Front Strut and Mount Replacement
The suspension in a high performance sports car is very important. Proper care and maintenance of your suspension should be at a priority level just as much as your engine. With little maintenance, your suspension will begin to wear, and wear rapidly. The age of these cars only increase the chances of the major components of your suspension to be worn to the point in which they need replacement.
Struts are a funny item on a car because you might not really be able to tell if they are in need of replacement. They wear gradually over their entire life. This is unlike many things that just decide to break or stop functioning all together. Also, if you purchased the car used with 50,000+ miles on it, you may not know what a set of good struts feel like on the car.
With that said, you might ask "How do I know if my struts are bad?"
The answer is not very easy to give. Most struts and shocks could use replacement at around 100,000 miles. In extreme situations, the kind that a sports car or a off road truck sees, could lower that lifetime to around 50,000 miles. Some people may also want to replace the struts if they want to have better handling. This is especially true if your car did not come with the M030 option. Struts and shocks will also begin to leak when they are "blown." If a strut or shock is blown, it needs replacement. Finally, some people may notice a thinking or clicking noise whenever they run over a large bump. This is hard to diagnose because it could be a bad bushing somewhere in the suspension system. If you have made sure that all of your small bushings are fine, but still get a bump, it could be the strut or the strut mount. It is possible for the mount to go bad, but not the strut.
If you find your strut mount is bad, you will need to replace it. Having brand new, high performance struts, is a waste if your strut mount is no good. Strut mounts on the '86 944 Turbo are not very stout. The '87+ 944 Turbos have a better strut mount. I do not have personal experience in that particular mount, but they are extremely expensive ($800). There are aftermarket strut mounts available as well. These can range anywhere from professional racing struts with camber adjustment, to a machined simple strut. Since one of my strut mounts was bad, I opted to purchase strut mounts manufactured by KLA Industries from 944 Online. Since I didn't want to spend the money on '87+ factory Porsche struts, and caber adjustment was outside my needs, I opted for these struts:
Finally an affordable alternative the factory mounts. The early factory mounts were mostly rubber with an adequate(barely) bearing. The late mounts were more substantial, and had the price to go along with them. Our mount is constructed from a steel plate that bolts to the car. An aluminum(6061) plate that bolts to the steel holds a spherical bearing. Simple, efficient, reasonably priced. New mounting hardware included
Also note that the strut for Porsche 944s and 951s changed in 1987. The earlier cars had a strut housing which featured a separate strut assembly. If you have those struts, you are lucky, you only need to purchase the strut inserts, open up the strut, put the insert in, and screw the strut back together. If you have a later style strut, they are considered non-serviceable. Koni does make strut inserts for them. You will have to physically cut your strut housing open, remove the strut, and then put the strut back together. This new strut is held in place by a bolt on the bottom of the strut, which goes through a hole drilled through the bottom of your strut. The following write up explains how to modify your later style struts to use these special inserts.
My car actually came with two sets of struts. He gave me the factory struts, which are the non-serviceable kind and told me that he replaced the struts. I eventually blew up a strut mount, and when I removed the struts, noticed he installed early model struts from a junk yard. This is possible, but the mounting holes are a little different, so you have to drill them out. You also have to install a piece of sheet metal as a shim. I could have just put new inserts in the early style struts, but I didn't like how you have to get them to work. Many people say that this method is fine, but I consider it pretty "hack." I opted to just to modify my current struts and use Koni adjustable struts. If you are changing over from factory Sachs struts to Konis, you'll also need to purchase the bump stops and dust boots. If you have any questions about what to buy, just give 944 Online a call and they will be happy to let you know. Also, if you read this article, and decide that this job is outside of your capability, you can send in your struts and they can be done for you for a nominal charge.
Some people may also choose to upgrade their springs at this time. You could even go with a coil spring conversion at this time for a little extra money. For a higher performance application, I recommend contacting Paragon Products and talking to them. They are very knowledgeable on this subject. They also can modify your strut housings for use of coil-overs. I decided that it was not necessary for me, and just stuck with the Konis.
To remove your struts, follow the method used on Clarks Garage. I did not spend time explaining how to remove the strut as he does a great job of explaining it on his site. Clark's site also explains how to change the strut cartridge if you have the earlier "serviceable" struts.
TIPS: I highly recommend getting an alignment done immediately after strut replacement! The camber is set with an eccentric bolt on the strut. Removing the strut removes the camber adjustment. I also recommend buying new upper and lower strut bolts/washers/nuts on each strut if you are replacing the strut. There is a high possibility that they are damaged from years of alignment changes. They may be a little expensive, but do it while everything is apart.
First, I'll just show you what the early "serviceable" struts look like. Note that on the top of the strut housing, there is a large threaded nut type fastener that holds the strut on. If you have struts like this, this article is not for you!
Here is what a late "non-serviceable" strut looks like. Notice that the strut insert retainer is permanently crimped on to the strut housing.
First you will need to remove the strut spring and strut mount. The whole strut is under tons of compression. You can rent a MacPherson strut compressor for free at any large auto parts store, but you'll need to give them a deposit. You can also buy them. I recommend not spending the money on buying one for just this one time use.
If you remove the strut yourself, please have someone familiar with how they operate with you. Do not put any body part above the strut during compression. Cheap strut compressors can loose the strut, and send the strut mount and spring flying, possibly into your face.
An option I recommend for a novice is to take them to a professional auto shop. They have very nice and expensive compressors that are safe. You can probably just pay them $10 or something to remove the springs and take them back to put them together later.
