Take a look at this photograph do you see anything wrong?
On the face of it all looks well, but it isn’t !…..
I had heard a slight groaning noise rather like a worn ball joint for the duration of the return journey from work, it was only apparent at very low speed so I dismissed it as an inspection job for the weekend. Curiosity got the better of me the following morning and I decided to take a quick glance under the wheel arch before leaving for work, glad that I did when I noticed ‘all was not well’. I took the van to work and when I arrived home I took off the wheel of the E Class to investigate further.
As you can see the front spring perch had pulled away from its mounting due to corrosion. The groaning noise was in fact the road spring scraping on the inside face of the shock absorber/damper! I had previously checked these out and all looked good at the last service as spring perches are known failure points with the Mercedes E Class W210 model series. I had previously strengthened the passenger side perch by plating the area that looked slightly suspect. Failure of this side was a complete surprise as the perch looked fine under my close inspection last season and I had every faith that it was sound. Just goes to show…
What happens is that over time water gets behind the perch seams that are only spot welded onto the inner wing, this corrodes the material from the back. It is feebly protected from leaving the factory with rubberised grey mastic, applied to all the seams before the paint process, but moisture gets behind it and gets to work. The original factory perches are spot welded on their lower ears and then one big spot weld inside the upper cup. Very poor design. Its not just Mercedes, Ford actually attached their suspension tops to the bodywork on the Sierra model with adhesive ! On warranty claim ‘failed’ cars, Mercedes Benz riveted new perches into place with ‘special’ rivets once they had ground off the original failed part, but in my opinion rivets are no better than poor spot weld. Next time your car fails its MOT on corroded structural bodywork, see if you can get away with ‘riveting’ a patch over it – I don’t think so. It is however quite easy to weld strong repair patches to this area using 1 mm steel and it does a great job in securing the perch, as you can choose where to reinforce the design and tie it to much strong inner wing metal in a several places.
I am not going to dwell on the dire situation that would face a driver if this component completely failed at speed, but thankfully all the reports I have ever read have always been at slow speed and always driver has just heard a large bang, on rare occasion I have also read that the vehicle drops to the ground – ‘wheel inside wheel arch’. …. Moving swiftly on with the repair…… You will need two jacks !
Stage one, open the bonnet / hood and remove the two 17mm nuts, plate washer and rubber pad that secure the shock absorber damper to the inner wing. Support the car and remove the road wheel. Remove the lower damper bolt and extract the damper assembly from the car. Place a trolley jack under the lower wishbone and support the cars weight so the spring is compressed as much as possible. Remove the 17mm nut from the upper wishbone ball joint and use a lever type ball joint splitter as shown below to split the joint (It’s usually very tight !).
Once the upper joint is free, undo the lower ball joint and split it using the lever tool. Finally undo the steering track rod end ball joint nut from the hub assembly and split the joint using the tool. Place the whole hub assembly toward the rear of the arch in which you are working, supported on a block of wood, taking care not to stretch or damage the brake hose or cables to the ABS wheel sensor and pad warning sensor that are fitted to the brake caliper/hub. Undo the single torx bolt from the roll bar link attached to the lower wishbone and move it out of the way.
Spring removal: The next procedure can be hazardous so take care and go steady.
I have read many E Class Mercedes Benz W210 owners writing that they have ‘easily’ removed and refitted front road springs without even the slightest hint of using spring compressors. – I have yet to discover how they do this as the spring is very long uncompressed indeed and not easily compressed without huge force – is just too long in its relaxed state to remove on the Elegance model anyway.
So here is how I do it… While the spring is compressed under the weight of the vehicle (Jack under lower wish bone) attach a pair of simple spring compressors and take up the tension equally on both sides. If you are worried about the compressors jaws slipping round the spring as they choose to do rather dangerously! Use a handful of fuel line jubilee clips either side of the jaws of the compressing tool, fixed around the spring – this works great and adds a higher degree of safety to the operation.
Once you have tension on the spring compressors, lower the jack beneath the lower wishbone or raise the body (a combination of the two works well) eventually the wishbone will descend enough allowing you to lever it down further and spring out the coil from its lower retainer. Be careful as even with the widest gap between the spring perch and lower wishbone there still may exist some tension in the coil spring. WATCH OUT! Do remember also to remove the rubber pad from inside the perch that locates the spring – before you start grinding or welding!
Once removed the spring can be wire brushed and painted along with the damper if necessary.
Now clean the spring perch area with a grinder and wire brush and remove all traces of rubberised mastic, paint, under seal and rust. Inspect the area and ascertain what will need to be done to restore the mounting. In my case I bent the perch back into its original position and tack welded it in place.
I then welded 1mm steel patches to either side of the perch, anchoring both sides of the perch to solid metal on the inner wing. To add further support and strength I also welded the rear perch lip to the inner wing using a short strip of plate steel.
Once the welding is complete and you are happy with it, use a Waxoyl type spray to coat all the areas you have welded, make sure that all seams are flooded as best you can with a couple of coats of the sealer as this will hopefully prevent further corrosion of the area. Assemble the spring using the spring compressor method as outlined above (don’t forget the jubilee clips for safety). You will have to fit the rubber mounting top to the spring before you insert it into the perch cup on reassembly as otherwise it will be a problem to locate correctly.
Once the suspension is all back together, paint on further under body protection or add more coats of Waxoyl, you may even spray the spring itself with the sealer as it aids in protecting it from the elements. Refit the wheel and lower the car to the ground. Job done ! (Note the slightly larger gap between the top of the tyre and wheel arch compared to the first ‘collapsed perch’ photograph)