Car rear suspension

Machuche · Jul 17, 2014

Car rear suspension too soft on Mercedes w124. Any help would be great. I have been told that 'spring adjusters might help.

Sproket · Jul 17, 2014

Have a read here & see if your car has the same rear suspension set up ...

Has it got self-leveling rear suspension fitted ?

WoodlandsCamper · Jul 17, 2014

Welcome to the forum.

(You might get your question answered sooner if a nice Moddy would move your post to 'Technical'.)

ProfJohnL · Jul 17, 2014

Machuche said:
Car rear suspension too soft on Mercedes w124. Any help would be great. I have been told that 'spring adjusters might help.

Hello Machuche,

Welcome to the forum.

Car manufacturers, especially the up market brands spend a lot of time and trouble to adjust the suspension to suit their target market. Provided the loads you add to the car are within the manufacturers specification, the suspension will almost certainly provide you with the safest combination.

Again with the top marques, they now have some very clever Electronic Stability Programs, which use sensors that are calibrated and set up to match the ex-works components. Tampering with suspension settings may compromise the ESP's and actually produce some unwanted results.

Even i you add spring assistance, you do not change the maximum loads you can apply, they remain exactly the same as described in the cars specification.

If you are unhappy with the cars suspension, the first thing to get checked is if its already overloaded, then if anything is worn or broken. Spring assistance must never be used to correct an out of speck or broken suspension.

Machuche · Jul 17, 2014

94 but yes my car is the same. W124

Machuche · Jul 17, 2014

Suspension is 6 months old and is fine but sits down when the van is hitched.

Machuche · Jul 17, 2014

Thanks. What now since I have some suggestions?

WoodlandsCamper · Jul 17, 2014

If the back of the car drops that much what is the measured nose weight of the van?

Machuche · Jul 17, 2014

I measured the noseweight this morning and it is 110kg which is 40kg more than it should be so will this change when I redistribute the load? I will have to move the gas bottles into the caravan to get the correct balance.

WoodlandsCamper · Jul 17, 2014

Yes, you will need to redistribute the load as per basic rules. However the gas cylinders need to stay upright in their designed location. Do you need to carry both cylinders, or will one suffice?

See here and here

Machuche · Jul 17, 2014

One would be OK but is this normal having to move stuff around to get the balance? Is the car at fault or is it the caravan? I am sure I am not alone in this but would it happen with a brand new outfit..........car and caravan?

WoodlandsCamper · Jul 17, 2014

See edit to previous post containing links.

Machuche · Jul 17, 2014

Thanks for your help. I am now going to eat and will be back tomorrow.

Sproket · Jul 17, 2014

Machuche said:
I measured the noseweight this morning and it is 110kg which is 40kg more than it should be so will this change when I redistribute the load? I will have to move the gas bottles into the caravan to get the correct balance.

What method or type of gauge did you use to measure your nose weight ? also what make & type of van have you got ?

Machuche · Jul 18, 2014

Hello
The Caravan is a Swift Challenger 400SE 1994 and I bought calibrated gauge which cost about £28. They had a cheap £8 one as well. Sorry but I am 12 miles from the van.

ProfJohnL · Jul 18, 2014

Machuche said:
Hello
The Caravan is a Swift Challenger 400SE 1994 and I bought calibrated gauge which cost about £28. They had a cheap £8 one as well. Sorry but I am 12 miles from the van.

First of all 40Kg is a massive overload and is dangerous. I have towed many caravans and I have always been able to achieve the desired nose load for the combination, either by redistributing payload items, or by adding ballast. I have always kept the gas bottle(s) and battery in their designated places which is a essential requirement for safety. One one occasion I had to empty the front lockers except for the gas bottles, but otherwise I have never been stumped.

With a 40Kg overload that would show up with virtually any measuring device, but frankly non of the currently available retail gauges (even the ones that claim to be calibrated) measure nose weight in the way it should be measured:-

[ol]
[*]Load your car and caravan with passengers and luggage exactly as if you are about to set off on your trip.
[*]Use a level (horizontal) piece of ground big enough for the coupled car and caravan.
[*]measure the vertical height of the hitch from the ground (EU Regs say it should be between 350 and 420mm measured to the center of the ball) If its out side of these limits then something is wrong.
[*]Chock the wheels (both front and back) of the caravan and uncouple it from the car.
[*]set up the nose weight measurement device to support the caravan hitch and make sure non of the steadies or jockey wheel are touching the floor and release the handbrake.
[*]Now adjust the noseweight gauge to set the tow hitch to exactly the same height that you measured.(I'll bet you can't do this)
[*]Only at the correct height will you record the true nose weight.

The height of the hitch is important as the force it produces varies with the height of the hitch. So as non of the retail nose weight gauges allow you to adjust their height, they cannot measure it accurately. Also as the compress with increasing load it all becomes a bit of a fudge. With regards to calibration, Unless you have the calibration details i.e the degree of error report, the calibration is of no value. If you search this forum for 'Nose weight' you will find a massive amount of information, but buried in it you will find how much error of reading some of the retail devices have been shown to give.

The CC and I recommend using a pair of bathroom scales with a length of wood to give you the correct hitch height. Another approach is to raise the the scales on the caravan steps and phone books to get the right height. Some forum members have produced their own adjustable H frames to sit on bathroom scales.

You current overload is dangerous, on a number of counts. The first is the additional load increases the friction in the over run ram of the hitch. This means when braking the caravan may not compress the overrun ram enough and thus the caravan brakes will not be correctly applied AND the cars brakes will have to handle more load than they are designed to take. Secondly the under pinning of the car where the tow bar is fixed will be put under more stress that they are designed for. The static load is not the problem, its the dynamic loads created when towing which multiply the static loads by many times. This may compromise the structural integrity of the car and tow bar.

It is also illegal to overload the tow coupling.

Willi-Wonti · Jul 22, 2014

A few years ago I had a Volvo 850 estate fitted with self levelling suspension
When returning to the car & van at Exeter services a policeman greeted me saying you have got a lot of weight on the backend of the car hmy:
I explained to him that the suspension had sunk whilst parked & that as soon as we start moving it will pump itself back to its proper height.
So I jumped into the car & drove round the lorry park a couple of times by which time the suspension had returned to it normal position.
I thanked him for his concern picked up swmbo & carried on to Cornwall

20170602yuanyuan · Jun 2, 2017

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Car rear suspension

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