Publi s hed: 11-May-2011
Front Disc Brake - Front Disc Brake
Des cript ion and Operat ion
COMPONENT LOCATION
• NOTE: i6 gas oli ne front dis c brake s hown; TD4 dies el front dis c brake si mil ar.
ItemPart NumberDescription1-Ant i-lock Brake Sys tem (ABS) s ensor cable
2-ABS s ens or ret aining s crew
ItemPart NumberDescription
A-Front brake cal iper - i6 gas oli ne vehi cl eB-Front brake cal iper - TD4 dies el vehicle
The cal iper as sembl y compris es a fixed carrier and s li ding caliper. The fi xed carrier i s mounted t o s t raddle t he brake di scand is at t ached t o t he wheel knuckl e wit h 2 bol ts . The fixed carri er provides the locat ion for 2 brake pads t hat aremounted on ei ther s ide of t he brake di sc, and is formed wit h guide channel s t hat al low t he brake pads t o s li de toward t hedis c s urface.
• NOTE: The 2 fixed carrier ret aining bol ts are pre-appl ied wi th a t hread locking adhesi ve and mus t not be re-us ed duringmaint enance. New fixed carri er ret ai ning bolt s mus t be us ed and t he ori gi nal bolt s di scarded.
The s li di ng cal iper is mount ed over the fixed carrier and ret ains t he 2 brake pads wi thi n the cal iper as s embly. The s li di ngcal iper is secured t o t he fixed carri er wit h 2 bus hed bol ts , and i s formed wi th a hydraul ic chamber cont ai ning a 60 mm(2.36 in) di ameter pis t on and annular s eal.
The s li di ng cal iper is connect ed via a fl exi ble hos e t o t he brake s yst em hydrauli c circui t, and als o i ncorporates a bleeds crew for maint enance purposes .
The 2 bus hed bol ts are machined wi th a s mooth surface and are protect ed from di rt and moi st ure ingres s wi th a col laps iblerubber boot . The bushed bolt s all ow t he s li di ng caliper li mi ted l ateral movement along t he fi xed carri er.
A hous ing s pri ng is locat ed on t he outer s ide of t he brake dis c, and is connect ed wit h formed hooks between t he fixedcarri er and sl idi ng cal iper. During operat ion of t he brake, t he s pri ng is tens ioned as the sl iding cal iper moves toward thebrake dis c. The s pring as s is t s to move t he sl idi ng cal iper away from t he brake di sc as the brake is released.
An anti -s queal s him i s ins tal led on t he outs i de edge of each brake pad and reduces Nois e, Vibrat ion and Hars hnes s (NVH)from the brake component s duri ng operati on.
The brake pads are not i nst all ed wit h pad wear s ens ors .
BRAKE DUST SHIELD
A formed brake dust s hiel d is locat ed between t he wheel knuckle and brake di s c, and i s s ecured to the knuckl e wit h 3s crews .
The brake dus t shi eld i s handed t o t he rel evant s ide of t he vehicle and protects t he brake component s from cros s axl es tone t hrows . The brake dus t shi el d als o prevent s debris and brake dust from s preading t o other part s of t he vehi cl e.
PRINCIPLES OF OPERATION
Brake Application
As t he brake pedal i s applied, ini ti al hydrauli c pres s ure i s fel t in the s l iding cali per chamber caus ing t he pis t on to ext endt oward t he brake dis c. The moving pis t on cont act s t he inner brake pad, forci ng the pad al ong the fixed carrier guidechannels and i nto cont act wi th the i nner s ide of t he brake di sc.
As t he pis ton ext ends from t he cal iper chamber, it pas ses t hrough an i nternal annul ar seal located wit hi n t he cal iper
The brake dis c al so forms t he locati on for t he parking brake component s . The brake d is c i nt ernal diamet er is 185 mm (7.28
in) and i s machined wit h a smoot h s urface to form t he brake drum. An int egral backpl
ate and brake dust s hiel d is mount ed
t o the rear of the brake di s c. The backpl at e enclos es the brake dis c and als o provi d es the mount ing l ocat ion for t he 2
parking brake shoes and operat ing component s.
An apert ure i s formed i n t he dust s hiel d and backplat e t hat al lows t he parking brake cable to protrude t hrough to the i nner
s ide of t he brake dis c, and connect to t he parki ng brake expander uni t. A hol e machi ned i n t he brake dis c outer hub
provides acces s t o t he parking brake manual adjus ter.
For addit ional informat ion, refer t o: Parking Brake (206-05 Parki ng Brake and Act uat ion, Descripti on and Operat ion).
