Question -
We had a crunching noise on our Merc S700 front suspension. Changed the shockers last week but it was there again as we set off this morning after being parked from Thursday. It was at every movement of the van but almost disapeared after a good run from Doncaster to Darlington. As we entered the gate to the CL here, John braked hard a couple of times and it was there on the way up after the initial dip from braking. The springs look fine. We have had this sound for the last 6 months but think it is getting worse. Suggestions.
Reply
I'm pretty sure I know what this is - you have described it pretty well. At the end of each leafspring, where the spring is formed into a circle for attachment to the body, is a bush - a circular chunk of rubber. The leaf springs attach to the body with brackets. But the springs have to pivot here, so they have a rubber bush with a pin through it, which acts as both a pivot and a shock absorber, allowing the spring to flex quietly and smoothly. I am pretty sure you will find these bushes to be worn out. The rubber wears away and eventually there is no (or very little) rubber between the pin and the bush, so it's metal on metal and that's what causes the crunch and groan - personally I call it "graunching"! The reason I am reasonably sure is that you say it does it on braking or bumps - that's when the springs are flexed - when the nose goes down under braking or gravity. At first you only hear it occasionally, but as the rubber wears away it gets gradually worse, until you notice it!
Mine got so bad a few years ago that I couldn't walk about the van without the springs graunching! When I got it fixed it was like getting in a Rolls - like a new van. It's a garage job unless you are skilled - probably around £200 if you are lucky - but could be more depending on your garage.
And don't forget to do both front and back spring bushes - thats 8 in all - it's usually the front springs, but it could be the rears too, and it's daft not to replace them all at the same time.
Now of course I could be wrong - I've been caught out several times! But I am sure enough to suggest it.
If you get underneath and look at each end of the leaf springs, you may well see bits of rubber sticking out - sometimes you even can see how the spring end joint doesn't quite look right. I can post a photo tomorrow if you want. If you see any evidence of this, then we are on the right track.
Mine got so bad a few years ago that I couldn't walk about the van without the springs graunching! When I got it fixed it was like getting in a Rolls - like a new van. It's a garage job unless you are skilled - probably around £200 if you are lucky - but could be more depending on your garage.
And don't forget to do both front and back spring bushes - thats 8 in all - it's usually the front springs, but it could be the rears too, and it's daft not to replace them all at the same time.
Now of course I could be wrong - I've been caught out several times! But I am sure enough to suggest it.
If you get underneath and look at each end of the leaf springs, you may well see bits of rubber sticking out - sometimes you even can see how the spring end joint doesn't quite look right. I can post a photo tomorrow if you want. If you see any evidence of this, then we are on the right track.
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