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Topic: Front end making more noise over bumpy roads (Read 1039 times) previous topic - next topic

Re: Front end making more noise over bumpy roads

Reply #20 –
Quote from: dsd –
Is there any difference between the two in regards to ride and noise ?

I like the polyurethane bushings as I haven't noticed and difference in harshness of ride or noise.

A lot of steering related problems are miss diagnosed as bad steering sector, tie rod ends, tire pressure, wheel bearings, or alignment of the front end. True all of these can cause steering wander and should be checked.  The thing is most places don't even look at the torque rod/trailing arms or panhard bar bushings. Due to the geometry of these coaches if these bushings have too much slop it will cause the coach to run doglegged down the road and due to oscillations in the road cause sawing on the wheel effect. Trying to keep this simple the panhard bar lets the axle move vertical and centered under the frame ( this is another reason the ride height is important to be set proper) so with bad bushings the axle can move side to side depending on the slop and arc of panhard bar. A lot of times this is thought of as a shimmy effect.

The trailing arms locate the axle in relation to the length of the coach. If these bushings are sloppy then  you can have the dogleg effect. Think have you ever came up behind an 18 wheeler and could see the side of his box from behind? He is running dog legged and this can happen to these coaches when one side of the axle is further forward/rearward than the other side.

Now this isn't here to as an all inclusive education on frame alignment just a simple brief answer some questions that have been sent my way. If you want more info the Hunter truck alignment school is pretty good.

Mike

Re: Front end making more noise over bumpy roads

Reply #21 –
When changing these out.  Are the Pan hard bars under tension/ compression?  ie do they need to be restrained before pulling the bolts?  Will the frame "rack" causing problems when reinstalling?
 

Re: Front end making more noise over bumpy roads

Reply #22 –
You do one at a time and you will probably have to raise/lower the coach during the job and remember to put the new bolts back in
the same direction as the old ones to make a removal easier.