wheeler73 Posted May 30, 2014 Share Posted May 30, 2014 Just rember camber is more of a wear angle. It can cause some pulling and wander but it usually has to be way out. Quote Link to comment Share on other sites More sharing options...
Mackpro Posted May 30, 2014 Share Posted May 30, 2014 In my notes here, My DSM said to make sure the caster is 3 to 3.5 degrees before installing the bronze bushings and steering stabilizer. This axle has been around and not changed since around 2005. Really dont know why we are getting all the complaints of "death wobble" and tire wear. Dont know what has changed lately. We also have some bad cab shake complaints on the full flaring day cabs whne following a van trailer. I have test drove and verified the cab shake on a new day cab and it was scary! mack does have a fix for that issue. Quote Link to comment Share on other sites More sharing options...
haulin-gas Posted May 31, 2014 Author Share Posted May 31, 2014 In my notes here, My DSM said to make sure the caster is 3 to 3.5 degrees before installing the bronze bushings and steering stabilizer. This axle has been around and not changed since around 2005. Really dont know why we are getting all the complaints of "death wobble" and tire wear. Dont know what has changed lately. We also have some bad cab shake complaints on the full flaring day cabs whne following a van trailer. I have test drove and verified the cab shake on a new day cab and it was scary! mack does have a fix for that issue.Beginning to wonder if there's an issue with the steering boxes. Two of us have had the boxes changed before 50k miles and within that time they both needed to have the sector shaft play adjusted. Before they changed my original steering box, it went from nice and snug to over 1/4 turn of free play in the steering wheel, followed by the shaft seal letting go.Did TRW start assembling their boxes in a 3rd world country lately? Quote Link to comment Share on other sites More sharing options...
Mackpro Posted June 3, 2014 Share Posted June 3, 2014 Changing a TRW box on a 2014 CXU today. We have no problems out of the Sheppard M series on the new trucks. One of our death wobble/tire wear problem CXU's had its steering box changed when it was a month old. Quote Link to comment Share on other sites More sharing options...
haulin-gas Posted June 7, 2014 Author Share Posted June 7, 2014 Changing a TRW box on a 2014 CXU today. We have no problems out of the Sheppard M series on the new trucks. One of our death wobble/tire wear problem CXU's had its steering box changed when it was a month old.So, is it possible to switch from a TRW box to a Sheppard without any modifications? One thing we have noticed on this P.O.S. is that the left steer axle spring is somewhat sagged compared to the right, and has been since I took delivery. Any thoughts as to this affecting the wandering issue? Mack parts guy says there are 2 different springs that are used in the CHU. On has a higher load rateing than the other and he thinks it may be possible that the factory screwed up and mismatched the springs on the assembly line. Quote Link to comment Share on other sites More sharing options...
wheeler73 Posted June 7, 2014 Share Posted June 7, 2014 The spring issue is from engine torque. Seen it alot. Usually put in a spacer to fix it. Have not seen it cause a major wandering issue. Quote Link to comment Share on other sites More sharing options...
staxx Posted June 7, 2014 Share Posted June 7, 2014 Have seen a few new trucks get dropped while being undecked after transport . Quote Link to comment Share on other sites More sharing options...
haulin-gas Posted June 7, 2014 Author Share Posted June 7, 2014 Have seen a few new trucks get dropped while being undecked after transport .This one was the pull truck so that wasn't the cause. My last Pete came up piggy backed and they had to replace the front springs. It had the air ride steer axle in it and the rear sections behind the air bags were both snapped off when the set her on the ground. Quote Link to comment Share on other sites More sharing options...
haulin-gas Posted June 7, 2014 Author Share Posted June 7, 2014 (edited) Edited June 15, 2014 by haulin-gas Quote Link to comment Share on other sites More sharing options...
wheeler73 Posted June 7, 2014 Share Posted June 7, 2014 My experience is our customers are suprised how good the trucks pull. We even have MP7's pulling 80,000 and no complaints. Yours may not have been spec correctly for the application. Have seen people by trucks from other dealers and not happy with the way the truck pulled due to it is not spec correctly for the application. Quote Link to comment Share on other sites More sharing options...
haulin-gas Posted June 8, 2014 Author Share Posted June 8, 2014 My experience is our customers are suprised how good the trucks pull. We even have MP7's pulling 80,000 and no complaints. Yours may not have been spec correctly for the application. Have seen people by trucks from other dealers and not happy with the way the truck pulled due to it is not spec correctly for the application.CHU, MP8-505C, T318LR, S40's @3.98 with 24.5 rubber. Speced by Mack for pulling 140,000# up to 8% grades. Top end power is ok, but it's the 1760 torque that causes the lack of bottom end holding power. Our company trucks have 550 Cummaparts with 2050 torque. Top 4 gears I can keep ahead of them but below that they're around me and gone. Quote Link to comment Share on other sites More sharing options...
