Strut and shock absorber replacement for mk4 VW

Aug 22, 2014 at 10:05 AM
Strut and shock absorber replacement for mk4 VW
  • Shock absorber replacement for Jetta, Golf, New Beetle

    This article shows how to install strut/shocks on a Jetta, Golf, New Beetle (for 1998-2006 mk4 body)

    difficulty: 3/5 (rears are very easy, fronts require special tools, see instructions)

    Introduction
    Another external writeup on struts is here. Reading both should give you a better idea of the procedure. Related suspension links: 1000q: lower control arm removal , 1000q: sway bar bushing/endlink

    Shocks/struts, springs, and other suspension bushings and mounts were not meant to last forever. As a rough test of strut condition, push down on a corner of the car. If it bounces and returns in one or two bounces, it is probably in good shape. The second bounce should be a lot smaller than the first. Also look at the shock/strut damper piston. If you can see the metal piston, consider changing the boot because the boot serves to protect the seals from dirt. Your VW TDI came stock with gas dampers. If you switched to liquid shocks, check for pooled or a noticeable amount of liquid around the shock piston which indicates bad shock seals. The OEM Boge/Sachs shocks are vilified because they're soft but their construction quality is good. But because they're so soft and combined with worn bushings, worn shocks result in a poor ride.

    A decent suspension refresh should include: upper shock mounts, shocks, front strut bearing, the lower control arm's rear bushing, and sway bar bushings. If your car has high mileage or other problems are detected, also consider the bump stops, ball joints, sway bar endlinks, and lower control arm's front bushing. Bump stops are rubber bumpers at the top of the shock. When you run out of suspension travel the bump stop prevents metal-metal contact and effectively increases the spring's action. They're cheap to replace but aren't normally worn out until higher mileage.

    Shock/strut/damper are often used interchangeably. A damper is any "shock absorber". A McPherson strut is used on your VW, it replaces the upper suspension arm and carries the spring on a perch. Struts do not change the ride height unless the spring perch is different from stock (like the bilstein HD for VW). The springs carry the weight of the car and control ride height, the struts just dampen the motion. On your VW, the fronts are struts and the rear is a shock.

    Here are some brand/models that people have been happy with in the past. Just remember that ride quality and harshness are highly subjective! Someone's soft ride may feel hard to you. Sporty to one person may be "kidney bruising" to you. The Monroe sensatracks are said to be comfortable. The Koni reds are hydraulic and are adjustable. Koni reds on full soft are about the same as new stock shocks. As a rough estimate, I would set them at 1/2 turn from soft to 1 full turn from soft, depending on what you want and tire size. The koni yellows are a sport ride and comparable to the bilstein HD. The Bilstein TC (touring class) shocks are gas economy twin tube design and is close the Koni reds but different. The Bilstein HD are a stiffer gas monotube shock and a good choice for a sportier (stiffer and rougher). Both are for stock height suspensions. There are also TC sport suspension which are designed to be used as replacement with the lowered sport suspension. These are only for the lowered or sport suspensions because of the strut length! I avoid the OEM VW sachs or boge replacements because they are expensive and are soft. Also remember that the tire sidewalls are an important part of the suspension, taller tire sidewalls (higher aspect ratio) will dampen more than thin short sidewalls.

    Your car will need an alignment after strut replacement. Drive around for a day or two to let the suspension settle in.

    Caution: As a rule of thumb, always tighten all suspension components in their normal resting position (not extended or fully compressed)! Install suspension bolts loose-wrench tight, rest the car on ramps, then tighten the bolts to their final torque. This prevents the bushings from being preloaded and wearing out prematurely. To load the suspension, rest the weight of the car car on ramps or wood blocks. You could use a jack to raise the suspension arm but be very careful to not rest the weight of the car on it and watch out for the car shifting! The rear shocks on Jetta/Golf should be tightened with the weight of 1 person in the rear.

    Parts (click links to compare prices, always double check the part # and quantity with your vendor)

    Notes - Some struts come with mounts, bearings, or boots so always check before ordering those parts! New strut mounts are recommended. This will restore the bushing and some report a clunking when not replaced. If you have good regular front bump stops and are lowering the suspension, you can cut the old stops to get to the correct length. Unless you have high miles, you can reuse the old bump stops. In your manual, you will see a few stretch bolts or self locking nuts used on the suspension, these are listed below.

