If the car has been used on South African roads for a long time, serious malfunctions can occur. For example, you may notice that the oil in the hydraulic booster is foaming. On this sign, most motorists do not pay attention. However, this is not recommended, as the consequences can be most unpleasant, up to the occurrence of a dangerous emergency. We understand why foam appears in the power steering and what to do in this case.

Power Steering Diagram

power steering diagram


Power steering (short for power steering) is the main steering mechanism. It creates an additional force that allows you to turn the steering wheel easily. This is made possible by a hydraulic drive. The hydraulic booster consists of the following elements: tank, working fluid, hoses, hydraulic cylinder, distributor, and also a pump. We study in more detail every detail.

A pump is needed to maintain pressure and to allow lubricant to move within the system. It is located on the engine, its operation is possible thanks to the belt drive of the crankshaft. Typically, vane-type pumps are mounted on hydraulic boosters.

The distributor is a device with high precision. Its task is to redirect the flow of lubricant into a specific cavity of the hydraulic cylinder, and then back into the reservoir. The distributor is mounted on the steering gear shaft or on the steering gear. Distributors are divided into rotary, when the movable element rotates, as well as axial, in which the movement of the spool occurs translationally.

The hydraulic cylinder, which is lubricated by pressure, rotates the wheels with the help of the rod and piston. It is located between the car body element and the steering gear. It can also be placed inside the steering wheel itself.

There is grease in the tank. It is equipped with a dipstick, with it you can find out the oil level. The tank is also equipped with a filter for cleaning the working fluid, which is fed into the system.

The working fluid is oil, due to which the forces are transmitted to the hydraulic cylinder. It lubricates all the elements of the hydraulic booster.

Hoses are necessary so that the lubricant moves freely along the hydraulic booster. High pressure connecting hoses allow lubricant to move between the hydraulic cylinder, distributor and pump. Low pressure hoses are needed to return oil from the tank to the pump and then back to the tank.

How power steering works

Why does the power steering oil foam

If the hydraulic oil foams, what is the reason? Few drivers understand why foam is formed, but in any case, you can not neglect this problem. This happens because:

  • a mixture of oil with another substance occurred;
  • system airing happened;
  • mud got into the power steering.

foamy power steering

We will analyze each problematic situation in detail.

  1. The oil foams due to the airing of the system. What is the reason for foaming oil in the hydraulic booster? This often happens because air has entered the lubricant. Hydration of the hydraulic system can occur due to the fact that the system is not tight or the power steering pump is functioning with the cap removed. Often air is mixed with grease due to the fact that cracks have formed on the nozzles and hoses. Visually, you don’t detect a leak, so it’s not easy to understand that the oil is foaming precisely because of this. When air enters the system, the car ceases to obey the driver. For example, when you make a turn, the steering wheel will twitch, it will become difficult to scroll, and you will not be able to complete the maneuver. The worst that can happen is that the steering wheel will jam. This means that the car will become completely uncontrollable.Of course, driving a car when air enters the power steering becomes unsafe. But the worst part is that the steering wheel lock occurs when it is completely turned to the left (or right) and the driver performs a complex maneuver. As a result, a serious accident may occur.
  2. Foaming oil due to pollution. In this case, the grease is mixed with any foreign substance. As a result, the oil begins to foam. All this leads to the fact that the car is worse controlled, the steering wheel is jammed. You must fix the problem as soon as possible. How to do it? Just replace the grease in the hydraulic booster with a new one.

replacing power steering fluid

How to remove air from the system

If the oil in the hydraulic booster foams due to air entering the oil, the following steps must be performed:

  • Start the car. You will need the help of a friend. Let your friend turn the steering wheel left and right. At this point you should see if there are bubbles on the hoses.
  • Visually you could not determine where the leak is coming from? Then carefully look at the connections, nozzles and the surface of the tank, there may be cracks on them.
  • Found cracked power steering parts? Replace them with new ones.
  • Could not independently determine the reason why foaming oil in the hydraulic booster? Then go to the service center. The amount you spend on diagnostics will be less than the amount required to replace the power steering.

