Prevost XLII Skin Delamination Repair

[cmillsap]

Prevost decided to convert from attaching the stainless panels to the structural forms with rivets to attaching the panels with an adhesive back about 16/17 years ago on their new XL2 model busses. I would think a lot of feasibility studies, R&D and engineering took place before they decided to switch to glued panels.

Surely, they must have expected the panels to stay securely fastened to the forms for at least 10 years. I say that because when panel delamination started to occur, they were quick to absorb the cost of repairs based on a prorated basis for the first ten years of a bus’s life.

For several years now, panel delamination has been randomly occurring on units of varying ages from near new to all the way back to year 2001 models. Once Prevost became aware of the issue, I’m sure they spent a lot of time trying to alleviate the problem. It’s pretty clear that they are dedicated to attaching the panels with adhesive because they continue to attach the panels on their new models the same way.

But the question of “Why is this happening?” still remains. I have yet to see any data from Prevost regarding answers to the question. So, everyone is left to their own speculation. This is an important question to existing XL2 and XL3 model owners. It remains a serious issue for anyone interested in purchasing one of those models.

From a purely speculative standpoint, it seems to me that there may be so many variables in the total application process as to cause it to be extremely difficult to duplicate the exact procedure as required from unit to unit as each bus travels down the assembly line.

By “variables” I mean things like variations in proper cleaning and preparing the bonding surfaces from bus to bus. Then there’s the need to apply the adhesive correctly and uniformly from bus to bus. Is there an acceptable and exact period of time between applying the adhesive and attaching the panel to the forms to attain the best adhesive coefficient being strictly followed from unit to unit? Add varying weather, ambient temperatures and humidity during the application process into the mix. I could add several other variables not mentioned here. So, it’s pretty easy to make a case that variables within the assembly process could be a possible reason why we have seen random delamination over several model years.

If variables are ever found to be the culprits and Prevost can’t eliminate them, we’re destined to live with possible delamination for years to come.