CALIPER ASSEMBLY Item
Part Number Description
A -Rear brake caliper - i 6 gasol ine vehicle
B -Rear brake caliper - TD4 di es el vehi cl e
The cal iper as sembl y compris es a fixed carrier and s li ding caliper. The fi xed carrie r i s mounted t o s t raddle t he brake di sc
and is at t ached t o t he wheel knuckl e wit h 2 bol ts . The fixed carri er provides the lo cat ion for 2 brake pads t hat are
mounted on ei ther s ide of t he brake di sc, and is formed wit h guide channel s t hat al l ow t he brake pads t o s li de toward t he
dis c s urface.
• NOTE: The 2 fixed carrier ret aining bol ts are pre-appl ied wi th a t hread locking ad hesi ve and mus t not be re-us ed during
maint enance. New fixed carri er ret ai ning bolt s mus t be us ed and t he ori gi nal bolt s d i scarded.
The s li di ng cal iper is mount ed over the fixed carrier and ret ains t he 2 brake pads w i thi n the cal iper as s embly. The s li di ng
cal iper is secured t o t he fixed carri er wit h 2 bus hed bol ts , and i s formed wi th a hy draul ic chamber cont ai ning a pi s ton and
annul ar seal.
The s li di ng cal iper is connect ed via a fl exi ble hos e t o t he brake s yst em hydrauli c c ircui t, and als o i ncorporates a bleed
s crew for maint enance purposes .
The 2 bus hed bol ts are machined wi th a s mooth surface and are protect ed from di rt an d moi st ure ingres s wi th a col laps ible
rubber boot . The bushed bolt s all ow t he s li di ng caliper li mi ted l ateral movement alo ng t he fi xed carri er.
An anti -s queal s him i s ins tal led on t he outs i de edge of each brake pad and reduces N ois e, Vibrat ion and Hars hnes s (NVH)
from the brake component s duri ng operati on.
An upper and lower brake pad ret aining spring are mounted bet ween the fixed carrier and s li di ng caliper. The retai ning
s prings are held i n pos it ion by t he 2 bus hed bol ts , and mai ntain pres sure on t he bra ke pads t o prevent radial movement of
t he pads away from t he brake dis c.
The brake pads are not i nst all ed wit h pad wear s ens ors .
BRAKE DUST SHIELD
A formed brake dust s hiel d and int egral parking brake backpl ate is l ocat ed bet ween t he wheel knuckl e and brake dis c, and
is secured t o t he knuckle wit h 4 s crews .
5-Brake shoe retai ni ng s pri ng
6-Brake shoe return s pri ng
7-Brake shoe mechanical adjust er8-Lower (l eadi ng) brake s hoe
9-Parki ng brake l ever cabl e
10-Parki ng brake cabl e equalizer11-Parki ng brake i nner cabl e
12-Equali zer fas t ener
13-Parki ng brake mi cros wit ch14-Parki ng brake l ever as sembl y
15-Parki ng brake outer cable
16-Brake dus t s hield
OVERVIEW
The parking brake is a manual ly actuat ed s ys t em t hat operat es brake s hoes located i n t he rear brake di scs . The ins idecent er of the rear brake dis c is manufact ured t o form the brake drum.
BRAKE SHOE ASSEMBLY
The brake s hoes are mount ed horizontal ly on an int egral brake dus t s hield and backplat e, and form an upper t rai li ng andlower l eading brake s hoe type s yst em. Retai ni ng pins pas s t hrough hol es in the dus t s hield and corres ponding hol es ineach brake s hoe bracket . Each pi n is secured t o t he brake s hoe wit h a ret ai ning cli p. The ret ai ning pins al low movement oft he brake s hoe toward the drum surface duri ng parking brake operat ion, but prevent si deways movement of the brake shoeaway from the dus t s hi eld.
An expander unit and manual adjust er are l ocat ed along t he hori zont al axis of t he dus t shi el d. The expander uni t isposi ti oned at the front of the dus t s hield and forms t he locati on for t he leading and t rai ling ends of t he brake s hoebracket s . The manual adjus t er i s mounted at t he rear of t he dust s hiel d and forms t he l ocati on and ful crum poi nt for theoppos it e ends of t he brake s hoe bracket s.
The manual adjus t er provides the means to adjust t he brake s hoe l ining t o drum clearance for maintenance purposes .Acces s t o t he manual adjus t er knurl ed wheel i s t hrough a formed hole in the front of the brake dis c. Adjust ment isrequired if t he brake s hoes or dis cs are renewed. A bedding-in procedure must al so be performed t o make s ure the drumbrakes operate sat is fact oril y.For addit ional informat ion, refer t o: Parking Brake Shoes Bedding-In (206-05 Parking Brake and Actuati on, GeneralProcedures).
The corres pondi ng ends of bot h t he upper and l ower brake shoe brackets are mai ntained i n contact wit h t he expander uni tand manual adjus t er by 2 ret urn springs . The return s pri ngs are l ocat ed bet ween t he ends of each upper and l ower brakes hoe and att ach to hol es formed in the brake shoe brackets . The ret urn springs pull t he brake s hoes away from t he drumwhen t he parking brake is released.