bbigrig Posted June 11, 2014 Share Posted June 11, 2014 I have a 14,600lb front with those Mack unitized hubs. In one year and 210,000kms I've had that truck lined up 3 times because of tire wear, wander and stiff steering in comparison to my 12,000 fronts with the same hubs. Think my 2013 CXU is in line for the same bushing issues??? Quote Link to comment Share on other sites More sharing options...
41chevy Posted June 12, 2014 Share Posted June 12, 2014 I'm sure MACK checked it, but I'm just curious, has anyone ever checked to see if the chassis rails to cross members all bolted or riveted to correct specs? I did a few D-500 Dodges in the 80's that wandered all over the road. We found the chassis rails were moving because there was a miniscule bit of movement between the rails and the cross members. We found the rivets compressed did not expand completely "tight" in the holes. The rivet diameter was a few ten thousands smaller than the holes. We set the chassis up on a chassis machine to "square" it and re fastened the cross members. Just a thought. Paul Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment Share on other sites More sharing options...
haulin-gas Posted June 15, 2014 Author Share Posted June 15, 2014 I'm sure MACK checked it, but I'm just curious, has anyone ever checked to see if the chassis rails to cross members all bolted or riveted to correct specs? I did a few D-500 Dodges in the 80's that wandered all over the road. We found the chassis rails were moving because there was a miniscule bit of movement between the rails and the cross members. We found the rivets compressed did not expand completely "tight" in the holes. The rivet diameter was a few ten thousands smaller than the holes. We set the chassis up on a chassis machine to "square" it and re fastened the cross members. Just a thought. PaulInteresting point. I just did my weekly crawl thru and noticed that the crossmember just behind the transmission is showing signs of rust between where the gussets are riveted to the crossmember. Can't turn the rivets with a vise-grip, but they could be tight and just wandering around in slightly oversize holes. Along with all the other issues on this p.o.s. I think it's time to have a little discussion with the dealer. Best place for this truck is parked against their fence, far away from a public road! Quote Link to comment Share on other sites More sharing options...
41chevy Posted June 16, 2014 Share Posted June 16, 2014 Interesting point. I just did my weekly crawl thru and noticed that the crossmember just behind the transmission is showing signs of rust between where the gussets are riveted to the crossmember. Can't turn the rivets with a vise-grip, but they could be tight and just wandering around in slightly oversize holes. Along with all the other issues on this p.o.s. I think it's time to have a little discussion with the dealer. Best place for this truck is parked against their fence, far away from a public road! They won't turn because the compression load is over 1750 psi to compress them (Mopar specs). What we found on the Dodge chassis was they were compressed tight on the heads but the shaft diameter was to under sized to "fill the hole diameter. A few ten thousands of an inch movement of each rivet and add that into the rail length and that will magnify that exponentially . The reason I thought of the chassis was because the number of trucks with the problem and I would bet the production dates are close. One off batch of rivets from the supplier would affect a few hondred chassis I imagine. Paul Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment Share on other sites More sharing options...
haulin-gas Posted June 27, 2014 Author Share Posted June 27, 2014 Thanks to everybody for your ideas. At this time they are no closer to finding a cure, or the cause for that matter. I have been assured that the engineers at Mack are working on the problem, but they are being very tight lipped about the whole thing. Wouldn't want word of this getting out to the FMVSS or Transport Canada, eh!Makes me feel a whole lot better knowing that after I lose control and roll it that the engineers have got my back! 1 Quote Link to comment Share on other sites More sharing options...
haulin-gas Posted July 3, 2014 Author Share Posted July 3, 2014 Well, it's heading into the frame shop in the morning. Hopefully they'll finally find out what's wrong with this thing once and for all! Quote Link to comment Share on other sites More sharing options...
