Today’s featured service is a Steering Rack Reseal on a 2008 Mercedes ML320, brought to us by a client from Gastown, Vancouver.
Our featured vehicle arrived with a substantial power steering fluid leak coming from the rack and pinion’s upper (pinion) seal.
When we service a vehicle with a leaking steering rack we always replace it with a rebuilt unit as dismantling, resealing and reassembling the unit is complex; and without specialized equipment usually leads to an unsuccessful repair.
For most vehicles rebuilt rack and pinion units cost around $300 to $500 which is quite reasonable. This Mercedes steering rack was difficult to find and prices varied from $900 for an aftermarket part to over $3000 from the dealer.
Seal kits are usually unavailable, not so however for this Mercedes ML320. This part was stocked by the dealer, though at over $500 it too seemed very expensive for a bunch of rubber seals.
After discussing options with the client we decided to go the reseal route and ordered the Mercedes kit. Upon opening the box we were pleased to find that this was a rather deluxe reseal kit containing a completely new pinion assembly. Mercedes has a high failure rate on these rack and pinions and obviously has upgraded the whole pinion unit.
We removed the rack, installed the replacement parts, reinstalled the assembly and cleaned off the leaked oil. After a lengthy road test the steering was good and no further leaks were present. It was another successful repair!
For more on the Mercedes ML series click here http://en.wikipedia.org/wiki/Mercedes-Benz_M-Class
For more about rack and pinion steering click here http://auto.howstuffworks.com/steering2.htm