Shocks or springs?

[AnthonyH]

Just been cruising this website and in the description further down the page it lists the brand as BaHuHa. ???!!! Don't very much like the sound of that. However I bought front struts for the Panda from S4p which were a make I'd never heard of before and they've been very good. I hope you find these are Ok. Here is a picture of the stuff I bought to overhaul Becky's front suspension:

View attachment 439920

Oh, and there you can see the shockers were "Topline" 2019 that was and they're still going absolutely fine without any sign of leaks etc.

Looks like a full overhaul. I'm sure it drives smooth as silk!

I'd quite like to do the springs on my car as well, but I'm mindful that this car isn't worth much. I paid around £650 for it in poor shape and have been repairing it gradually, I'm really just looking to stop it clanking over every little pothole

The heater stopped working yesterday, so this car keeps me busy, lets put it like that

 

[Pugglt Auld Jock]

Looks like a full overhaul. I'm sure it drives smooth as silk!

I'd quite like to do the springs on my car as well, but I'm mindful that this car isn't worth much. I paid around £650 for it in poor shape and have been repairing it gradually, I'm really just looking to stop it clanking over every little pothole

The heater stopped working yesterday, so this car keeps me busy, lets put it like that

Yes thank you, it drives beautifully. Negotiates speed bumps much more smoothly than the Ibiza I just traded in against my Scala but glad to say the Scala is much better than the Ibiza although not that much better than the Panda!

I'm afraid, usually, cheaper old cars are often an ongoing repair task. However, if you can do the repairs yourself it's usually financially worth it until something, like rust, finally punts it out of the ball park.

Heater not working? Do you mean the fan? if so have you tried it on all speeds? If it only works on the fastest speed then it's almost certain to be the resistor pack which is not too expensive but "great fun" to gain access to! If the fan works on all speeds but there's no heat coming out then QUICK, check the coolant level in the radiator. A cold heater is often a sign of low coolant level allowing an air lock in the heater matrix. Low coolant is to be avoided at all costs as it's a common cause of localized overheating in the engine and subsequent head gasket problems, So CHECK YOUR COOLANT LEVEL FREQUENTLY - I check Becky every Saturday morning. If the coolant level is good then it could still be an air lock in the matrix (are there sometimes "gurgly" noises from behind the dashboard - often a symptom of an air lock) In this case you should start by bleeding it out, which is quite simple to do but be careful of the little plastic screw valve on the heater pipe which is known to snap off if you get "tough" with it.

 

[vexorg]

lots of fake crap on eBay, I’d be careful buying new parts, and only buy from reputable sellers.

Cant be fake with no name on them

I'd still say I'd not fit anything critical on my car that came from ebay.

 

[Pugglt Auld Jock]

Cant be fake with no name on them

I'd still say I'd not fit anything critical on my car that came from ebay.

I would, but only from a trusted seller I'd previously bought from - for instance maybe a special offer from Demon Tweeks, Opie oils, etc. Personally I'd not have gone for the shocks our OP bought. My first port of call is still most likely to be our local factors.

 

[AndyRKett]

Cant be fake with no name on them

I'd still say I'd not fit anything critical on my car that came from ebay.

Fake in that they pretend to be car parts when they are made from carboard and sticky tape lol

 

[AnthonyH]

Yes thank you, it drives beautifully. Negotiates speed bumps much more smoothly than the Ibiza I just traded in against my Scala but glad to say the Scala is much better than the Ibiza although not that much better than the Panda!

I'm afraid, usually, cheaper old cars are often an ongoing repair task. However, if you can do the repairs yourself it's usually financially worth it until something, like rust, finally punts it out of the ball park.

Heater not working? Do you mean the fan? if so have you tried it on all speeds? If it only works on the fastest speed then it's almost certain to be the resistor pack which is not too expensive but "great fun" to gain access to! If the fan works on all speeds but there's no heat coming out then QUICK, check the coolant level in the radiator. A cold heater is often a sign of low coolant level allowing an air lock in the heater matrix. Low coolant is to be avoided at all costs as it's a common cause of localized overheating in the engine and subsequent head gasket problems, So CHECK YOUR COOLANT LEVEL FREQUENTLY - I check Becky every Saturday morning. If the coolant level is good then it could still be an air lock in the matrix (are there sometimes "gurgly" noises from behind the dashboard - often a symptom of an air lock) In this case you should start by bleeding it out, which is quite simple to do but be careful of the little plastic screw valve on the heater pipe which is known to snap off if you get "tough" with it.

