1994 FIAT PUNTO brakes

Maintenance procedures - diesel models ib.?
Every 10 000 miles (15 000 km) or 12 months
5 Brake warning lamp operation check 1
1 With Ihe ignition Key inserted and turned to the MAR position, open the bonnet and depress the button on the top of the brake
fluid
reservoir cap (see illustration). I
As
the button is pressed, the brake warning
lamp
on the instrument panel should light. 3 If Ihe lamp fails to illuminate, check the operation of the level switch using a continuity taster, then refer to Chapter t2, Section 5,
and
check the Instrument panel bulb.
6 Front brake pad check ^
I
1 firmly apply Ihe handbrake, then jack up the front of the car and support it securely on arie stands (see Jacking and vehicle support). Remove the front roadwheels. 2 Using a steel rule, measure the thickness of
the
friction material of the brake pads on both brakes. This must not be less than 1.5 mm. Ctefc the thickness of the pad friction material through the hole on the front of the caliper
|see
lustration), 3
For a
comprehensive check, the brake pads should be removed and cleaned. The operation of the caliper can then also bo checked, and the condition of the brake disc iteeil can be fully examined on both sides. Refer to Chapter 9 for further Information. 4 If any pad's friction material Is worn to the specified thickness or less, all lour pads must to renewed as a set. Refer to Chapter 9. 5 On completion refit the roadwheels and lower the car to the ground.
7 Underbody sealant check f^
1 Jack up the front and rear of the car and support on axle stands (see Jacking and
vehicle
support). Alternatively position the car over
an
Inspection pit. 2 Check the complete underbody, wheel housings and side sills for corrosion and/or damage to the underbody sealant. If evident,
rapairi

8
Hose
and fluid leak check
1 Visually inspect the engine Joint faces. g3skets and seals for any signs of water or oil leaks. Pay particular attention to the areas
5.1 Depress tho button on the top of the brake fluid reservoir cap
around the camshaft cover, cylinder head, oil filter and sump joint faces. Bear in mind that, over a period of time, some very slight seepage from these areas is to be expected -what you are really looking for is any indication of a serious leak (see Haynes Hint). Should a teak be found, renew the offending gasket or oil seal by referring to the appropriate Chapters In this manual, 2 Also check the security and condition of all the engine-related pipes and hoses. Ensure thai all cable-ties or securing clips are In place and in good condition. Clips which are broken or missing can lead to chafing of the hoses, pipes or wiring, which could cause more serious problems In the future. 3 Carefully check the radiator hoses and heater hoses along their entire length. Renew any hose which is cracked, swollen or deteriorated. Cracks will show up better If the hose is squeezed. Pay close attention to the hose clips that secure the hoses to the cooling system components. Hose clips can pinch and puncture hoses, resulting in leaks. 4 Inspect all the cooling system components (hoses. )olnt faces etc.) for leaks. A leak in the cooling system will usually show up as white or rust-coloured deposits on the area adjoining the leak, Where any problems of this nature are found on system components, renew the component or gasket with reference to Chapter 3. 5 With the vehicle raised, inspect the fuel tank and filler neck for punctures, cracks and other damage, The connection between the filler neck and tank is especially critical. Sometimes a rubber filler neck or connecting hose will leak due to loose retaining clamps or deteriorated rubber. 6 Carefully check all rubber hoses and metal fuel lines leading away from the fuel tank. Check for loose connections, deteriorated hoses, crimped lines, and other damage. Pay particular attention to the vent pipes and hoses, which often loop up around the filler neck and can become blocked or crimped. Follow the lines to the front of the vehicle, carefully Inspecting them all the way. Renew damaged sections as necessary.
6.2 Check the thickness of the pad friction material through the hote on the front of the caliper
7 With the vehicle raised, check along the length of the underside for leaks from the metal brake lines, caused by damage or corrosion. 8 At each front brake caliper, check the area around the brake pipe unions and the bleed nipples for hydraulic fluid leakage, 9 Remove the front roadwheels and chock for fluid leakage from the area around the caliper piston seal. Check that the tip of the piston dust seal is correctly located in its groove. If it has been displaced, the brake caliper should be removed and overhauled as described in Chapter 9, to check for internal dirt Ingress or corrosion. 10 Check the area surrounding the master cylinder and vacuum servo unit for signs of corrosion, Insecurity or hydraulic fluid leakage. Examine the vacuum hose leading to the servo unit for signs of damage or chafing. 11 From within the engine compartment, check the security of all fuel hose attachments and pipe unions, and Inspect the fuel hoses and vacuum hoses for kinks, chafing and deterioration. 12 Where applicable, check the condition of the power steering fluid hoses and pipes.
A leak in the cooling system will usually show up as white or rust coloured deposits on the area adjoining the leak.

