chopper35nj Posted October 23, 2015 Share Posted October 23, 2015 I have just gone through the front end on my truck, added a 2" spacer, and everything is in good shape. I reset my toe (1/16" in at the front) and added 3/32" caster shim each side. It returns to center fine and does not wander, but it does pull to the right a bit, won't track straight down the road. I have also noticed that it requires a bit more input from the steering wheel to turn left than right. I took some measurements and found that the wheel base is 3/8" longer on the right side than the left, is that a factory thing to compensate for crowned roads? My truck is straight and the chassis is square. I have an appointment to get new tires and don't want to scrubb off a brand new set of treads. Thoughts?? Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 23, 2015 Share Posted October 23, 2015 I have just gone through the front end on my truck, added a 2" spacer, and everything is in good shape. I reset my toe (1/16" in at the front) and added 3/32" caster shim each side. It returns to center fine and does not wander, but it does pull to the right a bit, won't track straight down the road. I have also noticed that it requires a bit more input from the steering wheel to turn left than right. I took some measurements and found that the wheel base is 3/8" longer on the right side than the left, is that a factory thing to compensate for crowned roads? My truck is straight and the chassis is square. I have an appointment to get new tires and don't want to scrubb off a brand new set of treads. Thoughts?? Yes. The left side wheelbase is ~10mm shorter on the drivers side for LHD vehicles to help it run straighter on crowned US roads. Link to comment Share on other sites More sharing options...
chopper35nj Posted October 23, 2015 Author Share Posted October 23, 2015 Any thoughts on my issue with it pulling right then? It would seem that it would pull left (maybe, just a little) because of the difference in length. Do you think I should go with a little more toe in? 1/8" maybe? Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 23, 2015 Share Posted October 23, 2015 What are your L & R caster measurements? Link to comment Share on other sites More sharing options...
chopper35nj Posted October 23, 2015 Author Share Posted October 23, 2015 Ooooooo, I haven't checked them individually, only at the dif. 87.5deg Link to comment Share on other sites More sharing options...
chopper35nj Posted October 23, 2015 Author Share Posted October 23, 2015 and if this is a question of caster, I don't think I can get any more. The lower CA bolts are pushed as far forward as they will go. I am about to lose access to the nut on the CA. Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 23, 2015 Share Posted October 23, 2015 Got an angle finder? Check the caster angle by sticking it on top of the L & R upper ball joint flats and check the positive angle. You must be sitting on level ground. Ideally it should be ~7.5* on both sides. And yes, at around 3" of lift you'll run out of room for shims behind the LCAs. and if this is a question of caster, I don't think I can get any more. The lower CA bolts are pushed as far forward as they will go. I am about to lose access to the nut on the CA. When shimming the LCA forward, the oval hole in the LCA will bottom out before you lose the threads on the clevis stud. Link to comment Share on other sites More sharing options...
A-man930 Posted October 23, 2015 Share Posted October 23, 2015 Have you tried swapping the front tires left to right? This solves "my car pulls" concerns just as much as alignment adjustments in my experience. I'm not against the "old fashioned" way of doing things very often, but I say get it measured up at a reputable alignment shop and see what's what. Yes. The left side wheelbase is ~10mm shorter on the drivers side for LHD vehicles to help it run straighter on crowned US roads. Maybe It's just Friday, but I'm having a hard time figuring out how a shorter wheelbase on the left would compensate for road crown... Link to comment Share on other sites More sharing options...
