The role of the 2CV spring tube
The 2CV spring tube is a determining element as regards the road holding of this vehicle. It ensures the suspension function of the vehicle in addition to the vehicle’s shock absorption that is handled by the hydraulic or friction shock-absorbers depending on the model year concerned. The spring tubes, positioned horizontally along the frame of the 2CV, provide the same function as the vertical springs that are present today around the shock-absorbers of contemporary vehicles. While the
shock-absorber absorbs the shocks, the spring tube allows the wheels of the vehicle to remain in contact with the ground as much as possible irrespective of the profile of the road or the quality of its surface. Its horizontal positioning facilitates access to this part and enables very easily adjusting the body height of the vehicle by adjusting the pressure of the springs constituting it using a nut. A spring tube is nothing but a case, a metal cylindrical tube, inside which there are two separate springs of which one connected to the suspension arm of the front wheel of the vehicle and the other to that of the rear wheel. Depending on the work of the
suspension arms, the tie rods can move horizontally from the front to the back and vice versa. Each 2CV or vehicles derived from the Citroën brand, like the Méhari or the Dyane, has two “coated” spring tubes on either side of the frame and fixed to the latter using supports integrated in the frame. Their installation is very easy and requires having two thrust bearings or two thrust bearing silent blocks and suitable nuts. All these parts are available on our website under this section. The connection with the wheel is ensured by a threaded rod called “suspension tie rod” on which a tie rod end piece is screwed on. It is the latter that is fixed on the suspension arm of the wheel by means of a front or rear spring tube axis according to the arm concerned. This part, of triangular section to limit the play and the wearing between the arm and the end piece of the spring tube, is also called “knife” by some and requires two pincers to be blocked from each side of the arm.
Maintaining the spring tubes on your 2CV
The 2CV spring tube does not undergo any significant wearing. On the other hand, it is necessary to change it in case of breakage, corrosion or loss of elasticity of any of the springs. The vehicle then slumps and generates noise when it moves or when you press on the bonnet or the rear of the 2CV to test its suspension when it is stationary. It is also strongly advised to change the 2CV spring tubes while restoring a vehicle to avoid any unpleasant surprises later. It is important to at least maintain them by applying a special lubricant in the spring tube after having first removed the bellows present at the level of the tie rods. After the lubricant layer is applied on the porous surface of the internal cup of the spring tube, it provides perfect lubrication of the inside of the pot and will limit any potential friction noise as well as corrosion. On the other hand, this lubricant cannot “treat” a spring nearing the end of its service life. It must be replaced.
Spring tube for 2CV sedan or van?
The technology of the spring tubes, which gave the 2CV its reputation right from its launch at the Paris trade fair 1948 when the visitors discovered that this vehicle was equipped with an extremely flexible suspension with great clearance, has changed little over the history of the vehicle. The first models were open and had a visible spring. They were then quickly replaced during the 50’s by the closed case model that was fitted in the legendary Citroën till the end of its production. On the other hand, there are two types of 2CV spring tubes, the first one for the 2CV, Méhari, Dyane and AK 250 and AK 350 light vans. These pots had a diameter less than the second model that was designed for the light vans of AK 400, Acadiane and Ami 6 or 8. You will also find these two references and the parts constituting them on our website.
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