List of Maintenance and Repairs to 85 Gold Porsche 928.
Fuel System
Gas tank – Drained and cleaned with Berryman’s B12. The
internal tank screen was replaced. Over time these become brittle
and will eventually fragment and kill the pump. The hose from the
tank to the fuel pump was replaced. These fail over time and begin
to leak. The fuel pump was cleaned with Berryman’s B12 and
lubricated with Marvel Mystery oil. This treatment increases pump
life while quieting its operation. The fuel filter was replaced.
Fuel Lines – The fuel lines to the engine were flushed.
All flexible fuel lines in the engine well and engine
were checked. Old and stiff fuel lines were replaced. The injector seals were
replaced on all of the injectors.
Engine
Timing Belt – The timing
belt was replaced with a Porsche belt. All of the rollers were inspected and
replaced as needed. The tensioner was removed, rebuilt and filled with oil.
The warning light circuit was cleaned and tested. The water pump was replaced.
Once the belt was in place, the valve covers were removed and the valve timing
was set. Setting the valve timing on a thirty two valve engine is critical to
performance and smooth operation. The belt tension was checked and
adjusted around 2000 miles. A belt is good for 5 to 7 years (yes they do age)
or 30,000 miles – which ever comes first.
Wiring – The engine has
new plug wires. The injection harness was inspected and rebuilt as needed. The
main engine harness was stripped, inspected and resealed with new shrink wrap.
Hoses – All of the water,
smog and vacuum hoses were inspected. Critical hoses that have a history of
failing were upgraded with silicon hose. This is the same hose used on fire and
police cars. As noted above suspect and bad gas lines were replaced with fuel
injection hose. Oil breather hoses were replaced.
Gaskets – Intake manifold
and the pan gaskets were replaced. When the pan was off the rod bearing were
inspected for wear. The end play on the crank was also measured and found to be
within factory specs. The cams and lifters were inspected for wear – none was
noted.
Powder Coating – The
intake manifolds, valve covers and numerous other parts were stripped to bare
metal, primed, smoothed, color coated and then followed by a clear coat.
Motor Mounts – The
collapsed “fluid filled” motor mounts were replaced with solid rubber after
market mounts. The engine and drive train floats on two motor mounts in the
front and two transmission mounts in the rear. Fresh motor mounts are critical
to a smooth running car.
Exhaust – The exhaust
manifolds are painted with high temp paint. The bolts holding the exhaust
system to the headers are stainless steel. The car has dual cats with a new O2
sensor. The car passed California smog test with no problems with readings well
below the average. The exhaust system is stock.
After running 500 miles there is no residue in the tail pipe.
Drive Train
Brakes – All of the
brakes were inspected. The pads and rotors are over 50%. The calipers, backing
plates and hubs were cleaned and painted with a high temperature paint. The
break hoses were inspected. The emergency brake cable and bands were inspected
and adjusted to spec. The front wheel bearings were cleaned and re-packed.
Suspension - All of the
points on the suspension were inspected and cleaned. The shocks do not leak and
are fully functional to factory specs. The axles were removed, the CV joints
cleaned, repacked and new boots were installed. The boots on the rack and ball
joints were inspected. The front and rear wheels were balanced and aligned.
Under Carriage – With the
car on the tilter the entire under carriage was cleaned with degreaser and
pressure washed. Any dirt on the under carriage was removed. Beyond making the
under carriage of the car look nice, cleaning facilitated inspect of all of the
many lines, hoses and bushing under the car. Any thing worn or broken was
replaced. The exhaust splash shields were removed, cleaned and painted in high
temperature paint. The inside of the wheels were cleaned and the splashed
shields removed, inspected and replaced as needed. The gas vapor recovery
system and charcoal canister were inspected for integrity and the Y connector
replaced.
