Fred I am assuming that you are talking about the upper and lower control
arms and the failures that several posters have described. You hit on an
area that I am very concerned about.
I have inspected my upper and lower control arms and after cleaning them up
they still have the original paint on them and appear to be in perfect
shape, and do not appear to be cracked or bent. They still have the
original upper and lower ball joints installed with the original rivets.
They have approx 70K miles on them.
In my opinion there are a number of things that contribute to front end
failures, and that includes bent drive axels.
1. Improperly installed ball joints. I would wager that none of the failed
units posters have described were on originally installed upper and lower
ball joints and control arms. Does anyone know? When new ball joints are
installed the rivets are removed and if one is not careful it is very easy
to enlarge the holes that later contain the new bolts that hold the ball
joints in. Do not remove them with an air chisel or torch. The air chisel
will surely enlarge the holes, and the torch may over heat the metal
changing its molecular structure.
On the original equipement ball joints, the hot rivets when installed
expanded to entirely fill the hole and ensure a very tight slop free fit.
When installing new ball joints if the holes have been enlarged even the
slightest or the bolts are not a good tight fit, the ball joint will slowly
work lose and design forces can be exceeded on the control arms. In my
opinion if new ball joints are installed one should ensure that the holes
are not enlarged and that the new bolts are a tight fit in both the ball
joint and the control arm. I would use nothing but Moog ball joints and
front end parts. In addition I would very carefully check each ball joint to
ensure that it is tight and the holes are the proper size before attempting
to install them. I believe it was Cinnabar that had a batch of bad ball
joints that were very loose. You may have to take a micrometer to the parts
house and mike several bolts until you find ones that fit properly both in
the control arm and the ball joint. The extra effort is worth it.
2. Changing of original equipment tires with wider ones thus changing the
steering axis inclination and increasing the forces on the ball joints. You
don't need wider tires than the originals if you stay within the load
recommendations.
3. Towing vehicles in excess of 1000 pounds. The coach was simply never
designed for the kinds of forces generated while towing these vehicles. And
yes there are increased forces on the front ends when towing, both during
emergency stops or quick turns, wash board roads where the coach changes
attitudes often etc. And forces passed from the hitch through the coach
frame to the front end. Everything is fine while towing in a straight
line,but when directions are changed fast....look out!
4. Using incorrect shocks on the front of the coach. The only thing that
limits the travel of the control arms is the shock, and it has to be a
double acting shock. I would use only KYB or Bilstein shocks. Reason, they
do not deteriorate like double tube shocks. All other shocks deteriorate
from the day that you install them. When I purchased my coach the front
shocks were in terrible shape. On one of them the rod was entirely busted
off at the top and the other was completely shot. And make sure that the
bushings on the front stabilizer bar are in good shape.
5. Driving with a malfunctioning rear suspension system. When it is not
set correctly the front suspension could be overstressed due to the improper
raising of the rear end. The rear height not only has to be properly set,
but maintained during driving. Several times on this net I have read posts
from owners that drive with the suspension system in hold because they can
not maintain the correct pressures. you are asking for trouble. The rear
suspension system has to work correctly all of the time.
6. Over loading the coach. The factory manual gives the correct GVW for
front (4200#) and rear (7500#). Exceed those limits and you are asking for
trouble. Most people I know exceed it. They tow cars that are to large and
drive to fast.
Lastly in my opinion the best insurance that you can buy is joining a GMC
club where you can regularly get "hands on" technical help. This forum is
super and a god send for most of us, but there is nothing like hands on
technical help from a knowledgable GMC owner when we run into problems that
we don't understand. Most clubs have regular technical sessions at all of
their meets where you learn the proper way to repair your coach. In
addition they usually have the expensive tools that most of us could not
individually afford. I can't say enough good things about these GMC clubs.
Just my observations gleaned from the short time that I have owned a GMC.
>Last week, there were a number of messages about lower control arm failures.
>
>Some contributers strongly suggested that the arms should be removed and
>further reinforced as a means of buying down the risk of them fracturing.
>
>Before doing that on arms that appear to continue to be fit for service, I
>would like to know some of the circumstances of failures that have occurred.
>For example -
>
>a. very high mileage (200+k miles)?
>b. preponderance of use on "washboard" roads?
>c. design loads on front wheels exceeded?
>d. what is lowest mileage in "normal" use that failures have occurred?
>e. just hitting a pothole?
>f. other?
