tdtony Posted June 14 Share Posted June 14 I replaced all the bushings on my truck, and found it easier to replace the control arms, rather then press out the bushings and press new ones in. After that I took my truck to Firestone and had them do an alignment. The caster was a degree of 2 negative, so the told me to shim the lower control arms forward. After getting the shims and crawling under the truck I found that the lower control arms were already shimmed as far forward as possible. https://www.1aauto.com/jeep-cherokee-comanche-wagoneer-front-upper-and-lower-6-piece-control-arm-set-trq-psa71577/i/1asfk05980/1165528/1987 These are the control arms I bought, I don't know if the uppers are too long or the lowers too short or something else entirely. Even though my truck isn't lifted I was thinking about buying adjustable lower control arms, just to fix the caster and help driveability. Anyone know what could have caused the caster to be off, or any suggestions on how to fix it without dropping a few hundred on new control arms? Link to comment Share on other sites More sharing options...
tdtony Posted June 14 Author Share Posted June 14 I've got 3 1/8" shims in there and still have negative caster. That's as many shims as I could fit and still get a bolt through the lower control arm Link to comment Share on other sites More sharing options...
Spinnakerblue89 Posted June 15 Share Posted June 15 I'm not the most savvy about suspension and steering diagnosis, I've only replaced CAs and had a shop do my alignments. That said, if a shop that I trusted were to tell me my caster was in the negative by 2, and that their recommendation was presently not a possibility, I would seriously keep the possibility of either the control arms themselves being not to true spec (probably the simplest answer), or you may have something else at play, which could be more of a major issue. I would reasonably expect that I wouldn't need to shim the control arms so much to get them to correct caster, you've already got, 3/8" in compensation to account for. That's like a socket drive worth of difference! I remind you, that's a rube's take on the matter. I've had some wicked weird luck in my life, both good and bad, so I've come to expect the unexpected... Which means that the unexpected is technically then expected, this rendering the saying pointless. Link to comment Share on other sites More sharing options...
gogmorgo Posted June 15 Share Posted June 15 Did you change the upper control arm bushings in the axle? Link to comment Share on other sites More sharing options...
tdtony Posted June 15 Author Share Posted June 15 @gogmorgo yeah I changed the bushing in the axle Link to comment Share on other sites More sharing options...
tdtony Posted June 15 Author Share Posted June 15 I just went out and measured the control arms from the center of one bolt to the center of the other bolt, the lower is about 16" and the upper is about 15" Which according to the Cherokee form is about the stock length https://www.cherokeeforum.com/f67/how-accurate-arm-length-chart-122740/ What else could be affecting my caster? Link to comment Share on other sites More sharing options...
gogmorgo Posted June 15 Share Posted June 15 Changes in ride height front or rear will affect caster angle because the whole truck tilts forwards or backwards relative to the road. It’s worth at least checking where your truck is sitting. I can’t riddle out in my head how suspension squat will affect your caster angle, too much geometry to keep track of. But if you’re not sitting level compared to factory ride heights it might be worth your time to use a jack to bring the body back to level and see where that gets you. You don’t need fancy alignment equipment, just use an angle finder or even your phone on a flat surface on the front axle to measure before and after to see if it’s moving in the right direction. The only other thing would be physical damage to a component. Something bent, probably from a collision. Hard to believe it would be the same on both sides, however. Improper tire pressure could affect things as well or worn ball joints with play in them, or different sized tires, but the alignment guys should’ve checked all that. Link to comment Share on other sites More sharing options...
ghetdjc320 Posted June 15 Share Posted June 15 I have to ask, where are you measuring your caster angle at? Link to comment Share on other sites More sharing options...
gogmorgo Posted June 15 Share Posted June 15 1 minute ago, ghetdjc320 said: I have to ask, where are you measuring your caster angle at? I'd have to ASSume the Firestone shop he took it to has an alignment rack for measuring everything. Link to comment Share on other sites More sharing options...
ghetdjc320 Posted June 15 Share Posted June 15 2 minutes ago, gogmorgo said: I'd have to ASSume the Firestone shop he took it to has an alignment rack for measuring everything. I’d grab an angle finder and double check. Are you having any weird driving issues like the wheel not returning to center? Link to comment Share on other sites More sharing options...
