On a 2005 Chevrolet Trailblazer, I need to know the size of the 8-sided nut that holds the front passenger lower control arm Mounting Bracket to the frame.

Torque settings Working on your car means you have to torque parts up when you fit them. Using correct torque levels is very important. Bolts will be tensioned when torquing up. Always use a torque wrench when installing parts on your car!
Too much tension means the bolt will be stressed too much and can ultimately break.
Not enough tension means the bolt can either run loose or it can move around. This will damage the bolt and it's brackets. This can ultimately also lead to catastrophic failures.
Only use 8.8 grade bolts in suspension applications. (wishbones, dampers etc.) 10.9 grade or even worse 12.9 grade bolts are hardened.

The hardening process will improve the maximum possible load on the bolt, but it will also make the bolt relatively brittle.

Within suspension parts, you would rather see bolts bend than sheer. 8.8 grade bolts have the tendacy to bend, any hardended bolts have the tendacy to sheer.
Below is a guideline to the torque levels used on Metric bolts.
Bolt grades are printed on the head of the bolt.
Bolt Size 8.8 10.9 12.9 A2-70 (Stainless) 6mm (M6) 9Nm 13Nm 14Nm 7Nm 8mm (M8) 23Nm 33Nm 40Nm 17Nm 10mm (M10) 45Nm 65Nm 70Nm 33Nm 12mm (M12) 80Nm 115Nm 125Nm 57Nm 14mm (M14) 125Nm 180Nm 195Nm 16mm (M16) 195Nm 280Nm 290Nm Note than when fitting bolts into Ally threads like rivnuts, manifolds and S1 uprights then the torque may need to be reduced.

Special note for Mr. Wiki - This is the thread size, not the head size.
Engine mount torque settings (K-Series) Nm RH engine mounting bracket to engine RH engine mounting bracket to rubber mounting RH engine rubber mounting to chassis RH engine steady arm bolts LH engine mounting bracket to rubber mounting LH engine mounting bracket to engine Lower steady arm bracket to sump Lower steady arm bolts Use Permabond A130(A912E7033V) on the sump end bolt on the lower steady arm
Front suspension torque settings (S2 K-Series) Nm Upper and lower wishbone pivot bolts Upper swivel joint to steering arm Lower swivel joint to plinth Steering arm to hub carrier Track rod end to steering arm Damper to lower wishbone Damper to top anchor bracket Damper anchor bracket to chassis Hub bearing unit to hub carrier Brake caliper to hub carrier Anti-roll bar rubber bush mounting clamps Anti-roll bar drop links Rear suspension torque settings (S2 K-Series) Nm Upper and lower wishbone pivot bolts Upper and lower swivel joint ball pins Upper swivel joint plinth to hub carrier Toe-link outer ball joint to hub carrier* Toe-link inner ball joint/wishbone to sub frame** Toe link ball joint lock nuts Damper to lower wishbone Damper to chassis Upper brake caliper to hub carrier (M10) Lower brake caliper to hub carrier (M8) Hub bearing unit to hub carrier Rear hub nut ,*Check batch number of ball joint is 43273 or later
,**Check batch number of ball joint is 43725 or later

The generator is located above the oil filter and axle shaft.

1. Disconnect the negative battery cable.
2. Remove the 2 bolts from the top of the heat shield on the generator.
3. Remove nut from the upper T-bolt adjustment bracket.
4. Raise vehicle and support.
5. Remove the right front wheel.
6. Remove the accessory drive splash shield.
7. Remove the lower heat shield bolt.
8. Remove the generator heat shield.
9. Unplug the field circuit from the generator.
10. Remove the B+ terminal nut and wire.
11. Loosen the accessory drive belt t-bolt.
12. Remove the pencil strut.
13. Loosen the lower generator pivot bolt.
14. Remove the generator belt, refer to the Cooling section for more information.
15. Remove the axle retaining nut.
16. Remove the lower control arm from the steering knuckle.
17. Remove the 2 bolts for the axle shaft bearing support.
18. Remove the axle shaft assembly. Put a container under the transmission to catch the transmission fluid from the transmission.
19. Remove the generator from the lower mounting bracket and set generator to the side.
20 . Remove the lower mounting bracket for the generator.
21. Remove generator through the axle shaft hole.

Instructions

1. Remove the Upper Control Arm
   • 1Disconnect the ground battery cable using a wrench.
     
   • Loosen the front wheel lugs located on the same side of the upper ball joint you need to replace. Use a lug wrench.
     
   • Raise that same front wheel off the ground using a floor jack and support the vehicle on a jack stand.
   • Finish removing the tire.
     