ib.14 Every 2 years - diesel models
Radiator flushing 7 To flush the radiator disconnect the top and bottom hoses and any other relevant hoses from the radiator, with reference to Chapter 3. 8 Insert a garden hose into the radiator top inlet. Direct a flow of dean water through the radiator, and continue Hushing until clean water emerges from the radiator bottom outlet. 9 II after a reasonable period, the water still does not run clear, the radiator can be flushed with a good proprietary cooling system cleaning agent. It is important that their manufacturer's instructions are followed carefully. If Ihe contamination is particularly bad, insert the hose in the radiator bottom outlet, and reverse-flush the radiator.
Engine flushing 10 To flush tho engine, remove the thermostat as described in Chapter 3. 11 With the bottom hose disconnected, direct a clean flow of water through the engine, and continue Hushing until clean water emerges from the radiator bottom hose. 12 On completion of flushing, refit the thermostat and reconnect the hose with reference to Chapter 3.
Cooling system filling 13 Before attempting to fill the cooling system, make sure that all hoses and clips are in good condition, and that the clips are tight. Note that an antifreeze mixture must be used all year round, to prevent corrosion of the engine components (see following sub* Section). 14 Remove the expansion tank filler cap. and fill the system by slowly pouring the coolant Into Ihe expansion tank to prevent airlocks from forming. Ensure that all bleed plugs/screws are open. 15 If the coolant is being renewed, begin by pouring in a couple of litres of water, followed by the correct quantity of antifreeze, then top* up with more water. 18 Once ihe level in the expansion tank starts to rise, squeeze the radiator top and bottom hoses to help expel any trapped air in
the system. Once all the air is expelled, top-up the coolant level to the MAX mark and refit the expansion tank cap. Close all bleed plugs. 17 Start Ihe engine and run il until it reaches normal operating temperature, then stop the engine and allow It to cool. 18 Check for leaks, particularly around disturbed components. Check the coolant level In the expansion tank, and top-up if necessary. Note that the system must be cold before an accurate level Is indicated In the expansion tank. If the expansion tank cap Is removed while the engine is still warm, cover the cap with a thick cloth, and unscrew the cap slowly to gradually relieve the system pressure (a hissing sound will normally be heard). Wait until any pressure remaining in the system Is released, then continue to turn the cap untH it can be removed.
Antifreeze mixture 19 The antifreeze should always be renewed at the specified intervals. This is necessary not only to maintain the antifreeze properties, but also to prevent corrosion which would otherwise occur as the corrosion Inhibitors become progressively less effective. 20 Always use an ethylene-glycol based antifreeze which is suitable for use in mixed-metal cooling systems. The quantity of antifreeze and levels of protection are indicated in the Specifications. 21 Before adding antifreeze, the cooling system should be complelely drained, preferably flushed, and all hoses checked for condition and security. 22 After filling with antifreeze, a label should be attached to the expansion tank, stating the type and concentration of antifreeze used, and the dale installed. Any subsequent topping-up should bs made with the same type and concentration of antifreeze. 23 Do not use engine antifreeze In the windscreen/tailgate washer system, as it will cause damage to the vehicle paintwork. A screenwash additive should be added to the washer system in the quantities stated on the bottle.
28 Brake fluid renewal

