Mk 2 rear suspension issue

[bkulcsar]

Originally Posted by Kevin_L

Hi - not sure - maybe springs not seated correctly?

sorry not to answer, but I'd like to know how you did your rear spring change - ie, did you need a spring compressor?

And if so, what type (internal or external)

Thanks

You need an internal spring compressor. Been there, done that.

[petey]

Not sure I’ve read this correctly, but you changed springs and not shocks and now it’s soft and bouncy or is it so stiff it bounces on the tyres?

If you’ve put springs that are too stiff, the damper won’t get a chance to do anything, the suspension will essentially lock out and you’ll bounce into oversteer at high rates across the road.
If the springs are soft, then it’ll wallow like a hippo getting a belly brush-wash in the zoo.
If it’s riding an inch higher all of a sudden then chances are it’s incorrectly mounted or the springs are too stiff.


(Tedious description time:- Suspension has three major stiffnesses (ignoring bushes and subframe stiffness for now):- absolute position (opposed by the spring) speed related (opposed by the damper) and relative position (opposed by the anti roll bar.
A too stiff spring simply won’t move as much for a given force, remembering that f=kx. You need a lot more f to get an x if k is too high.
If there’s no movement, how can dampers control it?
If the overall rate of the spring is tool low, then the car will roll around. Yes, it has an anti-roll bar, but that’s a tuning device, not the absolute definition of roll stiffness.)


However, there’s some history here thats not clear: why had you changed the springs and not the dampers? What caused you to come to the conclusion that the springs were somehow defective? Unless they’re actually rusted through and broken, they’ll outlive the dampers every time. Even if the springs are rooted, they won’t be as rooted as the dampers.
What else has been changed?

[gar v70]

Originally Posted by petey

Not sure I’ve read this correctly, but you changed springs and not shocks and now it’s soft and bouncy or is it so stiff it bounces on the tyres?

If you’ve put springs that are too stiff, the damper won’t get a chance to do anything, the suspension will essentially lock out and you’ll bounce into oversteer at high rates across the road.
If the springs are soft, then it’ll wallow like a hippo getting a belly brush-wash in the zoo.
If it’s riding an inch higher all of a sudden then chances are it’s incorrectly mounted or the springs are too stiff.


(Tedious description time:- Suspension has three major stiffnesses (ignoring bushes and subframe stiffness for now):- absolute position (opposed by the spring) speed related (opposed by the damper) and relative position (opposed by the anti roll bar.
A too stiff spring simply won’t move as much for a given force, remembering that f=kx. You need a lot more f to get an x if k is too high.
If there’s no movement, how can dampers control it?
If the overall rate of the spring is tool low, then the car will roll around. Yes, it has an anti-roll bar, but that’s a tuning device, not the absolute definition of roll stiffness.)


However, there’s some history here thats not clear: why had you changed the springs and not the dampers? What caused you to come to the conclusion that the springs were somehow defective? Unless they’re actually rusted through and broken, they’ll outlive the dampers every time. Even if the springs are rooted, they won’t be as rooted as the dampers.
What else has been changed?

springs were changed on the word of my mechanic as being weak and rusted but not rusted through.

the 1" difference in the ride heighth was due to placing both new and old springs together and measuring the difference.

when driving the car on a straight flat road the ride is good not hard or even too soft , its only when going over an uneven part of the road but only at one side or other like a drain cover or rough tarmac, it skits about.

shocks are standard and not nivomat.

[Simmy]

meyle shocks £65 pair on ebay from parts aliance

[petey]

First guest would be that you’ve fitted the wrong springs....
Springs don’t lose an inch of length through use unless bits break off.

[gar v70]

Originally Posted by petey

First guest would be that you’ve fitted the wrong springs....
Springs don’t lose an inch of length through use unless bits break off.

apparently so I've read, springs will lose about an 1" over approx. 100000 miles because the spring goes weaker and as mine has done 210000 its probably about right.. also I have measured the ride heighth and is correct to standard dimensions

[gar v70]

Originally Posted by Simmy

meyle shocks £65 pair on ebay from parts aliance

are these a good make compared to OE

[davebb]

They are made in china now, but do work well,
Dave

[Simmy]

im using them seem ok for the price but i dont tow or carry heavy loads . it takes abt 40 mins a side to fit them.

[gar v70]

What are monroe shocks like, are they any good