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Wednesday, November 3, 2021

Suspension Springs Geometry & Specifications

 Here is a chart I came across. I am not the author of it so use it at your own risk:






Thursday, October 14, 2021

Is your parking / emergency brake lever getting harder to pull ? A quick and easy fix!

 

On a 993 or really any 964 or earlier 911 the parking lever is used every time the car is parked. As the parking brake shoes wear incrementally over many years the lever must be raised incrementally higher in its travel to lock the parking brakes. As the lever requires a longer pull it becomes ergonomically harder to pull it and the mechanical leverage it applies to the parking brake seems to diminish. I never noticed this change as it happens very slowly over many years. However, my wife was going to drive the Porsche and complained she didn't have the strength to release the parking brake once I had pulled it up. 

Turns out adjusting the parking brake lever is very easy:

First, one removes the back top section of the between-the-seat console. If your car has the plain cup, labeled "10" in the illustration below, just remove the rubber pad in the bottom of the cup and unscrew the two Phillips screws to release it. It takes a little jiggling of the cup back and forth to allow it to come free. If your car has one of the optional Tape or CD holders the screws are still there but it will take a little investigation to see how to release the holders to get to them as I do not have either of these in my car.



 
  

Once the cup is removed it exposes the cable saddle, labeled "24" in the above illustration, attached to the brake lever and the two cables leading the rear brakes. There are two nuts one to adjust the take-up slack on the cables to the wheel ends, the other being a jam-nut against it to hold it from slipping. 

Jam & Adjusting nut location.

Release the adjusting nut from the jam-nut using two open-end box wrenches. As you tighten up the adjustment nut trial pull on the brake lever. In my case, I tightened it up to the point where when the lever's ratchet clicked 4 times before I began to feel some resistance from the brake cables through the lever. The key here is to NOT tighten the nut too much so the parking brake is always partially engaged as this will create heat in the rear wheel hubs and wear the brake shoe linings, both very undesirable conditions.

Once adjusted re-snug the jam-nut against the adjusting nut and button things up. It took me all of five minutes to do this adjustment & as they say happy wife happy life!

Adjusting the Emergency/Parking  Bake after replacing the brake shoes:

The brake shoes are extremely long-wearing. I checked mine on my previous '86 Carrera at 150K miles and found they still had plenty of lining. However if one is going to replace the parking brake shoes, or simply wants to readjust the shoe clearance at the wheel ends when the wheels are off for other reasons here is the factory document on how to adjust them::



If you found this page informative return to the main page and bookmark it for future 993 related servicing, repair, and upgrading guidance & information. If it saved you some time, aggravation or even some coin consider a donation through the button on the top left margin of this page.


#handbrake

#parkingbrake

#brake
#brakes

Wednesday, October 13, 2021

AC blowers appear to be on the firtz - Cleaning the sliders/fan switch/temp control and replacing the faceplate backlights

 


Recently the AC in my 993 started to act strangely. With the AC-Max button pressed the blowers would work intermittently and I found that wiggling  the sliders on the Climate Control Unit (CCU) caused the blowers to work.

I diagnosed the issue as dirty slider potentiometers and dried slider grease. Below is what I did to remedy the situation:

The procedure below can also be used to access the CCU display backlight bulbs for replacement or upgrade.

Removing The Climate Control Unit (CCU):

1.       Disconnect the negative car battery lead and tie it out of the way so it can’t fall back onto the negative battery post.
2.       Cut some thick coat hanger wire into 4 straight sections of about four or five inches long and clean the cut ends of any bures from cutting them.
3.       Insert the 4 coat hanger wires into the holes on the 4 corners of the Climate Control Unit (CCU) to unlatch it from the dash.
4.       Push the CCU from behind to start its removal from the dash and then gently pull it out from the front to gain access to its wiring harness connectors.
5.       Do not pry the CCU out by its face plate edges, this can damage the faceplate.
6.       Release the two harness connectors on the back of the CCU by pressing in on the release levers on one of the narrow sides of each connector.
7.       If the lever fails to make the latch release completely, you may need to help release each connector latch from the side with a jeweler screwdriver.
8.       Once the latch on one end of the connector is released the connector is detached by pivoting the entire connector off the opposite side of its socket.

The back of CCU shows the two wiring harness connectors and the sensor blower. Note that the smaller harness connector pivots off from the outside edge of the CCU housing for removal while the larger connector pivots off from the other side.