A-man930 Posted October 23, 2015 Share Posted October 23, 2015 Ok I'm reading about front setback... Link to comment Share on other sites More sharing options...
chopper35nj Posted October 23, 2015 Author Share Posted October 23, 2015 I am only running 2" of lift so I should have some adjustment left but..... I have not tired swapping front tires left to right but I don't think that's the problem. I think I may have committed the cardinal sin of tightening the front suspension with no weight on it, I'll have to check it out this next day off. Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 23, 2015 Share Posted October 23, 2015 I hear you A-man - I don't get it either. The source for the wheelbase factoid is Marcus Ohms (GoJeep), whom I consider one of the most knowledgeable Jeep guys in the world: Just a little note for Australian owners or any RHD ones, if you have trouble of it always pulling left following the camber of the road, check your wheel base left to right and you will find that the left side is 10 mm shorter than the right! This is so it will run straight on USA or on the right side of the road which of course is the opposite of what we want. I had to add an extra 10 mm shim to the left side LCA and also remove the UCA, weld up the diff end holes of it and re-drill them 10 mm forward so that my wheel base is the same left to right. It still follows a steeply cambered road a small amount but on freeways it is perfect. To follow the Jeep logic for this you would need to extend a further 10 mm to have the same as their stock setup! My tyres now wear nice and evenly too. Link to comment Share on other sites More sharing options...
gogmorgo Posted October 25, 2015 Share Posted October 25, 2015 Well this would explain why it feels like there's something gently pulling me towards the ditch when I'm passing. Never would have guessed that. Link to comment Share on other sites More sharing options...
A-man930 Posted October 26, 2015 Share Posted October 26, 2015 Well this would explain why it feels like there's something gently pulling me towards the ditch when I'm passing. Never would have guessed that. Road crown, caster, camber (not so much on our trucks), tire conicity, and (new to me) front setback can all contribute to a pull or drift; hard to say what explains your situation. Alignments regularly hand me my butt at work. To the OP, I would encourage you to switch your front tires left to right and verify you don't have a tire pull; I'm tellin' ya its worth a try ($$) before you pay someone to measure it up and perhaps find nothing wrong with it... Link to comment Share on other sites More sharing options...
Crash Posted October 26, 2015 Share Posted October 26, 2015 Honestly, after the different lift setups I have had on XJ/MJ etc. I will do at least one set of adjustable control arms. That clevis and shims for the lower is a PITA and annoying. I picked up my RK adjustable UCA's for 153$ fro ma Vendor on Jeepforum. Installed them on my MJ when I lifted it yesterday. I have not checked caster yet, and adjusted them slightly longer than the stock UCA's and they fit right on. I knew I wouldn't be able to swing adjustable lowers right away, but that is on the list too. My MJ is 2WD currently so Pinion angle is not an issue for me yet either. And, as others have said move/rotate tires etc. to eliminate the possible issue. Link to comment Share on other sites More sharing options...
1stDeuce Posted October 26, 2015 Share Posted October 26, 2015 Yup. Check tire pressure and swap them side to side before round do anything else. You can't change cross caster on a solid axle without offset balljoints, so none of the adjustments you have made should have caused a pull. Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 26, 2015 Share Posted October 26, 2015 Honestly, after the different lift setups I have had on XJ/MJ etc. I will do at least one set of adjustable control arms. That clevis and shims for the lower is a PITA and annoying. On lifts 3" or below, there is no need to spend extra $$ for adjustable upper or lower control arms, except if your rig is used mainly off-road and you need the extra beef. The procedure to set caster by using shims to lengthen the LCAs is simple and straightforward. Plus you can use the beefier curved fixed WJ lowers to prevent rubbing with wider tires since they are the same length as the stock LCAs. Anyone who finds using LCA shims a PITA or annoying probably doesn't fully understand caster alignment. But if you want to spend extra $$ for overpriced adjustables you don't really need, by all means go for it. Link to comment Share on other sites More sharing options...
1stDeuce Posted October 26, 2015 Share Posted October 26, 2015 Hornbrod, I say the same thing over and over. If people get it in their head that they need adjustable control arms or track bar, telling them they don't doesn't do any good... OP, if swapping tires doesn't change the drift, find a nice level place to use a bubble level to compare camber side to side. And check (feel for temp) the brakes to make sure you don't have a dragging caliper. Link to comment Share on other sites More sharing options...
