Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
SAE J191-2014: Power Steering Pressure Hose โ Low Volumetric Expansion Type
This article covers the essential aspects of SAE J191-2014, a stabilized standard for low volumetric expansion power steering pressure hoses used in automotive applications. The standard specifies materials, construction, dimensions, and rigorous testing procedures to ensure reliability across a wide temperature range. 🛠️
Scope and Construction
SAE J191-2014 applies to hose assemblies with two plies of braided fabric reinforcement and synthetic rubber inner tube and outer cover. These hoses are intended for flexible connections in power steering systems operating at average temperatures up to 121°C (250°F) with peaks of 135°C (275°F) and ambient lows of –40°C (–40°F). The standard emphasizes low volumetric expansion to minimize pressure losses and maintain steering response. Note that these hoses are not designed to reduce pump pressure pulsations.
Stabilized Notice: This document has been declared “Stabilized” by the SAE committee, meaning the technology is mature and unlikely to change. Users should verify continued suitability and check for newer technologies.
Key Specifications and Testing Requirements
The standard defines critical dimensions and pressure ratings. The following table summarizes the primary requirements for the 1/4-inch nominal ID hose (the most common size):
| Parameter | Metric | English |
|---|---|---|
| Nominal ID | 0.635 cm | 1/4 in |
| Nominal OD | 1.429 cm | 9/16 in |
| ID Tolerance | 0.699/0.61 cm | 0.275/0.240 in |
| OD Tolerance | 1.5/1.4 cm | 0.592/0.552 in |
| Maximum Working Pressure | 8.96 MPa | 1300 psi |
| Proof Pressure | 13.8 MPa | 2000 psi |
| Minimum Burst Strength | 41.4 MPa | 6000 psi |
| Minimum Tensile Strength (assembly) | 2001.7 N | 450 lb |
Concentricity between the bore and outer surface must not exceed 0.076 cm (0.030 in).
Testing is central to the standard. Key tests include:
- Impulse Test: Hose assemblies must withstand 100,000 cycles (inspection) or 225,000 cycles (qualification) at 135°C oil temperature, with 0–1300 psi pressure cycling.
- Low Temperature Flexibility: No cracking after 24 hours at –40°C and bending around a mandrel eight times the OD.
- Burst Strength: Minimum 6000 psi.
- Adhesion: At least 10 lb force to separate layers.
- Ozone Resistance: No cracks after 70 hours in 50 pphm ozone at 40°C.
- Length Change: +2% / –4% when pressurized to working pressure.
- Dry Heat & Oil Resistance: Limited reduction in tensile strength and elongation after aging.
Each production lot undergoes inspection tests per Table 2 of the standard, with sample sizes ranging from 1 to 6 assemblies per test. In case of failure, retesting with double samples is required.
Practical Considerations and Compliance
The low volumetric expansion characteristic ensures minimal pressure drop and consistent steering assistance. However, these hoses are not intended for pulsation dampening; if that is needed, a different hose type should be selected. 🔍
⚠️ Important Consideration: OEM specifications may supersede or supplement SAE J191. Always verify additional requirements with the vehicle manufacturer. The stabilized status means no further updates are planned – users must confirm that the standard still meets their application needs.
Frequently Asked Questions
- What is the operating temperature range for SAE J191 hoses?
The hoses are rated for –40°C to +121°C average, with peaks up to 135°C. - How many impulse cycles must the hose pass for qualification?
Qualification requires 225,000 cycles; production acceptance requires 100,000 cycles. - Can I use this hose for reducing pump pulsations?
No, SAE J191 states these hoses are not intended for applications requiring reduction of pressure pulsations. - What does “Stabilized” mean in the standard?
It indicates that the technology is mature and the document is no longer actively maintained. Users must verify the content still applies to current technology.
By understanding and applying SAE J191-2014, engineers can select and qualify power steering hoses that meet rigorous performance and safety criteria. Always cross-check with the latest OEM requirements and ensure proper lot testing. ⚠️
