My 99 Cummins has a 3.5mm spacer behind the front passenger tire. It came from the factory with this spacer and I was wondering if anyone knew the purpose of this spacer. My truck has always had a very slight pull to the right when driving down the road, even after several alignments. Does this spacer have anything to do with the slight pull? I recently replaced the front rotors, calipers, and passenger side hub assembly and was contemplating removing this spacer. Thanks for any advice!

 

Ya it was a factory *fix* for a front end pull.
I've done it on a few trucks but in my opinion it does little if any to decrease the pull.