Lesson Plan


Disc Brake Repair
Dean Brooks

Topic / Title:  Disc Brake Repair; a multi-day lesson plan

Student Profile: Any adult with need and interest and approximately 8th level reading ability. 

A.  Instructional goals / teacher goal:  Student will be able to recognize and repair safely

  • warped disc
  • worn pads
  • perform research using library, bookstore, computer, and / or indexed manuals

Academic Skills:  Reading, library and index research, web search, learning specialized vocabulary, speaking, some math related to torque wrench and micro measurements.

B.  Competency / Objectives:  Student will

  • Use and respond to specialized vocabulary, appropriate names of tools, and names of  parts while demonstrating repairs (vocabulary list attached);
  • Reference the owner’s manual for proper fluid (and by the way, capacities, engine oil specifications, maintenance schedules, etc.);
  • Find instructions using indexes, reference guide books, and library;
  • Access two of the web sites provided in the webliography; watch one video clip;
  • Create a successful web search using terms that might include ‘disk,’ ‘disc,’ ‘brake,’ ‘repair,’ ‘replace,’ ‘fix,’ ‘DIY,’ and make and model of car;
  • Jack a car at four different appropriate lifting points on one side, which are safe for the car and safe for people; safely place jack stand;
  • Break a nut free with the tire on the ground; will define and spell the words ‘break’ and ‘brake.’
  • Remove a wheel;
  • Find proper torque specifications in reference material, and use torque wrench to replace the wheel;
  • Remove the caliper, hang it with a wire to protect the brake hose; use a torque wrench to remount the caliper;
  • Compress the caliper piston and describe the purpose of this step;
  • Compensate for fluid level changes and explain why this occurs with caliper compression;
  • Remove disc, visually assess scoring, take it to be measured or resurfaced, or replace it;
  • Assess pads, remove them, reinstall the old ones or replace them with new ones as necessary; describe whether or not they are symmetrical and / or identical; replace shims;
  • Reassemble; lower the car; tighten lug nuts; pump brakes to insure first contact between pad and rotor; safely test the braking function.

C.   Rational: Becoming skilled in library, book, and computer research will have many applications.  Students will also practice speaking and listening  with a shopkeeper using a technical vocabulary.  Specifics of car repair will lead to some financial independence. This task, for example, may cost $25 in parts as compared to $150 if it is done in a shop.

D.   Content and Materials, Sites, Games Activity:

Webliography --  Some of these sources have video clips which can be viewed and discussed.

·         3.2.5) How do I change my front brake pads? http://www.faqs.org/faqs/autos/toyota-faq/RAV4/section-48.html

Web Search  -- Students will brainstorm and practice making successful web queries, using such words as ‘disc,’ ‘disk,’ ‘rotor,’ ‘brake,’ ‘break,’ ‘repair,’ ‘fix,’ ‘replacement,’ ‘DIY,’ and make and model of car.  Students will note whether correct spelling is suggested by Google.

Bibliography -- A homework assignment will be to find an appropriate reference book, or repair manual, and bring it or a photo copy to class. The appropriate section on disc brake repair will only be about 5 pages, plus a page with torque specifications.  Teacher can come prepared with a generic handout for each student. Accommodations can be made for students in the group who do not have easy access to a library, such as asking them to find a call number on line, or to write down a title that they find at an auto part store.

Guide books are easy to find at auto repair shops or at book stores.  At the public library they have the call number 629.287 and are organized on the shelf by car make, model, and year.  Popular publishers are Haynes, Chilton, Edmonds, and the For Dummies series by Hungry Minds.

Vocabulary  -- This is a suggested list of words needed to understand the repair guide books.  A few names of tools may need to be added.  Students can review repair manuals in groups to search for technical vocabulary, add words this list, or define words using this list. 

