1 / 21

Basic Brakes

Basic Brakes. Split systems/dual master cylinders. Used exclusively since 1960’s Most use front/rear split Some use diagonal split. Brake Fluid. Fluid ruins paint!!! Use DOT 3 in virtually all cars Never ever mix with petroleum based liquids

marah-livingston
Download Presentation

Basic Brakes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Basic Brakes

  2. Split systems/dual master cylinders • Used exclusively since 1960’s • Most use front/rear split • Some use diagonal split

  3. Brake Fluid • Fluid ruins paint!!! • Use DOT 3 in virtually all cars • Never ever mix with petroleum based liquids • When cleaning brake parts use only brakeclean, clean brake fluid, or denatured alcohol • Very hygroscopic • Some recommending flushing intervals

  4. Master cylinder • Primary piston is acted on by pushrod • Secondary piston is acted on by hydraulic pressure • Each piston will have it’s own: • Compensating port • Vent (relief) port • Return spring • Reservoir

  5. Master cylinder diagnosis • Usually fails with one cup bypassing • Low or no fluid pressure from one side of cylinder • Low pedal with brake light coming on • Moisture or petroleum in cylinder will destroy/swell cups

  6. Master cylinder repairs • Rebuilding rare today • Most “new” are rebuilt • MUST be bench bled before installation • If done completely system bleeding will not be necessary

  7. Power boosters • Can be vacuum or hydraulic boosted • Vacuum uses engine vacuum to assist pedal travel • Hydraulic shares power steering pressure off of pump to assist pedal • Both have fail safe if booster fails • Fail-safe will require increased pedal effort

  8. Vacuum booster testing • Pedal will fall away when engine started • Will store vacuum for two or three applications • If vacuum leaks off possibly check valve leakage or internal leakage • Brake fluid in booster indicates failed master cylinder and both must be replaced

  9. Brake hoses and lines • Steel lines are double wall • Use special double flare ISO flare steel or brass fittings • Never use single flare or compression fittings • Hoses • Usually double lined hoses • Lines on hose body should not twist when installed

  10. Brake hoses and lines problems • Hoses can balloon only under pressure causing spongy brakes • Inner wall can block off flow/pressure • Metal lines can rust from inside out

  11. Common hydraulic valves • Pressure differential valve • Metering valve • Proportioning valve

  12. Drum brake • Duo-servo vs. non-servo • Shoes • Primary / secondary • Riveted vs. bonded • Asbestos still around • Drums • Usually cast iron • Must carry heat away

  13. Drum brake service • Drum removal • Can be rusted around center of drum • Imports may have threaded removal holes • May need to adjust down shoes • If shoes are wet with brake fluid, oil, grease shoes must be replaced • Drums should be resurfaced • All dust MUST be wetted down or vacuumed away

  14. Drum brake service • Shoes should be replaced one side at a time for comparison purposes • Usually remove return springs first, hold downs second • Any weak or stretched spring needs new hardware kit

  15. Drum brake service • Adjuster should be cleaned and lubricated • Backing plate pads need lubrication • Roll back dust boots for inspection • Any grease or brake fluid on shoes should be cleaned off before installation

  16. Drum brake problems • Grabbing • Squealing when applied • Fading • Pulsating pedal • Must isolate front or rear • Snapping or clicking noise • Grinding when applied • Low brake pedal • Locked up on very cold days

  17. Disc brake • Two categories • Fixed • Moving • Calipers containing one or two pistons • Floating caliper and sliding caliper must move freely • Rotors usually cast iron - can be vented or solid • Pads often will have wear indicators

  18. Disc brake service • Most require R&R of calipers • Slides and pins must be cleaned and lubed • Some pads have anti-rattle plates or require anti-squeak adhesive to back of pads or will have retaining tabs • As pads wear fluid level will drop • Piston must be bottomed in bore • DO NOT allow caliper to hang by hose

  19. Disc brake problems • Pulsating brakes very common • Binding caliper piston or slides

  20. Drum/rotor resurface • Demo on car

  21. Brake bleeding • Demo on car

More Related