Need torque specs for suspension components

[derieuz]

Just got done doing a major overall with my car, brakes are still off the car and the car is on blocks for the night, nothing is torqued to spec as of Now, what are the torque specs if any for:

Rear subframe mounting points
Rear shocks (any bolts for rear spring assembling)
Front strut, strut top hat, sway bar end links
Brake calipers

Thank you in advance!

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[Tim Hilliard]

Just got done doing a major overall with my car, brakes are still off the car and the car is on blocks for the night, nothing is torqued to spec as of Now, what are the torque specs if any for:

Rear subframe mounting points
Rear shocks (any bolts for rear spring assembling)
Front strut, strut top hat, sway bar end links
Brake calipers

Thank you in advance!

First off most if not all of that hardware is one time use. Caliper, Strut, Subframe bolts all are to be replaced and not reused according to Ford Service manuals. Strut Service Part bolts are of a different design than OEM (Not Splined)

 

[Tim Hilliard]

PP 6 Piston Brembo Caliper install the 2 new brake caliper anchor plate bolts.
Torque: 85 lb.ft (115 Nm)
Tighten the 4 rear subframe bracket bolts.
Torque: 41 lb.ft (55 Nm) <<<These are reusable
Tighten the 2 new rear subframe forward bolts.
Torque: 129 lb.ft (175 Nm)
Tighten the 2 new rear subframe rearward bolts
Torque: 129 lb.ft (175 Nm)
Remove the 2 bolts and the brake caliper anchor plate. Discard the bolts.
Torque: 129 lb.ft (175 Nm)
Remove the 2 bolts and position the rear brake caliper aside.
Torque: 24 lb.ft (32 Nm) <<<These are reusable
Install the 3 new upper strut mount nuts.
Torque: 46 lb.ft (63 Nm)
Install the 2 new strut to wheel spindle bolts and nuts.
Torque: 184 lb.ft (250 Nm)
Position the wire harness bracket install the bolt.
Torque: 46 lb.ft (63 Nm)
Install the new front stabilizer bar link upper nut.
Torque: 85 lb.ft (115 Nm)



This Statement is in the service manual at the top of the page:

NOTICE: Suspension fasteners are critical parts that affect the performance of vital components and
systems. Failure of these fasteners may result in major service expense. Use the same or equivalent parts
if replacement is necessary. Do not use a replacement part of lesser quality or substitute design. Tighten
fasteners as specified.

 

[derieuz]

PP 6 Piston Brembo Caliper install the 2 new brake caliper anchor plate bolts.
Torque: 85 lb.ft (115 Nm)
Tighten the 4 rear subframe bracket bolts.
Torque: 41 lb.ft (55 Nm) <<<These are reusable
Tighten the 2 new rear subframe forward bolts.
Torque: 129 lb.ft (175 Nm)
Tighten the 2 new rear subframe rearward bolts
Torque: 129 lb.ft (175 Nm)
Remove the 2 bolts and the brake caliper anchor plate. Discard the bolts.
Torque: 129 lb.ft (175 Nm)
Remove the 2 bolts and position the rear brake caliper aside.
Torque: 24 lb.ft (32 Nm) <<<These are reusable
Install the 3 new upper strut mount nuts.
Torque: 46 lb.ft (63 Nm)
Install the 2 new strut to wheel spindle bolts and nuts.
Torque: 184 lb.ft (250 Nm)
Position the wire harness bracket install the bolt.
Torque: 46 lb.ft (63 Nm)
Install the new front stabilizer bar link upper nut.
Torque: 85 lb.ft (115 Nm)



This Statement is in the service manual at the top of the page:

NOTICE: Suspension fasteners are critical parts that affect the performance of vital components and
systems. Failure of these fasteners may result in major service expense. Use the same or equivalent parts
if replacement is necessary. Do not use a replacement part of lesser quality or substitute design. Tighten
fasteners as specified.