The fan is only working on the number 4 setting at this time, it has always been cool though, like the heater just doesn't work properly. I suppose I should fix the heater to make it warm, after sitting through the winter with it cool

I have previously heard a gurgling noise and thought it was the fuel pump, but its probably the water as you've mentioned it. Its a very unpredictable gurgle, I have just been out there and tried to replicate the gurgle but couldn't. The water level is fine. I replaced the coolant about 6 months ago, because after I bought the car I could see it is a murky swampy colour, i put new red in, but the colour immediately returned to swampy! Possibly I didn't put the coolant in slowly enough, if that is such a thing!

There was a little drama here this morning, in that the neighbours garage got burgled. I gave the police my video doorbell footage of 3 figures breaking into the garage at 2am and stealing fishing gear. They didn't touch the neighbours car, which of course wasn't in the garage it was on the drive.

Shocks are arriving via DPD at around 2pm today.

 

[AnthonyH]

The shocks came in a Falcao box, although there is no branding on the shocks themselves. They look new, and after pushing on them etc. seem to be consistent. I'll put these on, probably tomorrow.

The car is a 2008 plate, the shocks are supposedly guaranteed for 2 years so if they last that long the car will be quite close to end of life.

 

[Pugglt Auld Jock]

The shocks came in a Falcao box, although there is no branding on the shocks themselves. They look new, and after pushing on them etc. seem to be consistent. I'll put these on, probably tomorrow.

The car is a 2008 plate, the shocks are supposedly guaranteed for 2 years so if they last that long the car will be quite close to end of life.

View attachment 439971
View attachment 439970

Just googled Falcao and it comes up as a registered trade mark involved in vehicle suspension parts mainly but also marketing dual mass flywheels, clutch release bearings, torque converters, etc. I must say I've never heard of them but they do seem to be more than a "one trick pony". You must keep us informed as to how they perform and last once you've got them fitted.

 

[Pugglt Auld Jock]

The fan is only working on the number 4 setting at this time, it has always been cool though, like the heater just doesn't work properly. I suppose I should fix the heater to make it warm, after sitting through the winter with it cool

I have previously heard a gurgling noise and thought it was the fuel pump, but its probably the water as you've mentioned it. Its a very unpredictable gurgle, I have just been out there and tried to replicate the gurgle but couldn't. The water level is fine. I replaced the coolant about 6 months ago, because after I bought the car I could see it is a murky swampy colour, i put new red in, but the colour immediately returned to swampy! Possibly I didn't put the coolant in slowly enough, if that is such a thing!

There was a little drama here this morning, in that the neighbours garage got burgled. I gave the police my video doorbell footage of 3 figures breaking into the garage at 2am and stealing fishing gear. They didn't touch the neighbours car, which of course wasn't in the garage it was on the drive.

Shocks are arriving via DPD at around 2pm today.

So we can probably say right away that your fan resistor is burnt out (top speed only being available, the resistor elements are not in circuit for top speed). If you decide to fit a new one then change the pollen filter too - if your car has one. The air which cools the resistor (which gets very hot at lower speed settings) is actually the air being drawn into the heater unit so if the pollen (cabin) filter is pretty manky it reduces the airflow over the resistor which results in it overheating and failing early. All the cars I look after - the "Family Fleet" as I like to call them - all get pollen filters annually. Definite overkill, but for the price of the filter, discounted from my factors, is well worth the peace of mind and I can't remember when I last had one of our cars with a failed heater resistor.

From your description it sound like the cooling system is needing a very thorough flush through. The radiator is easily enough done by disconnecting the top and bottom hoses and sticking a hose pipe in one of the holes. If you can be bothered it's much better to reverse flush the radiator which means taking it out of the car and turning it upside down so you can stick the hose in the bottom thus flowing water through the matrix in reverse to how it normally flows (When running in the car, hot water from the engine goes in the top and cooler water is returned to the engine from the bottom)

The engine is the reverse. Cool water from the rad is pumped by the water pump into the lower parts of the cylinder block and rises under convection and the action of the water pump until it emerges from the thermostat into the top hose and thus into the top of the radiator. When the engine is cold the thermostat will be closed so sticking the hose into the thermostat housing will achieve very little - unless you want to remove the thermostat first, which may be a good idea as if the existing thermostat is old the system will benefit greatly from a new thermostat. If you're not wanting to disturb the thermostat then look to the rear of the cylinder head near where the thermostat is and you'll see where the heater top hose is connected. I'ts about half the diameter of the top hose. Disconnect this hose and stick the mains hose onto this "spigot" - not the hose - instead then turn on the water. This will bypass the thermostat and reverse flush the head and block..