A


Warning: Brake hydraulic fluid can harm your eyas and damage painted surfaces, so use extreme caution when handling and pouring It. Do not use fluid that has been standing open for some time, as It absorbs moisture from the air. Excess moisture can causa a dangerous loss of braking effectiveness. 1 The procedure is similar to that for the bleeding of the hydraulic system as described In Chapter 9. except that the brake fluid reservoir should be emptied by siphoning, using a clean poultry baster or similar before starting, and allowance should be made for the old fluid to be expelled when bleeding a section of the circuit. 2 Working as described in Chapter 9, open Ihe first bleed screw in the sequence, and pump the brake pedal gently until nearly all the old fluid has been emptied from the master cylinder reservoir.
ffffTOgf Old hydraulic fluid Is
lifcjllitt*
Invariably much darker In [HINT] colour than the new, making /{easy to distinguish the two.
3 Top-up to the MAX level with new fluid, and continue pumping until only the new fluid remains in the reservoir, and new fluid can be seen emerging from (he bleed screw. Tighten the screw, and top the reservoir level up to Ihe MAX level line. 4 Work through all the remaining bleed screws In the sequence until new fluid can be seen al all of them. Be careful to keep the master cylinder reservoir topped-up 10 above the MIN level al all limes, or air may enter the system and greatly increase the length of the task. 5 When the operation is complete, check thai all bleed screws are securely tightened, and that their dust caps are refitted. Wash off ail traces of split fluid, and recheck the master cylinder reservoir fluid level. 6 Check the operation of the brakes before taking the car on the road,

9«1
Chapter 9
Braking system
Contents
Brake disc - inspection, removal and refitting 4 Brake fluid level check See Weekly checks Brake fluid renewal See Chapter 1A or 1B Brake warning lamp check See Chapter 1A or 1B Front brake caliper - removal, overhaul and refitting 3 Front brake pad check See Chapter 1A or 1B Front brake pads - renewal 2 General information 1 Handbrake - checking and adjustment 9
Handbrake cables - removal and refitting 10 Hydraulic pipes end hoses - renewal 13 Hydraulic system - bleeding 11 Master cylinder - removal and refitting 12 Roar brake shoe check See Chapter 1A or 1B Rear brake shoes - renewal 5 Rear brake drums - removal, inspection and refitting 6 Rear wheel cylinder - removal, overhaul and refitting 7 Stop-light switch - adjustment, removal and refitting 6
Degrees of difficulty

Easy, suitable
far
novice with Sttle
experience ^
Fairly
easy,
suitable ^ (orbeginnerwith ®
some
experience
Fairly difficult, suitable
for
compe«ent ^ CHYmechanlc ^

Difficult, suitable for
experienced DIY « mechanic ^
Very difficult, ^
suitable
for
expert DIY
or professional ^
Specifications
Front disc brakes Type Disc with single-piston sliding calipers Disc diameter Petrol models with single-point Injection 240.0 mm Petrol models with multi-point Injection 257.0 mm Non-turbo diesel models 240.0 mm Turbodieselmodels 257.0 mm Disc thickness (new); Petrol models with single-point injection 10.80 to 11.10 mm Petrol models with multi-point Injection 11.80 to 12.10 mm Non-turbo diesel models 10.80 to 11.10 mm Turbodieselmodels 11.80 to 12.10 mm Minimum disc thickness (wear limit): Petrol models with single-pant Injection 9.20 mm Petrol models with multi-point Injection 10.20 mm Non-turbo diesel models 9.20 mm Turbo diesel models 10.20 mm Maximum disc runout 0.15 mm Brake pad friction material minimum thickness 1.5 mm
Rear drum brakes Drum Inner diameter (new) 180.0 to 180.25 mm Maximum drum diameter (wear limit) 181.35 mm Minimum brake shoe lining thickness 2.0 mm
Torque wrench settings Nm ibf ft
Bfeed
screw 6 4 Brake disc locating studs 12 9 Brake drum locating studs 12 9 Brake pipe and hose unions 14 10 Front caliper mounting bracket-to-hub carrier bolts 53 39 Front caliper-to-caliper bracket guide pin bolts 12 9 fleer wheel cylinder mounting boils 10 7 Roadwheel bolts 85 63

