kid-jensen
Senior Member
- Joined
- Nov 13, 2002
- Messages
- 942
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- Location
- Epsom Downs, Surrey
- Your Mercedes
- Ml320CDI 2007
Did a lot of Googling before I started this job, but couldn't find any help at all, so I thought this guide would help others when the Ball joint Creaks, or fails MOT.
The bottom Ball joint is a common MOT failure point on MLs and mine was creaking in an embarrassingly loud way, so here is the procedure to replace it.
In order to avoid taking parts of the suspension apart that are not strictly necessary, I decided to bite the bullet and buy an Extractor/Inserter set and not just "hit it with a big hammer". I will put this set up for sale in the For Sale section as I'm unlikely to do it again.
So, I'm assuming you have bought an Extractor Set before you start, along with a 36mm socket for the Drive shaft nut. No other "specialist" tools should be necessary. A Big hammer comes in handy, though...
1. Take the central Mercedes Emblem out of the centre of the wheel and use a 36mm Socket to undo the drive shaft nut whilst the car is still on the ground (with the brakes on - it will be tight).
2. Jack up the front-end and rest a solid-looking part of the underside on axle stands. Remove the appropriate wheel and throw it under the car "just in case".
3. Remove the drive shaft nut and tap the end of the drive shaft with a soft-faced hammer until it moves inwards slightly.
4. At the bottom end of the upright, you'll need a 24mm open-ended spanner to undo the fixing nut, as usually there isn't enough room to get the ring end in. A socket is a non-starter. Move the suspension up and down (with a jack) to allow the nut to wiggle out.
5. Remove the bolt holding the shock absorber to the Lower Control Arm (easier said then done in my case, but often it comes out without drama).
6. With the Ball Joint nut wiggled out, undo the nut holding the track rod end, take it off, turn the nut over and put it back on the thread until it's level with the end of the bolt. It's then easy to whack it downwards to separate the taper.
7. With the track rod end taper separated and the bottom ball joint also loose, you should be able to pull the bottom end of the upright away from the rest of the suspension (this is why the drive shaft needs to be loose). Move the Lower control Arm up or down to give access. Kink the drive shaft to one side and the upright to the other and the splines should slide smoothly out. This gives more room to pull the lower end of the upright as far upwards as it will go for access.
8. Time for a cup of tea.
9. Assemble the Ball joint extractor such that the tubes are on the upper end of the Ball joint, choosing the size of tube so that it completely clears the flange around it. On the other end of the extractor, just use any flat-ended spacer - there are usually a god few different sizes in the kit that comes with it.
10. Tighten up the extractor as much as you dare and then give the bottom end a couple of good hits with a hefty hammer. It's a bit awkward as you will be swinging the hammer slightly upwards, but with a good whack, it should move the ball joint slightly upwards in the upright. This is the beginning of the end. Keep on tightening the extractor and whacking occasionally, and it should come completely apart. If it stops suddenly, check the tube is long enough to allow the ball joint full movement upwards.
11. The old ball joints are an interference fit in the upright but the newer versions are belt-n-braces in that they also have a slim nut on them which is tightened with a C spanner (or tapped around with a big screwdriver).
12, I'll admit to a bit of filing of the new ball joint to reduce the diameter and get it to slip back in smoothly, but don't overdo the filing or it could rotate in the upright once assembled.
13. Use the Extractor to press the new ball joint in, combined with the occasional hammer blow on the compressing tube to help things along.
14. You should now have the ball Joint fully seated in the upright and from now on, as they say, "assembly is the reverse of the dismantling procedure".
15. Tighten the bolt holding the Shock Absorber to the LCA ONLY when the car's weight is on the suspension, or the rubber bush inside will be over stressed. You can use a jack to push the suspension up such that the car's weight is carried on the jack and this will put the LCA in the right position for final tightening.
That should be the end of any creaking or rattling/knocking, the Ball joint can be responsible for any of these noises, not to mention MOT failures.
Please have a look in the For Sale section for my Extractor if you are thinking of doing this in the future.
The bottom Ball joint is a common MOT failure point on MLs and mine was creaking in an embarrassingly loud way, so here is the procedure to replace it.
In order to avoid taking parts of the suspension apart that are not strictly necessary, I decided to bite the bullet and buy an Extractor/Inserter set and not just "hit it with a big hammer". I will put this set up for sale in the For Sale section as I'm unlikely to do it again.
So, I'm assuming you have bought an Extractor Set before you start, along with a 36mm socket for the Drive shaft nut. No other "specialist" tools should be necessary. A Big hammer comes in handy, though...
1. Take the central Mercedes Emblem out of the centre of the wheel and use a 36mm Socket to undo the drive shaft nut whilst the car is still on the ground (with the brakes on - it will be tight).
2. Jack up the front-end and rest a solid-looking part of the underside on axle stands. Remove the appropriate wheel and throw it under the car "just in case".
3. Remove the drive shaft nut and tap the end of the drive shaft with a soft-faced hammer until it moves inwards slightly.
4. At the bottom end of the upright, you'll need a 24mm open-ended spanner to undo the fixing nut, as usually there isn't enough room to get the ring end in. A socket is a non-starter. Move the suspension up and down (with a jack) to allow the nut to wiggle out.
5. Remove the bolt holding the shock absorber to the Lower Control Arm (easier said then done in my case, but often it comes out without drama).
6. With the Ball Joint nut wiggled out, undo the nut holding the track rod end, take it off, turn the nut over and put it back on the thread until it's level with the end of the bolt. It's then easy to whack it downwards to separate the taper.
7. With the track rod end taper separated and the bottom ball joint also loose, you should be able to pull the bottom end of the upright away from the rest of the suspension (this is why the drive shaft needs to be loose). Move the Lower control Arm up or down to give access. Kink the drive shaft to one side and the upright to the other and the splines should slide smoothly out. This gives more room to pull the lower end of the upright as far upwards as it will go for access.
8. Time for a cup of tea.
9. Assemble the Ball joint extractor such that the tubes are on the upper end of the Ball joint, choosing the size of tube so that it completely clears the flange around it. On the other end of the extractor, just use any flat-ended spacer - there are usually a god few different sizes in the kit that comes with it.
10. Tighten up the extractor as much as you dare and then give the bottom end a couple of good hits with a hefty hammer. It's a bit awkward as you will be swinging the hammer slightly upwards, but with a good whack, it should move the ball joint slightly upwards in the upright. This is the beginning of the end. Keep on tightening the extractor and whacking occasionally, and it should come completely apart. If it stops suddenly, check the tube is long enough to allow the ball joint full movement upwards.
11. The old ball joints are an interference fit in the upright but the newer versions are belt-n-braces in that they also have a slim nut on them which is tightened with a C spanner (or tapped around with a big screwdriver).
12, I'll admit to a bit of filing of the new ball joint to reduce the diameter and get it to slip back in smoothly, but don't overdo the filing or it could rotate in the upright once assembled.
13. Use the Extractor to press the new ball joint in, combined with the occasional hammer blow on the compressing tube to help things along.
14. You should now have the ball Joint fully seated in the upright and from now on, as they say, "assembly is the reverse of the dismantling procedure".
15. Tighten the bolt holding the Shock Absorber to the LCA ONLY when the car's weight is on the suspension, or the rubber bush inside will be over stressed. You can use a jack to push the suspension up such that the car's weight is carried on the jack and this will put the LCA in the right position for final tightening.
That should be the end of any creaking or rattling/knocking, the Ball joint can be responsible for any of these noises, not to mention MOT failures.
Please have a look in the For Sale section for my Extractor if you are thinking of doing this in the future.