I had never used a MacPherson strut compressor before, so I had some help from my best friend, and ASE Master Technician from Pro Automotive, Paul.
Since the strut body is not fully incased inside the strut housing, the strut housing is full of pressurized fluid. You'll need to drain this fluid. Drill a small hole as close as possible below the retaining crimp. Wear eye protection and drill over a container. As soon as you break through the metal, the strut fluid will blow all over the place. Quickly finish the hole, and then rotate the strut over so it blows out into the storage device. As soon as the pressure is finished, compress the strut over and over again forcing the oil out until there is very little or no oil left inside the strut housing.
Put the strut in a vise. You will now be cutting the strut housing open so that way you can insert the new sealed strut inserts. Measure from the bottom of the strut 12 15/16 inches (329mm). Place some tape around the strut at this measured location. Use blue painters tape (pictured) or some masking tape for this. Duck tape leaves a residue, which would have to be removed if you decide to paint these housings later.
Now it's time to cut the strut. I recommend putting some cardboard or something down on your work bench because the strut will probably start leaking while you're trying to cut. Use a "cold" cut method. Something like a band saw, angle grinder, or cut off wheel (pictured). A "hot" cut method like a torch or plasma cutter will warp the strut housing and won't make as clean as a cut.
Once you completely cut around the circumference of the strut housing, the factory strut body should pull right out.
Toughly clean the strut housing of all oil. If you used any kind of cleaning solvent, use brake fluid to get any residue left. Use a round file and clean up any burrs left from the cut. I also opted to give the strut housing a slight bevel to help the installation of the new strut insert.
Remove the strut insert and flip the strut housing over. You'll need to find the center of the strut. The strut housing body may not have a perfect circle, so just try to be as close as possible. Mark this with a paint pen, soap stone, or white out, and drill a 3mm (1/8") hole. This is where the bolt for the new strut insert will go through.
If you're not familiar with drilling larger holes, start with a small drill bit and gradually step up to the final size. Once the hole is drilled, like earlier, use a round file to clean up the hole you just drilled.
Test fit the new Koni strut insert inside the strut housing. The Koni strut insert has knurls that slightly protrude outside of the strut to help "grip" the strut housing. Do not push the strut all the way inside the housing yet. Stick your finger in the bottom hole you just drilled, and make sure there's enough room at the bottom for it to go inside enough to allow the knurls to seat inside the strut housing.
Clean up the struts really well. Remove any dirt, metal shavings, and oil. Hang them up and paint them Koni Yellow. Koni Yellow is not exactly readily available, but Plasti-Kote T-29 (School Bus Yellow) or Duplicolor DA 1663 (School Bus Yellow) are almost perfect matches. Allow proper drying time. You might also want to clean up and paint your springs at this time. I gave my springs a few coats of plain flat black.
Install the strut insert into the strut housing. Don't worry about trying to push the strut insert all the way down into the strut body, tightening the strut bolt will do this for you. Flip the strut housing over and thread the bolt (with associated washer and lock washer) into the strut housing. Tighten the bolt to 55 ft/lbs (75 Nm.). It is important to properly torque this bolt. It is also important to torque the bolt before you install the strut. There is very little clearance between this bolt and the control arm to properly torque it later.
Next, install the rubber piece. This is actually a seal to keep junk from getting inside the strut housing. The lip will be on the top of the strut housing, sealing off your cut from the elements. NOTE: Please ignore my crummy paint job.
Next, install the dust boot and the bump stop onto the strut. Look at the picture to see the proper orientation of both.
Install the spring and compressor tool.
Begin compressing the spring at small increments. Go ahead and install the spring hat at this time.
Here is a comparison photo of the stock pre '87 strut mount and the KLA Industries Monoball mount. Notice how beefy the KLA Industries mount is. Note that the factory Porsche mount uses studs with nuts, whilst the KLA mount has holes that use regular bolts with nuts. Since the KLA mount uses bolts with nuts, it is pretty difficult to install the strut to the body whenever you're attaching the strut to the fender well. I needed a friend to thread the nut on while I held the bolt in place. However, this is a small price to pay for the upgrade KLA gave. I only mentioned this so that you can prepare to have a friend handy if needed.
Also note that the KLA mount has five holes. I contacted KLA asking what the fifth hole was used for. I could not figure out what this fifth hole was for so I contacted KLA. They have excellent customer service and promptly informed me that this was used for later cars. Apparently they have some kind of alignment peen or something. I can't comment any further because I am not familiar with '87+ issues. If anyone can give me more information, I will address this in a future update. I just opted to face this fifth hole inwards on both sides for aesthetic purposes.
The factory Porsche mount uses a roller bearing, whilst the KLA Industries uses a ball heim-joint style bearing. In this picture, we can see that the bearing is held in place with a snap ring. So, heim style bearing should be replaceable by itself, if the time ever come. My only gripe is that this appears to not be a teflon lined bearing. However, this could be a good thing. In my experience, the teflon line heims wear out faster because the teflon degrades at a higher pace than the non-teflon line heims, which leaves a gap between the two metal surfaces. I have not spoken with KLA about this decision, and if I do, I will update this page.
Now that I'm done raving about the KLA strut mount, it's time to install it onto the strut assembly. If you decided not to upgrade your strut mounts, this procedure is just the same. You simply compress the spring down enough to allow the top strut nut to thread down onto the strut shaft. Tighten this nut to 120 ft.lb (165 Nm.).
Use Clarks Garage for instructions on how to install the struts back on the car. Don't forget that alignment!
