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Thread: Are my leaf springs ‘dead’?

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    Pit Crew Decade Plus User onecamohv's Avatar

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    Are my leaf springs ‘dead’?

    Hi Folks, im trying to diagnose a crappy handling problem on my mk2.
    It seems to be ‘skipping’ across rough tarmac/concrete targa rally tests rather than complying. I’ve no confidence in the rear of the car pushing on.

    At the moment, my setup is as follows:

    Single leaf Sport/RS leaf springs, polybushed
    Tramp bars, polybushed
    No lowering blocks – no isopacks – axle bolted straight to the spring
    Bilsten inverted grp1 dampers (piston rod bolted to the axle as opposed to the normal billies) seem in good nick, but unsure of rate?

    It’s hard to explain but it feels like the sag of the rear springs and the feel of them is just ‘dead’ anyone seen this with OEM leafs?
    What’s adding to this theory is the low ride height – this is my car with no lowering blocks, no spare in the boot and about 30L of fuel
    Way too low for a standard spring with no lowering blocks surely?

    Any suggestions /opinions?

    On that note, is there anywhere I can get 85-100lb springs that actually work rather than the 146lb stuff everyone seems to only sell?

    Thanks !





    Last edited by onecamohv; 15-10-2018 at 14:53.

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    Re: Are my leaf springs ‘dead’?

    I take it when you mean the piston rods bolted to the axle you mean that it's mounted to the u bolt plate and not directly to the axle. Are you sure the shockers are still in a good condition and in the std position.?

    Your std rears springs have probably lost some temper and gone soggy making the dampers work overtime. GP1 single leaf springs came in two rates, 116lb and 146lb from Ford back in the day. The problem with the after market springs that are available now is the poundage and ride height are never consistent, you pays your money and takes your chance. There was once a CD6 spring that was a multi leaf and 85lb, whether they are available now I don't know.

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    Re: Are my leaf springs ‘dead’?

    For that kind of rate i would just use std springs

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    Re: Are my leaf springs ‘dead’?

    There is a company in Portaloise that repair & strengthen leaf springs, if nothing else they should be able to test the rate/poundage of your current springs. They can also “adjust” the leafs to increase or decrease ride height.

    I was using single leaf springs on my last car and found it a bit soft at the rear, as a cheap fix I stripped one or two leafs out of an escort multi leaf spring set and fitted these leafs to the single leaf set to increase the spring rate, it worked great. I was able to boost the spring rate by about 30%.

    I (crudely) measured the spring rate by placing a bottle jack on a bathroom scale and compressing the spring by one inch, and seeing how much the scale needle moved on the scale. A spring is measured in pounds per inch, so if a spring is 100 lbs/inch and you apply 100 lbs of weight to the spring it will compress 1 inch, or in my case compress the spring 1 inch and 100lbs will register on the weigh scale, if you compress the spring another inch the scale will register 200lbs. This was all done between two parallel RSJ’s bolted roughly 3 feet apart, so when i worked the jack the only thing moving is was the spring. This can be a dangerous exercise, there is a lot of stored energy when you start compressing springs with car jacks, do so at your own risk, use your head and don’t injure yourself.


    Why do you want 85-100lbs springs? That seems a little soft to me, the car I mentioned above was approx. 115lbs, that was a road car that I wanted to keep comfortable. My tarmac rally car runs 160-180lbs progressive springs on the back and doesn’t feel too hard over rough ground, I think a set of 146lbs springs will be closer to what your need for motorsport use, but it’s your car you know what you want not me!
    Last edited by muckerbarry; 16-10-2018 at 08:01.

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    Pit Crew Decade Plus User onecamohv's Avatar

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    Re: Are my leaf springs ‘dead’?

    Quote Originally Posted by Forest_rallying View Post
    I take it when you mean the piston rods bolted to the axle you mean that it's mounted to the u bolt plate and not directly to the axle. Are you sure the shockers are still in a good condition and in the std position.?

