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Thunk then thumping noise
At the end of August, I got all new tires put on the bus by Prevost (Hayward) along with a level 3 service which came back clean.After picking up the bus I was driving around 25 MPH and heard a slight thunk, followed by a thumping sound. I pulled over but didn’t see anything wrong. I was about to turn around and head back to Prevost, but the thumping stopped so I continued on. When I was on the freeway I applied the brakes, and I heard another thunk which was much loader, but no thumping sound after and the bus felt and operated normal. I just thought maybe something was falling back into place after having been serviced.This last Sunday, I was stuck in traffic. When travelling between 5 and 10 MPH and went to change lanes to the left and heard a very loud thunk. It was so loud, I thought someone hit me, it shook the entire bus. Then the thumping noise began. I pulled over to check, thinking it maybe a blown tire, since the thumping noise increase/decrease with my speed, but I did not see anything. Since I was about 12 miles from Prevost Hayward service center, I drove right there and left the bus for them to check out. The thumping sounds like it is coming from the front of the bus as the tires rotate.Since the bus had a level 3 clean bill of health, not to say something can’t break after, but does this sound like something new tires would cause? Prevost said it may be wheel bearings, I am hoping to have an answer later this week. But they have no idea what would have caused the loud thunk that shook the bus.Has anyone ever experienced a loud thunk and know what may cause one that would shake the entire bus? -
11 Replies
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I would NOT expect new tires to cause the thunk or thud you heard.
I’m putting my money on something being loose. An artifact of the recent service.
Keep us posted!
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Something is definitely loose or some bushings may be worn or even missing. But the level 3 service should have found that. Interesting…
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Level 3 service is a fancy name for a lube job with extras. Is there anyone here that thinks a master mechanic has the responsibility to do a lube and oil change?
That type of work is usually delegated to the the least experienced, newest guy in the shop. Over the years we have had many posts about errors and omissions being a clear indication owners need to put pressure on the tech by standing and watching or getting proof the checklist was used to make sure nothing was missed.
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Yep, your right Jon excellent point. I do make it a point to watch as service is being performed and yes it always a good idea to have some eyes on it, if anything just to gain some knowledge about your coach.
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
I requested the level 3 inspection report and it was not able to be found. They are adamant that it was performed by a lower level tech that failed to do the check list. Tim Willmuth the service director for the western region has gotten involved and a new level 3 inspection is being performed.
They are a bit backed up with coaches, so I am in the queue. I drove by this morning and noticed a beautiful Newell waiting to be service.
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Newel at a Prevost service center???
Do they have Volvo engines?
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To close out this issue, here is what Prevost Service (Hayward) discovered.
“It seems that your steer axle bearings on the hub/spindle is seized, causing it to be damaged. We would have to replace the bearings on both sides and we also found the rotors to be out of specs. We also found one side caliper to be seized and we recommend to do them together since the other can potentially seize up as well.”
Safe travels,
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I’m at a loss attempting to know or understand why all of this was not caught in a level 3 service. I understand knowledge of the coach service history would help, but careful attention to things should have revealed everything.
To seize a bearing the hub was run dry or someone who did not follow tightening specs over torqued the hub nuts. If the caliper was seized the brakes and hub bearings could get very hot, with sufficient heat to distort the plastic hub cap, both showing visual damage.
Those two items are serious safety issues, especially because either could have resulted in a fire.
My attitude about doing all my own work is more and more justified by reading the prices companies charge for doing substandard work.
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simple they screwed up…!!! should be on them..for repairs!! would seek another service place.. Please post outcome as their reputation is in Question here…My opinion only..Keep any parts replaced and let them know up front you expect them before paying charge..
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I have owned the coach going on 4 years and it has been serviced yearly by Prevost. All recommendations from each service have been corrected no matter how big or small. I believe in preventive verses reactive maintenance, so I am very surprised at this type of failure.
This issue was either overlooked in past inspections, or possibly damaged when they installed the new tires.
This level of service is unfortunate for us who lack the knowledge to repair our own coaches. This is a bit of a wake up for me, since I was under the impression that Prevost Service Centers are top notch…Maybe I just drank to much of their cool aid…..
I appreciate ever ones comments which helps educate me along the way.
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Jerry, I have no idea what to call what I do, but I call it preventive maintenance when I do it on my coach. I use the Prevost shop manual schedule and the short version is I change oil, all filters, lube all fittings, check fluid levels such as differential and steer and tag hubs (when I did not have sealed hubs), do a complete visual inspection for leaks, damp spots, chafing of hoses, plus drain the air tanks in sequence.
Additionally any service due based on my maintenance schedule which includes everything including items no listed by Prevost such as air bags or Norgren valve replacement, etc gets included.
It is my ass on the line so I tend to be over particular. So far so good. Periodically I will raise the tires, one at a time, slightly off the floor, and using a bar see if I can get movement such as on a worn ball joint, or noise if I rotate the wheel.
Not a single thing I do is technical, it is just common sense. As a reference a normal maintenance (first paragraph) with the occasional raised wheel included takes about 1 1/2 old fart days which are less productive than young stud work days.
BTW, I will mention this because it is a pet peeve about the stupidity of some grease gun operators: I barely give more than a shot of grease to any fitting. On fittings with rubber boots I barely see the boot move, much less bulge and leak grease. Because of that I have never damaged or had to replace the boots.
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL
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