9*2 Braking system
2.3a Release tho locking clip ...
1 General information
The braking system is of the vacuum servo-assisted. dual-circuit hydraulic type. The arrangement of Ihe hydraulic system is such that each circuit operates one front ond ono rear brake from a tandem master cylinder. Under normal circumstances, both circuits operate In unison However, in the event of hydraulic failure in one circuit, lull braking force will still be available at two diagonally-opposite wheels. All models covered in this manual are fitted with front disc brakes and rear drum brakes. The front disc brakes are aotuated by single-piston sliding lype calipers, which ensure lhat equal pressure is applied to each brake pad. The rear drum brakes incorporate leading and trailing shoes, which are actuated by twin-piston wheel cylinders. A self-adjust mechanism is incorporated, to automatically compensate for brako shoe wear. As the brake shoe linings wear, the footbrnke operation automatically operates the adjuster mechanism, which effectively lengthens the shoe strut and repositions the brake shoes, to remove the llning-to-drum clearance. The mechanical handbrake linkage operates the brake shoos via a lever attached to the trailing brake shoe.
2.3b ... and remove the pad wear indicator wiring and brake fluid line from the suspension strut Load sensitive proportioning valves operate on the rear brake hydraulic circuits, to prevent the possibility of the rear wheels locking before the front wheels under heavy braking. Note: When servicing any part of the system, work carefully and methodically; also observe scmpulous cleanliness when overhauling any part of the hydraulic sysiem. Always renew components (in axle sets, where applicable) if In doubt about their condition, and use only genuine Fiat replacement parts, or at least those of known good quality. Note the warnings given in Safety first and at relevant points in this Chapter concerning fhe dangers of asoestos dust and hydraulic fluid.
Models with anti-lock braking system (ABS) Available as an option on certain models, the anti-lock braking system prevents skidding which not only optimises stopping distances but allows full steering control to be maintained under maximum braking. By electronically monitoring the speed of each roadwheel in relation to the other wneete, Ihe system can detect when a wheel is about to lock-up, before control is actually lost. The brake fluid pressure applied to that wheel's brake caliper is then decreased and restored (or modulated) several times a second until control
£s
regained. The system components comprise an Electronic Control Unit (ECU), four wheel speed sensors, a hydraulic unit, brake lines and dashboard mounted warning lamps.
The hydraulic unit incorporates a tandem master cylinder, a valve block which modulates the pressure in the brake hydrauli: circuits during ABS operation, an accumulator which provides a supply of highly pressursed brake fluid, a hydraulic pump to charge Ihe accumulator and an integral electronic control unit (ECU). The four wheel sensors are mounted on the wheel hubs. The ECU uses the signals produced by the sensors to calculate Ihe rotational speed of each wheel, The ECU has a self-diagnostic capability and will inhibit the operation of the ABS il a fault is detected, lighting the dashboard mounted warning lamp. The braking system will then revert lo conventional. non-ABS operation. II the nature of the laull ie not immediately obvious upon inspection, the vehicle must be taken to a Fiat dealer, who will have the diagnostic equipment
required
lo interrogate the ABS ECU electronically and pin-point the problem
2 Front brake pads - & renewal S

A


Warning: Renew BOTH sets ol front brake pads at the same
time
- NEVER renew the pads on
only
one wheel, as uneven braking may result

A


Warning: Note that the dust created by wear of the pads
may
contain asbestos, which is a health hazard. Never blow It out with compressed air, and don't inhale any of
it.
An approved filtering mask should be worn when working on the brakes. DO NOT use petrol or petroleum-based solvents to clean brake parts; use proprietary braks cleaner or methylated spirit only. 1 Firmly apply the handbrake, then jack up the front of the car and support it securely
on
axle stands (see Jacking and vehicle supporti. Remove the front roadwheeis. 2 Wording on one side of the vehicle, puth the caliper piston into its bore by pulling the caliper outwards. If necessary, press the piston back into its bore using a large G-clamp or a piston retraction tool. Keep a careful eye on the level of brake llufd in Ihe I reservoir as you do this - ensure that the
level
I does not rise above the MAX marking. 3 Whore applicable, release the locking dp and remove the pad wear indicator
wiring end
brake fluid line from the bracket at Ihe
base of
the suspension strut (see illustrations).
Petrol models without ABS 4 Remove the locking clip and exlracl the lower guide pin from the caliper (see illustrations) 5 Pivot the caliper body upwards and support In position with a length of wire or a cabie-fc. Avoid straining the hydraulic hose.
2,4a Remove the locking clip ... 2.4b ... and extract the lower guide pin from the caliper (petrol models without ABS)

