaining Bolts 47-63 35-46
Rear Axle Differential Front Insulator Bolts 77-104 56-76
Rear Differential Insulator Horizontal Bolt Plate Assembly Retaining Nuts 102-122 75-90
Rear Axle Differential Insulator-to-Rear Sub-Frame Bolts 77-104 56-76

Steering Coupling Pinch Bolt 28-40 21-30
Tie Rod End-to-Front Wheel Spindle Retainers 53-73 39-54
Front Engine Support Insulator Through Bolts (3.8L) 47-68 35-50
Front Engine Support Insulator Through Bolts (4.6L) 47-63 35-46
Driveshaft to Rear Axle Universal Joint Flange Retaining Bolts 95-130 70-96
Reinforcement Rod-to-Front Sub Frame Retaining Bolts 97-132 72-97
 

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Can you make a 'washer' out of some steel plate big enough to spread the load past the bowl?
 

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Just to satisfy my curiosity that that's not a misprint, be a dear and turn the page to the equivalent step for the 8.8 :tongue:
LOL :tongue:

Reminds me of reading welding codes. Make certain that you're looking at exactly the same criteria for exactly the same weld you're inspecting.

In Ian's defense, my guess is they'll be the same.
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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My eyes are still good, step 7
Uhh.... Evidently not.

Step 7 describes and provides figures for the bolts that go through the back of the diff, not the IRS subframe, which is step 8. You looked in the wrong place. Text and figures is BELOW the picture, not above.
 

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Uhh.... Evidently not.

Step 7 describes and provides figures for the bolts that go through the back of the diff, not the IRS subframe, which is step 8. You looked in the wrong place. Text and figures is BELOW the picture, not above.
:confused:

Looks like he is reading it correctly to me. #8 talks about index marks for the driveshaft.
 

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1994 Cougar XR7 DOHC/5-Speed
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Uhh.... Evidently not.

Step 7 describes and provides figures for the bolts that go through the back of the diff, not the IRS subframe, which is step 8. You looked in the wrong place. Text and figures is BELOW the picture, not above.
No he's looking in the right spot, although the specs in step 8 ironically are exactly what I torque the diff mount to :tongue:
 

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Discussion Starter #14
I can't believe I missed that this was the page for the 7.5" diff, not the 8.8"...Well at least on the bright side I got it tightened pretty good, and It's mostly back together, so once I wrap up the necessary mods, I'll limp it out to Hampton and swap out the sub frame with one from the yard.
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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If you insist, lol. Still looks like text goes to the pic above since there's no text above the top pic. I agree the text in step 8 doesn't at all describe what's in either pic... but the text in step 7 describes what you see in the top pic. Almost like there's a missing block of text.

I wouldn't mind seeing the whole page though or the page in the 8.8 section either though.

It is what it is at this point... nothing to do about it but clean up and move on. That's life for you.
 

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1994 Cougar XR7 DOHC/5-Speed
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I can't believe I missed that this was the page for the 7.5" diff, not the 8.8"...Well at least on the bright side I got it tightened pretty good, and It's mostly back together, so once I wrap up the necessary mods, I'll limp it out to Hampton and swap out the sub frame with one from the yard.
Honestly as long as the metal up top didn't shear off it's probably fine as is, I'd only seek replacement if it caved in on the bottom since it could throw off the pinion angle. Plus if you're pissed about this you'll be even more pissed when you end up snapping one or more of the captured nuts in the unibody trying to loosen the IRS mounting bolts :tongue:

If you insist, lol. Still looks like text goes to the pic above since there's no text above the top pic. I agree the text in step 8 doesn't at all describe what's in either pic... but the text in step 7 describes what you see in the top pic. Almost like there's a missing block of text.

I wouldn't mind seeing the whole page though or the page in the 8.8 section either though.

It is what it is at this point... nothing to do about it but clean up and move on. That's life for you.
I think the pic above step 7(step 6?) illustrates the positioning of the mount in place before securing it to either the subframe or diff cover... then again you'd think it or step 8 would show the diff mount to diff cover bolts being torqued to spec.
 

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I've noticed the lb-ft torque figures in the service manual are a little on the high side in two places..

The differential rear mount to cross member nuts and bolts..As well as the transmission cross member bolts..

With that in mind..As I torque things to spec..I pay attention to how things are reacting while getting close to the max lb-ft rating..

Like..If things start to cave in from over torqueing..Even though that's what the service manual says..

When I reached 130 lb-ft on mine..I stopped there just because I thought "damn that's a lot of focking torque!" :D

I think you'll be fine..Just back it down to 122-130 lb-ft..

If you're really worried about it though..Do like someone else mentioned and throw some thick azz washers on the bowled part of the subframe..

It would be wise for anyone in the future to pay attention to these particular torque ratings, and to use the lower end of the torque rating (122 lb-ft) vs (156 lb-ft)






Rayo..
 

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Yeah my 1994 Service manual says 80-100 ft lbs for the differential rear insulator to crossmember bolts. You dont need a new subframe, thats just going way too far .. just throw a washer on it and redistribute the load.

Oh yeah .. and HA HA .. you get an LOL for that one.
 

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Discussion Starter #19
I've noticed the lb-ft torque figures in the service manual are a little on the high side in two places..

The differential rear mount to cross member nuts and bolts..As well as the transmission cross member bolts..

With that in mind..As I torque things to spec..I pay attention to how things are reacting while getting close to the max lb-ft rating..

Like..If things start to cave in from over torqueing..Even though that's what the service manual says..

When I reached 130 lb-ft on mine..I stopped there just because I thought "damn that's a lot of focking torque!" :D

I think you'll be fine..Just back it down to 122-130 lb-ft..

If you're really worried about it though..Do like someone else mentioned and throw some thick azz washers on the bowled part of the subframe..

It would be wise for anyone in the future to pay attention to these particular torque ratings, and to use the lower end of the torque rating (122 lb-ft) vs (156 lb-ft)






Rayo..
80-100 ft lbs is actually the correct torque, the ones you stated above are the 7.5" axle.
 

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It's easy to mix up the NM and foot pound specs.

I've done once torquing my lug nuts. Luckily I stopped and double checked when it seemed like it was getting impossibly tight. Certainly a Doh! face palm moment.

I normally look at the specs in the manual and shoot for the middle or adjust things up or down from that taking in account things like thread wear and fastener type. Locking non locking etc. if it's used or new. I like to sneak up on stuff in several steps not just go for the summit in one shot.

If all else fails just remember the guys down at Midas are using a rattle gun 90% of the time. I use a torque wrench because I want to be sure. I don't do this full time. And I don't want stuff working loose. But frankly tight is tight. Most of us have a pretty good feel for when we are getting there or if something's not right.

Torque specs in books can be notoriously wrong too. For any given size bolt there's more or less a max torque. Depending on the material and hardness. Somewhere I have a booklet (from I beleive FelPro) that gives some recommendations. One of the more popular book it may have been "How to Hot Rod your Small Block Chevy" listed the wrong spec for the stock rod bolts. It was too high. Way to high. The old guy in the local machine shop told me about that. About once every two weeks some one would bring him a couple rods to repair where they had over torqued them and snapped them. I mention that because just because it's in print doesn't always mean it's right.
 
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