For 2004+ Highlander, Sienna, RX330 and RX350 owners a leaking steering rack is a common issue. Almost exclusively on the passenger side, the steering rack’s outer high-pressure seal fails leaking fluid into the inner tie-rod boot. Once the boot rots through it looks something like this:
There are a few options for repair of this condition on your Toyota or Lexus, including 1) rack replacement and 2) partial rebuilding with seal and O-ring replacement. Due to the snow, sand and salt of MN roads most racks will require replacement due to debris and moisture entering the steering rack through the open boot, causing corrosion to the rack’s inner seal bore and preventing a smooth surface for the seal to ride on. The above rack had a corroded internal bore:
In the above photo the inner tie-rod has been removed. This small rust is enough to condemn the rack entirely – any irregular surface inside the rack can damage the seal during installation or in operation, and as such CARspec can’t recommend replacing just the seal and O-ring. Digging deeper you find the culprit of the leak:
Here is the inner seal, still installed in the carrier for both the seal and the O-ring, removed. You can clearly see the crack in the outer ring. This is not a crack in the complete seal itself (there is an additional rubber seal that sits around and deeper than that purple ring), but is enough to allow for a slow leak out the rack end. If the rack was not corroded this seal and it’s outer O-ring would be replaced, the assembly reinstalled and the vehicle returned to service. In this case the guest was advised a factory new unit was the best option.
As Eden Prairie’s Toyota and Lexus repair specialist, we hopes this sheds some light on the issue for those that may be experiencing a leak from their steering rack and are proud to offer seal replacement as a service that many an auto mechanic are leaving to the dealer, when possible repairing them in house to respect a guest’s budget.