Steering rack grinding fixed with MOS2!

[IVIUSTANG]

Hey Guys,

I now have over 350,000k on my lifted XC70 and for the past year or so the steering rack has started binding and randomly grinding and progressively getting worse. I had some left over MOS2 powder from back in the day(when I used to add to engine oil on my S70) I added a fair bit to the power steering fluid and within a few blocks I had no more grinding or binding and steering effort even went down. It has been 1 month since I've added the Moly and have had zero issues of any sort.

I'm not saying this stuff is a panacea I wanted to give it a try as it was going downhill fast anyway, and I am not itnerested in spending $1000 on a new rack for such a high mileage car(even though the car is mechanically very sound.)

Just thought this knowledge might be useful for anyone with a failing(non leaky) steering rack.

Take care,
Jesse

[howardc64]

Yeah, MOS2 is like magic. Had a rebuilt manual transmission in a 88 VW with hard shifts afterwards. Shop put in MOS2 and it was like butter... drove it 150k miles and still shifted like butter when I sold the car. Makes you wonder why not just always put it in there. BTW This was for a manual 5 speed tranny. Probably not wise to mess with automatics.

Just a guess, the grind might be from pinion shaft bearings? I had a loose pinion shaft once (dealer service tightened the shaft nut incorrectly), car wouldn't self center on left hand turns as the rack's self centering force couldn't over come the bite it had with pinion's helical gear floating around. Besides these 2, I think everything else is just rubber seals.

Here is a rack rebuild for 850 for reference on the internals http://volvospeed.com/pdf/power_steering.pdf