Reasons of the rear beam problems

Rear beam problems, their reasons and consequences

The main reasons of the rear beam problems are excessive run of the needle bearing and getting of moisture to the arm unit. The corrosion and rust act as an abrasive and accelerate wear of rollers.

Unlike the other bearings, the needle bearings of the rear beam of Peugeot, Citroen, Samand doesn't make any noise because of wear, because of revolving on the low speed and over a small range. Despite little load the rear beam needle bearings of Peugeot, Citroen, Samand, Lifan may collapse and their needle rollers may fall out of the working area, having no inner race, especially when the cage is broken. It happens because of the fact, that the corrosion and rust act as an abrasive and accelerate wear of rollers.

The problem of the rear beam comes unnoticeable and gradually. At the best you will discover the breakdown on time or replace the needle bearing proceeding from run – then you will not face the restoration of the rear beam.

The car owners usually don't notice the breakdown of the bearing and go on using their cars, having no slightest idea about it. In this case the crumbled bearing rubs the rear beam pin sore. By then the stuffing box of the needle bearing outwears and starts leaking, which provokes corrosion, rust and speeds up the wear of the shaft. At worst the replacement of the pins will be needed.

Still the replacement of pins is not the worst in the rear beam restoration. Worse is it, when you need a repair of rear beam arms, but it occurs rarely.

You can find more information about the construction of the unit in the article The problem and design philosophy of the unit.

The arm has a matching site, in which the needle bearing is pressed. Together with the needle bearing arm is get on the rear beam shaft. That means that the shaft is a race for the bearing, pressed in a suitable place of the arm.

The crumbled bearing "kills" the surface of pin, which is not protected with a racer; the outer race of the bearing for some time saves the arm matching site from scuffing. When it lasts for a long time the outer race may turn or destroy, at the same time the surface and geometry of the matching site may be damaged, then the repair of the rear beam arm will be needed. You can find more information about the restoration of the rear beam arms of Peugeot, Citroen, Samand here.

The consequences of the needle bearing breakdown will be – necessity of the rear beam axle replacement and wear of the rear beam arm, which must be repaired.

The replacement of the pins and the rear beam restoration are both difficult procedures, and the demounting of the rear beam will be needed. But it is not necessary for repairing the rear beam arms.