Daewoo Nubira. Manual - part 56

SECTION : 4C

POWER BOOSTER

CAUTION : Disconnect the negative battery cable before removing or installing any electrical unit or when a tool
or equipment could easily come in contact with exposed electrical terminals. Disconnecting thes cable will help
prevent personal injury and damage to the vehicle. The ignition must also be in LOCK unless otherwise noted.

TABLE OF CONTENTS

SPECIFICATIONS

4C–1

. . . . . . . . . . . . . . . . . . . . . . . . . . 

FASTENER TIGHTENING SPECIFICATIONS

4C–1

. 

DIAGNOSIS

4C–1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

POWER BOOSTER FUNCTIONAL CHECK

4C–1

. . . 

MAINTENANCE AND REPAIR

4C–2

. . . . . . . . . . . . . . . 

ON–VEHICLE SERVICE

4C–2

. . . . . . . . . . . . . . . . . . . . . 

VACUUM HOSE

4C–2

. . . . . . . . . . . . . . . . . . . . . . . . . . . 

POWER BOOSTER ASSEMBLY

4C–3

. . . . . . . . . . . . 

GENERAL DESCRIPTION AND SYSTEM

OPERATION

4C–7

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

POWER BOOSTER

4C–7

. . . . . . . . . . . . . . . . . . . . . . . 

SPECIFICATIONS

FASTENER TIGHTENING SPECIFICATIONS

Application

N

S

m

Lb–Ft

Lb–In

Booster–to–Dash Panel Nuts (Right–Hand Drive)

22

16

–

Booster Pushrod Hex Nut

18

13

–

Brake Line Fittings

16

12

–

DIAGNOSIS

POWER BOOSTER FUNCTIONAL
CHECK

1.  With the engine stopped, eliminate vacuum in the

booster by pumping the brake pedal several times.

2.  Push the pedal down and hold in this position.

3.  Start the engine.
4.  The booster is OK if the pedal drops further be-

cause of extra force produced.

If the brake pedal does not drop, the vacuum system (vac-
uum hoses, check valve, etc.) is probably defective and
should be checked.

If no defect is revealed by checking the vacuum system,
the defect is in the booster itself.

4C – 2

I

POWER BOOSTER

DAEWOO V–121 BL4

MAINTENANCE AND REPAIR

ON–VEHICLE SERVICE

VACUUM HOSE

Removal Procedure

1.  Spread the clip on the vacuum hose connection at

the intake manifold and move the clip slightly to-
ward the brake booster.

2.  Pull the hose from the union nut connection. If the

hose does not remove easily or is deteriorated, pry
off and discard the hose.

3.  Spread the clip on the vacuum hose connection to

the brake booster, and move the clip clear of the
booster.

4.  Remove the vacuum hose.

Installation Procedure

1.  Mount the vacuum hose and ensure the connec-

tions are tight on each end.

2.  Install the vacuum hose clips.
3.  Check the function of the booster. Refer to

the”Power Booster Functional Check”in this sec-
tion.

POWER BOOSTER  4C – 3

DAEWOO V–121 BL4

POWER BOOSTER ASSEMBLY

Removal Procedure

1.  Remove the master cylinder. Refer toSection 4B,

Master Cylinder.

2.  Remove the brake lines to the hydraulic modulator

for vehicles equipped with ABS.

3.  Remove the shaft and the rubber O–ring.

4.  Remove the clip on the vacuum hose connection on

the booster.

5.  Disconnect the brake stoplamp switch from the

brake pedal bracket.

6.  Remove the brake pedal spring.
7.  Disconnect the clip and the pushrod pin from the

pedal bracket assembly. Refer toSection 4A, Hy-
draulic Brakes.

4C – 4

I

POWER BOOSTER

DAEWOO V–121 BL4

8.  Remove the booster mounting nuts from the studs

protruding from the dash panel and remove the
booster.

9.  Remove the rubber boot.

10.  Holding the hex nut, twist off the pushrod clevis.
11.  Remove the hex nut from the pushrod.