PARKING BRAKE LEVER
The parking brake lever is l ocat ed in t he floor cons ole bet ween the driver and pass enger s eats , and compri ses a toot hedquadrant , pawl and pres s-butt on rel eas e mechanis m. A si ngl e cabl e wi th a formed t hreaded rod-end connect s t he quadrantt o the equali zer unit , and is secured wit h eit her a locknut or a l ocking was her and nut.
The t hreaded rod all ows adjus tment s t o t he parking brake cable tens ion and parki ng brake lever travel t o be performed formaint enance purpos es.For addit ional informat ion, refer t o: Parking Brake Cabl e Adjus tment (206-05 Parki ng Brake and Actuat ion, GeneralProcedures).
The parking brake cable is routed from t he parking brake l ever equalizer, and al ong the chas si s t o t he rear parking brakeexpander uni t. The parki ng brake cabl e prot rudes t hrough t he brake dust s hiel d, and is formed wit h a nippl e that connectst o the expander unit . The oppos i te ends of each Left-Hand (LH) and Ri ght -Hand (RH) parking brake cabl e are formed wit h anipple that connect to the equali zer unit . The equal izer uni t makes sure t he LH and RH parki ng brake as s embl ies operat es imul taneous l y when the parking brake i s applied.
A micros wit ch is locat ed on t he base of the parki ng brake lever. The micros wit ch operates t he parking brake warni ngindicat or l amp l ocat ed in t he i ns t rument clus ter, when the parki ng brake i s appl ied.For addit ional informat ion, refer t o: Ins t rument Clus ter (413-01 Inst rument Cl us t er, Des cript ion and Operat ion).
PRINCIPLES OF OPERATION
As t he parking brake lever i s applied, t he toot hed quadrant rotat es and pul ls on the t hreaded rod and cable equali zer. Theequal izer pul ls t he 2 parki ng brake cables and operat es the 2 expander uni ts s i mult aneous ly. Movement of t he expanderunit caus es t he upper and l ower brake s hoes t o pivot agains t the manual adjus ter fulcrum, and t he brake s hoes cont actt he brake drum agai nst t he t ens i on of the 2 ret urn s pri ngs .
As t he parking brake lever quadrant rot ates , t he teet h on t he pawl engage wit h corresponding t eeth on the quadrant . Int he appl ied pos it ion, the pawl t eet h are held under spring t ensi on agai nst the quadrant teet h t o prevent the l ever fromdis engagi ng.
W i th the parki ng brake appli ed and the i gnit ion i n power mode 6 (ignit ion), t he mi cros wit ch connect s a ground to theins t rument clus ter and il lumi nat es t he parking brake warning i ndi cat or lamp.For addit ional informat ion, refer t o: Ins t rument Clus ter (413-01 Inst rument Cl us t er, Des cript ion and Operat ion).
W hen t he parking brake lever pres s-butt on is pres sed and t he l ever moved t o rel eas e t he parki ng brake, t he pawl teet hare rais ed clear from the quadrant t eet h. As the parki ng brake l ever i s lowered, t he parking brake cable cl oses t heexpander uni t and the brake s hoes are immediatel y moved away from the brake drum by the 2 ret urn s pri ngs .
ItemPart NumberDescription
1-Brake pipe t o LH front cali per2-ABS modul e
3-Brake pipe t o RH front cali per
4-Mas t er cyli nder primary circuit connect ion5-Brake pipe t o LH rear cal iper
6-HCU
7-Brake pipe t o RH rear cal iper8-Mas t er cyli nder s econdary ci rcuit connect ion
The HCU i s located on the rear LH s ide of t he engi ne compartment and i s an i nt egral component wit h t he ABS module. TheHCU i s a 4 channel uni t that modulat es the s upply of hydrauli c pres sure t o t he brakes under t he cont rol of the ABSmodule.
The pri mary and secondary outl et ports of t he mas ter cyli nder are connect ed via 8 mm (0.315 in) diamet er brake pipes t ot he primary and s econdary ci rcuit s of the HCU. The primary circui t in t he HCU provi des 2 s eparate out let port s t o t he RHfront and LH rear brakes . The secondary circuit in t he HCU provi des 2 s eparate out let port s t o t he LH front and RH rearbrakes.
The HCU i ncorporates 3 brake operati ng modes as fol lows :
Normal braki ng/ El ect ronic Brake Force Dis t ri but ion (EBD)ABS brakingActi ve braking.
