Tony Posted May 13, 2009 Report Share Posted May 13, 2009 1. Back ground of road springs. Today’s breeds of passenger cars almost unilaterally utilize coil springs as the suspension mode. The introduction of the coil spring both in it’s inclusion as a suspension component and even it’s design progression has taken place over many years to a point where today it is the “norm†to have cars fitted with coil springs at each road wheel. Predecessors of the coil spring were the leaf spring and the torsion bar. Both these designs have big disadvantages in both weight and inflexible performance and most important of all they were expensive to replace. 2. Spring deterioration. During the life span of a coil spring it will compress and expand millions of times. In doing so a progressive deterioration in the properties of the steel takes place. The result is a progressive loss of spring height and thus lowering the car body in relation to the road – more commonly known as “ride height.†Because the modern coil spring is a high performance item it is necessary to design the spring with high stress properties. Having these properties it is prone to breakage from such things as stone chips and impacts etc. The breakage point is usually where the stress is at a maximum (top or bottom) i.e. the first and second coils. 3. How to diagnose whether a spring has broken or whether a spring has settled. (A) One way is by “eye†inspection taking particular note of the end coils. NOTE: A broken spring is classified as failure point in the MOT. ( By measuring the ride height of the car and comparing the measurement with the new ride height from the attached charts. It is highly recommended that a broken spring be replaced as soon as possible on. Springs should always be replaced in pairs. Use the following guidelines when checking for height loss. The ride height dimension is of paramount importance and is the distance between the wheel arch and wheel center. This measurement is easy to take and can be made using a tape measure. Such factors as varying tyre pressure, mixed tyres, worn tyres and model derivatives are discounted. To achieve an accurate measurement it is advisable the car is positioned on level ground without passengers or heavy objects etc. After the removal of wheel covers / knave plates the measurement is taken from the center of the wheel to a point directly above this point on the wheel arch. It only remains to compare this measurement with the following ride height charts. If the two measurements are different by 10mm it is advised that a replacement spring is fitted. If the difference is 20mm or more then it is essential that a replacement should be recommended in the interest of safety. Quote Link to comment Share on other sites More sharing options...
CIH Posted May 13, 2009 Report Share Posted May 13, 2009 what happens when any anti-corrosion treatment fails and the steel starts to rust ? Quote Link to comment Share on other sites More sharing options...
Tony Posted May 13, 2009 Author Report Share Posted May 13, 2009 what happens when any anti-corrosion treatment fails and the steel starts to rust ? They snap Quote Link to comment Share on other sites More sharing options...
jiberjaber Posted May 20, 2009 Report Share Posted May 20, 2009 Cant see the attached charts Tony I have a boing clunk noise which I can hear and feel through the break peddal. I dont think it is the brake pads moving as I know what they sound like from previous experiance, my worry is broken springs!... I think it has Eibach's fitted to the IS300 (they were the ones you swapped over many many moons ago)... Any idea what the distance should be for them? Quote Link to comment Share on other sites More sharing options...
Tony Posted May 20, 2009 Author Report Share Posted May 20, 2009 Cant see the attached charts Tony I have a boing clunk noise which I can hear and feel through the break peddal. I dont think it is the brake pads moving as I know what they sound like from previous experiance, my worry is broken springs!... I think it has Eibach's fitted to the IS300 (they were the ones you swapped over many many moons ago)... Any idea what the distance should be for them? I can email them to you.... the format doesn't work in the visible forum. I doubt very much if you have a broken coil.... How does the car handle when you get the thud, does it pull to one side? Quote Link to comment Share on other sites More sharing options...
Rich Posted May 20, 2009 Report Share Posted May 20, 2009 I can email them to you.... the format doesn't work in the visible forum. Is it an image? Email it to me and I'll resave it Quote Link to comment Share on other sites More sharing options...
Tony Posted May 20, 2009 Author Report Share Posted May 20, 2009 I can email them to you.... the format doesn't work in the visible forum. Is it an image? Email it to me and I'll resave it Ok Quote Link to comment Share on other sites More sharing options...
