mackniac Posted July 18, 2013 Share Posted July 18, 2013 a new problem occuredMack RB688S1990E7-400camel back 46Kmulti-leaf shackle spring 18Kdump truckthe helper side tire is jerking up & down empty around 60 to 65 km(37 to 40 mph) and then get lot worst when loaded at around 70 km( 45 mph) . wheel seems to jump up & down tapping on the road . The steering is not jerking no feel of shimmy in the steering .The truck stays straight does not feel like it is going to bring me in the ditch nothing wobbles.what did I checked1- tires are good (not broken not used abnormaly)2- tires been balanced3- tire from helper side went to driver side and vice versa ( same problem)4- king pin been check and seems to have normal play5- bearing been check seems good too6- spoke wheel been checked seems good too7- brake drum been checked seems good too8- schock absorber been checked seems good too9- tie rod end are sound10- all spring leaf are ok no cracks not broken11- all power steering rods and all others rods are sound12-one thing that I found is that the shackle seem to be very close ( 1/8 )(see attached pics with the red arrow) to the rear holder helper side ,on the oposite side (driver ) it is aroud 3/4 of an inch of space , also there is a play in the front pin of the frontshackle .some people are telling it can be drive shaft related ( wich I checked and accordind to my knowledge all the plays seems to be within normal) .anyone had a similar problem ? Quote Makniac , collector and customizer of die-cast model in 1/50th scale Link to comment https://www.bigmacktrucks.com/topic/31974-jerking-helper-side-wheel/ Share on other sites More sharing options...
j hancock Posted July 19, 2013 Share Posted July 19, 2013 Sounds like everything has been checked except the kitchen sink!Has this problem just come on all of sudden? Is the problem the same under power or coasting?Worn spring pins and bushings would wear over time, but by the list that would be the next item to check.How is the rubber in the carrier bearing mount? It can look good without dry cracking and be too spongy. That might give the driveshaft a chance to whip a little. Jim Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/31974-jerking-helper-side-wheel/#findComment-194804 Share on other sites More sharing options...
thomastractorsvc Posted July 21, 2013 Share Posted July 21, 2013 Sounds like everything has been checked except the kitchen sink!Has this problem just come on all of sudden? Is the problem the same under power or coasting?Worn spring pins and bushings would wear over time, but by the list that would be the next item to check.How is the rubber in the carrier bearing mount? It can look good without dry cracking and be too spongy. That might give the driveshaft a chance to whip a little. JimI am with Jim, if the spring pins are bad/worn out that's where I would start. How did you check the driveline there should be no movement at all. maybe a pinch of movement at the carrier bearing. Quote Robert"I reject your reality and substitute my own." Link to comment https://www.bigmacktrucks.com/topic/31974-jerking-helper-side-wheel/#findComment-195005 Share on other sites More sharing options...
220cummins Posted July 21, 2013 Share Posted July 21, 2013 Driveline should be tight along with king pins, no play. Quote Link to comment https://www.bigmacktrucks.com/topic/31974-jerking-helper-side-wheel/#findComment-195008 Share on other sites More sharing options...
Back In Black Pulling Posted July 21, 2013 Share Posted July 21, 2013 check your alingment (know thats not spelled right) Quote Link to comment https://www.bigmacktrucks.com/topic/31974-jerking-helper-side-wheel/#findComment-195012 Share on other sites More sharing options...
miro Posted July 21, 2013 Share Posted July 21, 2013 Check your motor mounts and crossmembers. If these break the frame can flex and cause that kind of problem Quote Link to comment https://www.bigmacktrucks.com/topic/31974-jerking-helper-side-wheel/#findComment-195075 Share on other sites More sharing options...
2stacksuperdog Posted July 21, 2013 Share Posted July 21, 2013 U-joint? we had one go and you could only feel it in the passenger side and it felt like a front tire. 1 Quote Matt Link to comment https://www.bigmacktrucks.com/topic/31974-jerking-helper-side-wheel/#findComment-195079 Share on other sites More sharing options...
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