After months of rebuilding and updating, my wife and I drove our GMC (76 Palm Beach) from Santa Cruz California to Slippery
Rock Pennsylvania. We started on July 26th and drove over Donner Pass and through Nevada, Utah etc.
As we left Santa Cruz the tmp gauge showed us at about mid range - typical for the coach since we've owned it. Since I have
some intemittent gauge problems I assumed that the temp problem was yet another electrical glitch that I hadn't had time to
chase down. WRONG! The weather was quite hot (low 100s) as we went across the central valley - gauge remained about mid
range. As we climbed Donner Pass the gauge crept up. First to 3/4 - then higher. At the summit we topped out at full range
but no missing, knock or other symptoms that would make me really concerned. The temp droppped right back down as we went
down the backside of Donner. The higher speed limits (75 MPH) were fine with the coach, but we ran at 3/4 the whole way. Oil
concuption was a bit higher than I expected - about 1 Qt every 600 or so miles.
The radiator was clean inside. We had the right water pump. Water flow was good. And I heard the fan kick in. On the way
back to California I had to leave the coach in Albuquerque in order for my wife to make it back in time for her surgery. Ed
Osburn of Osburn's RV in Albuquerque and I talked about the symptoms, and I agreed to have him diagnose the problem. Bottom
line: a bad fan clutch. The old clutch sounded fine, but wasn't making the air move. From Alb to Santa Cruz yesterday I ran
75-80 MPH with temps never getting close to half range. For what it's worth, the old clutch sounded "rough," while the new
one starts slow and winds up, sort of like a turbo charger - smoothly.
We don't tow anything behind our coach so haven't changed the final drive. After pulling nearly every hill (except Donner)
at 50-55 MPH between here and Penn I'm not in such a hurry to make the change. Before I got to Albuquerque I noticed that
the engine was running a bit rich when starting after fueling. Ed diagnosed the problems. I replaced most of the rubber in
the coach before leaving: new gas lines, etc. But, the vacuum lines looked fine so I left them for when I got back. Big
mistake. Many of the lines disintegrated in the 5k miles before I got to ALb. So, the choke etc. wasn't working right.
Shifting was fine, so I didn't know that there were vacuum problems. Ed replaced all of the vacuum lines and discovered that
my carb needed rebuilding (no surprise there - another "on the list" project that didn't get done before we left). He also
replaced the choke with an electric one.
The carb rebuild made a big difference in performance. From Alb to Santa Cruz (rt 40 to 58, 99, 46,101, 183, 1) I never
pulled a hill below 50, and most at 60-65 MPH.
While driving to Penn I ran into several places that the ruts were a major pain. Mostly it was a matter of slowing down so
that the inadvertent movement was managable. Still, the coach was enough of a handfull that I would be reluctant to have my
wife drive it (I've put a lot of time in driving OLD busses, trucks, etc - much of it in poor condition). Ed found that the
pins in the rear end were partially stuck. Now the handling is much improved but I'm still considering the 4-bag suspension
mod. I want as much advantage for my wife to drive as possible. Part of making things work involves her being able (and
comfortable) to drive the coach while I work (and vice versa).
Overall I really like the GMC. The long distance trip showed us that we made the right MH decision. We just have a few more
kinks to work out. As my wife commented - we'd have this or a different set of things to deal with if we bought a brand new
high end coach. And we don't feel badly about ripping things out in order to make the coach work for us in our business.
The trip reminded me of how complex the coaches really are. It's tempting to think that they're simple because of the small
amount of electronics. But the mechanical systems are heavily interrelated so that something small in an area of the systems
that you've overlooked or put off 'till later can make a huge difference.
Now I get to rebuild the front end, finish the electrical, figure out if I have a leak or condensation, fix the
weatherstipping on the door, replace the front seats ....
Henry
Henry Davis Consulting, Inc / new product consulting
PO Box 1270 / product readiness reviews
Soquel, Ca 95073 / IP reviews
ph: (408) 462-5199 / full service marketing
fax: (408) 462-5198
http://www.henry-davis.com
Rock Pennsylvania. We started on July 26th and drove over Donner Pass and through Nevada, Utah etc.
