21134 Views Updated 28 September 2026

81521016304 MAN Equivalent Unloader Valve

301.01.0001

Summary

This heavy-duty unloader valve for MAN vehicles features M22x1.5 port sizes and a cut-out pressure of 8.1 BAR / 0.2 BAR. Designed for reliability in brake systems, it ensures precise pressure management within the pneumatic circuit. Equivalent to OE MAN 81521016304.

Product identifiers
EAN Code	8699031064352

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Compatible OEM Codes

MAN
- K0.00280-8514
- 85.50001-3210
- 85.50001-1813
- 85.50001-1617
- 85.50001-1569
- 81.52101-9132
- 81.52101-9123
- 81.52101-9085
- 81.52101-9083
- 81.52101-9076
- 81.52101-6304
- 81.52101-6199
- 81.52101-6177
- 81.52101-6155
- 81.52101-6132
- 81.52101-6123
- 81.52101-6119
- 81.52101-6114
- 81.52101-6112
- 81.52101-6103
- 81.52101-6085
- 81.52101-6083
- 81.52101-6076
MERCEDES BENZ
- 002 431 96 06
- 002 431 83 06
- 002 431 49 06
- 002 431 43 06
- 002 431 34 06
- 002 431 18 06
- 001 431 98 06
- 001 431 34 06
- 001 431 12 06
- 001 431 06 06
- 001 431 00 06
RENAULT TRUCKS
- 7700051785
- 5000819893
- 5000819345
- 5000464197
- 5000243947
FAUN
- 99701725373
- 1612050
- 1612049
- 1612037
- 1612026
STEYR
- 99100360002
- 79100360070
- 79100360002
NEOPLAN
- 1102733544138
- 1102435544308
IVECO
- 02516923
- 02516892
DAF
- BBU5210
- 1506504
WABCO
- 975 303 473 0
VOLVO
- 6789355
TEREX
- 32409540
SCANIA
- 2090402
NISSAN UD TRUCK
- 47540D8929
KRONE
- 9454310
KOMATSU
- 20G68K4520
IRISBUS
- 4804765
GOLDHOFER
- 160612
FENDT
- 822880020150
CASE
- 820010150

Description

What does an unloader valve do?

This unloader valve plays a critical role in maintaining correct pneumatic pressure within the air brake system of heavy commercial vehicles. By regulating the air flow, it ensures that the compressor operates efficiently and that the braking system receives consistent pressure levels during operation.

Vehicle and engine compatibility

Designed specifically for MAN trucks, this component is built to withstand rigorous heavy-duty conditions. It features M22x1.5 port connections (Port 1 and Port 21) and is engineered to meet strict technical requirements for air system stability.

Installation and maintenance

For workshop technicians, verifying the cut-out pressure of 8.1 BAR / 0.2 BAR is essential during installation to ensure proper system regulation. We recommend checking all port connections and ensuring the inflation valve functionality is intact to maintain optimal braking performance.

System performance guidance

Proper maintenance of the unloader valve helps prevent air leaks and ensures the longevity of the entire pneumatic circuit. Consult your authorized distributor.

OE cross-reference

301.01.0001 (Unloader Valve) is the equivalent of the MAN OE number. This part directly replaces MAN OE number 81521016304.

Technical Specifications

Technical Specifications
Port 1	M22x1,5
Port 4	-
Port 21	M22x1,5
Port 23	-
Plugged	OK
Cut-Out Pressure	8,1 BAR / 0,2 BAR
Inflation Valve	OK
Recycle Valve	-
Port 22	-

Other OEMs

CASE

820010150

DAF

BBU5210
1506504

FAUN

99701725373
1612050
1612049
1612037
1612026

FENDT

822880020150

GOLDHOFER

160612

IRISBUS

4804765

IVECO

02516923
02516892

KOMATSU

20G68K4520

KRONE

9454310

MAN

K0002808514
85500013210
85500011813
85500011617
85500011569
81521019132
81521019123
81521019085
81521019083
81521019076
81521016304
81521016199
81521016177
81521016155
81521016132
81521016123
81521016119
81521016114
81521016112
81521016103
81521016085
81521016083
81521016076
K0.00280-8514
85.50001-3210
85.50001-1813
85.50001-1617
85.50001-1569
81.52101-9132
81.52101-9123
81.52101-9085
81.52101-9083
81.52101-9076
81.52101-6304
81.52101-6199
81.52101-6177
81.52101-6155
81.52101-6132
81.52101-6123
81.52101-6119
81.52101-6114
81.52101-6112
81.52101-6103
81.52101-6085
81.52101-6083
81.52101-6076

MERCEDES BENZ

A0024319606
A0024318306
A0024314906
A0024314306
A0024313406
A0024311806
A0014319806
A0014313406
A0014311206
A0014310606
A0014310006
002 431 96 06
002 431 83 06
002 431 49 06
002 431 43 06
002 431 34 06
002 431 18 06
001 431 98 06
001 431 34 06
001 431 12 06
001 431 06 06
001 431 00 06

NEOPLAN

1102733544138
1102435544308

NISSAN UD TRUCK

47540D8929

RENAULT TRUCKS

7700051785
5000819893
5000819345
5000464197
5000243947

SCANIA

2090402

STEYR

99100360002
79100360070
79100360002

TEREX

32409540

VOLVO

6789355

WABCO

9753034730
975 303 473 0

Related Products

Repair Kits

Compatible Vehicles

Compatible Vehicles
Brand	Model	Engine
CASE
DAF
FAUN
FENDT
GOLDHOFER
IRISBUS
IVECO
KOMATSU
KRONE
MAN
MERCEDES BENZ
NEOPLAN
NISSAN UD TRUCK
RENAULT TRUCKS
SCANIA
STEYR
TEREX
VOLVO
VOLVO	B10B	D10A
VOLVO	B10M	D10A
VOLVO	B10M	TD100
VOLVO	B12	D12A
VOLVO	B12	TD120
VOLVO	F10	TD100
VOLVO	F10	TD101
VOLVO	F10	TD102
VOLVO	F12	TD120
VOLVO	F12	TD121
VOLVO	F12	TD122
VOLVO	F7	TD70
VOLVO	F7	TD71
VOLVO	FL10	D10A
VOLVO	FL10	TD102
VOLVO	FL10	TD103
VOLVO	FL12	TD122
VOLVO	FL12	TD123
VOLVO	N10	TD100
VOLVO	N10	TD101
VOLVO	N12	TD120
VOLVO	N12	TD122
VOLVO	NL10	D10A
VOLVO	NL12	D12A
WABCO

FAQ

What is the function of this unloader valve?

The unloader valve regulates air pressure within the pneumatic system, helping to balance pressure across various circuits in heavy commercial vehicles.

Which vehicle brands is this part compatible with?

This specific component is designed for use in MAN trucks and is compatible with their original pneumatic systems.

What are the technical port specifications?

The unit features M22x1.5 port sizes (Port 1 and Port 21) and is designed for high-strength performance in demanding environments.

How can I identify a faulty unloader valve?

Technicians should look for inconsistencies in cut-out pressure or air leaks around the M22x1.5 ports that may indicate component wear.

What are the OE reference numbers of this part?

301.01.0001 directly replaces MAN OE number 81521016304.