   • Take the cotter pin off the upper ball joint stud holding the steering knuckle arm. Use a pair of nose pliers.
     
   • Remove the castle nut from the upper ball joint stud using a wrench or ratchet, ratchet extension and deep socket.
     
   • Loosen the two bolts securing the back of the upper control arm to the mounting bracket. Use a wrench to hold the bolt head as you loosen the retaining nut with a ratchet and socket.
     
   • Pull the control-arm ball joint off the steering knuckle arm. You may need to use a Pitman arm puller to free the ball joint.
     
   • Finish removing the two bolts from the back of the upper control arm and lift the upper control arm off the vehicle.
     
   Install the New Upper Control Arm
   • Set the new upper control arm in place and install the two bolts and retaining nuts to secure the back of the upper control arm to the mounting bracket. Remember the bolt heads should point inward toward the shock absorber with the retaining nuts on the outside of the mounting bracket. Do not tighten the bolts yet.
     
   • 11Insert the control-arm ball joint on the steering knuckle arm and start the castle nut with your hand over the ball joint stud. Do not tighten the nut yet.
     
   • Tighten the two bolts on the mounting bracket to 67-foot lbs. (91 Nm) using a torque wrench. Hold the bolts with a backup wrench as you tighten the retaining nuts with the torque wrench.
     
   • Tighten the ball-joint castle nut to 45-foot lbs. (61 Nm) using the torque wrench, ratchet extension and deep socket.
     
   • Install a new cotter pin through the joint-ball stud hole using the nose pliers. If necessary, tighten the castle nut just a few degrees to clear the stud hole through one of the castle nut slots.
     
   • Mount the tire on the wheel assembly and install the wheel lugs using the lug wrench.
     
   • Lower the vehicle and finish tightening the wheel lugs.
     

Never use a tool myself other than a big hammer. Those forks don't work for me, though we have them. Hit the joint on the side and it will pop out. If not, you can always put the nut back on even with the ball stud and hit it from the bottom. The book also calls for a special tool to get the axle out of the hub. Have never used this either. If it doesn't slide out, I just hit it--I have a new one anyway (take it loose from the tranny before hitting it). Tools you will need are the big socket for the axle nut (around 22mm or so) and regular metric socket set, preferably 1/2 in drive. Also take the speed sensor and brake lines off the support bracket to free up the hub a little more. Note that you may need to also separate the tie rod end if you cannot otherwise swing the hub out far enough to get the shaft out. The book says to take off the stabilizer and shock and also separate the upper ball joint. I don't know if that's necessary or not, as I have not done one on this particular truck. You are doing the whole shaft, right? We don't do individual CVs anymore, as the labor is ridiculous compared to the cost difference to a whole half shaft. Take the axle nut off, unbolt the shaft from the tranny, and swing the hub out. Pull the axle out of the hub first, then the tranny. Reverse procedure to install. I will paste the book solution from autozone.com below. Lemme know if you have more questions.

1. Before servicing the vehicle, refer to the Precautions section.
2. Remove or disconnect the following:
   
   Front wheel and tire assembly Skid plate, as required. If equipped Drive axle hub nut and washer Brake line and wheel speed sensor support bracket from the upper control arm to allow extra travel of the control arm. Left outer tie rod attaching nut and cotter pin. Separate the tie rod from the steering knuckle
   
3. Position the tie rod aside and push steering linkage to the opposite side of the vehicle.
   
   Lower shock attaching nut and bolt; position the shock aside Left stabilizer bar bracket and bushing at the frame Stabilizer bar bolt, spacer and bushings at the lower control arm
   
4. Taking pressure off the upper control arm by placing a support below the lower control arm between the spring seat and the ball joint.
   NOTE Cover the shock mounting bracket and lower ball joint stud with a towel to prevent the axle boot from tearing during removal and installation.
   
   
   Upper ball joint cotter pin and loosen (do not remove) the upper ball joint attaching nut. Separate the ball joint stud from the steering knuckle. Remove the attaching nut.
   
