ATE Master Cylinder 24.2120-0502.3 Tandem 20.64 mm Original Made in Japan NOS
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Original ATE tandem master cylinder with part number 24.2120-0502.3, piston diameter 20.64 mm, new and unused (NOS) from Japan.
Genuine part (ATE) · NOS – new and unused · In original box, Made in Japan
Condition of this part
New old stock (NOS – New Old Stock), unused in the original ATE box with factory label Hauptzyl./mastercyl., Made in Japan, and the sticker Original spare part from Japan. Cast housing free of installation marks, flange and piston bore bare, reservoir clean and clear, connection threads undamaged. The box shows storage-related aging; the part itself is in perfect condition.
Function and location
The tandem master cylinder converts the pedal force, boosted by the brake booster, into hydraulic pressure. Two pistons in series in a common bore supply two separate brake circuits – if one circuit fails, the second remains functional. The mounted plastic reservoir buffers volume changes from pad wear and temperature; the connector on the reservoir is the warning contact for the brake fluid level.
Installation location: mounted on the front of the brake booster on the engine compartment bulkhead, with the push rod from the brake pedal and the brake lines at the side outlets.
How can you tell that a master cylinder is faulty?
- Brake pedal can be depressed far or feels soft/spongy
- Brake fluid leaks at the cylinder or the fluid level drops unusually fast
- Warning light for the brake fluid level comes on (contact on the reservoir)
- Reduced or uneven braking performance if one of the two brake circuits fails
Part numbers: The part number is 24.2120-0502.3 (ATE series 24.2120, bore diameter 20.64 mm). Within the 24.2120 series there are versions with different numbers of connections and different threads. Not to be confused with the number 03.3122-0502.3 (same final digits, but 22.2 mm bore and a completely different application) or with the bore groups 2119 (19.0 mm), 2122 (22.2 mm), 2123 (23.8 mm) and 2125 (25.4 mm).
⚠ Important: compare the part number before buying
No vehicle assignment can be confirmed for this number. The ATE hydraulics supply program, the ATE Classic catalogs, relevant parts portals, as well as eBay and Kleinanzeigen were checked – the number is no longer listed in any current database. It is most likely a discontinued number from an older ATE program for imported vehicles. The sale is therefore based on part number, bore diameter and photo. Please compare the number, bore diameter, number and position of the line connections, and the flange pattern with your old part before buying.
Does not fit:
- Cylinders with a different bore diameter – 2119 = 19.0 mm, 2122 = 22.2 mm, 2123 = 23.8 mm, 2125 = 25.4 mm are separate numbers and do not fit
- Within the 24.2120 series, versions differ by number of connections and thread – please compare with the old part
- Risk of confusion with 03.3122-0502.3: same final digits, but Ø 22.2 mm and a completely different application
- Brakes are safety-relevant: installation by qualified personnel only, followed by bleeding the brake system and checking its function
Does this part fit your car? Send us the VIN (chassis number) and model year – we'll check it for free: 0179 8991069 (Mon–Fri 8 am–6 pm) or via our contact form.
FAQ
What's included in the scope of delivery?
The scope of delivery is shown in the product photos.
Does the number 24.2120-0502.3 fit my vehicle?
No vehicle assignment can be confirmed for this number; the sale is based on part number, bore diameter (20.64 mm) and photo. Please compare the number, bore diameter, line connections and flange pattern with your old part before buying.
Can I return the part if it doesn't fit?
Yes, a 60-day return policy applies, with free shipping within Germany.
KFZTeile-Thot specialises in spare parts for Mercedes classic cars. Free shipping within Germany, 60-day return policy.
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