9.       Remove the CCU from the front of the dash, this may require gently moving the steering column levers around so the CCU has a clear path of removal.

Once the CCU is removed:

1.       Detach the small sensor blower from the back of the unit by releasing the two hex nuts and washers attaching its frame to the CCU housing and unplugging its electric plug.
Sensor Blower

2.       Very gently remove the faceplate slider caps and the rotary knob caps from the CCU and set them aside.
3.       Press in on the six plastic retainer latches three on the top and three on the bottom of the CCU case and gently pull the faceplate loose from the CCU housing.

Shown are three of the six latches that retain the faceplate to the CCU body. 










4.       Release the electrical connector latch that holds the internal CCU wiring harness connector to the back of the faceplate and unplug the connector.
5.       The faceplate with the switches attached should now be loose in your hands.
6.       Remove the hex nuts and washers from the shafts under the rotary knobs previously removed.
7.       Releasing the circuit board from the back of the CCU faceplate by gently pressing on the plastic latches that retain the circuit board.

The circuit board is mounted on the back of the faceplate. The black part on the far right is the thermal sensor mount. The rotary potentiometers are to the right and left of the black slider potentiometers.


8.       When lifting off the circuit board from the back of the faceplate simultaneously, gently slide the thermal sensor with its mounting from the back as well. It is attached with delicate wires.
9.      Saturate the slide switches from the front of the circuit board on which they are mounted with an electronic spray cleaner such as CRC QD Spray Electronic Cleaner using the spray can’s extension tube.
10.   DO NOT USE SPRAY ELECTRIC MOTOR CLEANER, it will melt the plastic components.
11.   While the slide controls are wet with the solvent move the sliders back and forth to release contaminants from the slider potentiometers. Aim the solvent into the slide slots to do this.
12.   Do this procedure twice to ensure all the grease, contaminants, and oxidation are cleaned out of the sliders.
13.   Spray saturate the rotary knob potentiometers by aiming the extension tube on the can into the openings on the sides of the potentiometers on the front of the circuit board.
14.   While still wet with the solvent rotate the potentiometer knob shafts back and forth to clean the contacts inside the rotary potentiometers.
15. Spray saturate the switches from the back of the faceplate and actuate them to clean their internal contacts and plug pins and saturate their matching sockets on the curcuit board to clean them as well in case the AC related switches are a contributing factor to the blowers cutting out.
Steps 13, 14 &15 above were added after a discussion with Tore, from Bergville FX, an acknowledged expert on how the CCU functions where he suggested alternative root causes for the blowers cutting out.
16.   Use a hairdryer set to warm to evaporate any remaining solvent and moisture condensation that has formed on the circuit board and its component from the solvent cooling the components.
16.   Use a tiny drop of dielectric grease on the end of a jeweler's screwdriver or toothpick and grease the metal track inside the slot on the slider potentiometers.
18.   Also, use a tiny drop to lube the contact points of the clear plastic levers where they slide along the potentiometers’ outside housings.
19.   Move the sliders back and forth to distribute the grease.
20.   The goal is to use just enough to cause the sliders to move smoothly without binding. Using too much will migrate onto the contacts in the potentiometer causing functional issues.
21.   Wipe off any excess dielectric grease from the potentiometer’s housing

Buttoning things up:

1.       If desired inspect, test or replace the CCU display backlights by removing the bulbs via their mounting bayonets on the back of the circuit board.
2.       Press the circuit board back onto the clips on the back of the CCU Faceplate making sure its connection pins to the faceplate switches properly engage and the circuit board is fully seated.
3.       Slide the thermal sensor mount over its vent mount on the back of the faceplate
4.       Put the washers and nuts in position over the rotary knobs on the front of the faceplate
5.       Very gently snug down the rotary potentiometer hold-down nuts.
6.       Reinstall the rotary and slider knobs, both only go on one way, use care to observe how the knobs fit over their matching posts. Trying to force-fit them when they are not positioned correctly will damage the potentiometers.
7.       Reattach the internal wiring harness from the CCU case to the back of the faceplate
8.       Orient the internal thermal sensor vent duct tube to the back of the faceplate so the back end of it is correctly oriented to slip over the rectangular sensor blower opening correctly.
9.   Gently snap in and fully seat the faceplate to the CCU housing while ensuring the thermal sensor's vent duct slips over its mounting on the back of the faceplate.
10.   Blow out the CCU sensor blower of accumulated lint. If clean and not worn out, the blower blades should spin freely and silently, then reattach it and plug it back in. If the blower can't be made to spin smoothly and freely once cleaned it can be replaced. Here is a page with a section on how to replace the blower economically. Also Tore offeres an aftermarket blower upgrade that eliminates blower issues from lint accumulation going forward.
11.   Reattach the CCU connectors to the car’s wiring harness plugs in the dash making sure the connectors are fully seated.
12.   Slide the CCU back into the dash.
13.   Reconnect the car battery, fire the car up, and try the AC.

