Hazards when using a spring compressor
Discussion
Hi all,
So I've decided to replace all of the shocks and springs on my Chimaera 450 as they are all very old now and the rear NS has failed and leaked out pretty much all of its oil.
I'm replacing with Bilsteins and Eibachs, standard rates.
What's the best type of spring compressor to use and how should it be used safely as I understand it's a pretty dangerous task as the compressors can fail or slip off.
I understand that even if I put the suspension on full droop, the spring may still be compressed and storing energy. So my question is what's the best kit and technique ?
Here's a video of some guys that appear to be pretty experienced removing a broken spring and the compressor fails or comes off:
https://www.youtube.com/watch?v=dLVvS6CuNlQ
Anyone any advice for please ?
Thanks.
So I've decided to replace all of the shocks and springs on my Chimaera 450 as they are all very old now and the rear NS has failed and leaked out pretty much all of its oil.
I'm replacing with Bilsteins and Eibachs, standard rates.
What's the best type of spring compressor to use and how should it be used safely as I understand it's a pretty dangerous task as the compressors can fail or slip off.
I understand that even if I put the suspension on full droop, the spring may still be compressed and storing energy. So my question is what's the best kit and technique ?
Here's a video of some guys that appear to be pretty experienced removing a broken spring and the compressor fails or comes off:
https://www.youtube.com/watch?v=dLVvS6CuNlQ
Anyone any advice for please ?
Thanks.
Several chaps have used the "Phillpot method" - scroll down to the pic from Glenrobbo in this thread - http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Hmmm maybe. Not sure I like the idea of using anything other than the dedicated tools for this type of job.
Although the spring compressor kits I have looked at don't inspire much confidence.
There's only 2 compressors. What's to stop them sliding round to the same side of the spring and the spring then coming out ?
Perhaps using both methods together ?
Although the spring compressor kits I have looked at don't inspire much confidence.
There's only 2 compressors. What's to stop them sliding round to the same side of the spring and the spring then coming out ?
Perhaps using both methods together ?
taylormj4 said:
There's only 2 compressors. What's to stop them sliding round to the same side of the spring and the spring then coming out ?
Use three ratchet straps if you're unsure?Friction will stop them sliding around, and even if they should the spring is still "contained" and won't launch itself off like a rocket!
A bit of Forum searching will throw up some other options from various clamps (that can jump off) to a set up using two old brake discs and some threaded rod.
If you are not confident, fear for your safety, don't have the right tools why not splash a bit of cash and have a garage change them for you?
If buying springs and shocks from same supplier they should come pre-assembled I'd have thought
Hi mate.
I've used the screw type spring compressors countless times. There is a serious risk, but it's very easily managed with some attention to very simple points.
The compressors themselves will happily slide or rattle around the coils when loose. A few turns on the screw with your rachet however and the friction imposed by the spring itself means you won't budge them.
The main danger is the spring twanging out of the compressors. There is very little probability of that happening though. You can bend the spring a long way with very lopsided compressors before it risks slipping out of the hooks.
Just make sure your compressors are diametrically opposite one another and screw each one tighter or looser a few turns at a time to keep the loads on each compressors similar and the spring roughly straight. They won't go anywhere.
With long springs it can be beneficial to have 2 pairs of compressors. The first pair can compress perhaps 3 coils together. If the spring is still firmly in the spring seats the the 2nd set of compressors can go between the first set and grab the already compressed coils and reach a bit further.
Do not remove dismantle the upper spring seat until the spring can be moved on the damper. If it's still planted in the spring seat the latter will come off like a cannon shell.
It's good practise to keep your body outwith the long axis of the spring, so that should anything happen despite good practise, you're not in the line of fire.
I've used the screw type spring compressors countless times. There is a serious risk, but it's very easily managed with some attention to very simple points.
The compressors themselves will happily slide or rattle around the coils when loose. A few turns on the screw with your rachet however and the friction imposed by the spring itself means you won't budge them.
The main danger is the spring twanging out of the compressors. There is very little probability of that happening though. You can bend the spring a long way with very lopsided compressors before it risks slipping out of the hooks.
Just make sure your compressors are diametrically opposite one another and screw each one tighter or looser a few turns at a time to keep the loads on each compressors similar and the spring roughly straight. They won't go anywhere.
With long springs it can be beneficial to have 2 pairs of compressors. The first pair can compress perhaps 3 coils together. If the spring is still firmly in the spring seats the the 2nd set of compressors can go between the first set and grab the already compressed coils and reach a bit further.
