The short version
- Hub retaining bolts thread in from behind the knuckle, which is why you cannot see them.
- Many are torque to yield or come with pre applied threadlocker, and those are single use.
- They break more often than any other fastener on this job, usually from being rushed.
- Order a set with the bearing. They cost a few dollars and they stop the job dead if one snaps.
On a bolt-on hub, four hub retaining bolts are the entire mechanical connection between the wheel and the car. They deserve more thought than they usually get.
They are also the fasteners most likely to end your afternoon.
Where the hub retaining bolts actually are
The bolts pass through the back face of the knuckle into the hub flange. Their heads point away from you.
Access is through the gap between the knuckle and the driveshaft. Turn the steering to full lock one way.
People conclude the hub must be pressed in because they cannot see any bolts. Turn the wheel and look behind.
The full front procedure is on the front replacement page.
Why they are single use more often than not
| Type | How to spot it | Reuse? |
|---|---|---|
| Torque to yield | Spec includes an angle stage | No |
| Pre applied threadlocker | Dry blue or red patch on the thread | No, the patch works once |
| Plain high tensile | Torque figure only | Usually yes if undamaged |
| Corroded or stretched | Threads look thinned or necked | No |
| Supplied with the hub | In the box | Use the new ones |
A torque to yield fastener is designed to be tightened past its elastic limit once. Reused, it yields earlier and clamps softer.
It still feels correctly tight on the wrench, which is exactly why this mistake is invisible.
The wider single use question is on the reuse page.
Getting them out without breaking one
These bolts sit in the wet, they are usually steel into steel, and they have often been there a decade.
Warm the knuckle around the boss and let penetrating oil work. Crack each bolt in small movements, not one long pull.
If a bolt starts to feel spongy rather than progressively tighter, stop. That is the moment before it shears.
What to do when one snaps is on the broken bolt page. Using heat safely is on the heat page.
Fitting the new hub
Corrosion in a blind thread absorbs torque, so the wrench clicks before the bolt has reached its real clamp load.
Run a tap or a thread chaser through, and wire brush the face the hub sits against.
Tighten in a cross pattern, in two or three passes, then apply any angle stage last.
Why an anti-seize film on the threads is a bad idea here is on the anti-seize page.
Working through it
- Turn the steering to full lock to reach the bolt heads behind the knuckle.
- Warm and soak before applying real force.
- Crack each one in stages, and stop if a bolt feels spongy.
- Chase the threads and clean the mating face before refitting.
- Torque in a cross pattern, adding any angle stage at the end.
The specification itself is on the torque specs page.
Common questions
Where are the hub retaining bolts?
Behind the knuckle, threading forward into the hub flange. Turn the steering to full lock to reach them.
Can I reuse hub retaining bolts?
Only plain high tensile bolts in good condition. Torque to yield bolts and pre coated threadlocker bolts are single use.
How do I know if mine are torque to yield?
The specification includes an angle stage, such as a torque figure followed by a further ninety degrees.
Why do they break so often?
They are steel in steel, exposed to water and salt for years. People also pull steadily rather than working them free.
Should I use threadlocker on the new ones?
Only if the manufacturer specifies it, and only the grade named. New bolts frequently arrive with it already applied.
Do I need to chase the threads?
It is worth two minutes. Corroded threads absorb torque, so the wrench clicks before the bolt is genuinely clamped.
What if one snaps flush?
Extraction becomes the job. Heat, a left hand drill bit and patience, or the knuckle comes off to a bench.