  • Allen wrench: Six-sided tool, often L shaped, which fits into a 6-sided hole on the head of a bolt. Also called hex key or hex wrench.  ‘Hex’ means six. Used to remove slide bolts on some cars such as Mazdas and Hondas.
  • break: To loosen a bolt or nut which is on tight, or “frozen” with rust.  Breaking takes a lot of pressure and so you should break lug nuts before you put a car on a jack so the car will not fall. This kind of break does not mean to damage.
  • breaker bar: Wrench with a long handle for loosening tight nuts and bolts
  • bolt: See dictionary for picture.
  • caliper: The part of the brake the squeezes the disc, to cause friction, and stop the wheel.
  • clamp, C-clamp: Tool, shaped like a C, used to squeeze and compress the brake piston.
  • capacities: This is the word in the index of most owner’s manuals which helps you find how much oil your car holds, how much gas it will hold, how much water, etc.
  • cylinder: A brake system has a master cylinder on the firewall (by the steering wheel, and a slave cylinder on each wheel.  These are full of fluid and they distribute pressure evenly to stop the car.
  • deep, depth: Measurement down from surface. Measure the depth of  wear to find out if disc needs to be thrown away
  • disc: The round, shinny part of a brake.  The disc is the only part which usually looks clean. Also called ‘rotor.’
  • disk: Alternative spelling of disc, often called ‘rotor’ in the US.
  • DIY: Do It Yourself; sometimes a useful term for web searches.
  • DOT: Department of Transportation; standard for fluid formula.  Most American cars use DOT-3 brake fluid.  Check owner’s manual
  • engine oil: This is the term used in the index of owner’s manuals.  If you look for ‘oil’ or ‘motor oil’ you will probably not find what you are looking for.
  • floor jack: A jack on wheels which is a very safe and easy tool for lifting a car.  The car will have a “scissor jack” or a “bumper jack” in the trunk for fixing flats on the road.  These jacks will also work for fixing brakes, but they are not as safe or easy to use.
  • grind: This is the sound brakes make when they are completely worn out.  It sounds something like rubbing a hammer on a stone.  If you hear this sound when stopping you will probably have to replace discs and pads. See ‘metal on metal.’
  • groove: scratches in discs.  These must be polished until the disc is smooth, shinny, and perfectly flat. See ‘score.’
  • hex key, hex wrench: See Allen wrench
  • hose: Rubber tube that holds brake fluid, attached to caliper. Take care not to break or twist this hose too much.
  • inner, inboard, inside: The side close to the engine.  Sometimes inner pads are different than outer pads. You must be careful not to confuse them.
  • jack: This word means many things in English, but here it is the tool to lift the car.
  • jack stand: A steel stand to rest the car on so it will not fall off the jack.
  • knuckle, steering knuckle: This is the part of the car that the front wheel is attached to.  Steering and suspension are also attached here.
  • lathe: A machine to smooth and polish discs.  You will take your discs to a shop to be measured and polished; lathes are too expensive for most people to own.  The word also refers to any machine used to cut something that is spinning; sometimes chair legs are made on a lathe.
  • lug nut: The heavy nut that holds the wheel on.
  • machine (verb): This word is used to describe smoothing the disc, as in “how much does it cost to machine my rotors?”
  • master cylinder: see cylinder
  • measure: It is important to measure how thick a disc is before replacing it.  If it is too thin, it will get hot easily and will cause problems.  Take your discs to the shop to be measured.  They will use the word ‘mic’ (sounds like ‘Mike’) as in “I will mic your discs to see if they are thick enough.”
  • metal on metal: Description of brake pads which are completely worn out and grinding on the disc.
  • micrometer: A tool to measure 1/1,000 x inch, used to tell if a disc is worn out.
  • mount: Attach a part to a larger part or to the car
  • nut: See picture in the dictionary.
  • outer, outboard, outside: The side away from the car.  Sometimes inner pads are different than outer pads. You must be careful not to confuse them.
  • pin: See ‘slide bolt.’
  • piston: This is not the piston in the engine.  This is the piston in the caliper which pushes the pads together, against the disc.
  • pulsate: When the disc is warped the car will shake when braking.  This is called ‘pulsating.’
  • rotor: American name for disc.
  • score, scoring: scratches on the disc. See ‘groove.’
  • shim, squeal shim, anti-squeal shim: Thin sheets of metal that fit behind the pads and reduce noise called ‘squeal.’
  • slide bolt: There are two bolts which hold the caliper on the car.  These bolts are threaded only at the very end, and they allow the caliper to slide inward and outward while braking.  These are called ‘slide bolts,’ or ‘caliper pins.’ Some older cars use slide pins that are installed with a hammer.
  • star wrench: Another name for  torx wrench.
  • torque wrench: A wrench which measures how tight a bolt or nut is. It uses ‘foot-pounds’ in America.
  • torx wrench: This is a wrench which fits into a hole shaped like a six-pointed star on the head of a bolt. It is used on some slide bolts, such as on old Ford Tauruses.  It is designed to take a lot of pressure without hurting the hole, which sometimes happens with other screwdriver shapes or wrench shapes.
  • trouble shoot: Find out what is wrong
  • turn (as on a lathe): Some times a shop keeper will say “Do you want me to turn your disc?” or “turn your rotor?” This means to put it on a lathe and cut or polish the surface.  It is the same as saying “Do you want me to machine your rotor?” or “Do you want me to resurface your rotor?” or “Do you want me to polish your rotor?”
  • vibrate: Shake. See ‘pulsate.’

Visual Aides -- The teacher should bring in one good example of a repair manual with pictures.  Teacher can photocopy part or all of the text and hand out to use for reading and vocabulary practice.  The teacher may want to bring in some tools related to brake repair to assist in vocabulary learning.  Good mechanics like to handle widgets.  To go the extra mile, the teacher could also bring in some auto parts -- pads, shims, rotor, etc.  Worn examples may be free for the asking at an auto part store. New parts might be loaned with a credit card.  A can of brake fluid would also be helpful for practice reading the label.