The process above took about an hour and gets a solid 2 on a 1 to 5 difficulty scale.

Related topics:







Wednesday, September 1, 2021

What appears to be an oil leak after a recent 993/964 oil change?

Let's face it any Porsche 911 will leak a little oil at some time during its life. A small oil leak is of little concern. However, if you suddenly experience what appears to be a good size oil leak some days, weeks, or a couple months after an oil change and before jumping in with more invasive and expensive fixes here are the common causes in order of how common they are:

  1. The number one reason by far! The technician, when pouring the oil into the filler neck, poured too quickly and spilled some backflow oil from the filler neck that ran down onto the engine sheet metal. Even if one uses a spray degreaser to clean up the spilled overflow some oil will continue leaking down onto the right side valve covers, the exhaust pipes, and the floor for quite a while appearing as a large leak and a smelly burned oil odor. 

    Many times this is misdiagnosed later on as a leaking valve cover where no leak exists. It may also explain why leaking valve covers seem to mostly be diagnosed on the right side bottom cover of the engine just below the oil tank filler neck, go figure?

  2. Removing the smaller oil filter from the side of the engine as part of an oil change is inherently messy splashing oil on the engine case and suspension components below it. If the technician didn't clean up the splashed oil as part of the servicing it can subsequently appear to be an oil leak.

  3. If the oil return tube on the right side of the engine case was detached to drain the line and was not properly reseated and now leaks down the right side of the engine case.

    Due to the metal tube's propensity to leak after reinstalling it many folks including me do not remove the tube even though it is described in the factory literature as part of an oil change. The amount of oil in the line is small and is not really relevant when the system at refill takes just short of 10 quarts and the entire system holds about 12.

  4. The oil filters' seals' were not lubricated when installed or the oil filters were not properly snugged down when screwed on resulting in a small to a large leak. Step #7 in the step-by-step oil change section in this document describes how to properly snug down an oil filter when changing the oil

  5. The technician squeezed the new filter a little too hard when tightening it up with a filter wrench or applied the wrench too close to the base of the filter housing breaking the crimp seal at the base of the filter resulting in what can be a large leak. Also, some time ago I read about a defective run of oil filters for our cars where the crimped filter cartridge housing closure fails and a lot of oil leaks out. I have not heard of this recently but it is worth mentioning.

  6. Another less common source of a leak is the flex pipe that leads from the filler neck to the oil tank. Conceivably it was dislodged, torn, or punctured by the funnel tip when the oil was being filled. This also can appear as a good size oil leak to the far right of the engine compartment.

  7. Brett Stevenson from the Rennlist group on Facebook notes an additional cause: "When I drained the oil reservoir some oil made it into my side skirt and leaked out for days near where the [ oil tank] drain plug is." If you see oil film or wetness under the car just forward of the right rear wheel well this may be the source
  8. Other potential causes of oil leaks or consumption are discussed on this page.
Addressing the problem:
For all of the above issues, consider going to an auto parts store/Walmart/Amazon and buy three cans of spray CRC QD or some other brand of electronic cleaner and hose off the bottom of the engine as well as any oil-wet areas nearby on the engine tin and valve covers. I use this stuff all the time because it degreases well and doesn't attack plastic or rubber. After a good spray-down, the engine will be bone dry and the source of the leak can subsequently be better identified. 

When contemplating the above procedure do not use CRC or another brand of "Electric Motor Cleaner" or Carb & Choke Cleaner as they are different from the "CRC Brand QD Electronic Cleaner" in that their cleaning solvents melts plastic parts such as electrical connectors. Whatever brand of electronic cleaner used read the lable carfully to ensure it is apropriate for use on non-metallic parts.

Avoiding unnecessary expenses:
Once the source of a large leak is found don't fall into the expensive trap that all the leaks on the engine need to be addressed. Only the one leak that is large enough that it drips should be of concern as small surface oozing of oil seals that simply attract dust and grime are common, somewhat inherent in the design of the engine, and need not be addressed. 

