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seeing if anyone can help me with this problem. on a 2000 CL713. i have Mack camel-back susp. the problem is when i go around a turn the rear tires hop. it all started when i changed the rear spring insulators/bushings. iv had it at mack and the chassis shop and they cant fine anything wrong with it. one guy at the chassis shop said it could be the insulators/bushings are to stiff. i used the dark blue ones. i was told there are 3 difference kinds but im not sure... has anyone had this problem or heard of it or if diff pads will help?? 

 

parts that are new

springs and trunnion and stand. basically everything in the rear susp wise has been replaced. had everything replaced bc the older versions are prone to cracking and wanted to get it done before that. 

Edited by 2000CL713

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Sounds to me either differential locks are locked or maybe something is broken and jamming the gears that let the tires spin at different speeds. 

The problems we face today exist because the people who work for a living are outnumbered by the people who vote for a living.

The government can only "give" someone what they first take from another.

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2 hours ago, Truck Shop said:

                                     Pull an axle on the back rear drive and switch the interlock in and take it through a figure eight on hard surface.

                                     Truck Shop

Can you go little more indepth on this? 

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                              By removing the axle you have rendered that axle useless. If it quits hopping you know you have a drive unit that has a problem. Side gears? Power divider?

                                 Truck Shop 

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5 hours ago, Truck Shop said:

                              By removing the axle you have rendered that axle useless. If it quits hopping you know you have a drive unit that has a problem. Side gears? Power divider?

                                 Truck Shop 

I dont think this will help as it will just try and drive thru the power divider which isnt really a power divider
If it was a diff it would happen just driving down a road with just a gentle turn 
If it was a power divider it would happen driving down a straight road as even the smallest of tyre changes or the like would cause any wind up to happen in a very short distance
I guess you could easily prove if the power divider is working by just jacking up one wheel and rolling the one wheel with the truck in neutral 

When you are turning sharp do the axles track, as in do the axles step out and follow out of align like they are meant to ??
has some one changed the rubbers in the spring carriers on the axles ( we all have different names for these)  and maybe these have been changed and dont allow the axles to track on a sharp turn 

Paul

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4 hours ago, mrsmackpaul said:

I dont think this will help as it will just try and drive thru the power divider which isnt really a power divider
If it was a diff it would happen just driving down a road with just a gentle turn 
If it was a power divider it would happen driving down a straight road as even the smallest of tyre changes or the like would cause any wind up to happen in a very short distance
I guess you could easily prove if the power divider is working by just jacking up one wheel and rolling the one wheel with the truck in neutral 

When you are turning sharp do the axles track, as in do the axles step out and follow out of align like they are meant to ??
has some one changed the rubbers in the spring carriers on the axles ( we all have different names for these)  and maybe these have been changed and dont allow the axles to track on a sharp turn 

Paul

ill have to take a good look next time to see how they are tracking. never really have taken a good look since this has been happening. 

when you say the "spring carriers" are you talking about the insulators that are in the clam shell at the end of the springs that attach them to the rear ends? if so. then yes those rubbers where replaced with the dark blue colored ones that are poly now.  

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3 hours ago, Timmyb said:

I had the exact same thing happen, only mine was on air bag which is completely different. I ended up putting new shocks and and bolts on mine and it went away. 

Can you get your old insulators and try them out?

no i dont have the old ones anymore. didnt think about keeping them at the time. this was a year ago if not more. 

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10 hours ago, 2000CL713 said:

ill have to take a good look next time to see how they are tracking. never really have taken a good look since this has been happening. 

when you say the "spring carriers" are you talking about the insulators that are in the clam shell at the end of the springs that attach them to the rear ends? if so. then yes those rubbers where replaced with the dark blue colored ones that are poly now.  

Yeah thats what Im talking about 
They have to flex a fair way so the axles track on tight turns 

KS I think put up a broucher some years ago of how the Macks work, if he reads this it would be good if he could share it again  

Anyway the Mack rear end is designed to steer and follow the front with a reduced tyre scrubbing 


Paul


 

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Ok little update to this. Taking a few notes while driving. Been driving like this for a good bit so I have just gotten use to things I guess lol

 

First off it doesn't hop when loaded as I thought it did before. Alot my axles track very little bit that I can tell. Nothing crazy. Just enough to notice something happening but can't be 100% sure on since to see that happening I need to be looking put back the whole time while turning which isn't the smartest thing to do lol this is in a dump truck so I can't look out my down window and see the axles. 

Haven't checked for play/gap in the bushing yet. One woild think since very little movement is happening that there isn't any.

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With out knowing your wheel base I would think the tracking should still be fairly easy to notice even if the wheel base was quite long 
Maybe just find a quiet car park and do some figure 8's and circle work 
At a guess my old Mack would track more than a inch when on full lock 

The fact that it doesnt hop when loaded I think would maybe hint that extra weight might help the to force the wheels to scrub or maybe even track better 

Paul

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8 hours ago, mrsmackpaul said:

With out knowing your wheel base I would think the tracking should still be fairly easy to notice even if the wheel base was quite long 
Maybe just find a quiet car park and do some figure 8's and circle work 
At a guess my old Mack would track more than a inch when on full lock 

The fact that it doesnt hop when loaded I think would maybe hint that extra weight might help the to force the wheels to scrub or maybe even track better 

Paul

Not 100% sure on the wheel base. It's a cl713 tri axle dump truck with 16.5ft bed. 

And it would see the load is doing as you said but would what make it do it when unload? Should I swap the bushing the factory rubber ones and take the poly ones out?

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