Braking system 9®9
6.8 Brake light switch assembly f Hexagonal' 3 Spacer section 4 Mounting bracket 2 Bush S Locating lug 6 Twist the switch anti-clockwise through about half a turn, and withdraw the switch from the pedal bracket. Note the position of the spacer and fitting bush.
10.3a Prise the bung (arrowed) from the access hatch in the rear of the relevant brake backplate
10.3b Unhook the cable end from the brake shoe lever (arrowed)
Refitting 7 Depress the brake pedal and hold it in this position. 8 Fit the bush and spacer over the end of the switch, then Insert the switch Into its mounting bracket. Rotate the switch body clockwise through 60° until the locating lug is felt to engage in its recess (seo illustration). 9 Release the brake pedal and allow It to rest against the switch spacer tab - this adjusts the position of the switch body Inside Ihe bush. 10 Now depress the brake pedal again - this has the effect of breaking off the spacer tab and fixes the position of the switch Inside the bush. 11 Restore Ihe wiring at the connector, then refit the facia lower trim panel. 12 Switch on the ignition and test the operation of the brake lights.
9 Handbrake - ^ checking and adjustment
Checking 1 Apply the handbrake by pulling it through three to four clicks of the ratchet mechanism and check that this locks the rear wheels, holding the vehicle stationary on an incline. In this position, there should be sufficient reserve travel in the handbrake lever to allow for brako shoe wear and cable stretching. If not. Ihe handbrake mechanism Is need of adjustment.
Adjustment 2 Remove the securing screws and lift off the handbrake lever trim cover - refer to Chapter 11. Section 19. for details. 3 Pull the handbrake lever through three clicks of the ratchet mechanism and leave it in this position. 4 The adjustment mechanism is underneath the handbrake lever. Hold the locknut with a ring spanner, then rotate the adjustment screw through one turn anticlockwise, so that the adjustment mechanism tensions the handbrake cable draw bar (see illustration). 5 Release the handbrake lever, then re-apply
10.5a Unscrew the bolts (arrowed) securing the handbrake cable bracket to the suspension lower arm
the handbrake it and check the operation of the handbrake as described in paragraph 1. Repeat the adjustment procedure as necessary. 6 Chock the front wheels then |ack up the rear of the car and support it on axle stands (see Jacking and Vehicle Support). Release the handbrake lever and check that the rear wheels are free to rotate v/ithout binding. Re-adjust the cable if the brakes appear to be binding. 7 On completion, tighten the cable locknut and refit the handbrake lever trim cover. Lower the car to the ground.
10 Handbrake cables -removal and refitting
Removal 1 There are two rear handbrake cables, one on each side of the vehicle. To renew either rear cable, proceed as follows. 2 Chock the front wheels, then jack up the rear of tho vehicle and support securely on axle stands (see Jacking and vehicle support). Release the handbrake fully, 3 Working under the rear of the car, prise the bung from the access hatch in the rear of the relevant brake backplato, Using pointed-nose pliers, compress the cable spring and release the cable end from the brake shoe lever (see Illustrations). 4 Extract the handbrake outer cable from the brake backplate. then withdraw the end of the cable from the brake assembly. 5 Unscrew the nuts and bolts securing the handbrake cable bracket to the suspension lower arm. Release the cable from the clips on the floorpan heatshield (see Illustrations).
10.5b Release the cable from the clips (arrowed) on the floorpsn heatshield

