Be Aware!

[dreamchasers]

As many of you know, I took my coach into Prevost's Fort Worth Service Center in November of last year and had to bring it back for considerable re-work a couple of weeks ago. All items, except one, were reworked and I referred to then in a previous thread. http://forum.prevostownersgroup.com/showthread.php?t=1692

I have procrastinated discussing the following item to assure myself that time had tempered my thoughts.

One of the items that was done in November of 2007, was to replace both seals both of the drive wheels. Well, one seal was leaking again (very evident), drivers side, and the other seal had minor evidence of a leak (800 miles since original work). When the technician pulled the drivers side hub and the bearing were inspected, it was obvious that both wheel bearings were damaged because of heat and were nearing a heat related failure. Prevost, Fort Worth, had adapted (within the last few weeks) a process for re installing hubs which includes checking for hub end play with a dial indicator gauge. The maintenance manual calls for end play of .001 to .007 thousands (Mine were set to .002 and .001 end play. To emphasize this critical point, when the hub end play is checked, the end play value has to be witnessed by another Prevost technician or supervisor. Apparently, I am not the only customer that has suffered issues with hub bearings being damaged because of improper setup on re-installation. Prevost did replace both the inner and outer bearings and races at not cost to me.

As a newbie, I am learning how important it is to understand all the coach components and to remain on site and vigilant anytime repairs are done. I am sure many use Prevost Service Centers with great results, however my enthusiasm has been tempered for using Prevost Service in Fort Worth because of the results I have experienced. I hope others experience better results.

2217
This is what the drivers side, outer wheel bearing looked like after driving 800 miles since they were re-installed. They were inspected when the technician pulled the wheel in November and looked new and shiny.

2214
This is what the inner bearing looked like. Humm, notice the gouges in the roller. i also had the differential oil drained and refilled with new oil.

2215
This is my coach, up on the lifts. I stayed at Prevost Fort Worth, 5 days in November and 5 days in January for re work. I now know all the employees on a first name basis. One of them commented, since I was there so much, I should be on the payroll!

2216
On the bright side (Much Brighter!), I did meet Ted and Jan, 'tdelorme' while I was there. They are a neat couple and they have a very, very clean coach. I only looked at the outside, but it is obvious this coach has receive 'TLC' through its life. It is CLEAN!

It is not my intentions to 'bash' Prevost Service, but to make owners aware that being closer to maintenance aspect of these complicated machines is very important. For those that have good experiences with Prevost, then great, because that is what one expects when above normal labor rates are paid. Prevost Service Centers do claim to provide 'Red Carpet Service'.

Hector

[truk4u]

Good post Hector, thanks...

[merle&louise]

Hector,

Great post and great pictures. I am glad to know that Prevost Dallas allowed you to stay and watch the work being done on your bus. I understood from previous posts that Prevost would not allow the customer in the service area. Glad to hear that that is not the case in Dallas. What better way to learn what is going on with your coach than to actually see & talk to the techs.

Thanks!:D

[JIM CHALOUPKA]

Informative post Hector. Is that your smiling face, or Ted's?

Talk a little more about the bearing if you will.
The bearing with only 800 mi. on it looks much older and very dirty. It makes me wonder if the old got reinstalled by accident. Did you witness the first repair?
There seems to be a black soot/smut on the metal. I wouldn't expect to see anything like that so soon.
The bearing you display also shows flaking and pitting and damage to the rollers from particles. It looks as though the housing for the bearings was not thoroughly cleaned before the installation of the new bearings. The particles would be from the previous failed bearings.
Also, I can't help but wonder if the old races were not pressed out and replaced as they should have been.
My .02 on the bearing preload is that the engineering specifications should be followed and I would personally favor the loose end of that tolerance.
In my estimation the failure was due to a poor cleaning of the hub/spindle components prior to new bearing installation.
My opinion is based on the assumption that the bearing always had proper lubrication.

[BrianE]

We have visited both the DFW and Mira Loma Prevost shops on more than one occasion. The foremen in both locations have welcomed us in the shop. We have found all of the employees we have dealt with to be friendly and courteous. We have also observed that many of the employees including the managers, are young men learning their trade and consequently we have had issues also. There are experienced mechanics in both facilities but they seem to be a very small percentage of the workforce. Members would be well advised to take full advantage of their open shop policy.

[Ray Davis]

Hector,

So, I'm curious what could have been done better in your case. It seems if I read your post correctly, you were there and watched the repairs, Prevost had a special policy in place regarding bearing replacement, which I think you indicated they followed.

And yet your bearings failed in 800 miles?

What could have been done to prevent this?


Thanks,
Ray

[dreamchasers]

Yes, I was there and observed the first repair, but unfortunately did not pay the attention deserved to the end play. As a matter of fact, during my first visit, end play was not checked with a dial indicator gauge, but the technician tightened the large nut holding the bearings in place, then backed of appox.1/8-1/4 turn. Then, placed the locking ring and backup nut in place and tightened with a large wrench. No torque wrench was used the first application.

