The Unofficial Abarth pages



Sooner or later metal fatigue will cause parts to fail. Two of the most common failures on Fiat-Abarths built on the Fiat 600 chassis are the 3.5 X 12" Fergat 7 vent wheels and rear stub axles. THE 750 FERGAT WHEES fails in the area shown by the red circle. Faint cracks appear first. When the wheel failes, the center stays on the car and the wheel sails off down the track.Magnaflux wheels before racing use and visually inspect frequently for cracks. STUB AXLE FAILURE. The shaft of the axle fails at the radius where it joins the flange shown by the red line. The "crushable bearing spacer" shown lower right in the photo should be replaced with a custom machined solid spacer made of chrome moly steel. This will help to extent stub axle life, but will not prevent an eventual failure. Only frequent magnaflux testing of the axle may catch a crack in time to avoid failue. The bearings must be under constant preload. This eliminates play in the bearings which can be a major cause of early bearing failure. The author has used this method successfully to set up the bearing/hub/axle assembly:

Remove the hub assembly from the car, disassemble, clean and inspect for wear, damage and cracks. Take the complete assembly to your machinist. He will need the stub axle, bearings, old spacer, seal spacer ring, flex joint and axle nut. Ask him to machine a new "solid" spacer so that the wheel bearings have exactly zero play when the axle nut is tightened to 95 foot pounds of torque. Then an additional.003" of material should be removed from the length of the spacer. When the nut is re tightened, this will establish the required preload on the bearings.
OTHER FAILURES KNOWN TO THE AUTHOR: CAMPAGNOLO WHEELS. These wheels, particularly the type without ribs in the center have been known to fail. Replica 4.5 X 13 Campagnolo wheels in aluminum have been available from PBS Engineering in Garden Grove, CA. http://www.pbseng.com FRONT LEAF SPRING FAILURE: The spring leaves can fatigue crack and shear off, particularly if the bottom spring has been turned up side down in an attempt to lower the car. Abarth manufactured "reverse eye"lowering springs have a second leaf wrapped over the uptirned eye to help prevent this. TRANSAXLE MOUNTS. The rubber will pull away from the metal plates it is bonded to, particularly under racing stresses. This problem will be made worse if the muffler is not tied by brackets to the oil sump, and attached with hanger straps to the muffler shroud panel. All Abarths on the 600 chassis had mufflers and racing exhausts set up this way. Many assume the hanger straps are to support the muffler, but their main function is to prevent the engine and transaxle from rocking under acelleration. That also hepls make gear changes more precice. GEARSHIFT ROD TO TRANSAXLE COUPLING: The couplings can fail and separate if oil soaked. These should be replaced if there is any question to their condition. The tapered screw that fixes these to the shift rod and tranaxle should be torqued to 16 ft lbs. Any looseness can cause mis shifts with disasterous results. If thee screws are missing find an original, or have a copy made. Do not substitute home made screws!