A frequent cause of brake system failure is because of brake caliper bolts failing. The issue is – in most situations, it’s because of human error. While changing brake pads is a fairly simple task, the issue happens when mechanics don’t take the time to correctly tighten the brake caliper bolts. To assist you avoid potentially catastrophic damage to your car or an accident that causes harm to you or others, here is a simple guide on how to tighten a brake caliper bolt in 5 simple steps.
Step 1: Correctly take out the brake caliper bolts
As with any other fastener, the brake caliper bolts work best when they are taken out and installed properly. Because of their location and tendency to get corroded with debris, the brake caliper bolts can get rusty and quite hard to remove. So, to lower the potential of damage, removing the bolts correctly is a vital first step. Here are 3 basic tips, but always refer to your service manual for the manufacturer’s recommended steps as not all brake calipers are produced from the same materials.
- Make use of a high-quality penetrating fluid to absorb rust on the bolt.
- Allow the bolt soak for at least five minutes before attempting to remove.
- Ensure to remove it in the correct direction. Note: While we are all taught that lefty-loosey – righty-tighty is the preferred method, some brake caliper bolts function in reverse thread. This is where referring to your vehicle’s service manual is imperative.
Step 2: Check the bolt and bolt holes on the spindle
Once your caliper bolts have been taken, and you’ve removed all brake parts that need to be changed,the next step before installing new part is to inspect the condition of the caliper bolt and the bolt holes found on the spindle. There is a very simple way to test the condition of each. If you remove the bolt and it’s rusty – throw it out and change it with a new one. However, if you’re able to clean the bolt with a mild steel brush or sandpaper, it can be reused. The key is to see how well it fits inside the bolt hole found on the spindle.
The bolt should easily turn into the spindle and should have zero play as you put it into the bolt hole. If you observe play, the bolt needs to be replaced – but, you also need to continue to the next vital step.
Step 3: Use a thread cleaner or “thread chaser” to rethread the bolt hole
If your bolt and bolt hole does not pass the “play” test above, you’ll have to rethread or clean the inner threads of the bolt holes before mounting. To accomplish this, you’ll require a thread cleaner – commonly referred to as a thread chaser – that matches the exact thread as your spindle. One helpful hint is to take a brand-new brake caliper bolt for your car and cut three small sections vertically on the bolt, and hand-tighten it slowly as it’s inserted to the bolt hole. Slowly remove this thread chaser and re-test the newly cleaned bolt hole with a new bolt.
There should be zero play and the bolt should fit easily and be removed easily before tightening. If your cleaning job doesn’t do the trick, stop immediately and change the spindle.
Step 4: Mount all new brake system components
After you’ve confirmed that the brake caliper bolts and the bolt hole on the spindle are in good shape, follow your car service manual and correctly install all replacement components in the exact procedure and order of installation. When it comes time to mount the brake calipers, ensure you follow these 2 critical steps:
- Ensure the new threads have thread-locker applied. Most replacement brake caliper bolts (particularly original equipment manufacturer components) will have a thin layer of thread locker already applied to the bolt. If it does not, use a liberal amount of a high-quality thread locker before installing.
- Slowly guide the brake caliper bolt into the spindle. Do not use air tools for this work. Doing so will likely cross-thread the bolt and over tighten it too.
Step 5: Make use of the recommended torque pressure to tighten the brake caliper bolts
This is where most amateur mechanics make a big mistake by searching online or asking a public forum for the right torque pressure for tightening brake caliper bolts. Since all brake calipers are unique to each manufacturer, and usually made from different materials, there is no universal torque pressure setting for brake calipers. Always refer to your car’s service manual and look up the correct procedures for using a torque wrench on your brake calipers. If you don’t want to invest in a service manual, a phone call to your local dealership’s service department may do the magic.