    Tools and hardware
    metric socket set
    7mm allen wrench
    spring compressor set - free rental at many auto parts stores
    impact wrench or strong arms and a breaker bar
    Metalnerd strut spreader MN3424 (pictured below), from metalnerd, or autotech strut spreader
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    Metalnerd MN2122 strut counterholder (pictured below), gearwrench pass through wrench, or can use modified 13/16" standard spark plug socket or other methods shown below. VW tool #3186 is not recommended if using aftermarket struts since they use different sized nuts. Can also use autotech deep offset box wrench
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    (2 total) VW# n 102 078 03 Strut pinch bolts
    (2 total) VW# n 101 064 02 Strut pinch nuts
    (2 total) VW# n 905 173 02 Rear shock bottom bolts
    (2 total) VW# n 102 861 02 Rear shock bottom nuts
    (4 total) WV# n 906 484 01 Rear strut bolts

    Front suspension

    (2 total) VW# 357 413 175a front strut boots
    (2 total) VW# 1j0 412 303 Sport (short length) front bump stops
    (2 total) VW# 1h0 412 303b Regular (regular length) front bump stops
    (2 total) VW# 1j0 412 249 front strut bearing, mount/bearing
    (2 total) VW# 1j0 412 311c front strut mount

    Rear suspension

    (2 total) VW# 1j0 512 131b Regular rear bump stops
    (2 total) VW# 1j0 512 131c Sport rear bump stops
    (2 total) VW# 1j0 513 353d rear strut mount, (sport mount replaced all earlier comfort mount #1j0 513 353g)

    Optional parts or other parts that you may want to replace

    10mm aluminum spacer (don't torque too tight) to raise the ride height 1cm (2 required), VW# 1j0 412 311a

    Procedure
    Feel free to sign up and ask a question about this article at the forums.

    CAUTION - do not rest the weight of the car on the suspension or rear axle. These can act like a fulcrum or move and cause the car to fall down. You need the suspension to be able to move while you work on it. To preload the suspension, rest the car on ramps or use a jack to raise the suspension arm (be careful to not rest the weight of the car on it and watch for the car shifting!) Always use the factory jack points as specified in the service manual. Then chock the wheels, apply the parking brake, and make sure the car is safe and secure before working on it! Never get under the car while it's supported by hydraulic jacks since these can fail - these are for raising the car only. This article is not a substitute for the factory service manual or the services of a professional mechanic. See the TOS Agreement for the full legal disclaimer.

    Summary: remove the bolts securing the struts and remove the strut assembly from the car. Compress the spring with a spring compressor and disassemble. Replace.

    Front strut replacement
    Take off the front wheels.

    Remove the 18mm pinch bolt/nut on the bottom of the strut. Counterhold the other side. If it's rusty you should soak it in PB Blaster and let sit. PB blaster makes it much easier to remove rusted/seized fasteners. Remove the ABS sensor wire and brake pad sensor wire if equipped.
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    The strut is pinched in a cup. You have to spread the cup to pull the strut up and out. You could use a heavy duty screwdriver or prybar but the easiest way is to buy the Metalnerd strut spreader MN3424 linked above. It fits in a 13mm socket/wrench and is the right shape/size to pry open the strut cup. As you get the strut to come up a little bit, put some WD-40 or PB Blaster around the edge of the strut to lubricate it further - this helps it come up much easier. You could also remove the top nut holding the strut in place to give you some more movement (detailed below)
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    Getting enough clearance to remove the strut
    The passenger side front strut doesn't have enough clearance to clear the control arm. If you are also removing the control arm to replace the bushing then just remove the 2x 18mm bolts that hold the control arm and the 3x 13mm ball joint bolts. This is what I did because the rear lower control arm bushing wears out and can be replaced with the Audi TT rear bushing. See the above link for more details on the bushing and removal.

