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This guide describes how to quickly and easily replace your car's front suspension lower ball joint. It specifically relates to the Mercedes E-Class (W210) lower ball joint, but the technique can be used for most rear wheel drive car's although the details and required tools may change. I don't think there's much risk in this repair procedure, but, as always, please read this disclaimer (click here) anyway.
Replacing your front suspension lower ball joint is probably one of the easiest and fastest jobs you can do, on Mercedes E-Class W210 and it does not require any special tools. In fact, this is a perfect task for a DIY novice as even a complete beginner can confidently tackle this job in about 30 mins. If you have some experience expect to spend nearer 15 to 20 mins per ball joint. The cost of the replacement parts is equally appealing - as long as you're not fixated on "genuine" Mercedes parts it should cost around £20 for a new ball joint if you cannot repair your old one, or 50p for a new seal if yours can be repaired. I'd really recommend that you consider using quality aftermarket parts rather than "genuine" Mercedes parts for this procedure as in this area the longevity of the parts will be the same or better than the originals. It should be noted that on other E-Class models (e.g. W211) specialist but common tools (like a ball joint splitter) are required, but the general approach is still roughly the same and the job (though a little more tedious) is not a hard one.
THE SYMPTOMS: How do I know if my suspension lower ball joint is failing?
When a suspension lower ball joint fails you will typically first hear a "clunk" noise as you drive your Mercedes E-Class over bumps, you will also see uneven tyre wear on the affected wheel. As things get worse over time, that "clunk" will turn into a "bang" sound and your steering will become sloppy. The usual failure mode for these ball joints is through dirt getting into the "ball". This happens because the rubber dust cover is split through a one-off "suspension pinch" or just becomes old and degraded. As a result it is worth sticking your head under the car every 6 months and checking these rubber dust covers for splits and cracks, as they're far cheaper to replace than the whole ball joint. This guide also describes how to replace these dust covers.
Tools and Equipment
Getting the right result without spending hours or skinning your knuckles is all about having the right stuff handy. What you need for this job is:
- 1 x Axle stand
- 1 x Jack
- 1 x Soft head mallet (or a large hammer and piece of carpet!)
- Socket set or spanners (a breaker bar or handle extension is useful though not essential)
- Allen key set
- 1 x Wire brush
- Penetrating oil (WD40 or similar)
- Copper grease (not essential)
- Multipurpose grease (only required for repairs not replacement)
- Decent stereo
MAIN PROCEDURE: How to replace or repair the front suspension lower ball joint
This procedure describes how to replace and repair the lower suspension ball joint on your Mercedes E-Class. This is a quick and simple job, plus suspension parts are built to take some serious abuse so you are very, very unlikely to brake anything even if you are seriously clumsy. Anyway, the lower suspension ball joint is attached to the lower suspension wishbone and the hub spider (that holds your hub) at the front of your car by two bolts (see photo). It is located directly behind and below the car's brake disc, in line with the wheel hub. It's function is to both allow the car's wheels to rotate for steering and at the same time allow the suspension to flex up and down for bumps in the road.
Step 2 - Prepare the front suspension lower ball joint for removal
Have a look at the photo to the right. (1) The first thing you need to do is spray both the indicated nuts with lubricating oil and then leave it for a few minutes to let it soak in. Then remove the nut you can access (2) which may require you to apply some serious force (this is where a breaker bar or extension handle is useful, if you don't have one you can use a tube over the end of your spanner or socket handle). Finally, drive out the ball joint stud from the spider using a soft headed mallet (3). This can require some serious hammering, but you must be careful not to damage the threads that hold the nut you've just removed if you intend to repair the ball joint (hence the reason for a soft headed mallet). A good tip here is to put the nut back on the stud and screw it up until the tip of the stud is level with the outer face of the nut - this provides more surface area to hit and reduces the chance of damage. If you do not have a soft headed mallet you can use an old piece of carpet to protect the stud/nut and use a standard mallet or hammer. Of course if you are replacing the ball joint with a new one, then you do not need to worry about damaging the threads. Once removed the lower suspension wishbone will drop a little (1cm), but not much and there is no need to support it with a jack as it is not under pressure from the spring.