The bearings reinstalled during the first visit were the bearings originally removed and were in good condition, all rollers were bright and shiny. No defects were noted. Both sets of wheel bearings were inspected during the first visit, and both wheels were fine.

The darkened color of the bearing rollers were a clear indication of excessive heat.

Also, all the employees were certainly friendly and accommodating, however, I did go to Prevost and paid the huge repair bill to get the coach repaired reliability. Kindness does go a long way with me, but if the wheel bearing would have failed leaving stranded, my kindness bucket would have more empty than full (Does that sound political correct or what!).

Please remember, I am a newbie. Certain things that you experienced guys would note, I will have to pay the price for experience.

Again, I am not Prevost bashing with this post. I am certainly am not angry at Prevost, but wish things would have had a different outcome. I thought it prudent to inform other coach owners of things that can go, not as expected.

Thanks for all comments.

Hector

[dreamchasers]

I forgot to mention, the 'Gentleman' in the picture is Ted of 'Ted and Jan', 'tdelorme'. You can see my mug shots at my personal website. Click on link below. Thanks....

Hector

[tdelorme]

What Hector is trying to let us all know (in a nice kinda way) is that the idiot who inspected his bearings and races the first time had no knowledge of the correct reassembly procedure. He cranked the spindle nut down so hard that the little bit of backing off he did was not sufficient to allow the wheel assembly to rotate freely. Thus, after only 800 miles the bearings and more than likely the races were damaged to the point of being dangerous and Hector is lucky that he didn't end up on the side of the road (or worse, in a ditch.)
While it's nice that Prevost allows the customer to remain with their coach and to watch as the work is being preformed, the fact that an untrained tech was allowed to do the work that was done on Hector's coach without his work being checked by an experienced tech raises several red flags.
With the cost of shop time at a Prevost facility being so high, we should be able to depend on a high level of technical competence. In hector's case, that did not happen. We should not have to stand, looking over a tech's shoulder to see if he is doing the job right.
Yes, Prevost is standing behind the work and is not charging for doing it right the second time. But, I don't think they are going to pay Hector for the expense of time and dollars that it took to return to Ft. Worth for a second try.
I personally had a good experience at Prevost Texas. The entire staff was friendly and helpful and having a secure spot with hookups was great. But, truthfully I believe we might just be better off finding a good local big rig repair facility to do the work that we don't do ourselves. Just my 2 cents worth.

[Orren Zook]

Would it be possible that the bearing and race installed in your wheel were incorrect? Did both the inner and outer sets show that type of wear?

The only time I have seen half of a roller like the ones in your picture was when the taper of the rollers did not match the cup, as in hi-miler vs standard bearing sets.

[Toy Box]

Sorry to learn of your bad experience. For what it's worth, most likely, the mechanic did not know that he had to fill the drive hub with oil as he was assembling it. It takes a few miles of turning the wheels before the oil in the rear end has a chance to "spiral" out of the housing and travel out to the bearings. Your observation on young fellows in training is all too common. We as a country have lost most of our experienced techs and the up coming young ones just want to play video games. Most of us in a mechanical repair industry know too well the huge problems facing all employers today. We really need the return of a trade school or apprentice training. Trouble is, most present day wanna-bees are only looking for the 100,000.00 salary.

[truk4u]

Hector,

I had a leaking wheel seal (driver side duals) replaced while at Prevost Nashville. They have an open policy also. I asked to be sure the hub was filed with oil prior to the reassembly and the Tech assured me that was their procedure as I watched.

Did they put oil in your hub?

[dreamchasers]

To answer some of the comments:


*****
Yes, differential lube oil was preloaded or spread over the bearings while the bearings were being installed. Oil was put into the hub cavity until oil ran over the lip of the hub. This was done during the first and second installation of the bearing set. This was done on both drive wheels.

*****
During the second visit, when it was discovered that the bearings were damaged. The bearings and races were replaced with new ones.

*****
During my initial visit the bearing that were removed were in fact the same bearings (In good condition.) that were re-installed.

*****
During the initial visit, I witnessed the technician cleaning the hub assembly. He moved the hub to a solvent parts cleaner bath and thoroughly cleaned the hub assembly.

Thanks for everybody looking this over and your comments.

Hector

[Joe Cannarozzi]

If someone does not pre-lube new bearings they will be squealing in 3 or 4 miles.

I replaced a seal and tightened down the inner nut as tight as I could with a cheater bar then backed it off 1/4 turn.

Per instructions from a reliable mechanic, same as our Pete, never had a bearing failure.

Once you know the feel you can tell if it is right by spinning the hub with the wheels installed but before the axle is reinstalled.