FORD FIESTA 1995
Manual de Servicio

9�10 Braking system
level attitude, but only if it is safe to do so. If it is not possible to achieve this safely, complete the remainder of the operation and bleed the brake hydraulic system with the vehicle on its wheels. 6 Check that all pipes and hoses are secure, unions tight and bleed screws closed. Remove the dust caps (where applicable), and clean any dirt from around the bleed screws. 7 Disconnect the wiring multi-plug from the fluid level warning indicator in the master cylinder reservoir filler cap, then remove the filler cap. Note that the filler cap must not be inverted. Top-up the reservoir with the specified fluid to the �Maximum� level (see �Weekly Checks�). Remember to maintain the fluid level at least above the �Minimum� level line throughout the procedure, otherwise there is a risk of further air entering the system. 8 There are a number of one-man, do-ityourself brake bleeding kits currently available from motor accessory shops. It is recommended that one of these kits is used whenever possible, as they greatly simplify the bleeding operation, and also reduce the risk of expelled air and fluid being drawn back into the system. If such a kit is not available, the basic (two-man) method must be used, which is described in detail below. 9 If a kit is to be used, prepare the vehicle as described previously, and follow the kit manufacturer�s instructions, as the procedure may vary slightly according to the type being used; generally, they are as outlined below in the relevant sub-section. 10 Whichever method is used, the same sequence must be followed (paragraphs 11 and 12) to ensure the removal of all air from the system. fluid level is maintained at least above the �Minimum� level throughout the procedure. 16 Have the assistant fully depress the brake pedal several times to build up pressure, then maintain it down on the final downstroke. 17 While pedal pressure is maintained, unscrew the bleed screw (approximately one turn) and allow the compressed fluid and air to flow into the jar. The assistant should maintain pedal pressure, following the pedal down to the floor if necessary, and should not release the pedal until instructed to do so. When the flow stops, tighten the bleed screw again. Have the assistant release the pedal slowly, and recheck the reservoir fluid level. 18 Repeat the steps given in paragraphs 16 and 17 until the fluid emerging from the bleed screw is free from air bubbles. If the master cylinder has been drained and refilled, and air is being bled from the first screw in the sequence, allow at least five seconds between cycles for the master cylinder passages to refill. 19 When no more air bubbles appear, tighten the bleed screw securely, remove the tube and spanner, and refit the dust cap (where applicable). Do not overtighten the bleed screw. 20 Repeat the procedure on the remaining screws in the sequence, until all air is removed from the system and the brake pedal feels firm again.

13 Hydraulic system - bleeding (conventional braking system)

3

Note: For vehicles equipped with an anti-lock braking system, refer to Section 14. Warning: Hydraulic fluid is poisonous; wash off immediately and thoroughly in the case of skin contact, and seek immediate medical advice if any fluid is swallowed or gets into the eyes. Certain types of hydraulic fluid are inflammable, and may ignite when allowed into contact with hot components; when servicing any hydraulic system, it is safest to assume that the fluid IS inflammable, and to take precautions against the risk of fire as though it is petrol that is being handled. Hydraulic fluid is also an effective paint stripper, and will attack plastics; if any is spilt, it should be washed off immediately, using copious quantities of clean water. Finally, it is hygroscopic (it absorbs moisture from the air). The more moisture is absorbed by the fluid, the lower its boiling point becomes, leading to a dangerous loss of braking under hard use. Old fluid may be contaminated and unfit for further use. When topping-up or renewing the fluid, always use the recommended type, and ensure that it comes from a freshly-opened sealed container. 1 The correct operation of any hydraulic system is only possible after removing all air from the components and circuit; and this is achieved by bleeding the system. 2 During the bleeding procedure, add only clean, unused hydraulic fluid of the recommended type; never re-use fluid that has already been bled from the system. Ensure that sufficient fluid is available before starting work. 3 If there is any possibility of incorrect fluid being already in the system, the brake components and circuit must be flushed completely with uncontaminated, correct fluid, and new seals should be fitted throughout the system. 4 If hydraulic fluid has been lost from the system, or air has entered because of a leak, ensure that the fault is cured before proceeding further. 5 Park the vehicle on level ground, and apply the handbrake. Switch off the engine, then (where applicable) depress the brake pedal several times to dissipate the vacuum from the servo unit. Note: When bleeding the system, the vehicle must maintain a level attitude, ie not tilted in any manner, to ensure that air is not trapped within the pressure control valves. During certain operations in this manual, instructions are given to bleed the brake hydraulic system with the front or the rear of the vehicle raised. In such cases raise the rest of the vehicle so that it maintains a

Bleeding - using a one-way valve kit
21 As their name implies, these kits consist of a length of tubing with a one-way valve fitted, to prevent expelled air and fluid being drawn back into the system; some kits include a translucent container, which can be positioned so that the air bubbles can be more easily seen flowing from the end of the tube. 22 The kit is connected to the bleed screw, which is then opened (see illustration). The user returns to the driver�s seat, depresses the brake pedal with a smooth, steady stroke, and slowly releases it; this is repeated until the expelled fluid is clear of air bubbles. 23 Note that these kits simplify work so much that it is easy to forget the master cylinder reservoir fluid level; ensure that this is maintained at least above the �Minimum� level at all times.

Bleeding sequence
11 If the system has been only partially disconnected, and suitable precautions were taken to minimise fluid loss, it should be necessary to bleed only that part of the system (ie the primary or secondary circuit). 12 If the complete system is to be bled, then it is suggested that you work in the following sequence: a) Right-hand front wheel. b) Left-hand rear wheel. c) Left-hand front wheel. d) Right-hand rear wheel.

Bleeding - basic (two-man) method
13 Collect a clean glass jar, a suitable length of plastic or rubber tubing which is a tight fit over the bleed screw, and a ring spanner to fit the screw. The help of an assistant will also be required. 14 Remove the dust cap from the first screw in the sequence (if not already done). Fit a suitable spanner and tube to the screw, place the other end of the tube in the jar, and pour in sufficient fluid to cover the end of the tube. 15 Ensure that the master cylinder reservoir

13.22 Bleeding the hydraulic system using a one-way valve kit

1595Ford Fiesta Remake