    Your std rears springs have probably lost some temper and gone soggy making the dampers work overtime. GP1 single leaf springs came in two rates, 116lb and 146lb from Ford back in the day. The problem with the after market springs that are available now is the poundage and ride height are never consistent, you pays your money and takes your chance. There was once a CD6 spring that was a multi leaf and 85lb, whether they are available now I don't know.
    yes of course sorry, to the plates. The shocks seem in good cond, no weeping or leaks etc, but of course without getting them tested its impossible to know what the condition of the valving inside is like.

    the 116lb GP1 is exactly what im after, only literally nobody seems to make them? softest you can get seem to be 146.

    Quote Originally Posted by Erikmex View Post
    For that kind of rate i would just use std springs
    i would, but i cant find any that are not 40 years old and the same as mine!

    Quote Originally Posted by muckerbarry View Post
    There is a company in Portaloise that repair & strengthen leaf springs, if nothing else they should be able to test the rate/poundage of your current springs. They can also “adjust” the leafs to increase or decrease ride height.

    I was using single leaf springs on my last car and found it a bit soft at the rear, as a cheap fix I stripped one or two leafs out of an escort multi leaf spring set and fitted these leafs to the single leaf set to increase the spring rate, it worked great. I was able to boost the spring rate by about 30%.

    I (crudely) measured the spring rate by placing a bottle jack on a bathroom scale and compressing the spring by one inch, and seeing how much the scale needle moved on the scale. A spring is measured in pounds per inch, so if a spring is 100 lbs/inch and you apply 100 lbs of weight to the spring it will compress 1 inch, or in my case compress the spring 1 inch and 100lbs will register on the weigh scale, if you compress the spring another inch the scale will register 200lbs. This was all done between two parallel RSJ’s bolted roughly 3 feet apart, so when i worked the jack the only thing moving is was the spring. This can be a dangerous exercise, there is a lot of stored energy when you start compressing springs with car jacks, do so at your own risk, use your head and don’t injure yourself.


    Why do you want 85-100lbs springs? That seems a little soft to me, the car I mentioned above was approx. 115lbs, that was a road car that I wanted to keep comfortable. My tarmac rally car runs 160-180lbs progressive springs on the back and doesn’t feel too hard over rough ground, I think a set of 146lbs springs will be closer to what your need for motorsport use, but it’s your car you know what you want not me!
    thanks for the info, i thought about doing that, but then couldnt be arsed. do you know the name of the company?

    na not too soft for what we do, its at a must slower speed than tarmac or forestry rallying, and i need the rear to be as compliant and soft as is generally possible while still handling. i tried 146 before and it was cocking a wheel during tight tarmac tests which was a disaster, it handled terribly unless i was flat in 4th through a forest, which happens on occasions but i need it to handle the slower stuff also.

    any road rally guys on here can share what they are running?

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    Re: Are my leaf springs ‘dead’?

    Not sure the company name, Portlaoise springs maybe. Have a google.

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    Re: Are my leaf springs ‘dead’?

    Quote Originally Posted by onecamohv View Post




    any road rally guys on here can share what they are running?
    116lb Genuine Ford single leafs for me. I was very, very lucky to drop on a pair of barely used ones that had been in someones shed since the mid 80’s.
    I tried 146lb and they were too hard.

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    Re: Are my leaf springs ‘dead’?

    Try a softer damper (like Koni yellow, or Bilstein fast road), it's just 4 bolts (2 each side).
    Had GP1 Bilsteins on my roadrally car and found them too hard.

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    Re: Are my leaf springs ‘dead’?

    I have group one Bilsteins rs springs anti tramp bars pretty much the same spec as yours and it feels great everywhere.

    One thing your tramp bars aren’t binding up under suspension movement I had to redo the mounts on a friends mk2 as they weren’t welded on parallel so they were binding up

    Have you tried running without the tramp bars?
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    Pit Crew Decade Plus User onecamohv's Avatar

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    Re: Are my leaf springs ‘dead’?

    i actually considered that and actually cut the brackets off the axle and welded on new ones to be sure!

    what height does your car sit at though? as low as mine?

    thanks for the feedback guys, i heard from nearly everyone that 146lb springs are too hard so il avoid. #
    il keep a look out for decent 116 if i can! might also try a firends set of dampers see if it feels any different

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    Re: Are my leaf springs ‘dead’?

    Working at Dougherty’s Ford in Runcorn in the 1980’s Ford OE single leaf springs would regularly sag and break on Mk2 Escorts. If yours are original equipment I would say they may passed their prime!
    Are we there yet?