As we left Santa Cruz the tmp gauge showed us at about mid range - typical for the coach since we've owned it. Since I have
some intemittent gauge problems I assumed that the temp problem was yet another electrical glitch that I hadn't had time to
chase down. WRONG! The weather was quite hot (low 100s) as we went across the central valley - gauge remained about mid
range. As we climbed Donner Pass the gauge crept up. First to 3/4 - then higher. At the summit we topped out at full range
but no missing, knock or other symptoms that would make me really concerned. The temp droppped right back down as we went
down the backside of Donner. The higher speed limits (75 MPH) were fine with the coach, but we ran at 3/4 the whole way. Oil
concuption was a bit higher than I expected - about 1 Qt every 600 or so miles.
The radiator was clean inside. We had the right water pump. Water flow was good. And I heard the fan kick in. On the way
back to California I had to leave the coach in Albuquerque in order for my wife to make it back in time for her surgery. Ed
Osburn of Osburn's RV in Albuquerque and I talked about the symptoms, and I agreed to have him diagnose the problem. Bottom
line: a bad fan clutch. The old clutch sounded fine, but wasn't making the air move. From Alb to Santa Cruz yesterday I ran
75-80 MPH with temps never getting close to half range. For what it's worth, the old clutch sounded "rough," while the new
one starts slow and winds up, sort of like a turbo charger - smoothly.
We don't tow anything behind our coach so haven't changed the final drive. After pulling nearly every hill (except Donner)
at 50-55 MPH between here and Penn I'm not in such a hurry to make the change. Before I got to Albuquerque I noticed that
the engine was running a bit rich when starting after fueling. Ed diagnosed the problems. I replaced most of the rubber in
the coach before leaving: new gas lines, etc. But, the vacuum lines looked fine so I left them for when I got back. Big
mistake. Many of the lines disintegrated in the 5k miles before I got to ALb. So, the choke etc. wasn't working right.
Shifting was fine, so I didn't know that there were vacuum problems. Ed replaced all of the vacuum lines and discovered that
my carb needed rebuilding (no surprise there - another "on the list" project that didn't get done before we left). He also
replaced the choke with an electric one.
The carb rebuild made a big difference in performance. From Alb to Santa Cruz (rt 40 to 58, 99, 46,101, 183, 1) I never
pulled a hill below 50, and most at 60-65 MPH.
While driving to Penn I ran into several places that the ruts were a major pain. Mostly it was a matter of slowing down so
that the inadvertent movement was managable. Still, the coach was enough of a handfull that I would be reluctant to have my
wife drive it (I've put a lot of time in driving OLD busses, trucks, etc - much of it in poor condition). Ed found that the
pins in the rear end were partially stuck. Now the handling is much improved but I'm still considering the 4-bag suspension
mod. I want as much advantage for my wife to drive as possible. Part of making things work involves her being able (and
comfortable) to drive the coach while I work (and vice versa).
Overall I really like the GMC. The long distance trip showed us that we made the right MH decision. We just have a few more
kinks to work out. As my wife commented - we'd have this or a different set of things to deal with if we bought a brand new
high end coach. And we don't feel badly about ripping things out in order to make the coach work for us in our business.
The trip reminded me of how complex the coaches really are. It's tempting to think that they're simple because of the small
amount of electronics. But the mechanical systems are heavily interrelated so that something small in an area of the systems
that you've overlooked or put off 'till later can make a huge difference.
Now I get to rebuild the front end, finish the electrical, figure out if I have a leak or condensation, fix the
weatherstipping on the door, replace the front seats ....
Henry
Henry Davis Consulting, Inc / new product consulting
PO Box 1270 / product readiness reviews
Soquel, Ca 95073 / IP reviews
ph: (408) 462-5199 / full service marketing
fax: (408) 462-5198
http://www.henry-davis.com