While you're about it disconnect the other heater pipe and stick the hose on here - that's not the one connected to the head which we just disconnected to flush the engine, on my Panda this is connected to the metal pipe which runs across the front of the engine and into the back of the water pump housing. Shooting water in here will reverse flush the heater matrix core. Of course there will be lots of water coming out of the other hose which you disconnected from the head earlier, so be ready for it - probably best not to have this hose dumping gallons of water all over the engine ECU! In all cases just keep the water flowing until clear water comes out. There is some small risk in doing this on an older car because it may be only the sludge and corrosion which is stopping the thing leaking in the first place, but most of the time you'll get away with it and the cooling system and heater performance is nearly always improved. Of course refill with new coolant.

 

[AnthonyH]

So we can probably say right away that your fan resistor is burnt out (top speed only being available, the resistor elements are not in circuit for top speed). If you decide to fit a new one then change the pollen filter too - if your car has one. The air which cools the resistor (which gets very hot at lower speed settings) is actually the air being drawn into the heater unit so if the pollen (cabin) filter is pretty manky it reduces the airflow over the resistor which results in it overheating and failing early. All the cars I look after - the "Family Fleet" as I like to call them - all get pollen filters annually. Definite overkill, but for the price of the filter, discounted from my factors, is well worth the peace of mind and I can't remember when I last had one of our cars with a failed heater resistor.

Thanks for the info. I can steal a heater resistor from a GP i've now got SORN so that will be an easy fix. I've never seen the pollen filter in this or any other car, I've just watched a youtube video and it showed me the location of the filter. No doubt that will need replacing. I will wear a face mask when changing that!

From your description it sound like the cooling system is needing a very thorough flush through. The radiator is easily enough done by disconnecting the top and bottom hoses and sticking a hose pipe in one of the holes. If you can be bothered it's much better to reverse flush the radiator which means taking it out of the car and turning it upside down so you can stick the hose in the bottom thus flowing water through the matrix in reverse to how it normally flows (When running in the car, hot water from the engine goes in the top and cooler water is returned to the engine from the bottom)

It looks like someone has put some kind of radiator repair liquid in there or maybe its rust. Changing the coolant was the first thing I did when I bought this car because the temperature gauge was wavering around unnervingly. The wavering did stop but I was hoping for the coolant to turn red in the visible overfill tank, but its still murky. I couldn't risk taking the radiator out of the car because something might break and i'd end up with more than I bargained for! But there's something still amiss here so a regular flush is in order.

The engine is the reverse. Cool water from the rad is pumped by the water pump into the lower parts of the cylinder block and rises under convection and the action of the water pump until it emerges from the thermostat into the top hose and thus into the top of the radiator. When the engine is cold the thermostat will be closed so sticking the hose into the thermostat housing will achieve very little - unless you want to remove the thermostat first, which may be a good idea as if the existing thermostat is old the system will benefit greatly from a new thermostat. If you're not wanting to disturb the thermostat then look to the rear of the cylinder head near where the thermostat is and you'll see where the heater top hose is connected. I'ts about half the diameter of the top hose. Disconnect this hose and stick the mains hose onto this "spigot" - not the hose - instead then turn on the water. This will bypass the thermostat and reverse flush the head and block..

I could possibly risk taking the thermostat off, its relatively easy to do. If it decides to break then i have a new one that went on the SORN GP last year.

I'm quite hopeful that with the flush the heater will be a lot hotter. Its possible / probable that there is some air in the matrix.

While you're about it disconnect the other heater pipe and stick the hose on here - that's not the one connected to the head which we just disconnected to flush the engine, on my Panda this is connected to the metal pipe which runs across the front of the engine and into the back of the water pump housing. Shooting water in here will reverse flush the heater matrix core. Of course there will be lots of water coming out of the other hose which you disconnected from the head earlier, so be ready for it - probably best not to have this hose dumping gallons of water all over the engine ECU! In all cases just keep the water flowing until clear water comes out. There is some small risk in doing this on an older car because it may be only the sludge and corrosion which is stopping the thing leaking in the first place, but most of the time you'll get away with it and the cooling system and heater performance is nearly always improved. Of course refill with new coolant.