5. Separate the axle shaft from the hub and rotor using tool J-28733 or equivalent.
   
   Axle shaft inner flange bolts and shaft
   

To install:

1. Lubricate the axle and hub splines with an approved high temperature wheel bearing grease.
2. Install or connect the following:
   
   Axle shaft in the hub Inboard CV-joint-to-flange bolts. Torque the bolts to 60 ft. lbs. (80 Nm). Upper ball joint to steering knuckle. Torque the stud nut to 61 ft. lbs. (83 Nm). New cotter pin through the upper ball joint stud and nut, lubricate the ball joint as required. Left stabilizer bar bracket and bushing at the frame Stabilizer bar bolt, spacer and bushings at the lower control arm Lower shock in the mount bracket and the attaching nut and bolt Left tie rod end at the steering knuckle. Torque the nut to 35 ft. lbs. (47 Nm). New cotter pin through the tie rod stud and nut Brake line bracket to the control arm, ensuring the line and/or hose is not twisted or kinked Skid plate, as required Axle hub washer and nut. Insert a drift through the rotor vanes to keep the axle from turning. Toque the hub nut to 180 ft. lbs. (245 Nm) Wheel and tire assembly
   

Removing the Ball Joint Step 1 Loosen the lug nuts on the front wheel assembly with the ball joint you need to replace. Do not remove the lug nuts.
Step 2 Set the transmission in neutral (manual) or park (automatic) and raise the wheel off the ground using a floor jack. Then support the car on a jack stand.
Step 3 Chock the rear wheels and apply the parking brake.
Step 4 Remove the wheel lugs and the wheel assembly.
Step 5 Remove the mounting nut and dished washer that secure the stabilizer bar to the control arm. Use a wrench or ratchet and socket.
Step 6 Unscrew and remove the mounting bolt and nut holding the inner side of the control arm to the car's body. This will relieve the tension on the stabilizer bar. Use a wrench to hold the mounting bolt as you unscrew the nut with a wrench or ratchet and socket.
Step 7 Unscrew the bolt on the steering knuckle that holds the control-arm ball joint to the knuckle. Use a wrench or ratchet and socket.
Step 8 Spread the steering knuckle joint that holds the control-arm ball joint to the knuckle. Use a large screwdriver or pry bar. Then separate the ball joint from the steering knuckle.
Step 9 Pull the control arm from the stabilizer bar.
Step 10 Remove the stabilizer bar spacer from the control arm and keep it in a secure place. You will need to use it on the new control-arm ball joint assembly.
Installing the Ball Joint Step 1 Insert the new control-arm ball joint stud into the steering knuckle joint. As you look through the mounting bolt hole on the steering knuckle, align the notch on the ball joint stud with the hole. Insert a new ball joint mounting bolt and start a new nut on the bolt. Tighten the nut.
Step 2 Mount the stabilizer bar spacer in the control arm, then insert the stud bolt at the end of the stabilizer bar into the control arm mounting hole and spacer.
Step 3 Set the other end of the control arm in its mounting position and insert the mounting bolt. Then start the mounting nut on the bolt by hand.
Step 4 Hold the head of the mounting bolt that secures the control arm to the car's body using a wrench, then tighten the nut.
Step 5 Secure the stabilizer bar to the control arm with the dished washer and mounting nut. Tighten the nut.
Step 6 Install the wheel assembly and lugs. Tighten the lugs with the lug wrench just enough to hold the wheel assembly firmly in place.
Step 7 Lower the vehicle and finish tightening the wheel lugs.
Step 8
Remove the chocks from the rear wheels.

REMOVAL & INSTALLATION

3.0L Engine

1. Disconnect the negative battery cable.
2. Raise and safely support the vehicle securely on jackstands.
3. Remove the terminal nuts, washers, and electrical leads from the starter motor.
4. Remove the passenger side catalytic converter.
5. Remove the passenger side engine mount nuts, and lower the vehicle.
6. Disconnect the resonance chamber-to-throttle body ducts.
   1. Detach the electrical connector for the Mass Air Flow (MAF) and the Intake Air Temperature (IAT) sensors.
   2. Disconnect the resonance chamber air intake hose from the air cleaner housing and MAF sensor.
   3. Remove the (IAC) inlet hose and the intake plenum air inlet hoses.
   4. Detach the electrical connector from the switchover valve and the remaining vacuum connections.
   
   
7. Install the engine support fixture J28467-A with adapters J28467-450 or equivalents and raise the passenger side of the engine.
   

NOTE Passenger side of the engine must be raised approximately 1.5 inches (38 mm).

1. Raise and safely support the vehicle securely on jackstands.
2. Remove the engine mount from the engine mount bracket and cradle.
3. Remove the engine mount bracket bolts and reposition the bracket.
4. Remove the starter motor from the vehicle.
   

