Power Steering Boxes
Power Steering Boxes
Power Steering Boxes are used by vehicle manufactures when space is a consideration. The steering box is compact but it also needs to be used in conjunction with other steering linkages. The steering wheel input shaft is attached to the vehicles steering wheel via linkages, the steering box converts the steering wheel rotation into lateral movement via these linkages that then moves the road wheels to steer the vehicle. This system is more compact but it requires extra steering linkages that can make this system more complicated but it is still very popular with most manufactures today
How does it work?
As the main input shaft (sometimes referred to as a worm shaft) rotates a piston moves back and forth along the shaft, this piston is linked to an out-put shaft (sometimes referred to as a sector shaft). This sector shaft is then linked to the linkage that then moves the road wheels to steer the vehicle.
To give hydraulic assist attached to the worm shaft is a control valve, when the input shaft valve is turned it controls the fluid that is supplied by the power steering pump and directs the fluid to a piston attached to the worm shaft then the fluid forces against the piston to give the sector shaft steering assist (i.e. power assisted steering).
As the main input shaft (sometimes referred to as a worm shaft) rotates a piston moves back and forth along the shaft, this piston is linked to an out-put shaft (sometimes referred to as a sector shaft). This sector shaft is then linked to the linkage that then moves the road wheels to steer the vehicle.
To give hydraulic assist attached to the worm shaft is a control valve, when the input shaft valve is turned it controls the fluid that is supplied by the power steering pump and directs the fluid to a piston attached to the worm shaft then the fluid forces against the piston to give the sector shaft steering assist (i.e. power assisted steering).
Manual Steering Boxes
The manual steering boxes like the power steering box are used by vehicle manufactures when space is a consideration. The steering box is compact but it also needs to be used in conjunction with other steering linkages.
How does it work?
The steering wheel input shaft is attached to the vehicles steering wheel via linkages, the steering box converts the steering wheel rotation into lateral movement via these linkages that then moves the road wheels to steer the vehicle. This system is more compact and it requires extra steering linkages that can make this system more complicated but it is still very popular with most manufactures today.
As the main input shaft (sometimes referred to as a worm shaft) rotates a nut moves back and forth along the shaft, this nut is linked to an out-put shaft (sometimes referred to as a sector shaft). This sector shaft is then linked to the linkage that then moves the road wheels to steer the vehicle.
Common Problems
The most common problems with most manual steering boxes are wear and tear on the unit. As the steering box is out of sight and out of mind the manual steering box is generally not looked at until it has major issues. Issues like free-play due to worn worm shaft or worn sector shaft bush or free-play in the sector shaft teeth due to misuse, excessive use or lack of maintenance on the vehicle.
To fix these issues the steering system need to be checked on regular intervals. Ultimate Power Steering recommend’s that the steering system is inspected by your mechanic at each service, this preventive maintenance will insure that the system functions correctly for as long as possible and this will save you money in the long run.
Technical - Boxes
As the steering box is out of sight and out of mind it is generally not looked at until it has major issues. Issues like free-play due to worn internal parts due to misuse, excessive use or lack of maintenance on the vehicle. In the cases of worn internal parts the only way to rectify this is to replace the hard parts i.e. the main worm shaft and the sector shaft, this is very costly, so to help save your money we recommend that your steering system is inspected by your mechanic at each service.
Bleeding the system
Most power steering box systems are self bleeding but if air is trapped inside the power steering box the steering assist will feel a bit vague. This will generally only be in one direction and is more apparent when the steering wheel is turned quickly. This is due to the air trapped inside the steering box compressing, this air will give the feel of vague steering assist.
Some power steering boxes have a bleed nipple on the top of the box to bleed out any air that can be trapped internally. If you vehicle is showing symptoms of vague steering assist and it has a bleed nipple on top of the box it should be bled to extract any air, this will improve the feel of the steering. We recommend that your power steering box be bleed by your mechanic when required.
Over the steering boxes life it needs to be adjusted to maintain the correct function and to eliminate free-play in the steering box. If this isn’t maintained it is possible for the internal parts of the steering box to wear and will require replacement
Rust is one of the largest issues faced with power steering boxes, this is even more apparent if the vehicle is used in extremely salty environments like the beach. Over time the sector and worm shafts rusts. Once the rust has damaged the shaft, the shaft seals cannot retain the fluid and the steering box will leak. In most cases this can be prevented by regular cleaning of the steering box shafts and spraying some rust inhibiter like CRC to lubricate the shafts to prevent any rust from forming.