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    Re: Are my leaf springs ‘dead’?

    Quote Originally Posted by muckerbarry View Post
    There is a company in Portaloise that repair & strengthen leaf springs, if nothing else they should be able to test the rate/poundage of your current springs. They can also “adjust” the leafs to increase or decrease ride height.

    I was using single leaf springs on my last car and found it a bit soft at the rear, as a cheap fix I stripped one or two leafs out of an escort multi leaf spring set and fitted these leafs to the single leaf set to increase the spring rate, it worked great. I was able to boost the spring rate by about 30%.

    I (crudely) measured the spring rate by placing a bottle jack on a bathroom scale and compressing the spring by one inch, and seeing how much the scale needle moved on the scale. A spring is measured in pounds per inch, so if a spring is 100 lbs/inch and you apply 100 lbs of weight to the spring it will compress 1 inch, or in my case compress the spring 1 inch and 100lbs will register on the weigh scale, if you compress the spring another inch the scale will register 200lbs. This was all done between two parallel RSJ’s bolted roughly 3 feet apart, so when i worked the jack the only thing moving is was the spring. This can be a dangerous exercise, there is a lot of stored energy when you start compressing springs with car jacks, do so at your own risk, use your head and don’t injure yourself.


    Why do you want 85-100lbs springs? That seems a little soft to me, the car I mentioned above was approx. 115lbs, that was a road car that I wanted to keep comfortable. My tarmac rally car runs 160-180lbs progressive springs on the back and doesn’t feel too hard over rough ground, I think a set of 146lbs springs will be closer to what your need for motorsport use, but it’s your car you know what you want not me!

    those guys in portlaoise are going to "un" camber my spings back to stock height and test them, then can modify them if necessary - seem like great guys, thanks!
    il report back.
    ideally id want to be in the CD6 - CD8 category so inaround 90-100lbs so lets start there and see if i need new dampers after that. cheers

    on that note, does anyone know the damping rates of the 'upsidedown' bilstein rear dampers or what they're designed for?

    thanks
    Last edited by onecamohv; 29-11-2018 at 16:03.

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    Re: Are my leaf springs ‘dead’?

    Quote Originally Posted by onecamohv View Post
    those guys in portlaoise are going to "un" camber my spings back to stock height and test them, then can modify them if necessary - seem like great guys, thanks!
    il report back.
    Great stuff!
    Ive dealt with those boys in portlaoise twice, they were on the ball and very helpful.

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    Pit Crew Decade Plus User onecamohv's Avatar

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    Re: Are my leaf springs ‘dead’?

    yep seem dead on, and said they'll do it while i wait on a saturday, thanks for the info

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    Re: Are my leaf springs ‘dead’?

    Quote Originally Posted by onecamohv View Post
    on that note, does anyone know the damping rates of the 'upsidedown' bilstein rear dampers or what they're designed for?
    The upside down Bilsteins are the older type of rear damper. For the unsprung weight this is better. Later in life Bilstein changed the constrcutuion of the dampers. Rating of the GP1 items is 207 / 100 (rebound/ bump).

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    Are my leaf springs ‘dead’?

    Quote Originally Posted by Miniliteman View Post
    The upside down Bilsteins are the older type of rear damper. For the unsprung weight this is better. Later in life Bilstein changed the constrcutuion of the dampers. Rating of the GP1 items is 207 / 100 (rebound/ bump).
    Thanks for the info - 100 seems very stiff for a rear damper?

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    Re: Are my leaf springs ‘dead’?

    Quote Originally Posted by onecamohv View Post
    Thanks for the info - 100 seems very stiff for a rear damper?
    Look at my earlier reply (8)

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    Re: Are my leaf springs ‘dead’?

    Quote Originally Posted by onecamohv View Post
    i actually considered that and actually cut the brackets off the axle and welded on new ones to be sure!

    what height does your car sit at though? as low as mine?

    thanks for the feedback guys, i heard from nearly everyone that 146lb springs are too hard so il avoid. #
    il keep a look out for decent 116 if i can! might also try a firends set of dampers see if it feels any different

    I think yours sits a bit higher than mine.
    I use inch lowering blocks on mine to get the height
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