A-man930 Posted October 26, 2015 Share Posted October 26, 2015 OP, if swapping tires doesn't change the drift, find a nice level place to use a bubble level to compare camber side to side. And check (feel for temp) the brakes to make sure you don't have a dragging caliper. Correct me if I'm forgetting something, but a failed ball joint or bent part (knuckle, inner-c, axle tube, etc) is pretty well the only way you'll get a significant cross-camber condition... The OP hasn't mentioned checking the ball joints. +1 on the dragging brakes. A partial hose restriction or sticky caliper can and will cause a pull. You can't change cross caster on a solid axle without offset balljoints You've got me thinking really hard here. Trying to alter caster with shims behind the LCA on one side only would accomplish nothing but trying to twist the axle. But would you perhaps influence the setback condition?? I guess it depends on the condition of all the bushings (especially the UCAs)... Link to comment Share on other sites More sharing options...
1stDeuce Posted October 26, 2015 Share Posted October 26, 2015 Correct me if I'm forgetting something, but a failed ball joint or bent part (knuckle, inner-c, axle tube, etc) is pretty well the only way you'll get a significant cross-camber condition... The OP hasn't mentioned checking the ball joints. You've got me thinking really hard here. Trying to alter camber with shims behind the LCA on one side only would accomplish nothing but trying to twist the axle. But would you perhaps influence the offset condition?? I guess it depends on the condition of all the bushings (especially the UCAs)... He didn't mention checking, but he just "refreshed" the front end, which I took to mean replaced ball joints. If not, it's time to check them also. Careful your terms... You say camber, but you're talking about adjusting caster with shims... And yes, it will affect setback (which is what you mean by offset I think..) It will NOT change cross caster, as you can't "twist" the axle tube differently left vs. right. There is a slight amount of cross caster built into our axles, so you'll normally have ~0.25° more caster on the right side than the left. This was done to help compensate for driving on crowned roads. (It's not common practice anymore, as crowning is now much less than it used to be, particularly now that we drive lots of miles on highways...) It's not really enough to do hardly anything really... And the OP has a right pull, which would be opposite what the cross caster would do. Barring tire and brake influences, that takes us to camber, which can be affected by worn ball joints and "smiling" axles. Both would be pretty common and believeable in a 30 year old truck... To check cross camber, air the front tires up to their max, then find a very level surface to park on. (Check it with a level, don't just "eyeball" it...) Place a bubble level against the bottom of of the tire sidewall and level it vertically. Measure or estimate the distance between the level and the top of the tire sidewall. (Our axles always have slightly negative camber, which is top-in.) Compare that measurement side to side. A difference of more than 1/8" or so would indicate opportunity for a pull from cross camber. For a right pull, the distance on the left side would be larger. (More negative camber on the left than on the right) I'm curious to hear from the OP if a tire swap helped... All else being OK, it usually does. If he did a bunch of needed parts replacing on the front, it's rather likely he has a "coned" front tire which is causing the pull, and it'll follow the tire when he swaps them, and it'll go away with new tires if that's the case. :) Link to comment Share on other sites More sharing options...
1stDeuce Posted October 26, 2015 Share Posted October 26, 2015 Just becasue I used them and they worked very well, I'll also add that there is now an easy way to change camber on our solid front axles. I got shims from O'Reilly that go between the hub and knuckle, just like the old "cosmo" shims that we used to use on spindle axles from the 70's. I put a 0.5° shim on the right, and a 1.0° shim on the left of my TJ to fix a cross camber issue. That fixed a left drift that always existed on my TJ, and got me just slightly positive camber on both sides. Positive camber helps do the same thing that caster does, but without making the steering feel heavy in turns. That way I can run a bit less caster for better front u-joint angle, and still get good return to center. I'm at about 5 degrees of caster now, and it drives pretty well. :) P/N's for the shims are 26012 and 26014. (~$10, and half an hour to install if your hub isn't seized in the knuckle.) They're from SPC, who also make the better option in offset balljoints, but those require a bit more effort to install... Chris Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 26, 2015 Share Posted October 26, 2015 P/N's for the shims are 26012 and 26014. (~$10, and half an hour to install if your hub isn't seized in the knuckle.) They're from SPC, who also make the better option in offset balljoints, but those require a bit more effort to install... Chris ^^ Good info. Less than $10/ea. Link to comment Share on other sites More sharing options...
