It is not always justifiable to spend the money on a specialty tool, however in the case of rear axles a little investment goes a long way.   The problem with many german cars and particularly E30’s is that the tolerance between the hub splines and the axles splines is VERY small causing a VERY tight fit.  Even the smallest amount of grease, dirt, and even oil will not allow the splines to go back in. What most people will do is clean the splines until they are very clean, inspect and remove any burs (especially in aftermarket re-manufactured axles) and then hope that they can re-install the axle without damaging anything; many people attempt to get leverage by putting a crowbar between the differential and the axle, DO NOT DO THIS, you risk damaging the diff output shaft and you will most likely bend the axle dust cover causing your newly installed axle to loose its grease and pre-maturely fail.   As far as tools go, there is two pieces of good news. The first is that there is a tool that was specifically designed to pull the hub in. This OE tool is fairly expensive at about $400. … Continue reading Re-installing rear axles into hub the right way with the proper tool (E30, BMW, Porsche, etc.)