I'll need to investigate this one further. I'm going to do the shocks first, then the heater repair, then the flush. The weather is improving too, and there will be lighter evenings from next month. To carry on with whatever else crops up

 

[Pugglt Auld Jock]

Thanks for the info. I can steal a heater resistor from a GP i've now got SORN so that will be an easy fix. I've never seen the pollen filter in this or any other car, I've just watched a youtube video and it showed me the location of the filter. No doubt that will need replacing. I will wear a face mask when changing that!



It looks like someone has put some kind of radiator repair liquid in there or maybe its rust. Changing the coolant was the first thing I did when I bought this car because the temperature gauge was wavering around unnervingly. The wavering did stop but I was hoping for the coolant to turn red in the visible overfill tank, but its still murky. I couldn't risk taking the radiator out of the car because something might break and i'd end up with more than I bargained for! But there's something still amiss here so a regular flush is in order.



I could possibly risk taking the thermostat off, its relatively easy to do. If it decides to break then i have a new one that went on the SORN GP last year.

I'm quite hopeful that with the flush the heater will be a lot hotter. Its possible / probable that there is some air in the matrix.



I'll need to investigate this one further. I'm going to do the shocks first, then the heater repair, then the flush. The weather is improving too, and there will be lighter evenings from next month. To carry on with whatever else crops up

Looks like you're going to be busy for a while with this Good luck with it all and please do keep us updated with how things go won't you?

 

[AnthonyH]

Looks like you're going to be busy for a while with this Good luck with it all and please do keep us updated with how things go won't you?

I got one of the new shocks on today, there was no time to do the second. I took the car for a little drive to see if anything was going to fall off! It was safe and sturdy but I'm wondering if the shocks weren't the problem and it was the springs... The old shock that came off was the original one from 2008, it was very rusty, kind of working weakly and then when I pushed on it firmly all of the remaining gas escaped and it worked no more.

You were right about the heater resistor being a problem, i took one off my other SORN GP. That resistor looked pretty new, so wasn't original to that car. They're £10, I made a small saving because its quite likely the SORN GP will get scrapped, so I may as well get as much off it as I can.

I remembered after my last post that when I changed the coolant 6 months ago I didn't bleed the radiator, this might explain the gurgling noise and lack of heat from the air conditioning! So I need to get the other shock on tomorrow and then flush the radiator and engine. Its possible that the radiator not working properly did for the heater resistor. And I'd like to get the rusty looking coolant out of the car.

A new pollen filter is coming tonight via Amazon. So that'll go on soon.

 

[AnthonyH]

The other shock went on OK, it does feel better going over bumps, but there isn't the big improvement I was hoping for. The springs are just as shot through and would need doing too. Oh well, i'll think about that another time.

The pollen filter went in OK. That'll save the heater resistor from frying!

I'll possibly make another thread about the engine/radiator flush and heater matrix problem. As that's not about shocks and springs and the topic of this thread is complete.

Thanks @Pugglt Auld Jock for the help.

​

 

[vexorg]

New shock should make it stiffer on the back end, less bouncy. Not quite sure what effect you are feeling or hope to improve.

 

[AnthonyH]

New shock should make it stiffer on the back end, less bouncy. Not quite sure what effect you are feeling or hope to improve.

It is less bouncy going over big bumps but I still feel the little bumps a fair bit. Maybe I'll do the springs at a later time.

All is good, I'm just getting used to it is all.

 

[Pugglt Auld Jock]

It is less bouncy going over big bumps but I still feel the little bumps a fair bit. Maybe I'll do the springs at a later time.

All is good, I'm just getting used to it is all.

Worth considering that if you're talking about quite small very sharp bumps then quality of ride is more down to tyres than suspension.

Why? well the moving parts of the suspension, so shock absorber, wheels and hubs and outer part of suspension arms together with part of the spring all together have considerable mass and therefore inertia. This is called "unsprung weight" When you go over a very sharp bump, those terrible rubber type speed bumps are a good example - you know the type which are screwed into the road surface - then the mass of all these heavy parts stop them being able to react and "jump" up quickly enough to avoid the shock being transmitted into the body structure. The tyre sidewall on the other hand, has very little mass and is pretty flexible - tyre people call it "compliance" - so what happens is that the suspension actually deflects very little under these circumstances but the tyre sidewall deflects a lot and absorbs the bump. Some tyres are better than others at doing this. Of course there's a down side to this. If the bump is a big one it can inflict enough stress on the tyre, especially as it gets old, to burst it - consider that when the tyre is deflected the air inside is greatly compressed due to the reduction in volume inside the tyre. Of course the bump may be big enough to completely compress the sidewall of the tyre until it hits the rim and that's when you end up with a bent rim!