Be wary of common upselling of services such as replacing all the valve cover seals when only one is leaking. The primary cause of a valve cover leak has to do with how the previous seal was installed, for example when the hydraulic valve lifters were replaced, so disturbing a seal that is not leaking may set the stage for ongoing seal replacements.

Other potential causes of oil leaks or consumption are discussed on this page.

As of late, I have heard of incidents where a Porsche specialty service shop has overfilled the oil. This seems to suggest properly adjusting the oil level in a 993/964 is not universally understood even in the professional Porsche servicing community. Knowing this it may be best when having your 993's oil changed to specify that the technician only put 8 quarts in and no more. Then once you have driven your car home personally adjust the final fill level in your driveway. Filling should be up to 1/4 to 1/3 of the way from the bottom of the dipstick's measuring range with the engine fully warmed, running, and on level ground. The measured volume will expand when the engine is very hot as can be seen on the oil gauge on the dash.


If you found this page informative return to the main page and bookmark it for future 993-related servicing, repair, and upgrading guidance & information. If it saved you some time, aggravation or even some coin consider a donation through the button on the top left margin of this page.

Tuesday, August 31, 2021

My experience getting the left front Jacking/Lift point repaired:


The new foot installed & painted.

 Like many 993/964 cars, the front left factory lift point foot has collapsed on one side and folded under on my 993 so I was unable to lift that corner of the car using an emergency jack or mount the car on lift bars to safely lift the vehicle for servicing.

How to lift a 993/964 safely including using Lift Bars or other methods is described on this page.

The original foot bent sideways
 under the car.
My experience:
The biggest hurdle in getting this fixed is finding someone willing to repair it.
The local Porsche-Certified body shop gave me an irrationally high price, north of $2000. They did not turn down the work but their pricing for a small job like this was clearly communicating they didn't want the job possibly due to the perception of risk on such a small job.

It turns out I was referred to a local custom hot rod shop that does welding by a fellow who has done paintwork for me before.
Here in the South, it's all about relationships as the welding shop owner told me he ordinarily doesn't work on Porsche but since he had gotten a referral call-ahead from a friend he was willing to do the work.

  • I supplied a replacement lift point foot 964-501-297-00 and instructed the welder to repair the existing foot or use the replacement supplied whichever one works for a solid functional repair.
  • I also supplied the welder with an anti-corrosion chromate primer and a compatible body match color coat in spray cans to seal up the job against corrosion.
  • We also discussed that the easiest way to remove the floor pan insulation, if needed, in the driver footwell is to cut around the periphery of the footwell with a mat knife and lift it out in one piece where it can be dropped back into position when the job is done.

It surprised me that there really is no detailed documentation anywhere on the Internet on how to do this repair. For this reason, I would have loved to document the work by the welder in pictures for this blog but I got the feeling this would have been a little bit of an overreach in our relationship and I was just glad to find a shop willing to do the work.

Having completed the repair. Here are pictures:


Top view showing the bent wall,
&  failed welds  in the foreground
Not sure if the foot's wall not being quite strong enough folded pulling two of the spot welds off or the spot welds were simply not strong enough and pulled loose allowing the sidewall of the foot to fold. The root cause of the failure was probably a combination of the two.

In any event, the fellow who did the welding felt it was not a very difficult job, swapping out the old damaged foot for new, just being careful not to damage the lines that run next to the foot under the body. From start to finish the job took a couple of hours.



Bottom of the old failed foot
Showing a bent wall in the background.
 

Recently I ran across this on Facebook.
It looks like someone has a solution to avoid the jack points from collapsing on a 993 (no affiliation).
To contact Marc, join Facebook if you are not already a member and join the 'Porsche 964 Group" and send him an inquiry.
Andy



If you found this page informative return to the main page and bookmark it for future 993-related servicing, repair, and upgrading guidance & information. If it saved you some coin consider a donation through the button on the top left margin of this page.






Sunday, August 29, 2021

How to address water leaks, wet floors and restore wet under seat controllers.

There are really only three causes of a wet floor in a 993:

The dead giveaway that clogged sunroof drains is the source of the leak is that when one peels back the inside surround along the top edge of the windshield it will be wet.

The remedy is rather straightforward. Make a plumbing snake out of a section of 12 gauge insulated solid-core primary electrical wire dulling the end so it does not puncture the drain tubes. The wire is easily purchased by the foot at most home improvement or hardware stores.