As t he HCU and ABS modul e is a ful ly i ntegrat ed unit , the des cript ion and operat ion det ai ls for the HCU and ABSfuncti onal it y, i ncl udi ng t he 3 braking modes , are det ail ed in the Ant i-Lock Control - Stabil it y As si st secti on of the manual .For addit ional informat ion, refer t o: Anti -Lock Cont rol - St abi li ty As s is t (206-09 Anti -Lock Cont rol - St abi li ty As s is t ,Des cript ion and Operat ion).
Servicing Information
The ABS module and HCU form a s ingle component and must not be s eparat ed. The ABS modul e and HCU as s embly i ss uppl ied i n a pre-fill ed s tat e. Aft er i nst all at ion, t he hydraul ic brake sys t em only requi res a conventi onal bleed of t hes ys t em; t here is no requirement to press ure bleed t he s ys t em.
• NOTE: The ABS module and HCU i s a fragil e component and mus t be dis carded if dropped or damaged.
PRINCIPLES OF OPERATION
As t he brake pedal i s pres s ed, t he front push rod i n t he brake boost er pus hes t he mas ter cyl inder pri mary pi st on along t hebore of t he housi ng. This produces pres s ure in t he pri mary pres sure chamber and i n conjunct ion wi th the primary s pri ng,overcomes the s econdary s pring and s i mult aneous ly moves t he s econdary pi st on along the bore.
The ini ti al movement of the pi s tons away from the pi st on s t ops cl os es t he pri mary and secondary cent er val ves l ocat edins ide the mas t er cyli nder. Further movement of the pi st ons then press uri zes the flui d in the primary and s econdarychambers and t he brake circuit s . The fl uid i n t he chambers behi nd the pi s tons i s unaffected by the movement of the
pis t ons and will flow unrest ri cted t hrough t he inlet ports , between t he chambers and t he res ervoir.
Pres s urized fluid ent ers the HCU that i s mounted on t he front of the ABS modul e. The HCU t hen modul ates t he s uppl y ofpres s urized fluid to the brakes under cont rol of the ABS modul e.For addit ional informat ion, refer t o: Anti -Lock Cont rol - St abi li ty As s is t (206-09 Anti -Lock Cont rol - St abi li ty As s is t ,Des cript ion and Operat ion).
1-Vacuum pi pe - i 6 engi ne
2-Vacuum pump - i6 engi ne
3-Vacuum pi pe - TD4 engine (up t o 2010 MY )4-Vacuum pump - TD4 engine
5-Check valve
6-Brake boost er
OVERVIEW
Power as s is t ance for the braki ng s ys t em i s provided by a vacuum operat ed, non-act ive brake boos ter.
The brake boost er is a compact unit t hat occupi es les s s pace than a convent ional brake boos t er, improving t he vehi cl escras h performance charact eri st ics . The uni t is ins tall ed wi th t andem diaphragms that are 203.20 mm (8.00 in) and 228.60mm (9.00 in) i n diamet er and operate as a s ingle uni t.
The unit i s located on t he driver's si de of the engine compartment , and is s ealed t o t he bulkhead wit h a gas ket ands ecured wit h 4 s t uds and locki ng nuts . The brake boost er act uati ng pus h rod i s att ached t o t he brake pedal wit h a clevispin. The boost er out put rod l ocat es in the primary pis ton of t he brake mast er cyl inder.For addit ional informat ion, refer t o: Hydraulic Brake Actuati on (206-06 Hydraulic Brake Act uati on, Des cri pt ion andOperat ion).
VACUUM COMPONENTS
For bot h t he i6 gas oli ne and TD4 dies el engi nes , t he vacuum requi red for brake booster operati on is creat ed by a vacuumpump mount ed at the rear of t he cylinder head. The vacuum pump i s dri ven by the i ntake cams haft.
A rigi d plas ti c pipe connect s the vacuum pump t o a check valve ins t al led on the front chamber of t he brake boost er. Thepipe l engt h and rout ing is different for LHD and RHD model s.
The check valve mai ntains the vacuum neces s ary for brake boos t er operat ion and prevent s air from ent eri ng the frontchamber.
Stop/Start Vehicles - From 2010 MY
Stop/St art Vehicl e Component s
ItemPart NumberDescription
1-Brake vacuum sens or
Brake vacuum s ens or
Publi s hed: 11-May-2011
Anti-Lock Control -
General SpecificationItemSpecification
Syst em make / typeConti nent al Teves - MK23E1
Wheel speed sensors:MakeConti nent al Teves
Yaw rate sensor:
Make / t ypeConti nent al Teves - RSC03Locat ionCenter cons ole in front of gear shi ft
Torque SpecificationsDescriptionNmlb-ft
ABS module to mount ing bracket nuts107
Accel erometer bolt s65Brake flui d t ube uni ons1511
Front road wheel s peed sens or to wheel knuckle bol t54
Rear road wheel speed s ensor t o wheel knuckle bolt54