Spinnakerblue89 Posted June 16 Share Posted June 16 5 hours ago, ghetdjc320 said: I’d grab an angle finder and double check. Are you having any weird driving issues like the wheel not returning to center? I just have to say this: I initially misread this as, "I'd grab and angle grinder..." Link to comment Share on other sites More sharing options...
tdtony Posted June 16 Author Share Posted June 16 Yeah I just took it to a shop and had them do the alignment, and they told me about the negative caster. I'll test it myself, does the truck need to be on a level surface? My driveways got a little angle to it so I'm not sure I'll be able to get a good measurement. And can I use the level on my phone or am I better off buying a tool to measure it? If I can use my phone where should I place it? Thanks for all the help! Link to comment Share on other sites More sharing options...
rokinn Posted June 16 Share Posted June 16 A level surface would be a lot easier but you should be able to calculate the difference by accommodating for the driveway angle. Jeep tech note I.S. 14E explains how to check the ride height on a Comanche. They use the chassis and suspension not the hubs and flares Front: ------ Measure vertical distance between top of axle tube (looks like just inboard of the LCA mount) to the under side of the frame rail. For the passenger side, measure from the axle tube just outboard of the vacuum disconnect housing. For 2WD models the distance should be 6-3/4" +/- 1/2". For 4WD models the distance should be 7-3/4" +/- 1/2" Rear: ------ Measure from the top of the axle tube to the underside of the frame rail inboard of the rubber bump stop. For 2WD models the distance should be 8.2" +/- 1/2". For 4WD models the distance should be 9.2" +/- 1/2" Link to comment Share on other sites More sharing options...
tdtony Posted June 16 Author Share Posted June 16 It's hard to get pictures while I'm measuring, but are these approximate the right places to measure? I'm getting about 7.5" in the front and 7 3/4" in the back. Based on your Numbers the back is on the low end of being in spec and the front is too tall out of spec. I replaced the shocks, could those be causing the problem? Link to comment Share on other sites More sharing options...
rokinn Posted June 17 Share Posted June 17 I would jack the body in the back up to the right height and see if anything changes in the front. I wouldn't think new shocks would make a difference. You probably have a number of things going on. Is there much rust on the ball joints? Link to comment Share on other sites More sharing options...
ghetdjc320 Posted June 17 Share Posted June 17 Grab an angle finder or your phone and check the caster. Ideally park someplace level and put the angle finder (or flat side of your phone with angle finder app) on the upper ball joint flat and perpendicular to the axle. Link to comment Share on other sites More sharing options...
gogmorgo Posted June 17 Share Posted June 17 If all you’re doing is trying to find something that’ll rock the axle backward to achieve more positive caster it doesn’t really matter where you measure. So long as it’s consistent between measurements. You just want to know what you’re doing will have a positive effect on it. So if you stick it somewhere and measure 20°, then make your test adjustment and it’s sitting at 15° you know you’re going in the wrong direction. How did the upper control arm tabs on the axle feel when you did the bushings? I don’t know what they’re like on the 2wd but they’ve got a reputation for flimsiness on the non-cad d30. If they’re bent or twisted that will affect things. Also on a similar note, did you you torque the control arm bolts at ride height? If you didn’t they can twist things when they move back down to standard position. Standard practise is to leave everything loose until you get it back on the ground and then give it some bounces or go for a rip around the parking lot to settle the suspension, and then torque it all down. If you didn’t do that it might be good to back the nuts off a turn or two and get them settled before retorquing. Even though you’re 2wd you’re still in the ballpark for 4x4 ride height. Looks like newer coil springs in there. There were a couple dozen factory coil options with different heights and spring rates depending on how the truck was equipped and the aftermarket replacements don’t give you many options there, just kinda go for a couple sizes that average everything out. Unless there’s different geometry on the 2wd axle to account for it I can’t imagine the range of caster adjustment wouldn’t account for the ride height difference, but I guess you can try tossing some weight on the front end somehow to push it down and see if that does anything. Link to comment Share on other sites More sharing options...
ghetdjc320 Posted June 17 Share Posted June 17 Check the caster angle Link to comment Share on other sites More sharing options...
tdtony Posted June 17 Author Share Posted June 17 Well I might have got ripped off and wasted everybody's time. The flattest spot on my driveway is about 1°. Measuring the upper ball joints both sides hovered between 7° and 8°. I just replaced all the a/c components and I'm gonna take it to a different shop to get it recharged, so i'll see if they can check the alignment @gogmorgo the tabs for the upper control arm bushing were really flimsy, I had to jam a socket in there to stop it from crushing when I was pressing the old bushings out, so there's probably a little messed up. I torqued everything to spec on the ground but didn't drive it or weight it at all. Link to comment Share on other sites More sharing options...
gogmorgo Posted June 18 Share Posted June 18 Well I guess in that case if it doesn't drive weird, it's maybe not even worth worrying about? Link to comment Share on other sites More sharing options...
ghetdjc320 Posted June 18 Share Posted June 18 12 hours ago, tdtony said: i'll see if they can check the alignment Why?? You’ve already confirmed there is nothing wrong with your alignment Link to comment Share on other sites More sharing options...
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