gogmorgo Posted October 27, 2015 Share Posted October 27, 2015 Personally I'd give up a bit of self-centering to prevent the loss of cornering grip that will come with positive camber, but to each their own I guess. :dunno: I'm also a little leery about changing the pad/rotor alignment. but I guess they'd wear in after a bit. If you spun them 120°, they'd do something interesting to your KPI... you'd be adjusting both caster and camber at the same time. Link to comment Share on other sites More sharing options...
Eagle Posted October 27, 2015 Share Posted October 27, 2015 I don't think positive camber helps with self centering. I've never encountered any source that recommended positive camber, for any reason. Positive caster is what contributes to self centering of the steering. Link to comment Share on other sites More sharing options...
1stDeuce Posted October 27, 2015 Share Posted October 27, 2015 It was very commonly done on older cars and trucks with manual steering. Lots of them had very little or even negative caster and a degree or so of positive camber to provide return to center. Gm and Toyota trucks still use lower caster numbers with slightly positive camber (like a quarter of a degree) to keep steering efforts down and still have good centering feel. <edit> I thought of a great example!! A deuce and a half (As in M35 military truck) actually has lightly negative caster (-1.5° or so) but lots of positive camber (+1.5° or so) and has good return to center and on-center feel, while being totally steerable by manual steering with ~6000lbs on the front alxe, so long as the truck is moving. Bias ply tires also helped with on-center feel, but if you've ever driven an older muscle car with radial tires, you know how light the steering is, but they still track straight and have some return to center. Most all of those older cars had pretty much zero caster, and slightly positive camber. It works. It was very common practice, and to a lesser degree, is still done on some platforms to keep steering efforts light for parking lot type maneuvers. Wow, we're way off topic aren't we... Well, hopefully it's still good info for anyone reading along... Link to comment Share on other sites More sharing options...
1stDeuce Posted October 27, 2015 Share Posted October 27, 2015 Personally I'd give up a bit of self-centering to prevent the loss of cornering grip that will come with positive camber, but to each their own I guess. :dunno: I'm also a little leery about changing the pad/rotor alignment. but I guess they'd wear in after a bit. If you spun them 120°, they'd do something interesting to your KPI... you'd be adjusting both caster and camber at the same time. Unfounded concerns on all accounts. 1. The difference in cornering grip between -0.3° and +0.2° on a Jeep with lots of sidewall isn't even worth talking about. Remember, on a vehicle with IFS, you start with whatever you set camber to, but when you corner, the body leans, and so does the tire. So on IFS, you get better handling by setting things fairly negative. On a solid axle, the tire doesn't lean at all when cornering, even if the body does, other than deflection of the rubber. If I was setting it to +2° or something like that, it'd be different, but LOTS of vehicles run with ~+.25° of camber as the preferred setting. (All Toyota trucks, All GM trucks...) Neither you or I would be able to tell the slight difference in ultimate handling on a Jeep. (I did chassis dynamics for a large portion of my career in the auto industry...) 2. Pads wear in VERY quickly. Because they are rotated toward the top slightly, they wear largely across the short dimension of the pad, not the long dimension. On my Jeep, I noticed a little extra brake travel for the first couple of days, then it was right back up to normal. (My Jeep has a very high and fast acting pedal for some reason, so it was very easy to tell there was a difference.) 3. Even if you rotate it, you're not changing king pin inclination at all. The shim is outboard of the ball joints, not inboard. You're only changing camber if you install it correctly, and if you rotate it, you're mostly changing toe. Link to comment Share on other sites More sharing options...
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