Trailing arm torque

[JohnnyB]

Hey guys,

I know there are already a few threads about this, but there's a few things that seem to be specified different.

I want to fit new trailing arms for the rear as well as a new panhard rod.
In my specs it's said, that the nuts should have a torque of 8 kpm (78 nm) and the nut for the lower arm to body with 3.5 kpm (34 Nm).

In my " "Haynes Repair Manual" it says 72 ft lbs (97 Nm) for all nuts.

I have a 124 sport coupe CC1 from 74 and I'm confused which torque is correct for my model.


Greetings, Daniel

[18Fiatsandcounting]

Daniel, I looked in the various manuals that I have for the sport spiders, and while yours is a coupe, I imagine the torque specs would be similar. I found values of 72 ft-lbs in a 1970 Fiat workshop manual and in the Haynes manual, and I found 58 ft-lbs in an early (late 60s) manual for the 124 series. If it were me, I'd split the difference and go with 65 ft-lbs. Within reason, I don't think you can overtighten these nuts, so anything from 65 to 80 should be fine.

The one important thing that the shop manuals noted is to do the final torquing of this nuts with the suspension loaded, that is, car on the ground with the full laden weight of two passengers or so. The reason is to avoid stretching of the bushings if they are fully tightened with the rear suspension hanging down and then lowered. So I'd suggest hand tightening the bolts/nuts when the car is in the air, then fully torquing with the wheels on the ground and (if possible) two passengers in the car. Plus a compliant dog in the back seat if available!

-Bryan

[FiatRunner]

I replaced my panhard rod about a month ago, and my Haynes manual told me to do 72 ft-lbs.

I had a pretty hard time getting both of the bolts to a full 72 ft-lbs. Same with what Bryan said, it would probably be pretty difficult to overtighten the bolts to the point that it would strip or snap, at least from under the car.

But again, it's likely most important to torque these when the car is loaded down, I only had one passenger available when I did mine, but I found that about 10 or 12 cinderblocks in the trunk worked just fine!

Good luck.

[Nut124]

I do not think the exact torque on these bolts is critical as long as they are tight and do not come loose.

I have never used a torque wrench on these.