41chevy Posted July 3, 2014 Share Posted July 3, 2014 Well, it's heading into the frame shop in the morning. Hopefully they'll finally find out what's wrong with this thing once and for all!If it's the fix . . . MACK owes us. : Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment Share on other sites More sharing options...
bbigrig Posted August 19, 2014 Share Posted August 19, 2014 Its just not offical yet and has to be approved by a DSM ( to get Mack to cover it under warranty or goodwill). We put the bushings in ( dont ream them, you want them tight) and install the steering damper/stabilizer. If that dont fix it, they have a new thicker front axle to install ( but this is rare). The newest trucks coming out just started having the heavier axle beam and bronze bushings. This all came out about 2 months ago but like I said still not official.Has Mack gotten anywhere on a fix for the 14.6 Mack front axle with unitized hub steering issues?????A friend of mine has just delivered a batch of CXU's with that front axle in the last few weeks and most are coming back to the dealer for steering issues.Is there a fix in the works as the DSM is basically having them chase steering box pressures etc.and he seems unaware of the amount of 14.6 front axle trucks with this issue.Sounds like a sweep this cluster-cuss under the carpet quick situation for Mack coming up. Quote Link to comment Share on other sites More sharing options...
gicknordon Posted August 19, 2014 Share Posted August 19, 2014 Interesting point. I just did my weekly crawl thru and noticed that the crossmember just behind the transmission is showing signs of rust between where the gussets are riveted to the crossmember. Can't turn the rivets with a vise-grip, but they could be tight and just wandering around in slightly oversize holes. Along with all the other issues on this p.o.s. I think it's time to have a little discussion with the dealer. Best place for this truck is parked against their fence, far away from a public road!Mack doesnt use rivets on their chassis. They use what are called huck bolts. The frames are also painted after being assembled so its not uncommon to see rust between crssmembers. Quote Link to comment Share on other sites More sharing options...
slpwlker Posted August 19, 2014 Share Posted August 19, 2014 What Ply tires are you running. when I had 14 plys on my Pete. this sob was a wandering whore. 16 plys really have helped and 20 plys on the front. Is it the front, Rear or both? also unless your constantly off road go to all position tires and get the lugs off the back. This really seemed to help my wandering Quote Link to comment Share on other sites More sharing options...
haulin-gas Posted August 19, 2014 Author Share Posted August 19, 2014 Mack doesnt use rivets on their chassis. They use what are called huck bolts. The frames are also painted after being assembled so its not uncommon to see rust between crssmembers.The outer flanges are huck bolted to the frame but the cross beam is riveted to the bracket They replaced the whole assembly and it got rid of 90% of the rear end sway. Now they are waiting for parts to rebuild the whole rear suspension (twin Y) to see if that will help with the front end wandering. Quote Link to comment Share on other sites More sharing options...
haulin-gas Posted August 19, 2014 Author Share Posted August 19, 2014 Has Mack gotten anywhere on a fix for the 14.6 Mack front axle with unitized hub steering issues?????A friend of mine has just delivered a batch of CXU's with that front axle in the last few weeks and most are coming back to the dealer for steering issues.Is there a fix in the works as the DSM is basically having them chase steering box pressures etc.and he seems unaware of the amount of 14.6 front axle trucks with this issue.Sounds like a sweep this cluster-cuss under the carpet quick situation for Mack coming up.What steering box do they have, TRW or Sheppard? Another CHU that was having issues had the TRW changed out to a Sheppard and it got rid of most of the wandering problem. It also had a bent frame rail (1-1/4"). Mack paid to have the frame straightened, which made the unit handle like a dream, but after about 5000 km it started wandering all over the place again. Quote Link to comment Share on other sites More sharing options...
haulin-gas Posted August 19, 2014 Author Share Posted August 19, 2014 Has Mack gotten anywhere on a fix for the 14.6 Mack front axle with unitized hub steering issues?????A friend of mine has just delivered a batch of CXU's with that front axle in the last few weeks and most are coming back to the dealer for steering issues.Is there a fix in the works as the DSM is basically having them chase steering box pressures etc.and he seems unaware of the amount of 14.6 front axle trucks with this issue.Sounds like a sweep this cluster-cuss under the carpet quick situation for Mack coming up.Mine isn't the unitized hub, but the DSM took it for a drive last week and agreed that there is no doubt something wrong with it. Also had a loose king pin bearing on one side that trashed a new steer tire. Of course the adjustment is not a warrantable failure! Quote Link to comment Share on other sites More sharing options...
gicknordon Posted August 19, 2014 Share Posted August 19, 2014 The outer flanges are huck bolted to the frame but the cross beam is riveted to the bracket They replaced the whole assembly and it got rid of 90% of the rear end sway. Now they are waiting for parts to rebuild the whole rear suspension (twin Y) to see if that will help with the front end wandering.Forgot about that sorry. You would be surprised how many trucks sitting right outside of the plant waiting to be shipped alreay have some rust coming from between framerails and crossmembers and other places the paint doesnt reach. Quote Link to comment Share on other sites More sharing options...
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