Racing cars are always trying to achieve reductions in unsprung weight because it allows the suspension to react to surface irregularities more quickly and thus allows the tyre to maintain better contact with the road surface. Trouble is this often can only be achieved using materials either too expensive to be used in road cars or unsuitable in terms of duration of life.

Hope that was interesting?

 

[AnthonyH]

Worth considering that if you're talking about quite small very sharp bumps then quality of ride is more down to tyres than suspension.

Why? well the moving parts of the suspension, so shock absorber, wheels and hubs and outer part of suspension arms together with part of the spring all together have considerable mass and therefore inertia. This is called "unsprung weight" When you go over a very sharp bump, those terrible rubber type speed bumps are a good example - you know the type which are screwed into the road surface - then the mass of all these heavy parts stop them being able to react and "jump" up quickly enough to avoid the shock being transmitted into the body structure. The tyre sidewall on the other hand, has very little mass and is pretty flexible - tyre people call it "compliance" - so what happens is that the suspension actually deflects very little under these circumstances but the tyre sidewall deflects a lot and absorbs the bump. Some tyres are better than others at doing this. Of course there's a down side to this. If the bump is a big one it can inflict enough stress on the tyre, especially as it gets old, to burst it - consider that when the tyre is deflected the air inside is greatly compressed due to the reduction in volume inside the tyre. Of course the bump may be big enough to completely compress the sidewall of the tyre until it hits the rim and that's when you end up with a bent rim!

Racing cars are always trying to achieve reductions in unsprung weight because it allows the suspension to react to surface irregularities more quickly and thus allows the tyre to maintain better contact with the road surface. Trouble is this often can only be achieved using materials either too expensive to be used in road cars or unsuitable in terms of duration of life.

Hope that was interesting?

It is very interesting. I was reading this thinking "I didn't know that". I've just been out to check the tyres and they are both summer ones on the back and manufactured in the year 2021. I checked the tyre pressure recently and they were OK. They aren't the same brand though. I'm still musing the implications of this, I definitely bought those tyres in pairs so they're just on another car at the moment.

 

[Pugglt Auld Jock]

It is less bouncy going over big bumps but I still feel the little bumps a fair bit. Maybe I'll do the springs at a later time.

All is good, I'm just getting used to it is all.

Worth thinking also about what the shock absorber is primarily doing. The "shock" it is "absorbing" is the energy stored in the spring as a result of it being depressed by the irregularity in the surface it's traversing. Now that's a bit of a funny thought isn't it? What it's not doing is "absorbing" the "shock" induced into the vehicle's structure by the bump in the road! pfwoar! that takes a bit of getting the head round doesn't it?

So let's think about this a wee bit more. First thing to say here is we are thinking about standard road vehicles with simple shock absorbers here, which is what ours are. To get a good ride the tyre, wheel and moving suspension parts must be able to rapidly deflect upwards when they encounter something like a speed bump. If the shock absorber offered significant resistance to the upward movement of the wheel then you'd feel the bump even worse so we don't want it to do this. Consequently you'll find most shock absorbers offer little real resistance in compression (doesn't mean the average puny human will find it's easy to compress one by hand though! when it's off the vehicle. However, once the wheel is getting over the bump, what we don't want is for the, now compressed, spring to become dominant and "fling" that corner of the car up into the air. Therefore the shockabsorber is designed to provide resistance when it's extending (internal valving and oil) which controls the spring on return and stops oscillations building up. All this because it's controlling the wheel and keeping it in contact with the road surface.

So it's important to realize that shock absorbers are primarily controlling the energy contained in the springs by virtue of their compression by the action of the suspension. New shock absorbers will often make a vehicle feel much more positive to drive and improve the road holding but may not necessarily improve the shock forces transmitted into the body structure by going over a bump. So, I suppose what I'm saying is that the perceived benefits of fitting new shockers may not be particulary noticed as a dramatic improvement in ability to improve how the vehicle feels when going over bumps, especially short sharp violent types of bump.