To install:

1. Install the starter motor to the vehicle and tighten the bolts to 44 ft. lbs. (60 Nm).
2. Position the engine mount bracket and install the bolts. Tighten to 30 ft. lbs. (40 Nm).
3. Install the engine mount to the engine mount bracket and cradle. Partially lower the vehicle.
4. Lower the engine. Have an assistant guide the engine mount into place while lowering the engine. The engine mount locator tab must engage the slot in the cradle.
5. Reinstall the resonance chamber-to-throttle body ducts.
6. Raise the vehicle.
7. Install the passenger side engine mount nuts. Tighten the upper nut to 30 ft. lbs. (40 Nm). Tighten the lower nut to 41 ft. lbs. (55 Nm).
8. Install the passenger side catalytic converter.
9. Plug in the electrical leads, install the washers, and terminal nuts to the starter motor. Tighten the battery cable terminal nut to 115 inch lbs. (13 Nm). And the solenoid terminal nut to 35 inch lbs. (4 Nm).
10. Lower the vehicle.
11. Connect the negative battery cable.

4.6L Engine

1. Disconnect the negative battery cable.
2. Disconnect the positive battery cable.

NOTE In order to get to the starter assembly the intake manifold must be removed. Refer to the procedure for removing the intake manifold.

1. Reposition the front bank spark plug wires.
2. Remove the air intake duct from the throttle body.
3. Detach the electrical connectors for the intake manifold, Throttle Position (TP) sensor, and Idle Speed Control (ISC) motor, Evaporative Emission (EVAP) Control solenoid and Cruise Control Servo.
4. Disconnect the vacuum hoses at the brake vacuum booster, fuel pipe bundle and to the body.
5. Disconnect the PCV hoses at the intake manifold.
6. Unhook the accelerator cable at the throttle body and position it out of the way.
7. Relieve the fuel system pressure. Disconnect the fuel pipe quick connects at the fuel pipe bundle in the engine compartment.
8. Remove the EVAP solenoid bracket at the rear (or right) cam cover.
9. Reposition the transaxle range control cable away from the cruise control servo.
10. Disconnect the coolant hoses at the throttle body and to the coolant reservoir and plug the hoses. Wrap a shop towel around the hoses when disconnecting to avoid spillage.
11. Remove the four intake manifold bolts and lift the intake manifold with the throttle body out of the engine compartment.
12. Unbolt the solenoid 'S' terminal nut and battery cable nut. Remove the starter motor mounting bolts, and lift the starter motor out of the manifold cavity.

To install:

NOTE Before installing the starter motor to the engine, tighten inner nuts on the solenoid terminals to be sure they are secure in the cap. Tighten the inner nuts on the battery terminal and motor terminal to 71 inch lbs. (8 Nm). If the nuts are not properly tightened, the starter may fail later due to the terminal or cap damage.

1. Install the solenoid switch lead, and tighten the nut to 22 inch lbs. (2.5 Nm).
2. Install the battery cable nut and tighten to 71 inch lbs. (8 Nm).
3. Install the starter motor and tighten the mounting bolts to 22 ft. lbs. (30 Nm).
4. Install the intake manifold with the throttle body onto the engine and install the four bolts. The four intake manifold bolts must be tightend in a specific sequence to 71 inch lbs. (8 Nm), then an additional 120°.
5. Connect the coolant hoses at the throttle body and at the coolant reservoir. Add coolant as needed.
6. Position the transaxle range control cable to the cruise control bracket.
7. Fasten the EVAP solenoid bracket to the rear cam cover.
8. Reconnect the fuel pipes quick connects at the fuel pipe bundle in the engine compartment.
9. Hook the accelerator cable up at the throttle body.
10. Connect the vacuum hoses at the brake vacuum booster, fuel pipe bundle and to the body. Install the PCV hose at the intake manifold.
11. Install the electrical connectors for the intake manifold, the TP sensor ISC motor, EVAP solenoid and the cruise control servo.
12. Install the air intake duct to the throttle body.
13. Reposition the front bank spark plug wires.
14. Connect the negative battery cable.
15. Connect the positive battery cable.

4.5L and 4.9L Engines

1. Disconnect the negative battery cable.
2. Raise and safely support the vehicle securely on jackstands.
3. Remove the starter motor shield.
4. Remove the exhaust front and rear pipe assembly.
5. Remove the flexplate inspection cover.
6. Disconnect the solenoid 'S' terminal nut and battery cable nut.
7. Unbolt the starter motor mounting bolts, and remove the starter motor.
   

Fig. Typical starter mounting on early models


Fig. Later model starter location and mounting on the 4.9L engine



Fig. Starter mounting on 4.5L engine with a starter shield


To install:

1. Install the starter motor, and tighten to 32 ft. lbs. (43 Nm).
2. Install the solenoid 'S' terminal nut. Tighten the nut to 35 inch lbs. (4 Nm).
3. Install the battery cable nut and tighten to 12 ft. lbs. (15 Nm).
4. Install the flexplate inspection cover, the front and rear exhaust pipe assembly and the starter motor shield.
5. Lower the vehicle.
6. Connect the negative battery cable.