Do not remove dismantle the upper spring seat until the spring can be moved on the damper. If it's still planted in the spring seat the latter will come off like a cannon shell.
It's good practise to keep your body outwith the long axis of the spring, so that should anything happen despite good practise, you're not in the line of fire.
Edited by jamieduff1981 on Thursday 19th February 06:44
jamieduff1981 said:
Hi mate.
I've used the screw type spring compressors countless times. There is a serious risk, but it's very easily managed with some attention to very simple points.
The compressors themselves will happily slide or rattle around the coils when loose. A few turns on the screw with your rachet however and the friction imposed by the spring itself means you won't budge them.
The main danger is the spring twanging out of the compressors. There is very little probability of that happening though. You can bend the spring a long way with very lopsided compressors before it risks slipping out of the hooks.
Just make sure your compressors are diametrically opposite one another and screw each one tighter or looser a few turns at a time to keep the loads on each compressors similar and the spring roughly straight. They won't go anywhere.
With long springs it can be beneficial to have 2 pairs of compressors. The first pair can compress perhaps 3 coils together. If the spring is still firmly in the spring seats the the 2nd set of compressors can go between the first set and grab the already compressed coils and reach a bit further.
Do not remove dismantle the upper spring seat until the spring can be moved on the damper. If it's still planted in the spring seat the latter will come off like a cannon shell.
It's good practise to keep your body outwith the long axis of the spring, so that should anything happen despite good practise, you're not in the line of fire.
Thanks Jamie,I've used the screw type spring compressors countless times. There is a serious risk, but it's very easily managed with some attention to very simple points.
The compressors themselves will happily slide or rattle around the coils when loose. A few turns on the screw with your rachet however and the friction imposed by the spring itself means you won't budge them.
The main danger is the spring twanging out of the compressors. There is very little probability of that happening though. You can bend the spring a long way with very lopsided compressors before it risks slipping out of the hooks.
Just make sure your compressors are diametrically opposite one another and screw each one tighter or looser a few turns at a time to keep the loads on each compressors similar and the spring roughly straight. They won't go anywhere.
With long springs it can be beneficial to have 2 pairs of compressors. The first pair can compress perhaps 3 coils together. If the spring is still firmly in the spring seats the the 2nd set of compressors can go between the first set and grab the already compressed coils and reach a bit further.
Do not remove dismantle the upper spring seat until the spring can be moved on the damper. If it's still planted in the spring seat the latter will come off like a cannon shell.
It's good practise to keep your body outwith the long axis of the spring, so that should anything happen despite good practise, you're not in the line of fire.
Edited by jamieduff1981 on Thursday 19th February 06:44
Good advice.
I have done a lot of mechanics on cars but that just makes you experienced enough to know that these things are potentially very dangerous. Plus when you see experienced mechanics nearly getting their head taken off (countless examples on You tube etc) it shows you how it can happen to anyone.
Thought about paying someone to do it but this is one thing I haven't done on a car before so I'd like to have a go at it myself.
taylormj4 said:
Hi all,.......snippity..........I'm replacing with Bilsteins and Eibachs, standard rates....snip
Thanks.
Shirley if Standard they come "complete" and as such you mount them on the car "complete" and there will be no need for compressors?? You only need to set ride height/corner weighting??Thanks.
When I've changed springs, I use motorcycle spring compressors as they are able to fit between coils better than "automotive" compressors designed more for McPherson Strut Springs? I would say a "challenge" rather than pose a hazard, as you are only compressing a 10 inch coil not a McPherson 18 inch coil? "Man-up??"
Glad you have made a decision??
T
K4TRV said:
Shirley if Standard they come "complete" and as such you mount them on the car "complete" and there will be no need for compressors?? You only need to set ride height/corner weighting??
When I've changed springs, I use motorcycle spring compressors as they are able to fit between coils better than "automotive" compressors designed more for McPherson Strut Springs? I would say a "challenge" rather than pose a hazard, as you are only compressing a 10 inch coil not a McPherson 18 inch coil? "Man-up??"
Glad you have made a decision??
T
Ha ha, "man up"? cheeky sod ! A man should be able to take a spring in the face is it ?When I've changed springs, I use motorcycle spring compressors as they are able to fit between coils better than "automotive" compressors designed more for McPherson Strut Springs? I would say a "challenge" rather than pose a hazard, as you are only compressing a 10 inch coil not a McPherson 18 inch coil? "Man-up??"
Glad you have made a decision??
T
....and stop calling me Shirley !
