torque specs: wheel hub bolts

[chessy56]

hey folks-
I need to replace my front left wheel bearing hub on a 2001 K2500 Silverado, ext cab with the Dmax. I need the following torque specs:
wheel hub bolts
outer drive shaft bolt (behind the dust cover)
brake caliper bolts

Also, I see 4 different bolts on the front brake calipers- 2 appear to be the mounting bolts for the caliper to the yolk, the other 2 for the caliper itself. Would it be easier to just remove the 2 caliper-to-yolk bolts and pull the caliper that way, or does this mounting plate not need to be removed?

Finally, do you need to pull the tie rod on that side to access one of the hub bolts?

Can anyone help with these specs?

Thanks a bunch!
Chessy56- South Milwaukee, WI

[jbplock]

I replaced both hubs on my 03 a few months back and used the following values:

Hub and Bearing Assembly to Steering Knuckle Bolts - 133 lb ft
Axle Shaft Nut - 177 lb ft (was 155 prior to a TSB revision)
Caliper Mounting Bracket to Knuckle, Front - 221 lb ft

The Caliper bracket bolts can be tough to break loose.. I used a 24" breaker bar with a 6 point socket and they came off with no problem ..

No need to pull the tie rod .. Here's and an Excellent write up on Hub R&R: http://www.mcratracing.com/wheel_bearing.html

And here's a good source for the OEM Timken Hubs: DmaxStore

[chessy56]

Thanks for the info on the torque specs. I did a little additional checking before reading jbplock's reply. Interesting spec on the caliper mounting bracket (221 ft.lbs.). I found a spec of 122 ft.lbs. both from a web site used by my local NAPA store and the same from a local Chevy dealership. This leaves me with the question of whether the '03 brake hardware is different from that of the '01? I've got my caliper torqued to 122 currently, but I'll have to do a little more digging to insure I'm not grossly undertorqued.

The caliper bracket bolts were tough to break loose, suggesting the 122 ft.lbs. spec may be a little light (it wouldn't be the first time GM had a typo in their service specs). Then again, the truck is 8 years old and there's bound to be a little corrosion contributing to the difficulty in removing these 2 bolts. I'll look into this further- and thanks again for the reply!

chessy56.....

[jbplock]

... Interesting spec on the caliper mounting bracket (221 ft.lbs.). I found a spec of 122 ft.lbs. both from a web site used by my local NAPA store and the same from a local Chevy dealership...

Chessy,

Per the factory service manual via ALLDATADIY.com the lower number if for the 1500 Series trucks .. 221 is the one to use

Caliper Mounting Bracket to Knuckle, Front (15 series): 175 N.m/129 lb ft
Caliper Mounting Bracket to Knuckle, Front (25/35 series): 300 N.m/221 lb ft

[JohnC]

Holy carp! How big are those bolts?

221 and 122 look like typo twins to me... (Or Dyslexia)

[DmaxMaverick]

Holy carp! How big are those bolts?

221 and 122 look like typo twins to me... (Or Dyslexia)

Big (about 12mm+)...and tight! When I did my first one on my 2001, I was out of town, camping. I couldn't get them loose with brute force alone. I had to use a long cheater on a box wrench, and lower the front of the truck to get them loose (placed block below the wrench, and lowered the jack). It could have been ugly, but it worked in a pinch. 221 lb/ft sounds about right.

From the manual:

• Tighten the brake caliper bracket mounting bolts to 175 Nm (121 ft. lbs.) (15 Series).
• Tighten the brake caliper bracket mounting bolts to 300 Nm (221 ft. lbs.) (25 and 35 Series).

Doesn't look like a typo.

[JohnC]

I'm not disputing it, just amazed. 12mm is less than 1/2". A standard 1/2" aircraft bolt loaded in shear has a torque of 40 - 60 lb-ft and a maximum of 91 lb-ft (90,000 psi preload.) To get even to a maximum around 221 you have to go to a 5/8" bolt (about 16mm.) To get a standard torque in that range you're up to a 7/8" bolt, around 22mm.

IIRC, the bolts on the Yukon had 18mm heads, so the bolt is likely 12mm. It had some sort of thread locking compound on it, which helps account for the high break-away torque.

A 12mm class 10.9 bolt has a recommended torque of 135 n*m or roughly 100 lb-ft.

[DmaxMaverick]

12mm was a WAG (not to be confused with a SWAG). It's likely much larger than that, but it's been a while. After further reflection, it seems they were closer to 5/8" or more. And, they do (did) have thread locker on them (blue). Once the initial turn was started, it wasn't too bad with an 18" breaker bar. Torquing was a bear, with my 1/2" x 18" wrench, and it maxes out at 250#. A real chore, considering the limited working space.

I dunno. The book said 221#, so that's where I put 'em. I've done both of mine (front hubs), and a few others since. The bolts didn't seem to be strained by the event.