Hope trhis help (remember comment and rated this).

first remove the wheel,then remove brake caliper by removing two mounting bolts,then remove the caliper mounting bracket two more bolts 15 mm socket,now remove the axle nut 30 mm socket,before removing axle the lower ball joint has to be dislocated and lifted out of lower control arm.tie rod also has to be dislocated to make job easier,now push axle out of wheel bearing then remove the three bolts that hold it in,in most cases you have to beat a chisel in between the bearing and its housing reverse installation.

This is for the 2WD model:

2-Wheel Drive

1. Raise and support the front of the vehicle safely using jack stands.
   
2. Using an open end wrench, hold the shock absorber upper stem to prevent it from turning, then remove the upper stem retaining nut, the retainer and rubber grommet.
   

Common front shock absorber mounting-2WD vehicles

1. Remove the shock absorber-to-lower control arm retaining bolts and lower the shock absorber assembly from the bottom of the control arm.
   
2. Inspect and test the shock absorber; replace it, if necessary.
   

To install:

1. Fully extend the shock absorber stem, then push it up through the lower control arm and spring so that the upper stem passes through the mounting hole in the upper control arm frame bracket.
   
2. Install the upper shock absorber nut and tighten to 100 inch. lbs. (11 Nm) on 1994 models 145 inch lbs. (16 Nm) on 1995 models, 54 ft. lbs. (73 Nm) on 1996 models, or 106 inch lbs. (12 Nm) on 1997-99 models while holding the stem with an open end wrench. Be careful not to crush the rubber bushing.
   
3. Install the shock absorber-to-lower control arm retaining bolts and tighten to 20 ft. lbs. (27 Nm) on 1994-95 models and 54 ft. lbs. (73 Nm) on 1996 models, or 22 ft. lbs. (30 Nm) on 1997-99 models.
   
4. Remove the jack stands and carefully lower the vehicle.
   

Item Part Number Description 1 5310 Front Coil Spring 2 18124 Front Shock Absorber 3 3A130 Tie Rod End 4 1104 Wheel Hub 5 3K185 Front Wheel Knuckle 6 3078 Front Suspension Lower Arm 7 5482 Front Stabilizer Bar 8 5K484 Stabilizer Bar Link 9 N806899-S60 Bolt (4 Req'd) 10 5486 Stabilizer Bar Bracket 11 5484 Rack and Pinion Mounting Bracket Insulator (2 Req'd) (Position Slits Toward Front of Vehicle) 12 W520214-S60 Nut (2 Req'd) 13 N807144-S60 Nut (2 Req'd) 14 N803990-S60 Bolt (2 Req'd) 15 N806364-S60 Nut (2 Req'd) 16 N808466-S428 Nut (2 Req'd) 17 N808391-S100 Bolt (2 Req'd) 18 N807089-S101 Nut (2 Req'd) 19 W500746-S426 Bolt (2 Req'd) 20 W520214-S60 Nut (2 Req'd) 21 N804608-S1428 Nut (2 Req'd) 22 N804002-S100 Washer (2 Req'd) (Dished Side Up) 23 18183 Front Shock Absorber Mounting Bracket (2 Req'd) 24 3B455 Front Suspension Bearing and Seal (2 Req'd) 25 N811008-S100 Washer (2 Req'd)(Dished Side Up) 26 N803766-S60 Nut (6 Req'd) A — Install With Color Code at Bottom of Link — Green—RH Side, Red—LH Side B — Tighten to 30-40 Nm (22-29 Lb-Ft) C — Notches and Stamped "Front" Toward Front Of Vehicle D — Tighten to 47-63 Nm (35-46 Lb-Ft) E — Tighten to 77-103 Nm (57-75 Lb-Ft) F — Tighten to 98-132 Nm (72-97 Lb-Ft) G — Tighten to 68-92 Nm (50-67 Lb-Ft) H — Tighten to 53-72 Nm (39-53 Lb-Ft)

NOTE Hold the shock absorber stem with a wrench while backing the nut off.
Wheel Mounting nut


Retaining nut and grommet Shock absorber-to-lower control arm bolts Shock absorber Replace the parts, as necessary.

Fig. Front shock absorber mounting-2WD vehicles


To install:

1. Fully extend the shock absorber stem, then push it up through thelower control arm and spring so that the upper stem passes through themounting hole in the upper control arm frame bracket.
2. Install or connect the following:
   
   Retaining nut and grommet on the stem. Tighten the nut to 106 inch lbs. (12 Nm).
   
   
   Shock absorber-to-lower control arm bolts and tighten to 22 ft. lbs. (30 Nm) Wheel