They did come from the same place but they arrived separately, so I have a box of springs and the dampers arrived today. So my expectation (although I've not looked at them yet) is that I will need to compress the springs to get them onto the dampers.
Did notice Frost had motorcycle spring compressors and wondered if they would be better. Going to get a set from Machine Mart tomorrow as they have better securing clips. Hoping they won't be too big. The springs are pretty small but the front in particular feels very stiff. I can almost get two of them inside a Range Rover spring !
Decided to go for the standard set to begin with, in the hope that changing from tired to new gives a tighter suspension but there is still the opportunity to get them tweaked for Tuscan S setup in future if needs be (info from Ben ex TVR suspension mechanic).
Edited by taylormj4 on Friday 20th February 16:37
Thanks for the comments. Like the two home-made compressor tools, very good. I do have an old brake disc lying around but nothing that could make a 71mm hole in it ! I don't have a lathe unfortunately.
I will take the spring and damper down to machine mart and see what fits. They make motorcycle spring compressors too.
Know what you're saying about save money and use the ratchet straps but I'm already saving a lot by doing the job myself and would rather have a tool that is rated for the job. However, it's a great back up so if I can't geta compressor that will fit, I'll be using that idea. Thanks.
Here's a nice pic of the new parts awaiting assembly. One of the dampers is even stamped with the proper TVR
logo.
What is it about new car parts that is so exciting ?!
I will take the spring and damper down to machine mart and see what fits. They make motorcycle spring compressors too.
Know what you're saying about save money and use the ratchet straps but I'm already saving a lot by doing the job myself and would rather have a tool that is rated for the job. However, it's a great back up so if I can't geta compressor that will fit, I'll be using that idea. Thanks.
Here's a nice pic of the new parts awaiting assembly. One of the dampers is even stamped with the proper TVR
logo.
What is it about new car parts that is so exciting ?!
Quinny said:
Yes, good bit of kit that Quinny. Wish I had one of those !Tried Machine mart this morning and as feared, the compressor fingers were too large to get betewen the coils even when fully uncompressed. They didn't have any ratchet straps that fed back on themselves, so I bought a standard pair and modified them to make them feed back on themselves.
However, after much cursing and sweating, whilst I can compress the springs quite a bit, I'm finding it very difficult to compress them far enough to get the the end cap on. The ratchets I bought are too big really, the webbing is getting caught on the damper body and they are quite difficult to keep opposite one another.
The ratchet units scratched my new springs too....grrrr!
The ones that Phillpot used seem a lot smaller. Machine Mart had some of those but they were only rated at 250kg, which seemed a bit low for comfort. The next ones up were the ones I bought which are rated at 3ton !
I'll keep perservering but think I could be out looking for a conventional one again tomorrow. Other prospect is a motorcycle unit which I could get ordered in by Tuesday.0
Used conventional compressors a couple of months back and the lower hook section scored absorber wall as clearance was small, was only able to get one hook onto the spring (instead of 2) so it wasn't ideal.
I used ratchets in the end, trusted them more than the compressors.
You probably for more money get a 'sport' type compressor.
Good luck though.
I used ratchets in the end, trusted them more than the compressors.
You probably for more money get a 'sport' type compressor.
Good luck though.
Not a bad price: http://www.amazon.co.uk/MacPherson-strut-Spring-Co...
Alternatively, pop them down to your local garage and ask them to remove them. Won't take them long.
Alternatively, pop them down to your local garage and ask them to remove them. Won't take them long.
K4TRV said:
taylormj4 said:
Hi all,.......snippity..........I'm replacing with Bilsteins and Eibachs, standard rates....snip
Thanks.
I would say a "challenge" rather than pose a hazard, as you are only compressing a 10 inch coil not a McPherson 18 inch coil? "Man-up??"Thanks.
T
What matters is the spring rate which is governed by the grade of metal used as well as the diameter of the wire and the coils.
The fundamental point is that a spring with a k factor of 350 pounds of axial force required to compress it 1 inch will store exactly the same potential energy as another spring of 350lb/in even if one is compact and the other large and ponderous.
Both will be applying 1400lbs of force on the spring seats when compressed 4 inches in some spring compressors.
It is completely wrong to assume that a physically smaller spring isn't every bit as dangerous as a larger spring. It's only the spring rate and the distance it has been compressed by which matters - absolutely nothing else is relevant whatsoever to forces the springs apply to the tools or spring seats.
Such a fundamentally wrong assumption about how springs work would be a major concern to me and and would make me question whether I really knew what i was doing...
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