>
>Thanks,
>
>Fred Hudspeth
>'78 Royale
>
>
arms and the failures that several posters have described. You hit on an
area that I am very concerned about.
I have inspected my upper and lower control arms and after cleaning them up
they still have the original paint on them and appear to be in perfect
shape, and do not appear to be cracked or bent. They still have the
original upper and lower ball joints installed with the original rivets.
They have approx 70K miles on them.
In my opinion there are a number of things that contribute to front end
failures, and that includes bent drive axels.
1. Improperly installed ball joints. I would wager that none of the failed
units posters have described were on originally installed upper and lower
ball joints and control arms. Does anyone know? When new ball joints are
installed the rivets are removed and if one is not careful it is very easy
to enlarge the holes that later contain the new bolts that hold the ball
joints in. Do not remove them with an air chisel or torch. The air chisel
will surely enlarge the holes, and the torch may over heat the metal
changing its molecular structure.
On the original equipement ball joints, the hot rivets when installed
expanded to entirely fill the hole and ensure a very tight slop free fit.
When installing new ball joints if the holes have been enlarged even the
slightest or the bolts are not a good tight fit, the ball joint will slowly
work lose and design forces can be exceeded on the control arms. In my
opinion if new ball joints are installed one should ensure that the holes
are not enlarged and that the new bolts are a tight fit in both the ball
joint and the control arm. I would use nothing but Moog ball joints and
front end parts. In addition I would very carefully check each ball joint to
ensure that it is tight and the holes are the proper size before attempting
to install them. I believe it was Cinnabar that had a batch of bad ball
joints that were very loose. You may have to take a micrometer to the parts
house and mike several bolts until you find ones that fit properly both in
the control arm and the ball joint. The extra effort is worth it.
2. Changing of original equipment tires with wider ones thus changing the
steering axis inclination and increasing the forces on the ball joints. You
don't need wider tires than the originals if you stay within the load
recommendations.
3. Towing vehicles in excess of 1000 pounds. The coach was simply never
designed for the kinds of forces generated while towing these vehicles. And
yes there are increased forces on the front ends when towing, both during
emergency stops or quick turns, wash board roads where the coach changes
attitudes often etc. And forces passed from the hitch through the coach
frame to the front end. Everything is fine while towing in a straight
line,but when directions are changed fast....look out!
4. Using incorrect shocks on the front of the coach. The only thing that
limits the travel of the control arms is the shock, and it has to be a
double acting shock. I would use only KYB or Bilstein shocks. Reason, they
do not deteriorate like double tube shocks. All other shocks deteriorate
from the day that you install them. When I purchased my coach the front
shocks were in terrible shape. On one of them the rod was entirely busted
off at the top and the other was completely shot. And make sure that the
bushings on the front stabilizer bar are in good shape.
5. Driving with a malfunctioning rear suspension system. When it is not
set correctly the front suspension could be overstressed due to the improper
raising of the rear end. The rear height not only has to be properly set,
but maintained during driving. Several times on this net I have read posts
from owners that drive with the suspension system in hold because they can
not maintain the correct pressures. you are asking for trouble. The rear
suspension system has to work correctly all of the time.
6. Over loading the coach. The factory manual gives the correct GVW for
front (4200#) and rear (7500#). Exceed those limits and you are asking for
trouble. Most people I know exceed it. They tow cars that are to large and
drive to fast.
Lastly in my opinion the best insurance that you can buy is joining a GMC
club where you can regularly get "hands on" technical help. This forum is
super and a god send for most of us, but there is nothing like hands on
technical help from a knowledgable GMC owner when we run into problems that
we don't understand. Most clubs have regular technical sessions at all of
their meets where you learn the proper way to repair your coach. In
addition they usually have the expensive tools that most of us could not
individually afford. I can't say enough good things about these GMC clubs.
Just my observations gleaned from the short time that I have owned a GMC.
>Last week, there were a number of messages about lower control arm failures.
>
>Some contributers strongly suggested that the arms should be removed and
>further reinforced as a means of buying down the risk of them fracturing.
>
>Before doing that on arms that appear to continue to be fit for service, I
>would like to know some of the circumstances of failures that have occurred.
>For example -
>
>a. very high mileage (200+k miles)?
>b. preponderance of use on "washboard" roads?
>c. design loads on front wheels exceeded?
>d. what is lowest mileage in "normal" use that failures have occurred?
>e. just hitting a pothole?
>f. other?
>
>Thanks,
>
>Fred Hudspeth
>'78 Royale
>
>