Looks like I have just about everything torqued to spec, is there information on the rear swaybar? I did undertorque the calipers which I will get back to, they are at about 60 ft pounds as of now, do you think this is a critical as in emergency to torque these to specs?

 

[TorkN8R]

Looks like I have just about everything torqued to spec, is there information on the rear swaybar? I did undertorque the calipers which I will get back to, they are at about 60 ft pounds as of now, do you think this is a critical as in emergency to torque these to specs?

Now that was some excellant and useful information from Mr.Hilliard. Guys awesome! Thanks Tim. :cheers:

I'd be surprized if you had gotten them all torqued to spec. I never would have thought that the 2 new strut to wheel spindle bolts and nuts would need the jubilee twist of Torque: 184 lb.ft (250 Nm). Dang...the wheel lug nuts are 150 lbs. Good job though.

 

[Tim Hilliard]

$10.95 right from from Motorcraft's Service website. Again this car uses very high torques, fasteners are not designed to be reused.

 

[BMR Tech]

It gets a little more complicated than "do not re-use fasteners"

The issue with the general idea of mandatory fastener replacement is, there is much more engineering into fastening systems than most know.

For an example, I will use a chassis bolt on a Mustang. This would be, the bolts that hold the front and rear cradles to the chassis of the car, or the bolts that fasten the transmission crossmember to the chassis.

Technically, you are to replace the bolt and the nut. The first few threads of the nut (or in my example, the OEM threaded inserts on the chassis) support the majority of the load/clamping force - AND, the accepting nut/insert material is softer than the bolt material as it is designed to form to the bolt.

What happens when you remove an M14 OEM IRS Cradle bolt and re-install it? Well, to achieve the designed clamping force, you will likely have to step the TQ value up from 129ftlbs to 145ftlbs. Then you run the issue of exceeding the yield strength of the bolt, and putting the bolt into a "plastic" state.

What happens when you remove said M14 cradle bolt, throw away, and install a new bolt? You have a thread mismatch, as the chassis nut inserts have formed to the previous bolt threads under stretch. "Technically" this is just as wrong as re-using an OEM fastener.

In both scenarios, the engineered/designed clamping force will not match what it is designed for. If the clmaping force is 7500lbs from the factory, re-using the OEM bolt and torquing it to spec may give you 6500ftlbs. Purchasing and re-installing the new bolt may also give you 6500ftlbs due to the thread mismatch.

Just thought I would share. Damned if you do, damned if you don't. The "right" way is to replace the entire fastening system, not re-use one of the other.

 

[Tim Hilliard]

The front cradle nut inserts are actually to be replaced which aligns with what you said. Typically nut inserts are hardened and a finer thread which gives lots of surface area, even if the first few threads are distorted you still have full thread engagement engagement to accept the load and a new un-stretched bolt in a used insert will still stretch to the designed distance providing the same theoretical clamping force as OE. Most of the clamping force is under the head, the shaft of the fastener is providing the stretch and threads provide surface area far greater than the head surface.

I'm not disagreeing with your point, I need to think about it some more. I do disagree with over stretching (increased torque) engineered fasteners mainly because no data exists to know how they react outside the intended parameter. Also the weld-nuts (inserts) are pushed outside their design limits and it sucks when those need to be cut out and replaced

 

[BMR Tech]

2005-Current Mustangs have plenty of bolts that are inserted into the chassis, that are not fine thread and do not feature serviceable nut inserts. Many times said nut inserts are "welded" secure.

So on that note, we can take it even further. Wheel studs and lug nuts?

As for the majority of the clamping forces, it is a fact that the first threads of the female end of a fastener receive the most clamping load. The bolt head side may provide the most mounting/support load, though, when talking of support for the item being fastened - due to the forces applied during use.

This is going back some years, but I do recall the nut end of a fastener receiving close to 70% of the entire load of a fastening system. 30% elsewhere.