Note: Before going on let
me inject a note here. Brakes, exhaust systems, suspension and wheels are the
most common up grades made to the 928. When I bought the car, it had 17 inch
twist wheels. The owner kept these and replaced them with the original stock
wheels. Since these are the most common upgrades, I did no more than maintain
the stock equipment and made sure they are in good order. The same can be said
for suspension. The stock suspension is the best all around suspension for the
car. It is soft and comfortable for long trips and damps the car out at high
speeds. The 928 is incredibly forgiving in turns allowing the driver braking
ability well into a turn. However, for auto cross of other types of driving
there are better third party suspension set ups. With each choice there are
trade offs. Increase the stiffness of the suspension for tight handling and
lose the damping for high speed runs and risk damage to your kidney’s on rough
roads. This car is stock for these reasons and offers a good point for the new
owner to add upgrades.
Exterior
Paint – Most of the paint
on the car is original. The front bumper and mirrors suffered from the typical
rock chips. They were stripped and repainted. The sunroof had problems with
the clear coat. The sunroof is made of a cast metal, which disagreed with the
clear coat over time causing bubbles and cracks. The sunroof was removed,
stripped and repainted.
Body – There is no
evidence of major body damage to the car. There are a few very small dimples on
the body here and there. Most of these could be removed by the people who do
paintless dent repair. I had one guy look at it and he gave me a $200 estimate
for several of the most noticable small dings. The front spoiler is not
installed - I have one i will include with the car for an additional
$200 -but will not install it. There are a couple of scratches and
some of the attachment points will need washers.
Accessories
Sunroof – As mentioned
above the sunroof was removed and painted. The cables were removed the tracks
cleaned and lubricated. The plastic guides were replaced and the drains were
flushed out. The most common cause of leaky sunroofs comes from clogged
drains. The sunroof operates smoothly and without any manual assistance.
Rear Hatch – The plastic
tongue in the rear hatch has been replaced. This is a common cause of rear
hatch rattling or popping open. The rubber side bumpers are adjusted to insure
a tight close. The electric hath release is functional – a rare occurrence for
these cars.
HVAC – The external
blower fan was removed and the area cleaned. The rubber drain below the fan was
removed and cleaned. The A/C evaporator was vacuumed. A common source of leaks
is the accumulation of debris around the fan. This debris clogs the rubber
firewall drain causing water to overflow into the passenger compartment shorting
out the fuse panel. The heater valve was replaced and connected to the block
with silicon hose. These valves are vacuum driven and often fail in the open
position causing the heater to remain on constantly. The HVAC control system
was tested for vacuum leaks and solenoid failure. The center console was
removed and the center flap actuator was replaced – again a common source of
failure. The climate control unit was removed cleaned and the slide knobs
replaced. You will find very few 928s with good sliders. The cap on the
interior temperature sensor was replaced and the outside temperature sensor was
tested and connected correctly to the alternator snorkel. The A/C system was
evacuated, checked for leaks and filled with Freon R12.
Windshield Wipers and Washers
– All of the windshield wiper linkages have been inspected, cleaned and
lubricated. The high intensity washer system was removed. This is a
complicated system with check valves that commonly clog up from the cleaner used
in the high intensity washer. Instead, the windshield washers have been
replaced with a simplifier single and more reliable loop including an after
market and more reliable pump. The head light
washers work.
Dash – The dash and pod
have been repaired to remove the cracks using my custom process. The instrument
cluster was removed, the speedometer rebuilt and all of the contacts cleaned.
The trip odometer reset does not seem to work. Any burnt out warning lights were
replaced. All of the gauges and warning lights work. There are no warning
lights triggered when the car is running. The contacts on the fuses and relays
on the main fuse panel have been cleaned. All of the main ground points have
been cleaned. Bad grounds are a common point of failure on the 928.
