My Sportsman 400 will suddenly start pulling hard to the right. I have to fight it to stay straight. But does not do it consistantly. I don't know why it quits pulling and then will be fine. Any suggestions on what may be causing it to pull hard.

 

my scrambler 400 was doing this it would only do it occasionally in 2 or 4wd i jacked it up all 4 in the air and gassed it and it pulled hard right even in 2wd just when i gassed it good and let off!
well i ripped into both sides, changed armature plates and cleaned and inspected everything else changed the fluid twice and it still did it #$%$@# i then unhooked one tie rod end form the strut to isolate which side it actually was (the opposite than i thought) seems the left side cv joint was badly worn and must have been binding up occasionally jerking me to the right
if you have a torn or bad cv boot you may want to pull the half shaft and check the cv joint and u joints in the axles while you have them out
i changed mine and it rides like new again
while you have it apart be sure to check the ball joints too i put the first side all back together on mine without checking it and just by chance checked the other side and was surprised how worn it was, and replaced it (easy job with strut stripped anyway) i ended pulling the other side back apart and doing that one too , and i'm glad i did i think that may put stress on the cv joint too

good luck

 

might be the hub on the right side is kicking in. could be a wheel wearing going bad. try changing the hub fluid if you havent for awhile. as mentioned jack the wheeler up and spin the wheels to check for sounds or feel of a bad bearing.

 

miss alignment my guess

 

lol
he wishes i bet

 

it wouldnt a miss alighment when it only does it part of the time. most likely a bad bearing or the hub is kicking in to give that side power and not the other side causing it to pull w/ power w/ that wheel.

 

i'm stickin with a CV joint thats about to let loose in my experience low hub fluid will keep them from kicking in but not make them kick in unexpectedly
you need to pull the hub apart and inspect it carefully, look at the garter spring ,too loose of spring may cause it also
i pulled everything apart in less than an hour/side the hardest part was getting the roll pin out so i could remove the axle

does it have a damaged cv boot?

 

Change your hub fluids and good things will happen. Hard to were the front bearing on the hub locking front ends because the bearings are always submerged in hub fluid and require no grease,so you do not hear of them wearing out.

 

he should pull them apart for a visual inspection at least, then add the new fluid
and as far as your bearing theory , thats assuming there was clean fluid in the hubs or at least fluid at all!
take the time do it right you'll see that its not as intimidating as it sounds ripping the front hubs apart plus its good piece of mind knowing how everything works and then you can eliminate some parts as being the cause