Rotors, Brake Hoses and More

Rotors, Brake Hoses and More

Brake Service Basics

With everything that could go wrong, servicing brakes can sometimes feel overwhelming. Over the years we have found if we keep it simple and use tried and true service methods your brake work can be very successful.

The following pictures and text present brake service repair tips and methods learned over the years or shared with us from seasoned professionals.

Line Locks

Professional brake service people normally use line locks like the one shown. Line locks are diagnostic tools in addition to being service tools. If you are changing a caliper and don't want the system to run dry because the hose is dripping constantly then block it off with a line lock tool. There are several types. Just don't use locking pliers.

Valve Stem Block

If you have a "banjo" type of hose to caliper connection you can block the fluid flow while changing the caliper by inserting a valve stem into the large bolt opening of the hose.

Use Soap and Water

If you have your rotors turned wash them off with soap and water before reinstalling them. Even if they have been sprayed with a brake clean type of product it is best to wash them with soap and water. Brake cleaning products remove oil based film but it takes soap and water to really clean everything.

Rotor Coating

Some new rotors have a petroleum coating while other have a unknown coating or some even say to remove from the box and install on the car. Some coatings are supposedly ok to make contact with a new set of pads and do no harm, but many knowledgeable professionals still wash all rotors before installation. Most professionals suggest washing new rotors with a brake clean type of cleaner then a soap and water wash. This is the safe way to be sure they are really clean and ready to use.

Rotor Run Out

If you see a shiny spot on a rotor such as the one shown it's an indication of excessive rotor run out (wobble). This problem may have been caused by either rust and scale behind the rotor hub face, the wrong method or value of torque when tightening the wheels or hub run out that caused the rotor to not track at zero run out.

Hanging Caliper

Don't ever hand a caliper by its attaching hose. Use a wire hook, a flexible wire wrap or something to positively hold it from hanging on the attaching hose.

Excessive Heat

The separation of the hose from the crimp holding the attaching end was caused by excessive heat. In this case a torch was used to heat the end to enable the flare nut on steel brake line to be loosened. While not common, extremely high brake operating temperatures can also cause this connection to be weakened or fail.

Rust Build-Up

Just because a hose looks ok doesn't mean it is. This hose has an internal restriction caused by rust and scale building up on the inside of the wrap around clamp holding the flexible hose in place. As the rust formed it caused inward pressure on the hose until it squeezed the hose enough to block the small fluid opening inside. This caused a brake pull to the other side of the vehicle. Appearances can be deceptive.

Locking Plier Problems

This hose also appears to be ok. There are no external cracks yet the vehicle has a pull to the opposite side. What has happened is someone at one time used locking pliers instead of a line lock on the hose. This cause the internal layers of the hose to break down and a piece of the internal liner has broken free and is now blocking the fluid from reaching he caliper.

We hope you learned something that can make your work day a little easier. Please let us know if there are any specific repairs or tips you want us to explore in the future.

For questions or comments you can email me at

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