Brake Hydraulics Identification Chart
Label Part No Description Quantity Comments
1 GMC153 Master cylinder 1 See table for details
1 GMC159 Master cylinder 1 See table for details
1 GMC160 Master cylinder 1 See table for details
1 GMC167 Master cylinder 1 See table for details
1 GMC171 Master cylinder 1 See table for details
1 GMC172 Master cylinder 1 See table for details
1 GMC227 Master cylinder 1 See table for details
1 GMC90376 Master cylinder 1 See table for details
2 GWC101 Front caliper / Wheel cylinder 1 See table for details
2 27H4652 Front caliper / Wheel cylinder 1 See table for details
2 27H4653 Front caliper / Wheel cylinder 1 See table for details
2 27H4654 Front caliper / Wheel cylinder 1 See table for details
2 27H4655 Front caliper / Wheel cylinder 1 See table for details
2 27H4656 Front caliper / Wheel cylinder 1 See table for details
2 27H4657 Front caliper / Wheel cylinder 1 See table for details
2 GBC131 Front caliper / Wheel cylinder 1 See table for details
2 GBC132 Front caliper / Wheel cylinder 1 See table for details
2 GBC138 Front caliper / Wheel cylinder 1 See table for details
2 GBC141 Front caliper / Wheel cylinder 1 See table for details
2 GWC102 Front caliper / Wheel cylinder 1 See table for details
2 GWC103 Front caliper / Wheel cylinder 1 See table for details
2 GWC126 Front caliper / Wheel cylinder 1 See table for details
2 GWC127 Front caliper / Wheel cylinder 1 See table for details
3 GWC1102 Rear wheel cylinder 1 See table for details
3 GWC1101 Rear wheel cylinder 1 See table for details
3 GWC1126 Rear wheel cylinder 1 See table for details
3 GWC1129 Rear wheel cylinder 1 See table for details
3 GWC1131 Rear wheel cylinder 1 See table for details
3 GWC1134 Rear wheel cylinder 1 See table for details
4 21A1774 Regulator valve 1 See table for details
4 21A2031 Regulator valve 1 See table for details
4 4 way switch 13H5905 Regulator valve 1 See table for details
4 FAM7821 Regulator valve 1 See table for details
4 None Regulator valve 1 See table for details
DescriptionMaster cylinderBore sizeFront caliper /cylinderBore/discRear wheel cylinderBore sizeCast No.Regulator valve
Dry suspension Mini 1959 to chassis number A2S7 359770 to 1962 GMC153 .750" GWC101 .9375" GWC1102 .750" 12 21A1774
Dry suspension Mini from chassis number A2S7 359771 1962-67 GMC102 use GMC171 .70" GWC101 .9375" GWC1101 .625" 10 21A1174
All hydrolastic Mini MK1 Minis from September 1964 on GMC102 use GMC171 .70" GWC102/3 .8125" GWC1101 .625" 10 21A1774
MK2 Mini and derivatives 1967-75 GMC102 use GMC171 .70" GWC126/7 .9375" GWC1102 .75" 12 21A1774
MK3 Mini October 1968 on and derivatives, single line to 1977 GMC171 .70" GWC 126/7 .9375" GWC1102 .75" 12 21A2031
997 Cooper to chassis number
 
C-A2S7 213829 to Feb 1962 with 21⁄8" pads
K-A2S4 213550 with 21A655 brake booster
GMC103
Use GMC153
.75" 27H4652
27H4653
7" disc
GBP101 pad
GWC1102 .75" 12 21A1774
997 Cooper
 
C-A2S7 213829-382831 Feb 1962 to March 1963 with 21⁄8" pads
M-AS4 213551-382183
GMC104
Use GMC171
.70" 27H4652
27H4653
7" disc
GBP101 pad
GWC 1102 .75" 12 21A1774
997 Cooper dry C-A2S7 382832 March 1963 on with 2 3⁄8"
998 Cooper hydrolastic
pads
K-A2S4 382184 on
GMC171
was GMC105
.70"
.625"
27H4654
27H4655
7" disc
GBP102 pad
GWC1101 .625" 10 21A1774
Cooper'S' MK1/2 with servo 21A1293 GMC172 .70" 27H4656/7 7.5" disc GWC1101 .625" 10 21A1774
Cooper'S' MK3 1275GT with servo 13H7939 10" wheel GMC172 .70" 27H4656/7 7.5" disc GWC1101 .625" 10 21A1774
1275GT Single line brakes chassis number 19416-21569A 1974-76 GMC172 .70" GBC138/141 8.4" disc GWC1129 .6875" 11 21A1774
1275GT Diagonal split chassis number 19416-21569 on 1974-76 GMC160 .70" GBC138/141 8.4" disc GWC1129 .6875" 11 None
1275GT Single line brakes chassis number 21570A on 1976-77 GMC172 .70" GBC138/141 8.4" disc GWC1126 .500" 8 21A1774
1275GT Diagonal split chassis number 30001 on 1977-78 (Metric pipe unions) GMC167 .70" (17.5mm) GBC138/141 8.4" disc GWC1126 .500" 8 None
1275GT Front to rear tandem 1978 on (Metric pipe unions) GMC227 .70" GBC138/141 8.4" disc GWC1102 .750" 12 FAM7821
850/998 Diagonal split Imperial union Master (Europe)
(not UK) 1976-77

Japan/Norway
GMC160
GMC160
.70"
.70"
GWC126/7
GWC126/7
.9375"
.9375"
GWC1126
GWC1134
.500"
.5625"
8
6
4 way switch 13H5905
850/998/1100 Front to rear (Belgium Netherlands and Luxemburg countries)
1974-75 (Belgium built)
GMC159 .70" GWC 126/7 .9375" GWC1102 .750" 12 4 way switch 13H5905
850/998 Diagonal split except van/pick up 1977-78 (1976-79 Europe) Metric GMC167 .70" (17.5mm) GWC 126/7 .9375" GWC1131 .5625" 9 None
850/998 Front to rear October 1978 on (1980-84 Europe) was GMC173 Imperial GMC227 .70-.75" (17.8-19mm) GWC126/7 .9375" GWC1102 .750" 12 FAM7821
Mini van/pick up diagonal split 1977 on (Metric pipe unions) GMC167 .70" (17.5mm) GWC 126/7 .9375" GWC 1102 .750" 12 None
998 Mini front to rear 1984 on (Metric pipe unions) - stepped bore GMC227 .70-.75" (17.8-19mm) GBC138/141 8.4" disc GWC1102 .750" 12 FAM7821
Innocenti (1275GT not UK) Front to rear 10" wheel with AXE244 servo GMC159 .70" 27H4656/7 7 1/2" disc GWC1129 .6875" 11 4 way switch 13H5905
998/1300 Latest 1990 Mini with built in servo GSM119. was GMC242 GMC90376 .8125" (20.6mm) GBC138/141 8.4" disc GWC1102 .750" 12 FAM7821
ERA Turbo with built in servo GSM119. was GMC242 GMC90376 .8125" (20.6mm) GBC131/2 8.4" vented GWC1131 .5625 9 None