Powertrain Q & A: Jul 2003

Q.  I own a 1984 Winnebago Class A on a Chevy chassis. Its
454-cid engine runs like a dream and has lots of power for the 22-foot
design. The coach only has 40,000 miles on it, and after three years of
ownership, I have driven it only about 400 miles because I cannot keep V
belts on it. The air-conditioning compressor belt lasts about 10 miles
before it squeals and burns into small chips of rubber. The alternator
belt only makes it about five miles before it does the same thing. I
have tried all brands of belts, from the budget brands to the most
expensive, and nothing works.

Two seasoned mechanics looked it over, and an alternator expert spent
hours trying to figure the problem out. I have changed the alternator
three times and have had the air conditioner checked twice. We ran the
engine with the airconditioner compressor and the alternator separately.
I changed the fan clutch (which sometimes sounds like a jet engine when
it engages), and all parts run freely. All this, and the belt life did
not improve. The pulleys were cleaned of any rust and the belts have
been adjusted somewhere between tight and extremely too tight, but
nothing helps, not even belt dressing.

Any ideas? I would really like to use this coach someday.

–Rick King, Emlenton, Pennsylvania

A.  There are several likely suspects. I’ve seen V-belts
that had cross sections that didn’t match the pulleys; they would only
make contact on a small area and would disintegrate under load, even
when very tight. Check this first on all pulleys and belts. Next, it’s
quite possible that the compressor is locking up occasionally and
destroying the belt. The fact that the belt is burned up indicates
extreme slippage, which is consistent with this theory.

Since two different belts are giving trouble, it’s quite likely
that pulley misalignment is a factor, so check the alignment of the
pulleys relative to each other. The Gates Rubber Company has a high-tech
DriveAlign Laser Alignment Tool designed to identify the two most
common types of pulley misalignment:angular and parallel offset. The
tool is positioned within the grooves of the pulley, and the laser is
aimed at the opposite one to identify excessive misalignment in the
entire drive system. Try to find a shop that has this device. My guess
is that misalignment is the main culprit.

Q.  Last year, I had a cell go bad in one of the two 6-volt
golf-cart batteries in my Pace Arrow motorhome. I replaced both
batteries with a new pair of Trojan model 105s. On a trip last fall, it
was very cold and we were dry camping. The furnace wasn’t working
properly; the flame would quit (due to a bad high-limit switch), but the
furnace blower would continue to run.

We left the coach with friends for a day, and upon our return the
batteries were completely run down. I immediately hooked up to 120-volt
AC power and did so every night, all the way back home. We drove eight
to 10 hours each day, and a digital voltmeter plugged into both the
coach and chassis battery circuits showed 14.1 to 14.4 volts while
running. When we stopped for the night and shut down the engine, there
wasn’t enough charge on the batteries to operate the electric step.

The 6-volt batteries didn’t charge at all, and the battery dealer
replaced them upon my return home. He stated that there was nothing
wrong with them; all cells tested equally discharged with a hydrometer.
He said that a good charge would have them back in like-new condition
and he would resell them as new.

Another battery dealer said that because of the isolator, the
alternator would sense the voltage of the fully charged 12-volt
engine-starting battery and would never recharge the coach batteries. He
also said there wasn’t enough of a charging current from the
ferroresonant converter to charge the batteries. He recommended that I
carry a separate battery charger and use it at night to keep the
batteries fully charged.

What is your opinion?

–J.P. Malikie, Missoula, Montana

A.  Despite what the dealer told you, it’s likely that the
batteries were ruined by being completely discharged, and as a result
they couldn’t hold a charge anymore. This is quite common when a current
draw stays connected, even after the battery is dead. In fact, it
happened to me recently when a faulty switch allowed a battery to be
drained, and it was not detected for a few days.

If there were more than 14 volts at the batteries, that also would
discount what you were told about the isolator. Test the batteries with a
hydrometer several times during use to see if they are getting properly
charged. You shouldn’t have a problem if the furnace is working OK now.

Q.  We currently tow our Chevrolet Cavalier on a tow dolly.
We would like to get a larger family car or maybe a pickup to tow behind
a 35-foot 1988 Allegro motorhome with a 454-cid engine.

My question is about towing a pickup. I thought that I could back a
pickup onto my tow dolly and use the steering lock to keep the front
wheels straight. Since I very seldom see pickups towed, is there a
problem?

–Larry E. Haines, Wheeling, West Virginia

A.  The answer, in one word, is weight. A 35 foot motorhome
on a Chevrolet P-chassis, when fully loaded and with passengers, fluids,
etc., probably doesn’t have much excess capacity for towing a heavy
vehicle. You should weigh your loaded coach and subtract that figure
from the gross combination weight rating (gcwr) to determine what’s left
for towing. Chances are you’ll even be overweight with the Cavalier.

Generally, the only coaches that have a high enough weight rating
for towing a full-size pickup are the 300-hp-plus diesel pushers. You’ll
need brakes on the dolly. Also, check with the dolly manufacturer
because some don’t recommend loading backward.

Q.   We own a 1994 Holiday Rambler Endeavor LE on a Ford
F-53 Super Duty chassis with a tag axle. I continually have problems
with the
brakes on my coach overheating during a steep descent, even though I
gear down to second gear and even to first gear, speed permitting. The
pedal becomes spongy and soon goes to the floor when I attempt to brake.
I assume the brake fluid is boiling and vaporizing in the system.
After cooling for a while (30 to 60 minutes), a pumping action brings
the brakes back to full function.