    If you are not then you definitely won't have enough clearance. You could lower the subframe on the right side by loosening the 2 subframe bolts on that side. Support the subframe's weight with a jack while you loosen the bolts. Don't take the bolt all the way out since it will be difficult to put back, 1 inch should be enough clearance. Once they are loosened, gently lower the subframe to get a little more clearance.

    The Bentley says to remove the axle on the pass side. If you have the large socket for the axle nut and don't want to remove the LCA or lower the subframe, this is another option.

    The last way to remove the strut is to compress the spring while it's still on the car. This is somewhat dangerous because you could get pinched and you need room to put on the spring compressors. Some need to be installed upside down due to clearance and this could cause an issue when tightening the compressors. If the spring compressors fail then the sudden extension and release of spring energy can cause serious damage and injury. The socket is there because Autozone's free loaner (with deposit) compressor is too long. (Always use 2 spring compressors on opposite sites, pic is for illustration).

    CAUTION: Be careful when using spring compressors since any failure or slipping could result in the sudden release of the spring, strut, or other stuff on the assembly! Don't stick your hands near the springs while the springs are being compressed! You could get pinched or the spring compressors could fail! Always point the spring and strut away from yourself so that if it does fail, it doesn't hit you!

    For best results, put some washers around it and lubricate the compressor's threads. You may have noticed the painted dots on the spring, these are color codes to identify spring rate.
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    *If you have koni reds and want to adjust them without removing them from the car, compress the springs, remove the strut nuts, and use an allen socket with an extension to press down and turn the shaft. The shaft must be pressed down all the way to turn the internal adjuster.

    Whichever method you used, you should have enough clearance to remove the strut assembly. You can also remove the top strut nut at this time to get more movement. Make sure the brake line doesn't get pulled or stressed! If the brake line is damaged then you could lose braking action! While you're working on one side make sure the other side hasn't fallen down!

    Pull off the plastic cover for the strut and remove the 21mm nut at the top holding the strut. If you have an impact wrench, you can use it for removal but don't use it for tightening that nut! If you don't have an impact wrench, you can use the Metalnerd MN2122 strut counterholder, a gearwrench pass through ratchet, or a 13/16 spark plug socket, to counterhold the strut shaft. If you counterhold then the strut shaft will just spin and you won't loosen anything. These techniques can also be used when you have to tighten the nut. VW tool #3186 will work but it doesn't have sizes for aftermarket nuts, the metalnerd MN2122 does.

    For New Beetle only: the strut tops are under a cover. Remove the firewall rubber strip and lift the plastic windshield trim. Remove the brackets and metal shelf (2x 10mm bolts) covering the strut tops to get access.

    The advantage of the metalnerd tool is that it has a square cutout for adapting a torque wrench (always mate at 90o angle!), is cheaper than buying a new wrench set, and works. It also has both 21mm and 22mm ends for OEM and aftermarket struts.
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    Here is the gearwrench pass through ratchet. It lets you loosen the bolt while using an allen wrench to counterhold the shaft.
    [​IMG] [​IMG]

    A 13/16" spark plug socket works but remember that some aftermarket nuts are 22mm. You also have to cut slots into the side to hold the socket.
    [​IMG]

    Here is another idea to counterhold the shaft - two nuts tightened against each other. The VW strut did not have enough threads to do this and I had the tools.
    [​IMG]

    First strut removed. Once the strut assembly is out of the car, use 2 spring compressors on opposite sides to compress the spring. It should look like the below picture. Lubricate the threads with WD-40 or grease so that there is less resistance to tightening it. CAUTION: Be careful when using spring compressors since any failure or slipping could result in the sudden release of the spring, strut, or other stuff on the assembly! Don't stick your hands near the springs while the springs are being compressed! You could get pinched or the spring compressors could fail! Always point the spring and strut away from yourself so that if it does fail, it doesn't hit you! I use an air wrench to easily tighten the compressor bolts. If you don't have a spring compressor, they can be loaned at many auto parts stores for free.
    [​IMG]
    The strut mount rubber bushing on top should just pry off. Below that is another nut that you have to counterhold or use an impact wrench on. The springs should stay compressed as you remove the nut holding the upper spring perch or else the spring will jump off. Note the order of the bushings, mounts, etc.
    [​IMG]

    While still compressed, put your springs onto the new shock. Remember that you can't use an impact wrench to tighten the nuts, counterhold the strut shaft against an allen wrench on the shock shaft. Use hand tools to tighten. The metalnerd tool has a spot to adapt a torque wrench (must be attached at a 90o angle or else it changes the lever arm and torque spec, picture below is for illustration.) and has 21mm and 22mm sockets, another reason to get it.