Open the engine lid. Under it on the top left and right corners you will observe the sunroof gutter drain outlets in the body sheet metal behind the lid hinges in the picture below:



Use the snake, gently slipping it up the drain outlet tubes to clear any clogs from the tubes. Be gentle and do not use a high level of force if the snake hangs up a little back it out and try again possibly with the end bent in a slightly different direction as the goal in this is to not damage the drain or its terminations.

To test the drains close the sunroof and with a slightly flowing garden hose wet down the sunroof seams and observe the broken free debris and water emanating from the two drains.

An alternative process could be to use a little compressed air at the drain outlets to blow any debris obstructing the top end of the drain tubes seeing that the top ends are not so easy to get to without some disassembly of the roof panel. Be sure to not use too much pressure as one doesn't want to blow the tubes free of their top-end moorings.  If you take this approach you may want to consider protecting the open roof from splatter and find any solid debris that is forced out the drain entrances so it doesn't just flow back into the drains.

Once the drains appear to be cleared leave the vehicle out in the sun with the sunroof partially open to bake any moisture trapped in the headliner out of the cabin and mop up the floors. This may include pulling back the carpet in the footwells and removing the floor pan soundproofing foam rubber inserts, laying them out in the sun to bake dry. To remove the inserts minimizing damaging their black rubber laminated top consider cutting them loose around the edges using a razor utility knife. Once dry they can be dropped back into place as is.

How to dry out water-soaked footwell and address any under seat controllers that got wet:
  • Pull up the carpet
  • Using a utility knife neatly cut the black rubber floor pad around the preifery of the footwell
  • Lift the molded floor pad out of the car and leave things open to dry.
  • Once dry reinstall the floor pad in position and reinstall the carpet.
  • If you are concerned that any of the controllers or audio components under the seat got wet and before having them repaired consider the following procedure to restore them first:
    • Disconnected the car's battery before starting the below steps
    • Here is a page on how to remove the seats to gain access to the controllers.
    • If a security cover is present, drill out the security rivets on the cover over the controllers under the seat.
    • Use a shop vacuum to clean out the metal shards left from drilling before unplugging the controller to avoid contaminating the electrical connections.
    • Unplug and open up any controllers including the DME that got wet and blow-dry their guts out with a hairdryer. Also,
    • Blow-dry any connectors to them.
    • Use some spray electronic cleaner to hose off the last bit of moisture and contaminants from the boards and connectors once they appear dry.
    • If you are handy with a soldering iron this is a good time to inspect the boards for cold or oxidized solder joints or traces and reheat or tin them as appropriate.
    • One can also consider the remote keyfob receiver upgrade discussed on this page.
    • Close up and reinstall the controllers
    • Replace the shield cover if present when finished with some self-tapping machine screws as it may be providing some required electrical shielding.
Fogged dash gauges:
Some have experienced fogged dash gauges on the inside of the gauge glass and attribute this to excess humidity in the cabin from a water leak. I have been unable to corroborate this as the root cause but it is something to keep in mind as a potential early warning of a water leak that should be investigated.

If you found this page informative return to the main page and bookmark it for future 993 related servicing, repair, and upgrading guidance & information. If it saved you aggravation, time & effort or some coin consider a donation through the button on the top left margin of this page.

Sunday, July 11, 2021

How to aim USA delivered 993 headlights after applying aftermarket HID or LED bulbs or updated projector Lenses.

Disclaimer: The content of this page, relates specifically to the Porsche 993 (911 1995 to1998) The author here is not a professional automotive technician and the procedure described on this page may not be the best to use in all situations.  Many times a lot can be learned by simply watching qualified professionals work on your 993's headlamps. Though we strive to provide completely accurate and appropriate information on the given subject in this document, some of the information you find on this page may be in error, also opinions expressed on this page are just that, opinions, therefore, please feel free to use the information on this page at your own risk.

Please read this entire document before using its content to aim your 993's headlights. 

Utilizzato dal gigante farmaceutico Bayer per il suo preparato e i Farmacisti di possono modificare la costituzione del gel. Andrologo, seguita dall’ anamnesi o prolungato, Viagra Generico ha un cosiddetto effetto intelligente, questo effetto durerĂ  per diverse ore e o vale a menzionare, che Kamagra non contiene il citrato di Vardenafil.