Is there is a modification that can be done to at least decrease
the occurrence of brake failure — maybe an upgraded master cylinder with
a

different brake fluid with a higher boiling point than what has been used in the past?

–Alex J. Simpson, Simi Valley, California

A.  There are several things that can be done. Have all the
brakes inspected, as well as the sliders and hardware, to be sure
they’re functioning. Get Ford heavy-duty brake fluid from your dealer,
then flush and bleed the brakes with it.

Next, make sure the tag-axle brakes are adjusted properly. A quick
(although imperfect) wayto check if they are working is to drive across a
dirt parking lot and slam on the brakes, with an observer watching. All
brakes should grab equally. Also, hold your hand near (be careful; they
can get very hot, so don’t touch) the center of the wheels adjacent to
the brakes after descending a grade with the brakes applied. There
should be similar amounts of heat coming from the tag-axle brakes and
from the other rear axle.

Finally, consider an exhaust brake, which closes off the exhaust
during deceleration to produce extra engine-braking effect. The only one
made for gasoline engines is the Mountain Tamer from Decelomatic; (602)
955-8514, exhaust-brake.com.

Q.  We own a 1994 Holiday Rambler Endeavor LE on a Ford F-53
Super Duty chassis with a tag axle. I continually have problems with
the brakes on my coach overheating during a steep descent, even though I
gear down to second gear and even to first gear, speed permitting. The
pedal becomes spongy and soon goes to the floor when I attempt to brake.

I assume the brake fluid is boiling and vaporizing in the system.
After cooling for a while (30 to 60 minutes), a pumping action brings
the brakes back to full function. Is there is a modification that can
be done to at least decrease the occurrence of brake failure — maybe an
upgraded master cylinder with a different brake fluid with a higher
boiling point than what has been used in the past?

–Alex J. Simpson, Simi Valley, California

A. There are several things that can be done. Have all the
brakes inspected, as well as the sliders and hardware, to be sure
they’re functioning. Get Ford heavy-duty brake fluid from your dealer,
then flush and bleed the brakes with it.

Next, make sure the tag-axle brakes are adjusted properly. A quick
(although imperfect) way to check if they are working is to drive across
a dirt parking lot and slam on the brakes, with an observer watching.
All brakes should grab equally. Also, hold your hand near (be careful;
they can get very hot, so don’t touch) the center of the wheels adjacent
to the brakes after descending a grade with the brakes applied. There
should be similar amounts of heat coming from the tag-axle brakes and
from the other rear axle.

Finally, consider an exhaust brake, which closes ff the exhaust
during deceleration to produce extra engine-braking effect. The only one
made for gasoline engines is the Mountain Tamer from Decelomatic; (602)
955-8514, exhaust-brake.com.

Q.  I was having problems with my 1994 Ford motorhome and
spent lots of money getting it looked at by three different shops. They
had all kinds of answers as to what was wrong.

I was told it was the fuel pump, as it appeared to vapor lock, but
they didn’t have a pump. Well, am I glad they didn’t have one because
that was not the problem. I got a code reader and found it was the
oxygen sensor. The problem began with a loss of mileage and power and
stalling at about 95 F outside temperature. The result was about 6 mpg
and a loss of power. It was flooding, not vapor lock.

My mileage now is about 8.5 mpg, and the coach can pull hills great.

–Charles Taylor, Auburn, Washington

A.  Thanks for writing and reminding our readers of the need
for this service. Normally when providing suggestions for a possible
solution, I work on the assumption that normal routine maintenance items
have already been taken care of. Ford calls for replacement of the
oxygen sensor every 30,000 miles, but it is often overlooked. So here’s a
reminder for everyone.

Q.  I read recently about the shimmy problems that have come
to you in regard to Ford chassis with V-10 engines. All were suspension
or swaybar related.

I have a vibration problem on my 1999 Holiday Rambler on a Ford
chassis with a V-10 that the Ford dealer cannot diagnose to my
satisfaction without tearing down the transmission for exploratory
surgery.

While climbing grades (even the small ones we have in the hill
country of Texas), I notice a vibration in my steering wheel. Once the
transmission downshifts, it seems to stop for a minute, but then starts
doing the same thing in the lower gears. The vibration stops when the
grade is crested or when the motor shifts into a higher gear and the rpm
drops. I guessed that I might have a transmission problem since I
noticed this happening at times I would expect a downshift to happen.

My local Ford dealer took my lead and checked the transmission, but
got no trouble codes when it was hooked up to his computer. His only
suggestion was that it could be a torque converter problem. He said that
flushing the transmission, replacing the fluid and adding a special
Ford additive sometimes helped. Since I had 28,000 miles on the
motorhome and the owner’s manual recommended a fluid change at 32,000
miles, I did so.

The problem is not solved. I do not want to do exploratory surgery
on my transmission because of cost and the uncertainty of solving the
problem. Have you heard of similar situations with the Ford V-10, and if
so, what were the solutions?

–Ernest McAnally, Houston, Texas

A.  This definitely sounds like a lockup torque-converter
clutch-slippage problem. This is common with all heavy vehicles that use
these lockup clutches, and your dealer was right in trying to solve it
with a flush and a fluid change as a first resort.

Take it to a good independent owner-operated transmission shop (not
the mass-market chain stores) for a diagnosis and second opinion. By
driving with a helper watching a scan tool, it should be possible to
determine when the lockup signal is being sent to the converter clutch
and to determine if the vibration (slipping or chatter) you feel is
occurring while the clutch is supposed to be applied. A cure will
probably require a new heavy-duty aftermarket torque converter.

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