Rear brakes : Somerford Mini - Mini Specialists, Providing the complete ...

Backplates, Handbrake Levers and Brake Adjusters
Over the 41 years of Mini production, at least seven (and probably several more) different designs of rear brake backplate were used on all the different permutations of Mini braking systems. The engineering theory behind all the different designs was to physically stop the marriage of the wrong type of wheel cylinder (and there were several to choose from, as you'll see further down the page) to the many different braking set-ups. In the interests of your sanity and ours, plus of course commercial restraints, they have been rationalised down to... one!

The truth is, the market can get away with only one backplate design, so long as owners of a minority of Minis are willing to make one small modification to make the backplate appropriate for their cars (because we trust you not to try to fit the wrong wheel cylinder): On the back of most of the wheel cylinders, alongside the threaded boss for the brake pipe, is a small roll pin used to secure the cylinder in the correct position in the backplate. If the corresponding hole in the backplate is in the wrong place, simply drill a new one in the correct position. That's it.

Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
1	21A1058KIT	BACKPLATE COMPLETE ASSEMBLY, RH	1
	21A1060KIT	BACKPLATE COMPLETE ASSEMBLY, LH	1
Backplate complete assembly includes backplate, brake shoes and springs, adjuster assembly, GWC1102 wheel cylinder (3/4" bore) and handbrake lever. Genuine AP manufacture.

Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
2	21A1058	BACKPLATE, RH	1
	21A1060	BACKPLATE, LH	1
New genuine backplates are to the latest (1997 on) spec. and will require a blanking plug part no. AEU1541A to be fitted if used on a pre-1997 car.

Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
3	AEU1541A	BLANKING PLUG, backplate	2	1997 on, plus all new genuine backplates.
4	21A1669	BRACKET, handbrake cable, RH	1	1959-92.
	SPU10002	BRACKET, handbrake cable, RH	1	1992 on.
	21A1670	BRACKET, handbrake cable, LH	1	1959-92.
	SPU10003	BRACKET, handbrake cable, LH	1	1992 on.
5	SH605081	SCREW, bracket and backplate to radius arm	6
6	53K3437	DISTANCE PIECE, bracket to backplate	4
7	LWZ205	WASHER, locking	6
8	FNZ105	NUT	6
9	SMN10005	LEVER KIT, handbrake	1	Includes RH and LH levers.
10	AAU4936	LEVER, handbrake, RH	1	Included in lever kit.
11	AAU4937	LEVER, handbrake, LH	1	Included in lever kit.
12	17H7612	GAITER, handbrake lever	2	Sometimes included in wheel cylinder repair kits – check before you buy!
13	17H7620	ADJUSTER KIT, for one backplate	2	Includes 1 wedge and 2 tappets.
14	17H7619	WEDGE, adjuster	2
15	17H7618	TAPPET, adjuster	4
There's sometimes confusion when customers place orders as to what the component parts of the brake shoe adjuster should be called. Please note that the two parts that push against the brake shoes should be referred to as tappets, not wedges. The wedge is the screwed part that forces the tappets apart.

Brake Shoes and Fittings
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
16	GBS834AF	BRAKE SHOE SET	1	Axle set of four 1 1/4" wide brake shoes.
17	GBS834FK	BRAKE SHOE FITTING KIT	1	Axle set of four return springs.
18	17H8092	SPRING, shoe return, cylinder end	2
19	17H7621	SPRING, shoe return, adjuster end	2

Wheel Cylinders and Fittings
The only easy thing to say about Mini rear wheel cylinders is that they started in 1959 with GWC1102 and finished in 2000 with GWC1102. In the meantime, several other designs of wheel cylinder were employed, each matching the operating pressure of the system which was governed by master cylinder size, various pressure limiting valves and the presence of, or lack of, servo assistance. Another factor was the different hydraulic routes used around the car: single line, front/rear split dual line or diagonally split dual line.

If you are happy that the wheel cylinders already fitted to your Mini are the correct ones, then choosing a replacement wheel cylinder or a wheel cylinder repair kit is simple: each type of cylinder has a different bore diameter, so you can measure yours before choosing from the list below (there is an exception to this rule, of course - but one of the two cylinders which both have a 9/16" bore has a locating roll pin in the back, whereas the other one hasn't, so you can still tell them apart).

If you don't trust what's already fitted (or your car's being restored from a bodyshell and several tea chests of assorted rusty bits, so nothing's currently fitted at all), then with any luck the list below will help. You should start off by determining what hydraulic routing system your Mini has - turn to the brake pipe pages and look at the illustrations to get a clue of what to look for. If you're still undecided or unhappy, give us a call and we'll do our best to sort it out. The chances are you need GWC1102 anyway…

Wheel Cylinders - Single Line System, 1959-75 (Not Cooper, Cooper S or 1275 GT)
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
20	GWC1102	WHEEL CYLINDER, 3/4" bore	2	1959-62 (Mk I), with 0.75" bore master cylinder.
	GWC1101	WHEEL CYLINDER, 5/8" bore	2	1962-67 (Mk I), with 0.7" bore master cylinder.
	GWC1102	WHEEL CYLINDER, 3/4" bore	2	1967-75 (Mk II on), with 0.7" bore master cylinder.

Wheel Cylinders - Single Line System, 1961-69 (Cooper)
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
	GWC1102	WHEEL CYLINDER, 3/4" bore	2	1961-63, 997cc with callipers using 2 1/8" wide pads.
	GWC1101	WHEEL CYLINDER, 5/8" bore	2	1963-69, 997cc and 998cc with callipers using 2 3/8" wide pads.