In that case, the nut end must be softer in all cases, as it must distribute that 70% throughout multiple threads. Example being, the first thread will see 40%, second thread 20% and third thread 10%.

No arguing. I am just presenting information that I know to be correct. A fastening system with a harder material on the nut side, would produce bolt fatigue and failure before applying proper clamping loads.

You often see bolts being damaged when people mismatch fasteners - with the user being baffled at why it happens. On the flip side, you often see people replace their lug nuts on their vehicles, or stripping their spark plug insert in their heads - witout damaging the male side.

On that note, going back to the clamping forces - surely you are aware that a studded fastening system applies more clamping load than a bolted system, correct? Exhaust studs, head studs, Axle nuts, pinion nuts, are just quick references. ;)

 

[ETCH]

It gets a little more complicated than "do not re-use fasteners"

The issue with the general idea of mandatory fastener replacement is, there is much more engineering into fastening systems than most know.

For an example, I will use a chassis bolt on a Mustang. This would be, the bolts that hold the front and rear cradles to the chassis of the car, or the bolts that fasten the transmission crossmember to the chassis.

Technically, you are to replace the bolt and the nut. The first few threads of the nut (or in my example, the OEM threaded inserts on the chassis) support the majority of the load/clamping force - AND, the accepting nut/insert material is softer than the bolt material as it is designed to form to the bolt.

What happens when you remove an M14 OEM IRS Cradle bolt and re-install it? Well, to achieve the designed clamping force, you will likely have to step the TQ value up from 129ftlbs to 145ftlbs. Then you run the issue of exceeding the yield strength of the bolt, and putting the bolt into a "plastic" state.

What happens when you remove said M14 cradle bolt, throw away, and install a new bolt? You have a thread mismatch, as the chassis nut inserts have formed to the previous bolt threads under stretch. "Technically" this is just as wrong as re-using an OEM fastener.

In both scenarios, the engineered/designed clamping force will not match what it is designed for. If the clmaping force is 7500lbs from the factory, re-using the OEM bolt and torquing it to spec may give you 6500ftlbs. Purchasing and re-installing the new bolt may also give you 6500ftlbs due to the thread mismatch.

Just thought I would share. Damned if you do, damned if you don't. The "right" way is to replace the entire fastening system, not re-use one of the other.

Kelly,

so if im putting in a CJ Pony lowering springs in my 2015 GT, what parts would I need to replace, so I can get those lined up?

thank you

rich

 

[BMR Tech]

Kelly,

so if im putting in a CJ Pony lowering springs in my 2015 GT, what parts would I need to replace, so I can get those lined up?

thank you

rich

Rich, based on Ford's recommendation, or mine?

Ford recommends replacing every suspension pivot point bolt. As a matter of fact, they recommend replacing ANY mounting bolts when being removed.

In my experience, I only replace bolts if they do not pass my physical inspection - and if I feel the yield has been exceeded on the previous installation. You will not know by looking that a bolt yield has been exceeded - but after R&Ring bolts so many times, you get a feel for specific mounting bolts and the "feel" when re-applying the spec TQ load to them.

By rights, I can not tell you what pieces you need to replace as that is up to the maker of the components you are installing. But I can tell you, I typically re-use bolts on my personal cars.

 

[Tim Hilliard]

Looks like I have just about everything torqued to spec, is there information on the rear swaybar? I did undertorque the calipers which I will get back to, they are at about 60 ft pounds as of now, do you think this is a critical as in emergency to torque these to specs?

You cost me $10.95

 

[derieuz]

How in the world do you torque something that needs an Allen key to hold it steady? Is there a special type of torque wrench?

 

[Todd15Fastback]

How in the world do you torque something that needs an Allen key to hold it steady? Is there a special type of torque wrench?

http://lmgtfy.com/?q=allen+key+torque+wrench

 

[Tim Hilliard]

http://www.ebay.com/itm/Snap-on-3-8-drive-torque-adapter-FRDH161-1-2-/141663683215

Torque Adapter

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