9*10 Braking system
10.6 Disconnect the relevant handbrake inner cable (arrowed) from the draw bar 6 Working inside ihe vehicle, remove Ihe screws and lift off the handbrake lever trim panel (refer to Section 9 for more detail). At the base of the handbrake lever, full/ slacken off the handbrake adjusting screw and locknut, to remove oil tension from the cable draw bar, then disconnect the relevant handbrake inner cable from the cable draw bar (see illustration) 7 Release the cable grommet from tho floor-pan, then withdraw the cable from the vehicle.
Refitting 8 Refitting Is a reversal of removal, bearing in mind the following points: a) Ensure that the cables are securely fastened In the clips on the floorpan beetshield and lower suspension a/m. b) On completion, check the handbrake adiustment, as described in Section 9.
11 Hydraulic system -bleeding

A


Warning: Hydraulic fluid is poisonous; wash off immediately and thoroughly In the case ot 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
11.17 Bleeding a rear brake line
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 fresh water. Finally, it Is hygroscopic (it absorbs moisture from the air) • old fluid may be contaminated and unfit tor further use. Whan topping-up or renewing the fluid, always use the recommended type, and ensure that It comes from a freshly-opened sealed container.
General 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 syslem. 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 com-ponents and circuit must be Flushed completely with uncontamlnated, correct fluid, and new seals should be fitted throughout the system. 4 If hydraulic fluid has been lost from the system, or air has ontered because of a leak, ensure that the fault is cured before proceeding further. 5 Park Ihe vehicle on level ground, switch off the engine and select first or reverse gear (or P), then chock the wheels and release the handbrake. 6 Cheek that all pipes and hoses are secure, unions tight and bleed screws closed. Remove Ihe dust caps (whore applicable), and clean any dirt from around the bleed screws. 7 Unscrew the master cylinder reservoir cap, and top Ihe master cylinder reservoir up to the MAX level line; refit the cap loosely. Rememoer to maintain the fluid level at least above the MIN level line throughout the procedure, otherwise there is a risk of further air entering the syslem. 8 There are a number of one-man. do-It-yourself 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 Ihe 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 Ihe removal of all air from the system.
Bleeding sequence 11 If Ihe system has been only
partial!?
disconnected, and suitable precautions wwe taken to minimise fluid loss, it should be necessary to bteod only that part of the system (le the primary or secondary circuit). 12 If the complete system Is to be bled, then It should be done working in the following sequence: a) Left-hand rear wheel b) Right-hand front wheel. c) Right-hand rear wheel. d) Left-hand front wheel. Note: When bleeding the rear brakes
on a
vehicle ritled with load proportioning valves: i the rear of the vehicle has been jacked
up to
allow access to ihe brake wheel cylinder,
tha
rear suspension must be compressed
(eg
raising the beam axle with a trolley
jack) so
that the load proportioning valves
remain open
throughout the bleeding process.
Bleeding -basic (two~man) method 13 Collect a clean glass jar, a suitable length of plastic or rubber tubing which Is a light fit over the bleed screw, end a ring spanner lo
Rt
the screw. The help of an assistant will also tie 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 Ihe tube In the jar. and
pour in
sufficient fluid to cover the end of the tube. 15 Ensure that the master cylinder reservoir fluid level is maintained at least above the
MIN
level line throughout the procedure. 16 Have the assistant fully depress the brefce pedal several times to build up pressure, then maintain it on the final downstroke. 17 While pedal pressure is maintained, unscrew ihe bleed screw (approximately one turn) and allow the compressed fluid and orto flow into the
Jar,
The assistant should maintah pedal pressure, following the pedal down to the floor if necessary, and should not rrtaase Ihe pedal until instructed to do so. When ihe flow stops, tighten the bleed screw again, have the assistant retease the pedal sfowty, and recheck the reservoir fluid level (see Illustration). 18 Repeat Ihe steps given in paragraphs 16 end 17 until the fluid emerging from the bled screw is free from air bubbles. If Ihe master cylinder has been drained and refilled,
and
at Is being bled from the first screw In the sequence, allow approximately five seconds between cycles for the master cylinder passages to refill. 19 When no more air bubbles appear, tighter, the bleed screw securely, remove Ihe tube arc spanner, and refit the dust cap (where applicable). Do not overtighten the bleed sew. 20 Repeat the procedure on tho remaining screws In the sequence, until ail air is removed from the system, and the brake pedal feels firm again.