Doors and Windows – The
door locks were adjusted and lubricated. A common symptom is for the doors to
self lock. While I strongly suggest removing the key from the ignition every
time you exit the car, properly functioning door locks can prevent phantom lock
outs. The central locking button works. The window guides in each door were
replaced. The guides are plastic running on a metal post. Over time the
plastic wears and the windows begin to jump and rattle. All of the moving parts
in the door and windows were lubricated. The windows now operate smoothly as
new. The vapor barrier was glued in place when replacing the door panels. Many
people leave this important part out when working on the doors allowing moisture
to warp and rot the lower parts of the door panel. The doors close smoothly and
tight. All of the locks were cleaned and lubricated. It is common for the
locks to get moisture and the tumblers to hang up preventing the key from going
into the lock.
Cruise Control – The cruise control has been
tested and functions properly.
Interior
Seats – The seats were
removed, cleaned, repaired as necessary, the leather conditioned and re-dyed
with natural Leatherique dyes. The motors were cleaned and the tracks
lubricated. The switches were treated with DeOxIt to insure continued and
reliable operation. The seats are eight way power seats without the heater or
adjustable lumbar support.
Carpets – All of the
carpets were removed, shampooed and re-glued. The backing to the main carpets
were replaced. The foam rubber pads under the front carpets were replaced with
a combination of aluminum insulating bubble pack and jute. This gives a firm
but comfortable feel to the floor carpets while acting as heat and sound
barrier.
Panels – The arm rests
where the plastic typically fails were re-welded with special plastic welding
rod and the holes re-drilled to the factory size. There is no warping on the
rear quarter panels, but there are some minor creases in the vinyl. The guy I
was fixing the car for thought it minor so I let it go. The headliner had a
little warping on the edges and the front and has been secured with additional
upholstery screws.
Miscellaneous - The
steering wheel has a hub extender putting the wheel 2 inches closer to the
driver. There is a second party leather cover on the steering wheel giving it a
bit thicker feel. The driver’s seat is set back to the furthest position. The
guy I was fixing the car for was over six feet, but his wife was short. Setting
the seat back to the furthest position gives the most legroom and adds an inch
or so head room. Generally, the head room in sunroof cars is limited. Setting
the seat back provided more head and leg room.
These are not the only
adjustments that Porsche allows for the comfort of the driver. The pedals can
be adjusted front and back and the steering column adjusts up and down.
Summary
The car is still a twenty one
year old car. It is also a 928. All 928s have minor quirks from time to time.
This is what makes them so lovable. I have put 4-00 miles on the car since putting
it together trying to shake out as many issues as possible. During that time
the engine has used no oil, the brakes and steering function as they should,
there are no major creaks or rattles. The car handles predictably in turns,
brakes straight and true and handles admirable at high speeds. The transmission
shifts smoothly and kicks down as it should. There is no drive line noise.
There do not appear to be any leaks from the drive train. The front seal
and left valve cover gasket were replaced. The car accelerates and is a monster above 3000 RPMs. I did a mileage
check and found about 20 MPG on the open road and about 14 MPG around town.
Your mileage may vary.
Let me give a bit of a pitch for
the 85-86 cars. Every year 928 has its advantages and trade offs. These were
the first of the 32 valve engines. The 32 valve engine is not as quick to rev
but it has monster power when it gets rolling. Above 3000 RPMs and the engine
pulls much stronger than the early cars. Four cams gives the engine a smooth
feel. The LH injection system was first used in the 85 and is a very
sophisticated system – even by today’s standards. It is a miser on gas in
normal driving but has performance on its mind. The first LH systems are more
reliable than the ones used later from 87 on up. While the S4 car has a little
more low RPM performance and a bit more horsepower, the 85-86 are not as
susceptible to sudden brain death. The electronics are simpler and have fewer
inputs to fail.
The older body style is
classic. These were the last years of the older style. As with all cars there is
a cost of operation and maintenance. Many of the parts on the 85 can be sourced
from the older cars at a considerable savings. At the same time the 85-86 cars have
the modern Ricardo seats. For reliability and performance the 85-86 offers the
best bang for the buck.