E.  Instructional Procedures:

These steps are in a somewhat chronological order for performing the repair.  It would be an easy thing to take some steps out of order to accommodate the length of a class period.  The web searches, reading, role playing, artifact show-and-tell, manual reading, vocabulary discussions, hand cleaning, are examples of things that could be put in any order.

·         Identify which students have cars and who have interest in doing repairs. Identify which students may have experience.  If there are many with interest, divide into small groups of 2 to 4, dispersing the experienced students among the groups.

·         Discuss lesson objectives -- this can be part of the identification and assessment step above.

·         Present repair guide photocopy handouts (usually only 4 or 5 pages).  Read together and search for and highlight new vocabulary.  Discuss page formatting and numbering.

·         Display tools and parts and go over some vocabulary.

·         Introduce tricks for keeping hands clean -- gloves, Vaseline, hand cleaners.

·         Practice loosening lug nuts. Find reference for proper torque (tightness). By the way, check torque specifications for slider bolts. These fact are usually not in an owners manual, but will be in the repair manual. (Small car lugs are sometimes about 80 foot-pounds, larger cars are at about 90.) Use torque wrench to replace nuts. Use and discuss tools in car trunk for emergency tire replacement.

·         Practice jacking a car, using the owner’s manual to locate appropriate lift points.  Discuss importance of lift points for safety of the car and safety of people.

·         By the way, use owners manual to determine proper brake fluid.  Bring in a can of fluid so students can practice reading label.  Also use this moment to go over engine oil specifications, and maintenance intervals.  Owner’s manuals are a little quirky and it is necessary to practice using the index. 

·         End of first day, assign homework to go to library and find a repair guide appropriate to their car.  If they don’t have a car, assign a nominal car which will be easy to find, such as a Taurus or Caravan.  Assign students to find proper torque specifications for a given mode.

·         In class, if computers are available, perform web searches as suggested above.  This could also be a homework assignment if students have access to a library or home computer. Note whether Google suggests corrected spelling for ‘brake’ and ‘disc.’  Note which words are not helpful.  Note which sites want to sell books and parts, and which sites actually provide instructions.

·         Practice placing jack stand in appropriate points. These are in the owner’s manual.

·         Remove wheel; remove brake caliper; hang brake caliper; remove disc; remove pads; put all parts back.  This should take about 5 min per student.

·         Remove pads again and examine wear.  Pad should be much thicker than its steel backing; rivets which hold pad to the steel backing should be well below surface of pad.

·         Examine disc.  If possible, students should take a field trip to auto part store to resurface disc and to purchase pads.  In class, students can role play practicing asking for this service.  See ‘machine,’ ‘measure,’ and ‘turn’ in vocabulary list above.  As often as not, the old disc will have to be discarded and replaced.

·         Compress piston. This can only be done once per wheel, so give everyone a moment of hands-on experience. Examine brake fluid level in master cylinder reservoir before and after this step.

·         Install new pads, shims, and reassemble all parts; lower car to ground.

·         In park or with emergency brake on, start car and have one student pump brakes and describe what happens.  Cautiously, release emergency brake, put in gear and allow it to idle forward to test brakes.

·         Wash hands.

·         Do other side.

·         High fives all around.

F.   Assessment:

Assessment should take place at every step particularly with library and index searches until it is clear that students understand steps and vocabulary along the way. Make sure each student gets to demonstrate hands-on each mechanical step.  Given time, a student could learn on one brake and be assessed on another.

G.  Group Activities:

·         Role-play the experience of going to the shop, purchasing parts, and asking for the rotors to be polished. See the vocabulary list and try to use the words ‘rotor,’ ‘disc,’ ‘turn,’ ‘machine,’ ‘polish,’ ‘lathe,’ ‘mic,’ and ‘measure.’ There are several variant words that can be used in these situations and the students should mix up the vocabulary.

·         Students should collaborate and brainstorm to find successful web searches for repair instructions.  They can experiment with miss-spelled words such as ‘disk,’ ‘break,’ and variants such as ‘rotor,’ ‘repair,’ ‘fix,’ ‘replace,’ etc.

·         Reading and discussing the repair manual (or handout) and looking for and highlighting vocabulary words can be done in groups.

·         Small groups of 2 to 4 can also work together on the actual repairs, but it is important that each demonstrates an understanding of each step, including loosening and tightening the lug nuts.

H.   Alternate Plans:

It is best if the students are assessed for interest before setting out on this lesson plan.

There may be some reticence among women. This lesson plan could be shortened to jacking and tire repair which would have a broader appeal. It is well adapted for people who prefer to hold things, participate, and watch activities. 

The academics of web searches, library and index searches, vocabulary lists, role playing and reading are important skills and could be adapted as a stand-alone lesson.  In that case it might be best to pick a research topic (or several) with broader appeal than car repair.  If working in small teams there may be group members who prefer to follow the repair manual or talk to a shop keeper, while others may prefer to get their hands dirty.



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CDE Adult Education and Family Literacy, Center for At-Risk Education (CARE)