Step 3 - Remove the front suspension lower ball joint
With the ball joint's stud removed from the spider you will be able to swing the whole hub/spider/brake disc assembly out of the way to gain access to the second nut (see photo to the left). Be careful when you do this not to place too much tension on the black rubber brake hose that goes to your caliper or the two electrical wires. You may need to unhook or unplug these electrical wires to gain full access. Once you have access you need to remove the exposed nut. This stud and nut goes to the inner ball on the ball joint and may start swiveling as you remove it making undoing the nut difficult. As a result there is an Allen key socket in the head of the stud to allow you to hold it still (see photo to the left). However, don't use the Allen socket yet as breaking the seal will be helpful in removal at this stage so you actually want the stud to rotate in the socket. Of course once the seal has broken and the joint has started to rotate then use an Allen key to hold it still and remove the nut fully. If the seal does not break you will need to hammer out the stud like you did in Step 2. You will now have removed the lower ball joint and you will be able to take it away for repairs or replacement.
Step 4 - Replace or Repair the front suspension lower ball joint
If you are replacing the whole ball joint then all you need to do is smear a little copper grease on the new ball joint studs and threads to prevent them seizing in future. Because the ball joint has an Allen key socket in the stud to hold it still, you can safely grease the studs without making your refitting job difficult (this is not always the case so please check the studs first and grease or not as appropriate). However, if the ball joint has yet to fail (i.e. no "clunk" noise) and you are only replacing a split or degraded dust cover, then you need to remove the old cover by prizing off the circular metal clips (top and bottom, see photo). Once the cover is off, clean out the ball joint with a rag and then squeeze some fresh grease into the ball. Finally, squeeze some grease into the new dust cover and refit it with the circular metal clips. You can get replacement dust covers online (see photo to the right), but perhaps the easiest and cheapest way is to pop along to your nearest independent garage. These guys buy dust covers in all sizes in bulk and will be very likely just to give one to you as they see them as disposable items! Of course before you fit your newly repaired ball joint, give it a good clean up with a wire brush (be careful of the rubber dust cover!) and smear a little copper grease on the studs and threads to prevent them seizing in future.
Step 5 - Refit the front suspension lower ball joint on the car
Refitting is just a reversal of the above removal steps (i.e. Step 3 and then Step 2). Straighten the stud connecting to the inner ball of the ball joint first before fitting it so it is not refitted at the extremes of its movement. Also placing a trolley jack under the lower wishbone can sometimes help with getting the ball joint's stud's aligned for refitting to the wishbone as it allows you to raise or lower it - however, this is not essential. Make sure you tighten all the nuts with as much force as you can and check you have refitted any wires you unclipped during removal.
Step 6 - Finishing up (The Triple Check)
Although the Triple Check is less important for a simple item like replacing the front suspension lower ball joint, it is still really important for safety so please make sure you complete it. While garages will complete Checks 1 and 2, they are not able to complete Check 3, but you are. Over the years, Check 3 has proved it's worth more than once, so although it's a hassle I'd really recommend you complete the Triple Check below:
Check 1 - Recheck everything in-situ. Before you put the wheels back on and lower the car to the ground you need to check everything you replaced in situ - this includes checking that the bolts are properly tightened. It is not essential to use a torque spanner for this operation, just check they've been tighten up with as much force as you can muster. If everything is secure then put the wheels back on the car and lower it to the ground.
Check 2 - Recheck everything after a short test drive. Take the car for a drive, take the car over a few bumps, around a few corners and gently check the brakes. Finally do an emergency stop. You should not have disturbed the brakes at all during the replacement, so this is more to check the role of the suspension in braking. Take the car back home, jack up the car (safely!) and repeat the procedure in Check 1. If everything is OK proceed to the final check (Check 3).
Check 3 - Recheck everything after you have driven 50 miles. Drive the car normally, but avoid long journeys if possible. After you have completed around 50 miles in it you need to carry out the final checks. As before, jack up the car (safely!) and repeat the procedure in Check 1. If everything is OK then .... Congratulations! You have completed the triple check and successfully replaced your front lower suspension ball joint! Grab a brew you deserve it!
Save money and time by replacing or repairing your Mercedes' front suspension lower ball joint yourself.
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