macattack Posted May 27, 2011 Share Posted May 27, 2011 my 96 mack mr cabover has a wobble issue at around 40 mph. when i increase the throttle it seems to smooth out. i just noticed that my mack has only one transverse rod.(from axle to frame) it is on the rear axle. my question is shouldnt there be one for the front tandem axle? my international has 2 rods. i am thinking maybe thats why i have a wobble. i was told that i can add one to the front axle. does anybody have info on this or a kit. would a worn trunion bushing cause a wobble?thanks gang. Quote Link to comment Share on other sites More sharing options...
Lmackattack Posted May 27, 2011 Share Posted May 27, 2011 You have 38k rears?... if so you only need one track rod. Yes a 2nd rod will help keep things in line but its not needed. Check the brushings,tire wobble, and spring/pad ends if any of these are bad it can cause the rears to walk and fight the road causing a wobble.. Quote Link to comment Share on other sites More sharing options...
macattack Posted May 28, 2011 Author Share Posted May 28, 2011 thanks. is there a way to tell if my rears are 38k by looking? just noticed on my bill of sale that states 44,000lb rear end and 20,000 lb front. so i guess i should have a transverse rod on the 2nd axle also. anybody have an idea where i can get a transverse rod kit if available.thanks again Quote Link to comment Share on other sites More sharing options...
Bollweevil Posted May 28, 2011 Share Posted May 28, 2011 thanks. is there a way to tell if my rears are 38k by looking? just noticed on my bill of sale that states 44,000lb rear end and 20,000 lb front. so i guess i should have a transverse rod on the 2nd axle also. anybody have an idea where i can get a transverse rod kit if available.thanks again 44's will have 6 axle retaining studs, or bolts. Quote Link to comment Share on other sites More sharing options...
rhasler Posted May 28, 2011 Share Posted May 28, 2011 I don't think I've ever seen transverse rods on the front drive axle unless the suspension was air ride or if it had a vendor axle/suspension. I think a 34K suspension has no transverse rod, 38K and up will have a rod between the rear differential and the frame. Does this truck have a Mack camelback suspension or is it Hendrickson? Quote "Mebbe I'm too ugly and stupid to give up!" Link to comment Share on other sites More sharing options...
Lmackattack Posted May 28, 2011 Share Posted May 28, 2011 Yep...34k has no rods.38k and up will. Air ride will have a rod for each axel. Can't comment on what to look to see the weight rating. I would count the spring stack and that may give a clue? I don't think putting a rod on the forward tandem will do much. The trunion is bushed to limit the axel walk. The rear rod ties that axel to the frame and furthermore keeps the axel walk in check. Yes a 2nd rod will tie the forward axel and keep it in line but if any of your brushing are bad it will wobble. Look for a bad bashing or pad and if you can't see any issues the add the rod to the forward axel...Just my .02Trent Quote Link to comment Share on other sites More sharing options...
macattack Posted May 28, 2011 Author Share Posted May 28, 2011 thanks. it is a mack camelback suspension. i believe 10 leafs. where does a person place jacks to check trunion bushing wear? Quote Link to comment Share on other sites More sharing options...
rhasler Posted May 28, 2011 Share Posted May 28, 2011 There are a couple of different types of trunnion bushings/housings. There is a brass bushed trunnion that has greaseable caps (this trunnion needs to be adjusted periodically to keep the correct thrust on the trunnion), a one piece encapsulated rubber bushing (no good at all in my opinion), and the split trunnion with rubber bushing. Roll under the truck and look for a gap between the trunnion bushing housing and the dead axle. There should not be much difference in gap when comparing the top of the trunnion to the bottom. You can jack against the trunnion housing between the u-bolts and watch to see how much the housing moves up before the rest of the truck starts to raise off of the ground.If I remember correctly haven't you been looking for the source of this wobble for awhile now? You might re-post what you've tried so far. Quote "Mebbe I'm too ugly and stupid to give up!" Link to comment Share on other sites More sharing options...
macattack Posted May 29, 2011 Author Share Posted May 29, 2011 yah i have been hunting this for a while. the thing is i dont operate very much at this time because i have another older truck that i am using quite a bit. the mack is my newer truck. i will get under neath and take a peak. my caps do have grease nipples so i take it that there brass. how does one adjust these.i replaced the insulator top and bottom pads on the bad side and a broken leaf on the opposite side. retorque and checked the transverse rod. seems ok. what i have is slight walking on one side front rear axle. i get a truck wobble around 30-40 mph. it seems to smooth out as i increase my speed. if i go downhill and dont give it any throttle truck starts to wobble. thanks for your expertise. Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted May 29, 2011 Share Posted May 29, 2011 44's will have 6 axle retaining studs, or bolts.I guess that would be the studs that have the cones in the axles also?The The stamp # in the banjo housing at the rear also tells the rating if you know how to read it. Quote glenn akers Link to comment Share on other sites More sharing options...
rhasler Posted May 29, 2011 Share Posted May 29, 2011 The problem with the brass bushed trunnions is that the adjusting nut can eventually work loose. If it gets loose enough it will knock a hole in the aluminum cover. The procedure says that the spring should be removed in order to adjust the trunnion, since you're just looking to check it I wouldn't worry about pulling the springs. Might want to recheck the u-bolt torque (if you have large enough tooling to do so) and raise the weight off of the trunnion and grease it.trunnion adjustment.pdf Quote "Mebbe I'm too ugly and stupid to give up!" Link to comment Share on other sites More sharing options...
macattack Posted May 29, 2011 Author Share Posted May 29, 2011 thanks guys. gonna take a closer look and will post findings. i am thinking maybe my wobble/wiggle problem could also be bad kingpins. anybody have a wobble or truck wiggle and find that you had bad kingpins. the wobble feels like as if your driving over pot holes on one side. Quote Link to comment Share on other sites More sharing options...
