Common Rack & Pinion Cobra (leaf spring chassis) Service Parts

[Dan Case]

For general information, completely stock rack and pinion steering roadster chassis as AC Cars built them. Does not cover modifications that Shelby American developed for convenience or endurance racing.

When I started doing service work on late Cobras in the 1980s I started my own data tables for Cobra rack and pinion chassis service parts. Buying terribly expensive parts from dealers in Cobra parts that removed part numbers from packages wasn’t for me. In 1984 a single part from a ‘Cobra parts dealer’ cost more than a complete chassis SET at the local industrial supply sales counter. It only takes a little time to clean original parts as removed and record the information marked on them or use a handbook to identify them if they were not marked.

As time goes on fewer and fewer owners of original cars seem to be doing their own service work but there are some because I still have owners wanting a copy of the information. Here’s my working list.



Using a plain bearing handbook instructions and specifications I made cylindrically ground mandrels to install plain bearings. One is shown below as an example. This particular tool is used to install plain bearings in the lower rear vertical link (a.k.a. upright). The tool finishes the final inner diameter sizing and sets the bearing insertion depth so that the shaft seals are not interfered with.



Special Notes On Front Axle Inner Cone: Cobras were fitted with very thin pressed all steel “seals” for their inner front axle cones (a.k.a. tapered roller bearing). Original ‘seals’ are somewhat fragile. They also only keep out large particles. They don’t exclude fine solid particles or water. A very common ‘modification’ owners have made since the 1960s is use the same size cone made for boat trailers. The boat trailer cone assemblies have integral rubber lip seals. These boat trailer parts go a long way in keeping the grease in front hubs clean and dry. If one chooses to use the boat trailer cone assembly extra care must be taken on how bearing preload is set during assembly. The rubber coating on the back flange of the assembly will slowly crush and take a permanent set. This can leave front bearings without enough preload to prevent the race of the cone assembly from spinning on the front stub axles. Having bearing races spin on the axle is not good. Axles can wear very quickly and get so hot the metal turns blue. Bearing races can be friction welded to the axle if spinning is severe enough long enough.

[1795]

Dan,

Thanks for a lot of useful information. Keep it coming!

[MAStuart]

Thank you Dan!

Mark

[Dan Case]

Originally Posted by 1795

Dan,

Thanks for a lot of useful information. Keep it coming!

Originally Posted by MAStuart

Thank you Dan!

Mark

You are welcome.

[MAStuart]

Dan I did not see your comments on the front wheel bearing . Glad you said something about them. On Friday I went to a local bearing place looking for bearings. Others have stated I needed bearing cone LM67000LA and cup LM67010. Below is a picture of the bearing and race. Also in the picture is the standard lm67048 bearing and lm67010 race. Does this sound like the right bearing numbers to you.

Mark

[Dan Case]

Originally Posted by MAStuart

Below is a picture of the bearing and race. Also in the picture is the standard lm67048 bearing and lm67010 race. Does this sound like the right bearing numbers to you.

Mark

My bearing books are at the shop but the cone with integral seal is the right type for boat trailers. Based on my experiences I would recommend checking them (visual inspection) a few times during the first month of use no matter how many miles are driven to verify that the bearing races are not slipping on the axle.