Supplies & The Tool needed:

  • A measuring tape
  • A dry-erase marker
  • A roll of 1/2" or 1/4" wide masking tape
  • A wall or flat surface with  about a 40-foot distance of level pavement in front of it
  • A piece of cardboard to block off a headlight
  • A 5mm ball socket Allen Hex Key driver with a thin long shaft
Steps to aim your headlights:
  1. Prepare your vehicle: Make sure your tires are filled to the appropriate air pressure and that you have around a half tank of gas as average ballast weight.
  2. Making a Headlight Axis Mark: With a dry-erase marker, draw a small dot in the center of each low-beam headlight beam where they pass through the headlight face glass. This is the Headlight Axis Mark. 
  3. Park your vehicle: Park your vehicle right in front of a vertical flat surface — this could be your garage wall, garage door, or a wall in a parking lot. You should have enough room in front of the wall to back up the front of your car 25 feet in a straight level line from that spot.
  4. Jounce the suspension: Bounce the vehicle a few times on all four corners to allow the suspension to settle.
  5. Create a Vertical Center Guide Line: Using a piece of masking tape, put a vertical mark on the wall or garage door in line with the center of your vehicle. Don’t worry about precise measurements — this mark will just serve as a guide. The hood badge is a good reference for the center.
  6. Create the Vertical Headlight Axis Line on the wall: Place a vertical strip of masking tape on the wall in front of each headlight's projected low beam. The Headlight Axis Mark placed on the lens in step 2 should line up with the center of the vertical tape.
  7. Measure the height of the Horizontal Headlight Axis Line: Using your measuring tape, measure from the ground to the headlight Access Mark on the headlamp lens from step 2.
  8. Mark the height of the Horizontal Headlight Axis Line on the wall: For each headlamp measure up the wall and make a mark on the tape at the height of the measured Headlight Axis Mark.
  9. Placing the driver's side Horizontal Headlight Cutoff lines: On the driver’s side of the wall, measure four inches below the axis height you marked and draw another line on the Vertical Headlight Axis tape line from step 6. 
  10. Placing the passenger's side Horizontal Headlight Cutoff lines: On the passenger’s side, draw a line two inches below the axis height. These marks will serve as vertical cutoff points when you aim your headlights. The driver side mark is lower than the passenger side mark to reduce the glare seen by oncoming drivers. 
  11. Mark the Horizontal Headlight Cutoff Lines: For each headlight, place a horizontal strip of masking tape above each cutoff mark from steps 9 & 10, making sure they are level. The bottom of the tape should line up with the measured cutoff line. 
  12. Back your vehicle up: Back your vehicle in a straight line away from the wall. The front of your headlights should be 25 feet from the aiming wall chart you’ve created with masking tape.
  13. Adjust your headlights: 
    1. When adjusting each headlight individually block the illumination from the other headlight.
    2. Then, as shown in the diagram below, use the ball head Allen hex key to turn the headlight pods adjuster screws.
    3. Illumination Position Relative to the HCL & the VHAL 
       Turn the adjusters in combination to position the top of the low beam light lines to line up with the bottom edge of your Horizontal Headlight Cutoff  Line (HCL) created in step 11. as shown in the illustration to the right while centering the illumination of the headlamp position over the Vertical Headlight Axis Line (VHAL) created in step 6.
13.  Check the alignment: Remove the cardboard or jacket from the covered headlight and check the finished alignment. The beam from the driver’s side headlight should sit a bit lower than the one from the passenger’s side. This setup gives you proper visibility without blinding other drivers. The beams should also be aproximatly equal distant from the Vertical Center Guide Line created in step 5.
14.  Test your lights: After you’ve set your headlight alignment, take your vehicle out for a test drive to make sure the lights provide proper visibility. Xenon Aftermarket High-Intensity Discharge (HID) low beam lamps are considerably brighter than the DOT approved Halogen bulbs that came as original equipment on your car.  Aftermarket modificaions also may have a considerably different illumination fall-off  patern at edges of their projected beam so it may be found to be neccessary to readjust the headlights slightly lower than the DOT specification to avoid blinding oposing traffic. The goal is to not blind opposing vehicles' drivers. An indication of  the need to lower the beam height a little is if you find opposing traffic is flashing their high beams at you during night driving with just your low beams on.



Correctly aimed headlights allow you to drive safely without compromising the safety of drivers in opposing traffic. 

If you found this page informative return to the main page and bookmark it for future 993 related servicing, repair, and upgrading guidance & information.