Lmackattack Posted May 30, 2011 Share Posted May 30, 2011 The one thing that I have noticed is that these older spring ride macks all seam to have that vibration from 30-40mph.. I hear lots of r model owners say the same thing. I think someone even said that a bad power divide can cause vibrations...my RS likes to buck when empty. The no air ride cab makes it worse. I tried new cab rubbers and shocks with no luck.. it seams that the spring ride and no air bags on the cab just makes for a harder ride than the newer trucks??? Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted May 30, 2011 Share Posted May 30, 2011 My superliner does the same thing. For two and half years its bounced some were and new tires did not do nothing for it. Drive line is perfect in line and balacned so i dont let it bother me. Its just a camel back ride to me.I have seen them ride good. But with daton wheels they are not always inline as good as they could be. Quote glenn akers Link to comment Share on other sites More sharing options...
leversole Posted May 30, 2011 Share Posted May 30, 2011 My truck had a ridiculus bounce around 35 mph...I attributed it to the 10 old different brand tube type tires...so, I bit the bullet and purchased 8 like new and two new front and changed to tubeless, also, 10 brand new accuride rims...I thought I had it beat...till I got to 50 mph...hopped like it did before! It hops at 25-26 mph and 48-50 mph, smooth at other speeds, I know I have one really bad king pin...hoping new king pins will cure the problem, if not, will keep digging! This is not just an annoying hop, or bounce, but feels like the cab will come off! I cannot feel any shake in the steering, but I am hoping it is the worn front end causing it...Does it happening at 25 and at 50 bring any thoughts about cause? Quote Link to comment Share on other sites More sharing options...
HK Trucking Posted May 30, 2011 Share Posted May 30, 2011 Before the mid 80's I never saw a transverse torque rod on any of the Mack rears on camelback. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment Share on other sites More sharing options...
macattack Posted May 30, 2011 Author Share Posted May 30, 2011 My truck had a ridiculus bounce around 35 mph...I attributed it to the 10 old different brand tube type tires...so, I bit the bullet and purchased 8 like new and two new front and changed to tubeless, also, 10 brand new accuride rims...I thought I had it beat...till I got to 50 mph...hopped like it did before! It hops at 25-26 mph and 48-50 mph, smooth at other speeds, I know I have one really bad king pin...hoping new king pins will cure the problem, if not, will keep digging! This is not just an annoying hop, or bounce, but feels like the cab will come off! I cannot feel any shake in the steering, but I am hoping it is the worn front end causing it...Does it happening at 25 and at 50 bring any thoughts about cause?this sounds like what i have. i am begining to think my king pins also. my steering wheel does not shake, just the truck has a wobble and like you said it feels like the cab is going to fly off. my happens around 35-45. if i give it throttle it smooths out. i am gonna get one tire changed out and see what happens. Quote Link to comment Share on other sites More sharing options...
macattack Posted May 31, 2011 Author Share Posted May 31, 2011 well changed out a tire that i thought was bad. it didnt look too bad. but i had a chance to see how much movement there is in the trunnion bushing when the tire man jacked her up. never measured it, but it did seem like the trunnion moved a fair bit befor the truck began to move. i guess i am off to the bushing store. i will post what i find. it might be a few days. Quote Link to comment Share on other sites More sharing options...
macattack Posted June 11, 2011 Author Share Posted June 11, 2011 well got my trunnion bushings today and my kingpin set. now just to get these installed. did another road test today just to make sure i know my problem.this is what it feels like. at around 30- 40 mph the truck begins to wiggle side to side. just like if someone is pushing on the front bumper from left to right, NOT up and down. i kind of think my front kingpins maybe worn as my front seems to hit the potholes pretty hard. dont see any spring breakage,but i may also change the front spring pins. i think its more of a front problem.what you guys think. Quote Link to comment Share on other sites More sharing options...
MACKS Posted June 11, 2011 Share Posted June 11, 2011 You can check the king pins by jacking up the front end and using a bar under the tire,I drove Macks that had a lot of walk in the rear axles and neaver noticed any kind of wheel hop or shimmy,most likly your problem is in the front end,check your tie rod ends good,get someone to rack the steering wheel hard while you get under the truck and look for any free play,Good Luck Quote Link to comment Share on other sites More sharing options...
DCR Posted June 11, 2011 Share Posted June 11, 2011 My truck had many of the above symptoms also. I had the king pins replaced, the front springs taken apart and the rust and junk cleaned out and the front end aligned. It is like a new 1958 Mack. The shake, rattle and roll is gone. It rides better, steers much easier and the road wandering is gone. Denny Quote Denny330-550-6020A "Mack Pack" Charter Member Link to comment Share on other sites More sharing options...
macattack Posted June 11, 2011 Author Share Posted June 11, 2011 thanks guys. yah started to realize my problem is in the front. i had the tie rods changed next is my kingpins and front spring inspection.let you know how it goes. got to hunt down some help and get those pins changed.thanks again makes me feel a little better. the truck i am talking about is my avatar pic. Quote Link to comment Share on other sites More sharing options...
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