 

[Pugglt Auld Jock]

It is very interesting. I was reading this thinking "I didn't know that". I've just been out to check the tyres and they are both summer ones on the back and manufactured in the year 2021. I checked the tyre pressure recently and they were OK. They aren't the same brand though. I'm still musing the implications of this, I definitely bought those tyres in pairs so they're just on another car at the moment.

So two to three years ago? They are still comparative youngsters - Properly stored tyres stored in conditions of humidity, heat etc where they suffer minimum degradation are allowed to be sold as "new" until they are 5 years old I seem to remember (may have changed since I made a living at it though) One big factor worth always remembering about tyres though is that the rubber oxidizes and heat and sun etc exacerbate this so the conditions in which it's been stored have a lot to do with it if the tyre is not fresh out of the factory. A brand new tyre needs to "break in" by not subjecting it to extremes of use for about 100 miles or so. This allows the casing in particular to become more supple and the tread surface to "work harden" to a certain extent (it's much more complicated than this and I'm not a chemist or tyre designer but we were always taught to advise customers to drive with care and not subject the tyre to violent braking, cornering or acceleration for the first 100 miles or so (unless there's no option of course). By the way, just while we're on the subject of advice, I've was involved in performance tyre testing back in the 1970's - endurance, grip, etc etc. and found that tyres with less than 2mm of tread depth suffered a considerable reduction in grip on wet road surfaces compared to identical tyres with more depth of tread. It's all due to the tyre's ability to displace the water and allow the rubber to get through to the road surface. Of course things vary in degree between makes of tyre and car. Weight of the vehicle, age and width of the tyre and how much water is on the road surface all introduce variable factors but once you drop below the 2mm things become much more dodgy in the wet! It's noticeable how much more sharply the graph line dipped at that point.

As your tyres age keep an eagle eye out for sidewall cracks and cracks around the bead area. Also look into the tread grooves for cracking at the base of the grooves. Because the surface will oxidize much more quickly mild cracking which is surface only, especially on sidewalls, can probably be lived with but if the cracking anywhere exposes part of the internal cords of the tyre it needs to be scrapped immediately - in fact it's an offence and the boys in blue will be very unhappy about it. Oh, and remember that tyres can, and often do, degrade or suffer damage on the inner sidewall where you can't easily see it. So every now and again take a good look at the inner sidewalls of your tyres. This is especially good advice if the vehicle is often driven on vary poor surfaces or frequently mounts the curb.

 

[AnthonyH]

Worth thinking also about what the shock absorber is primarily doing. The "shock" it is "absorbing" is the energy stored in the spring as a result of it being depressed by the irregularity in the surface it's traversing. Now that's a bit of a funny thought isn't it? What it's not doing is "absorbing" the "shock" induced into the vehicle's structure by the bump in the road! pfwoar! that takes a bit of getting the head round doesn't it?

So let's think about this a wee bit more. First thing to say here is we are thinking about standard road vehicles with simple shock absorbers here, which is what ours are. To get a good ride the tyre, wheel and moving suspension parts must be able to rapidly deflect upwards when they encounter something like a speed bump. If the shock absorber offered significant resistance to the upward movement of the wheel then you'd feel the bump even worse so we don't want it to do this. Consequently you'll find most shock absorbers offer little real resistance in compression (doesn't mean the average puny human will find it's easy to compress one by hand though! when it's off the vehicle. However, once the wheel is getting over the bump, what we don't want is for the, now compressed, spring to become dominant and "fling" that corner of the car up into the air. Therefore the shockabsorber is designed to provide resistance when it's extending (internal valving and oil) which controls the spring on return and stops oscillations building up. All this because it's controlling the wheel and keeping it in contact with the road surface.

So it's important to realize that shock absorbers are primarily controlling the energy contained in the springs by virtue of their compression by the action of the suspension. New shock absorbers will often make a vehicle feel much more positive to drive and improve the road holding but may not necessarily improve the shock forces transmitted into the body structure by going over a bump. So, I suppose what I'm saying is that the perceived benefits of fitting new shockers may not be particulary noticed as a dramatic improvement in ability to improve how the vehicle feels when going over bumps, especially short sharp violent types of bump.

This does make sense and I can see why it is of value getting shocks and springs done at the same time. The old springs can't hold as much energy as they used to and so to some extent putting new shocks on won't help as much, they're kind of over powered for the weakened springs. I might get the springs done too. I had a look a moment ago and I could get two for £35, which is pretty reasonable.