Wheel Cylinders - Single Line System, 1963-71 (Cooper S)
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
	GWC1101	WHEEL CYLINDER, 5/8" bore	2	1963-67 (Mk I), with Type 5 1/2 servo.
	GWC1102	WHEEL CYLINDER, 3/4" bore	2	1967-69 (MkII), with Type 5 1/2 servo.
	GWC1101	WHEEL CYLINDER, 5/8" bore	2	1969-71 (Mk III), with Type 6 servo.

Wheel Cylinders - Single Line System, 1969-77 (1275 GT)
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
	GWC1101	WHEEL CYLINDER, 5/8" bore	2	1969-74, with Type 6 servo and 7 1/2" discs.
	GWC1129	WHEEL CYLINDER, 11/16" bore	2	1974-75, with 8.4" discs.
	GWC1126	WHEEL CYLINDER, 1/2" bore	2	1975-76, with 8.4" discs.

Wheel Cylinders - Front/Rear Split Dual Line System, 1969-2000 (All Models)
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
	GWC1102	WHEEL CYLINDER, 3/4" bore	2	1968-2000, with or without servo.

Wheel Cylinders - Diagonally Split Dual Line System, 1974-82 (Not 1275 GT)
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
	GWC1134	WHEEL CYLINDER, 9/16" bore, without locating pin	2	1974-75, with round reservoir master cylinder.
	GWC1131	WHEEL CYLINDER, 9/16" bore, with locating pin	2	1976-79, with square reservoir master cylinder.
	GWC1102	WHEEL CYLINDER, 3/4" bore	2	1976-82, Clubman Estate, Van and Pick Up only (diagonally split system only optional after 1980).

Wheel Cylinders - Diagonally Split Dual Line System, 1974-77 (1275 GT)
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
	GWC1129	WHEEL CYLINDER, 11/16" bore	2	1974-75, with round reservoir master cylinder.
	GWC1126	WHEEL CYLINDER, 1/2" bore	2	1976-77, with square reservoir master cylinder.

Wheel Cylinder Fittings
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
21	GRK2014	REPAIR KIT, wheel cylinder	2	For 3/4" bore cylinders (GWC1102).
	GRK2076	REPAIR KIT, wheel cylinder	2	For 5/8" bore cylinders (GWC1101).
	GRK2004	REPAIR KIT, wheel cylinder	2	For 11/16" bore cylinders (GWC1129).
	BHM7015	REPAIR KIT, wheel cylinder	2	For 1/2" bore cylinders (GWC1126).
	GRK2003	REPAIR KIT, wheel cylinder	2	For 9/16" bore cylinders (GWC1131 and GWC1134).
22	513118	BLEED SCREW, cylinder, 1/4 UNF	2	Included in GWC1102, GWC1101, GWC1129 and GWC1126 cylinder assemblies.
	3H2428	BLEED SCREW, cylinder, 3/8 UNF	2	Included in GWC1131 and GWC1134 cylinder assemblies.
23	37H4642	GASKET, wheel cylinder to backplate	2
24	17H7949	'E' CLIP, wheel cylinder to backplate	2
25	CCT001	TOOL, Lockheed, 'E' clip fitting	1	Makes fitting 'E' clips somewhat easier.

Brake Drums and Fittings
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
26	GBD105	DRUM, brake, standard	2	1959-84; not 1967-69 Cooper, 1969-84 Switzerland, Cooper S, 1275 GT or Mini 25.
	21A1457	DRUM, brake, with integral 1/4" spacer	2	1967-69 Cooper, 1969-84 Switzerland and some other European markets.
27	CMZ407	SCREW, standard brake drum to rear hub	4
	CMZ412	SCREW, 1/4" spacer brake drum to rear hub	4
28	GBD106	DRUM, brake, with integral 3/4" spacer	2	1963-84 Cooper S, 1275 GT and Mini 25; 1984 on, all models.
29	CMZ422	SCREW, 3/4" spacer brake drum to rear hub	4
30	MINIFIN	DRUMS, alloy finned type, with 3/4" spacer, pair, premium quality	1	Superior heat-dissipating alternative to GBD106.
	MINIFINP	DRUMS, alloy finned type, with 3/4" spacer, pair, budget	1	Superior heat-dissipating alternative to GBD106.

Monday:	09.00am to 18.00pm
Tuesday:	09.00am to 18.00pm
Wednesday:	09.00am to 18.00pm
Thursday:	09.00am to 18.00pm
Friday:	09.00am to 18.00pm
Saturday:	09.00pm to 14.00pm

Rear brakes

GROMMET-OVAL, RUBBER- REAR BRAKE BACK PLATE

KIT- REAR BRAKE ADJUSTMENT ( 1x ADJUSTERS 2 x WEDGES)

REAR BRAKE AND BACKPLATE ASSEMBLY-LH (GEN CAPARO)

REAR BRAKE AND BACKPLATE ASSEMBLY-RH (GEN CAPARO)

SCREW-COUNTERSUNK-1/4 UNF x 3/4''

MINIFIN REAR BRAKE DRUMS- SPACED, PAIR, BUDGET

USE: GBK1834

MINIFIN REAR BRAKE DRUMS-SPACED, PAIR

SCREW-COUNTERSUNK-1/4 UNF x 1 3/8''

BRAKE DRUM-REAR-SPACED '84 ON & 'S'

DRUM-BRAKE-REAR-COOPER-'67-'69.('69-'84 SWITZERLAND!)

BRAKE DRUM-'59-'84 - FRONT & REAR -EXCEPT 'S' & GT

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