Hatch

Technical Information and Restoration Parts for the 928

Rear Hatch

There are a number of components on the rear hatch that require special attention or additional explanation.

Lock

The rear lock on the hatch changed with year models and options. Starting in 1983 Porsche added an electric release button to the interior. This is probably one of the most common parts to fail on the 928. Starting in 1980 Porsche offered an optional alarm system. Using the "long key" the alarm can be activated from the lock on the hatch.

Repair Electric Release - The electric release is not hard to repair, but unless things are checked in the proper order it is easy to get caught in an endless loop. There are a lot of rumors on a fix even using pennies but few work. The design on the lock is such that it wears over time and relieves the tension that is necessary to spring the hatch open. There are several things to watch for here.

	Shims - Before starting any repairs check both the bottom and top latch for any shims that may have been installed in previous attempts to make repairs. Remove all shims that are not factory installed.
	Motor Operation - Open the hatch and activate the automatic release. Look inside the lower latch to make sure that the metal latch operates with the motor. If the motor does not work move on to the electrical trouble shooting section
	Spring - The motor on the latch cycles from open and back to close is a short period of time. The spring in the middle section of the latch pushes up on the hatch and forces it open during the cycling of the latch. Check to make sure the spring has tension and is not broken. The spring is located under the round center plastic piece in the lower latch.
	Worn Catch - Inspect the plastic moving catch in the upper latch. This part is meant to wear over time saving other expensive parts of the latch. If it is worn it will have to be replaced before things will work reliably. The dealer sells the catch as a separate part from the upper latch. Be sure to get a new rivet. The old one has to be drilled out to remove the catch.
	Latch Release - Remove the upper latch from the hatch. Push it down into the lower latch. Operate the motor to verify that the latch pops out when when the motor cycles. If this does not then the bottom latch is not releasing enough to to clear the top catch. The design of the latch is for the upper catch to operate with the key and the lower catch to operate with the motor. The lower catch operates on an arm in the bottom of the latch. The arm can become disconnected or the bushing in the arm can wear causing the lower catch to be restricted in its travel.
	Alignment - If the latch releases when not attached to the hatch then the automatic release is working correctly and the problem is in the alignment of the hatch. If the upper latch binds in the lower latch then the spring will not be strong enough to push up on the hatch during the open cycle and the hatch will remain locked.
	Upper Hinges - Check the hatch alignment. The hatch can be adjusted side to side and front to back by loosing the hinges where they are attached to the roof. There are two small plastic access panels in the headliner that cover the bolts for the hatch hinges. The hatch should have equal spacing on all the margins. Often due to previous damage the holes in the car are not big enough to allow for a complete adjustment. The holes can be elongated to allow a more complete adjustment. The hinges can also be shimmed higher. When aligning the hatch it is convenient to leave the upper latch off during the adjustment.
	Hatch Bumpers - The hatch rides on four rubber bumpers and the hatch gasket. The back part of the hatch is supported by two round threaded bumpers that can be adjusted up pr down by turning. The middle of the hatch is supported by a rectangular bumper attached by a single bolt in the middle. The bumper is adjusted by loosening the bolt and sliding diagonally. The hatch should contact the rubber gasket evenly around the whole opening. If necessary the side bumpers can also be shimmed out.
	Installing the Upper Latch - With the upper latch disconnected from the hatch and locked down in the lower latch, put some grease or marking paper on the top of the latch. Push the hatch down on the upper latch. Install the upper latch over the mark left on the hatch.
	Alignment - With the upper latch installed use grease or marking paper to mark the lower latch. Slowly lower the hatch until the latches meet without locking. Use the markings to make the final adjustments insuring that the two latches do not bind.
	Final Adjustment - If all this fails and there is still not enough tension on the hatch then shims can be added to both the top and lower latch.
	Operation - The hatch fits tight both to keep the water out to prevent float and wind noise at high speeds. Before opening with the key push town on the hatch to take the tension off the latch. This will prevent the plastic catch from wearing and will take strain off internal parts of the lock.

Leaks

The rear hatch area is subject to leaks in a number of areas.

	Hinges - The hatch hinges are sealed with a rubber gasket between the body and the hinge. These can be left off when work is done on the hatch. Access to the hinges is through the two access holes in the headliner covered by two plastic access panels.
	Hatch Gasket - While the large hatch gasket can fail and leak, there are two smaller gaskets on each corner of the hatch that bare often left off when repairs are made. These gaskets fit into three holes in the upper inside corner of the hatch. When these gaskets are missing the mounting holes can cause leaks.
	Roof Rack Mounts - Inside the hatch channel near the roof are two threaded holes on each side of the car. Theses holes are used to mount roof racks. When the racks are not mounted the holes are sealed with plastic screws with gasket washers. Without the screws sealing these holes they can leak.
	Roof Channels - The two roof channels are separate aluminum strips that clip on to the roof. The ends of the strips are held in place by two channel holders at the end of the strip by the corner of the hatch. These holders are held in place with a Phillips screw. Sometimes they are left off or when being installed will not be sealed. The factory installation uses a bit of body sealant under the holder to seal out the weather.