Gme parabolics hard ride

[youngengineer]

I recently installed some GME parabolic springs on the front and rear of my series 3 military 109.

I was expecting quite a noticeable difference from my rusty OEM springs but in all honesty the difference has been very subtle.

When I tightened the bush bolts down I used an impact gun on medium setting whilst the car was jacked up on blocks which would have been at maximum articulation. 

Have I possibly overly tightened the bolts leading to reduced articulation?

I may have incorrectly assumed that the bushes would move freely within the ends of the leafs regardless of the toque setting of the bolts.

I'm running new britpart shocks. I'm not expecting coil smoothness but it still feels like a rough ride to me.

 

Edited January 1, 2020 by youngengineer

[Retroanaconda]

The bushes shouldn’t move within the spring eye at all. The outer sleeve is an interference fit with the eye so is fixed to the spring. The inner sleeve is clamped between the shackles by the bolt, so is fixed to the shackle. All the movement is within the rubber.

The bushes should be tightened with the vehicle sat on all four wheels in a normal level condition. So you may want to redo them. Not sure if it would cause your ride quality issue, but it will damage the bushes if not rectified.

[youngengineer]

Thanks for the fast response. I shall retorque the bolts with the vehicle flat on the ground and see if that improves things. I heard many people complaining about parabolics being too soft so I was quite suprised to find them almost as stiff as the 40 year old leafs. Hopefully it's a simple fix.

[lo-fi]

You might be surprised how much of a difference tightening the bushes incorrectly will have. As said, you'll also wreck the bushes very quickly unless the bolts are tightened with the vehicle at ride height. New dampers can take seem very firm too and sometimes take time to settle. 

One other thing worth mentioning: never fully tighten safety critical bolts with an impact gun. It's very easy in some situations for an impact gun to "bounce" giving the illusion its tightened. Its also all too easy to over tighten a fastener, so as a rule best avoided unless you're simply using it to whizz a bolt down using the lightest setting, then finish with the proper tool and torque setting. 

[youngengineer]

8 minutes ago, lo-fi said:

You might be surprised how much of a difference tightening the bushes incorrectly will have. As said, you'll also wreck the bushes very quickly unless the bolts are tightened with the vehicle at ride height. New dampers can take seem very firm too and sometimes take time to settle. 

One other thing worth mentioning: never fully tighten safety critical bolts with an impact gun. It's very easy in some situations for an impact gun to "bounce" giving the illusion its tightened. Its also all too easy to over tighten a fastener, so as a rule best avoided unless you're simply using it to whizz a bolt down using the lightest setting, then finish with the proper tool and torque setting. 

 

15 minutes ago, lo-fi said:

You might be surprised how much of a difference tightening the bushes incorrectly will have. As said, you'll also wreck the bushes very quickly unless the bolts are tightened with the vehicle at ride height. New dampers can take seem very firm too and sometimes take time to settle. 

One other thing worth mentioning: never fully tighten safety critical bolts with an impact gun. It's very easy in some situations for an impact gun to "bounce" giving the illusion its tightened. Its also all too easy to over tighten a fastener, so as a rule best avoided unless you're simply using it to whizz a bolt down using the lightest setting, then finish with the proper tool and torque setting. 

I try to avoid using the gun for final torque settings. But in this case I did all four springs in an afternoon so it was a quick job. I can loosen then and re-torque. Is there a reference for torque settings?

[Cornish Rattler]

1 hour ago, youngengineer said:

 

I try to avoid using the gun for final torque settings. But in this case I did all four springs in an afternoon so it was a quick job. I can loosen then and re-torque. Is there a reference for torque settings?

I've had the same problem with mine, when i was building my new galv chassis up on new paras i just ratched the bolts up and found the the springs was very soft and stayed like that till i had finished the rebuild then when it was ready for its MOT i tightened them up with a torque wrench and i found them very hard, someone said try slacken them off and load the landy to normal working load and retighten which i did and are still the same i have the engine out at the moment so once its back in i will slacken them off and ratchet them up again and see what hapens .

[Chicken Drumstick]

Is the vehicle sitting higher too? You may want some longer shocks if they are fully extended. Also a good modern shock is likely to help. The pics look like you have 2 and 3 leaf parabolics, they should be softer than the stock leaf packs. Although remember there will still be limitations of being a leaf sprung vehicle.

I'd also look at using as many polybushes in your setup too (remember to grease them too).

[David Sparkes]

On 1/1/2020 at 2:18 PM, youngengineer said:

 

....  Is there a reference for torque settings?

Series 3 Workshop Manual.

[jerboa]

 

On 1/1/2020 at 1:00 PM, youngengineer said:

I was expecting quite a noticeable difference from my rusty OEM springs but in all honesty the difference has been very subtle.

