ATE Master Cylinder 24.2122-0504.3 Tandem 22.2 mm Brake Cylinder Japan NOS OVP
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Tandem master cylinder ATE 24.2122-0504.3 with 22.2 mm piston diameter, NOS from Japan.
NOS – unused in original box · Piston diameter 22.2 mm factory-marked · Two separate brake circuits
Condition of this part
New old stock (NOS – New Old Stock), unused in the original ATE box with factory label HAUPTZY./MASTERCYL. and the sticker Original spare part from Japan. Cast housing free of installation marks, flange and piston bore bare, reservoir clear and clean, connection threads undamaged. The box shows storage-related aging and a torn corner; 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 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 further or feels spongy
- Warning contact on the reservoir signals low brake fluid
- Decreasing or uneven braking performance if one circuit fails
- Visible fluid leakage at the housing or at the line connections
On the yellow ATE factory label, the number is clearly legible as .2122-0504.3; the first two digits are partly covered by an ink stain, with the first digit 2 recognizable. Based on the ATE numbering system and the sister part from the same delivery, 24. is the obvious reading, so the part is offered under the number 24.2122-0504.3. In ATE hydraulic cylinder numbers, the block 2122 codes the piston diameter 22.2 mm – for comparison: 2119 = 19.0 mm, 2120 = 20.64 mm, 2123 = 23.8 mm, 2125 = 25.4 mm.
⚠ Important: compare the part number before buying
No vehicle assignment can be confirmed for this number – the ATE Classic catalogs C3 and C4, the ATE manufacturer catalogs on the relevant parts portals, as well as eBay and Kleinanzeigen, were checked. 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.
Does not fit:
- Cylinders with a different bore diameter – 2119 = 19.0 mm, 2120 = 20.64 mm, 2123 = 23.8 mm, 2125 = 25.4 mm are separate numbers.
- Within the 24.2122 series, versions differ by number of connections (2, 3 or 4) and connection thread (M10x1 or M12x1) – please compare with the old part.
- Buying by vehicle model alone: no vehicle list is available, please buy based on number and dimensions.
- 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
Is the part number reliably deciphered?
On the factory label, .2122-0504.3 is clearly legible; the block 2122 stands for the piston diameter 22.2 mm. The first two digits are partly obscured by an ink stain and were completed as 24. based on the ATE numbering system and a sister part from the same delivery. We're happy to send an additional photo of the label on request.
Which vehicles does this cylinder fit?
No vehicle fitment can be confirmed for this number, so we deliberately give no vehicle list here. Please compare part number, bore diameter (22.2 mm), number of connections and connection thread with your old part.
What's included in the scope of delivery?
The exact scope of delivery can be seen in the product photos.
KFZTeile-Thot specialises in spare parts for Mercedes classic cars. Free shipping within Germany, 60-day return policy.
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