So, you found out that the airing happened. In this case, you can remove the air without disassembling the hydraulic booster:

  • Turn the ignition key, the engine should run for several minutes.
  • Now you should turn the steering wheel to the right all the way and wait 15 seconds, then repeat this action again, but now turning the steering wheel to the leftmost position.
  • Repeat the above steps 2-3 times, and the oil in the hydraulic booster will no longer foam.
  • To make sure that there is no air in the lubricant, look at how much oil is in the tank when the machine is started and then when the engine cools down. The difference should be no more than 0.5 cm.

In some cases, the steps described will not help remove air from the lubricant. Notice that the power steering oil is still foaming? Then you should disconnect the return hose from the tank, and then plug the place where it was inserted.

The tip of the hose is placed in a clean basin or bucket. To remove air from the power steering start the car, scroll the steering wheel. Lubrication must flow out of the hose. Then we turn off the engine, and pour the collected oil into the tank. We repeat these manipulations until there are no air bubbles in the lubricant coming from the hose. It is recommended that this work be carried out with an assistant. Only in this way you can track whether the oil in the hydraulic booster is foaming or not, and turn off the engine in time.

Causes of dirt getting into the system

Why is the hydraulic oil foaming? Another reason for this is pollution of power steering. How dirt can get into it:

  • fittings clogged;
  • the filter in the tank has become unusable;
  • hoses tore.

We will analyze each reason why the oil is foaming in the hydraulic booster, in detail:

1. The hose burst .

In this case, the only thing you can do is install new hoses instead of broken ones.

power steering hose

2. The fittings are clogged .

To clean them, you must perform the following steps:

  • dismantle the wheels;
  • using the eight key, remove the protective cap;
  • we attach a hose with a diameter of 6.5 mm to the fitting;
  • use this hose to remove grease;
  • to prevent the oil from falling below the minimum mark, simply add grease to the power reservoir;
  • Have you noticed that oil comes in from the nozzle that does not foam? This means that the work was carried out efficiently;
  • now proceed to pumping GUR. To do this, turn the steering wheel all the way left and right when the engine is running.

To replace it, you will have to find the power steering reservoir. Usually it is under the hood, you will immediately notice it. What to do next:

  • dismantle the tank cap;
  • remove grease;
  • remove the old filter and mount a new one.

power steering check

If the reason why the oil in the hydraulic booster is foaming was in a dirty filter, then after all the manipulations performed, the pump will function normally.

At first glance, it might seem that there is nothing wrong if the oil in the hydraulic booster foams. However, this malfunction can lead to a dangerous accident. It is recommended to eliminate the malfunction as soon as possible, while the repair should be done with high quality. Work should be carried out carefully, and after completion of all manipulations it is necessary to check whether the hydraulic booster is functioning properly.

In reality, only one out of four drivers are able to completely eliminate air from power steering systems. This means, when you find that the oil in the hydraulic booster is foaming, you should immediately go to a proven auto repair shop. After all, driving a car with such a breakdown can lead to a serious accident.

What do motorists think that foaming oil in the hydraulic booster

  • After replacing the power steering pump, I noticed that the oil in the power steering foams “I could not immediately understand what was the reason. Two days later, I realized that I had not put the hose clamp on the hose at the pump inlet. I installed the clamp and the problem is gone. “
  • A similar situation was encountered by a friend on the Golf 3 “We noticed that the oil in the hydraulic booster was foaming, the lubricant was squeezed out, the pump was buzzing, the steering wheel was also malfunctioning. First of all, we decided to find a filter, we thought that it was on the tank, but it was not there. As a result, it was found out that the hydraulic booster functioned without a filter. We checked the supply hose to the pump, there were no cracks, new clamps were installed, but the oil in the hydraulic booster continued to foam. Filled with new grease. And everything seemed to be fine, but then the foam reappeared. Dismantled the pump, the shaft began to play. Eliminated this problem, of course, the foam disappeared.Summing up, I will say that the reason was in the play, because of this the oil was mixed with air. But I used to think that the stuffing box, on the contrary, should prevent the leakage of grease from the pump. ”
  • The reason why the booster oil foams is because moisture or air gets into the oil “The solution is to fill in a new high-quality fluid, having previously checked that air does not penetrate the power steering through the radiator.”
  • Power steering foams on my Honda “The foamed oil even exited through the lid, which fits snugly. Replaced the oil seal, installed a new bearing. So that before the repair the car was on the move, the mechanic invented a special device: he attached a piece of foam rubber to the probe. This device collected oil, which I then squeezed back into the tank.”