I picked up on this comment - I installed some Rocky Mountain Parabolics a few years ago. Supplied as part of a set, to include Pro Comp 3000 Series Shock’s, they may have been 9000 series shock. Whilst I could tell the difference within a metre of driving it, I went on to have exactly the same thoughts. After having been in my mates truck cab, ex-mil 109" with coil-spring smooth ride (which is what convinced me to buy them in the first place) I was mildly disappointed in the outcome of my venture.

Now, when I spoke to my mate about it - he said that is what he thought about his springs when he put them on. He put it down to the shocks - and swapped them out for standard range rover shocks - albeit by modifying the shock mounts. Solved the problem for him. I have not done mine as my LR has been laid up for various reasons. I did not get chance to try to put some miles on either.

Incidentally, the price of the complete set of springs, shocks etc from Rocky Mountain has more than doubled in the time that I've had them.

 

Also, I loaded my 109" Station Wagon up with about 330kg of sandbags prior to tightening the bolts. To set the bushes about half way between laden and unladen. Not sure looking back if that was the right thing to do...

[FridgeFreezer]

Switching from ProComp to Bilstein 5125 shocks (as suggested by ToyRoverLander) transformed my 109's ride on TIC parabolics.

[youngengineer]

On 1/5/2020 at 9:08 PM, jerboa said:

 

I picked up on this comment - I installed some Rocky Mountain Parabolics a few years ago. Supplied as part of a set, to include Pro Comp 3000 Series Shock’s, they may have been 9000 series shock. Whilst I could tell the difference within a metre of driving it, I went on to have exactly the same thoughts. After having been in my mates truck cab, ex-mil 109" with coil-spring smooth ride (which is what convinced me to buy them in the first place) I was mildly disappointed in the outcome of my venture.

Now, when I spoke to my mate about it - he said that is what he thought about his springs when he put them on. He put it down to the shocks - and swapped them out for standard range rover shocks - albeit by modifying the shock mounts. Solved the problem for him. I have not done mine as my LR has been laid up for various reasons. I did not get chance to try to put some miles on either.

Incidentally, the price of the complete set of springs, shocks etc from Rocky Mountain has more than doubled in the time that I've had them.

 

Also, I loaded my 109" Station Wagon up with about 330kg of sandbags prior to tightening the bolts. To set the bushes about half way between laden and unladen. Not sure looking back if that was the right thing to do...

Thanks for the advice. Last night I re-torqued all the bushing bolts to 90NM and there has been no difference. 

On the topic of shocks however, I did noticed that the OEM shocks dampened both on forward and return whereas the Britparts only on return.. Hmm I would assume that dampening on compression would make the ride very hard. Either way Britparts dampen only on return so I cant see any improvement to be made from procomps. I may be wrong.

Edited January 11, 2020 by youngengineer

[Snagger]

Comparing my original springs, also rusty, to how my Heystee HD (3 leaf front and 4 leaf rear) behave is chalk and cheese.  I did have Procomp ES9000s as part of the kit, but later replaced them with 3000s which gave a far better ride, but even with the 9000s, it was better than the old springs.  Like the others, I think your problem is the dampers.

[youngengineer]

Just thought I would add to this thread after around two years of heavy use. 

The Britpart shock's ended up being the problem.

The ride quality continued to worsen to a point where I could no longer bare to drive the vehicle. 

I could feel every crack in the road, every pebble. Hitting a speedbump and more then 10mph would send you through the roof.

When I removed the shocks completely the ride was transformed to coil like softness. The Britpart dampeners had almost seized and becoming very hard and notchy. (They were bad to begin with)

 

I am now looking at Bilstein 5125 as recommended. Never touching Britpart again.

Edited April 10, 2022 by youngengineer

[Cornish Rattler]

18 hours ago, youngengineer said:

Just thought I would add to this thread after around two years of heavy use. 

The Britpart shock's ended up being the problem.

The ride quality continued to worsen to a point where I could no longer bare to drive the vehicle. 

I could feel every crack in the road, every pebble. Hitting a speedbump and more then 10mph would send you through the roof.

When I removed the shocks completely the ride was transformed to coil like softness. The Britpart dampeners had almost seized and becoming very hard and notchy. (They were bad to begin with)

 

I am now looking at Bilstein 5125 as recommended. Never touching Britpart again.

I replaced mine ( britpart std shocks ) for britpart Dinamique ones and the ride has been trans formed from britpart std shocks 🙂

[youngengineer]

2 hours ago, Cornish Rattler said:

I replaced mine ( britpart std shocks ) for britpart Dinamique ones and the ride has been trans formed from britpart std shocks 🙂

Those are the gas/foam filled ones?

 

Do you have photos or a video of articulation? 

[Cornish Rattler]

9 minutes ago, youngengineer said:

Those are the gas/foam filled ones?

 

Do you have photos or a video of articulation? 

No sorry as i don't off road it but do carry a roof tent and making the back of my landy into a camping / cooking area as well so adding the weight seems to make it feel better 🙂