Tony Posted May 20, 2009 Author Report Share Posted May 20, 2009 Did you get it Quote Link to comment Share on other sites More sharing options...
jiberjaber Posted May 20, 2009 Report Share Posted May 20, 2009 Cant see the attached charts Tony I have a boing clunk noise which I can hear and feel through the break peddal. I dont think it is the brake pads moving as I know what they sound like from previous experiance, my worry is broken springs!... I think it has Eibach's fitted to the IS300 (they were the ones you swapped over many many moons ago)... Any idea what the distance should be for them? I can email them to you.... the format doesn't work in the visible forum. I doubt very much if you have a broken coil.... How does the car handle when you get the thud, does it pull to one side? No pulling to one side, just a boing every now and again, there were a couple of little boings tonight on the drive home which I heard but felt more through the break peddal... hmmm wonder what it is... I might jack the car up tomorrow night and take a look. Quote Link to comment Share on other sites More sharing options...
Tony Posted May 20, 2009 Author Report Share Posted May 20, 2009 If the handling remains stable then it's a compression issue..... Drop-links, ARB or something like that, if it were real play or a broken coil the car would dart off to one side because the compression would be uneven. Quote Link to comment Share on other sites More sharing options...
jiberjaber Posted May 20, 2009 Report Share Posted May 20, 2009 Ah - anything I can see when I jack it up and take the wheel off then to confirm? Quote Link to comment Share on other sites More sharing options...
Rich Posted May 20, 2009 Report Share Posted May 20, 2009 Did you get it Added to OP mate Quote Link to comment Share on other sites More sharing options...
Mark H. Posted May 20, 2009 Report Share Posted May 20, 2009 The w140 s classes snap coils for fun. My dads car failed its mot on one, but it was fine a week before when the mechanic checked it over. Seems it didnt like driving down country lanes it was taken on in the week inbetwen. No noticeable difference to the ride quality. Quote Link to comment Share on other sites More sharing options...
Tony Posted May 21, 2009 Author Report Share Posted May 21, 2009 Ah - anything I can see when I jack it up and take the wheel off then to confirm? Still look for a broken coil and pull "up/down" on the drop-link and feel for a knock, another option is to turn the steering (at the wheel) and feel for tight spots. Quote Link to comment Share on other sites More sharing options...
jiberjaber Posted May 24, 2009 Report Share Posted May 24, 2009 LOL - well I found the clunk noise.... I was working in the shed yesterday and needed my socket ratchet drive for something I was doing..... no where to be seen. Last time I used it was when I changed the battery about a month ago. Guess where it was! Jammed between two pipes in the engine bay! I must have knocked it off where I had rested it, and forgot to count all the tools back in after doing the work! At least I think I have found the source of the clunk now! Quote Link to comment Share on other sites More sharing options...
Tony Posted May 24, 2009 Author Report Share Posted May 24, 2009 What are you like........ Quote Link to comment Share on other sites More sharing options...
jiberjaber Posted May 24, 2009 Report Share Posted May 24, 2009 What are you like........ Wel I am a lot happier now I know what it was! - (he hopes... going to still listen out for the clunk noise though! ) Quote Link to comment Share on other sites More sharing options...
Tony Posted May 24, 2009 Author Report Share Posted May 24, 2009 Well looking outside of the box is what wim is all about .... but it's not normally the toolbox Quote Link to comment Share on other sites More sharing options...
CIH Posted May 24, 2009 Report Share Posted May 24, 2009 you really like that Lion picture eh ? did you ever findout about those strange rear lower springs where the top couple of coils are tightly compacted ? I had a Punto in a while ago and it was the same. Quote Link to comment Share on other sites More sharing options...
Tony Posted May 24, 2009 Author Report Share Posted May 24, 2009 you really like that Lion picture eh ? did you ever findout about those strange rear lower springs where the top couple of coils are tightly compacted ? I had a Punto in a while ago and it was the same. I often feel like that lion, so yes i do like it....... As for the coil issue "no", i had another example yesterday where the "helper coil" or preload coils as i call them were totally closed.......... what's the point if they only work on full doop? Quote Link to comment Share on other sites More sharing options...
CIH Posted May 24, 2009 Report Share Posted May 24, 2009 I'm often told a solid rear, with minimal travel, improves FWD traction by reducing squat under thrust hmmmm..... Quote Link to comment Share on other sites More sharing options...
Tony Posted May 24, 2009 Author Report Share Posted May 24, 2009 Odd thing to say when this is a trailing wheel?.... It can be said there are benefits geometrically by keeping the rear trim stable on a FWD but i wouldn't put this in the realm of squat, more like reducing the front lift, in which case there's a damper argument to be had. Quote Link to comment Share on other sites More sharing options...
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