Pulling Tools
The expression is widely spread and has been common in the motor car workshop for as far back as one can remember. Earlier, where there were not yet that many different bolt heads, the missing puller was almost
the only obstacle when larger repairs had to be made.
From a purely mechanical aspect the respective methods used in repairing motor cars hasn't really changed all that much. There are still components which are screwed or bolted together, indeed, they are sometimes
secured or replaced by a pressing or shrinking process.
We distinguish between the mostly quite simple pullers and the more complicated hydraulic devices. A particular characteristic of both is the robust, mostly somewhat oversized design. The mechanical devices always
have a threaded shaft, mostly with an unusually large diameter and more than likely, a low thread-pitch. The low thread-pitch is chosen so that the normal strength of a person is multiplied by changing the effort-to-
result ratio.
Thus, tie-rod-ends can be easily removed making it possible to change the wheel-bearings on a front-wheel drive in no time at all. The dismantling of, e.g., a manual gearbox however, requires a more stable hydraulic
device (see picture 5). This can not only, increase the power transmission but also has less losses. Indeed, one should know exactly what one is doing, because the delivered forces can of course, have a negative
affect. The brute force excercised can also be very destructive.
Pullers are still an essential element in the repair workshop and, added to the special tools for the newest models, there are possibly also special puller devices. They are sometimes a protection against the free
workshop competition, moonlighters and backyard mechanics. Therefore, before doing repairs on one's own vehicle, one should check just how many special tools are necessary and whether the expenditure is
worthwhile or not.
One can sometimes be fortunate. During the last, self-conducted inspection on one of our vehicles we discovered additional tapped holes in the rear brake drums, where we could screw in normal bolts and easily
remove them from the flanges. Built-in pullers, as it were … 07/11
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