    The strut mount isn't in place while you tighten the lower nut. After you tighten it, then you can release the spring compressors. Then put the mount in place and put the assembly back onto the car, then you tighten the upper nut that holds the strut in place. Both nuts torque: 44 ft- lbs. Remember to lube the strut cup to help it go into place.
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    Once in place, the lower bolt is torqued to 44 ft-lbs + a little over 1/4 turn. The front suspension components should be tightened in their normal resting position - not fully extended and not fully compressed. Hand tighten the fasteners before loading the suspension and tightening to their final torque. I lower the car onto ramps or wood blocks to do this. You could use a hydraulic jack on the lower control arm (with a wood block to avoid damaging the metal) to load the suspension but make sure it doesn't carry the weight of the car and shift it off the jack stands. Make sure to tighten the subframe bolts if you loosened them, to 74 ft lbs + 1/4 turn. The lower control arm 18mm bolts/nut are 52 ft lbs +1/4 turn. These bolts are all one use bolts. Replace the heat shield or wires as needed.

    Repeat for the other side. The front driver side is easier since you don't need to need to lower the subframe to get clearance. You may have to disconnect the antisway link (1x 16mm) to get more movement on the lower control arm, pictured below.
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    The rest of installation is the reverse of removal.

    Here is a video from dieselgiant showing strut replacement

    Rear suspension
    Raise the rear end, taking all the precautions as mentioned before - chock the front wheels, rest the car on jack stands, etc.

    Use a hydraulic jack to load the rear suspension arm to a slightly loaded position. The service manual says with the weight of 1 person in the rear. This can be done by raising the rear suspension arm to a slightly loaded position like shown below. The picture below is for illustration, a torque wrench is not for loosening. Counterhold the 16mm bolt/nut at the bottom of the shock and remove.
    [​IMG]

    Remove the 2x 16mm bolts at the top mount. The shock will come out. If you want to remove the springs, lower the jack and the spring will just come out. Note the orientation of the spring against the bushings if you remove the springs.
    [​IMG]

    Remove the top plastic cover to the shock. You can use an impact wrench to zip off the nut but don't use it to tighten the nut! Use a 17mm offset wrench and allen wrench to counterhold the shock shaft while loosening/tightening.
    [​IMG]

    The bump stop threads into the protective plastic cover and pushes into the upper mount. Torque the replacement locknut to 18 ft-lbs.
    [​IMG]

    Again, the service manual says to tighten the rear suspension with the weight of 1 person in the rear. This can be done by raising the rear suspension arm to a slightly loaded position but make sure the hydraulic jack doesn't carry the weight of the car! Make sure it doesn't shift off the jack stands!

    Tighten the upper strut mount bolts to 22 ft-lbs + 1/4 turn. The lower bolt/nut is 30 ft-lbs + 1/4 turn.

    Repeat for the other side. Drive for a day or two to let the suspension settle in and then get an alignment.

    Here are all the torque specs in case you forgot: For tips on how to use a torque wrench, see 1000q: torque wrench FAQ.

    Subframe bolts: 74 ft-lbs + 1/4 turn

    Front upper (top) strut nut: 44-ft lbs
    Front upper (middle, holding the strut assembly) nut: 44 ft-lbs
    Front lower strut bolt/nut: 44 ft-lbs + slightly more than 1/4 turn
    Front sway bar/link nut: 37 ft-lbs + 1/4 turn

    Rear upper strut bolts: 22 ft-lbs + 1/4 turn
    Rear lower strut bolt/nut: 30 ft-lbs + 1/4 turn
    Rear shock mount nut: 18 ft-lbs

    Wheel lug bolts: 81 ft-lbs (dry spec)