Vibration / Shutter on Take Of

[david allan]

greg
did you try the spacers beforemaking the centre rubber harder

[GregSR]

No, in my eagerness (and waiting for the Sikaflex to dry) I stuffed up the first rule of research, make 1 change at a time.

I stiffened the bearing dampener and added the 25mm spacer, great result, small amount of vibration left but only noticable if you know what to look for.

I then decided (God knows why) that the benefit was gained through the Sikaflex not the spacer and replaced the 25mm with a 20mm, shudder returned, reduced from before Sikaflex but noticeable.

25mm back in, great again.

[david allan]

Bringing this thread back to the top.

Im considering upgrading my rear OME Med leafs to the heavy duty ones by adding an extra leaf.

I have learned to live with the vibration that the lift has caused.

But the concern that I have is, if I add an extra leaf in will this cause the vibration to get worse?.

For the guys that have had a vibration/shudder problem
-what rear suspension did you get (med/heavy etc)
-how much lift did you get when the vibration was experienced
-have people experienced a vibration with the med leafs.
- Reading above matske said he had a vibration problem when he had the OME heavy duty leafs, but then he removed a leaf, which turned it into a med leafs & now the vibration had dissapeared. Have other people experienced this

Any thoughts would be appreciated

[david allan]

matsake

am curious that ur vibration has gone after you removed a leaf which made it into a med rating lift.

Did the vibration disapear coz it actually sat lower in the rear when the leaf was removed?.

how much higher did it sit with the extra leaf.

After this long weekend, im really considering putting an extra leaf in (Have med at moment) just to hold the rear better when you put the weight in.

[Skog07]

David.
If you are going to put the 400kg constant springs in you will find the ride particulary harsh if you drive around empty all the time. Especially with the LT tyres. I would "Air bag" it as it is a good go between as you get the benefits of still having the medium springs and rasing the pressure when you put a heavier load in. The heavy springs wouldnt really solve the problem of drive line shudder it is a drive shaft angle issue that has to be shimmed to correct it. There is some good info in the above posts.
Cheers
Skog

[david allan]

skog

you are right in saying that i wouldnt get the same ride quality as the med springs. But i dont think it would be that much worse by adding a leaf in.

The real concern that i have is, if i put the extra leaf in, then will it make the vibration worse.
I think the more you raise the vehicle the greater the vibration will be.
So i wonder how much higher it will get with an extra leaf in.

I remember that when the suspension was new, it did sit higher and the vibration was worse than it is now as the rear has settled abit.

Really adding an extra leaf shouldnt cause a huge detoriation in ride quality, should it?.
Except again for the unkown vibration getting worse maybe

[Skog07]

David.
You will probably find that the vibration will get worse due to the driveline angles increasing due to the lift and increased spring rate, causing the whip shudder problems previously mentioned. And the arse end wont even compress on the slightest bump causing a jackhammer effect coming through the suspension which would be far more unpleasant than the shudder itself.
Have you weighed the amount of gear you put in the back and how much ball weight the boat puts on the hitch. Alot of adjsuting can be done with the trailer axles itself as well.
Post a photo up with the boat connected. The good thing about the bags are they they are infinately adjustable, the springs are fixed. The only adjustment is tyre pressures.
Hope this helps.
Cheers
Skog

[GregSR]

David,
The shudder is caused, as Skog says, by driveline angles.
There is a shit load of technical detail to driveline angles that I won't pretend to understand.
I spent a full day with a bloke who does this stuff for a living, we tried a lot of different setups.What experimentation took us to is, drop the centre bearing by 25 mm and using 3 degree wedges between the diff and the leaf packs.All I can say is two things,
1/ It works great, I think smoother than with the original suspension.
2/ I'm not saying this setup will work for others, but it's worked a treat for me.So, it's not about an extra leaf or not, it's about the driveline angles and it can be fixed.

[david allan]

mark.
Thats what i was worried about. If i do put an extra leaf in then it would increase my driveline angle causing the vibration to get worse.
Yeah you are prob right that the arse wont properly compress when it is unloaded causing the rear to be an uncompfortable ride.

I would say i have the following constant weight during the week.
Fuel 70kg
Rear step tow bar 50kg
hard cover 20kg
misc 50-100kg
Total Max 240kg approx

On weekends/travelling
Total above 240kg
Boat 100kg say
Other 100kg - 150kg say
Total weekends/ travelling 490kg approx say

Interesting if anyone has the constant 400kg & drives around with minimum weight. What is it like?

Would getting the constant 400kg leafs from ARB be the same as putting an extra leaf into the med ones.
or are the med ones a different spring rate than the constant 400kg ones

Greg
When i had the vibration originaly I tried (ARB) lots of different things like putting wedges in & dropping the centre bearing. But nothing would help. Just learned to live with it. Just dont wont it to get worse if an extra leaf is added.
Toyota also had a look at it & said they couldnt do anything unless the original suspension was put back

Dave

[Skog07]

Dave.
Here is what I carry around in mine day to day as traveller and work truck.
Longrange tank. 140l from empty to full. The tank itself weighs 30 kg without fuel. I still have the original plastic which weighs at least 10kg.
So 100 kg for fuel avg
E size Argon bottle 30kg
Welder 10kg.
Welding rods. 15 kg.
Tool box. 20kg
Tools. 150kg.
Plus all the accessories. Bullbar, winch, dual batts
My fat arse 105 kg ( being kind) lol
Miscellaneous equipment 0 - 30kg.
Plant trailer. Weigh bridged at 2.2 tonne with a ball weight of 200kg.
Recovery gear. 10 kg
Hope this gives you a little idea of the weight that I carry around, the plant trailer does not get towed every day.
Alot of the heavy gear gets pulled out when we go camping but camping gear itself weighs alot to.
Hope this helps
Cheers
Skog

[GregSR]

Dave,

The difficulty is that no-one can really say wether it will get worse or not unless they have done exactly the same thing as you are suggesting.

The extra leaf will make the angles worse,

By how much? I don't know.

Will it effect the shudder? I don't know.

Have ARB or EFS done enough research on their product to inform their customers? No!



Good Luck.

Greg

[david allan]

ARB said that adding an extra leaf will not make the shudder worse but then again they say that they have never heard of a hilux vibrating except for mine, what a load of .......

I drove a stock standard hilux on weekend & noticed that the rear stock suspension is firmer than my ARB med setup. Does this mean that the rear stock suspension would handle the weight better than mine?.

In theory if I add an extra leaf then it will firm up the arse making it like the stock standard suspension but with extra height. Does this sound right

[hiluxdan]

David,
Like Greg says the extra leaf will increase your driveline angle=increase vibration.
I wasn't happy with the height/load carrying capacity of my first efs comfort springs which did produce the vibration. Went with the next heavier one up and vibration got heaps worse with the extra 40ish mm.
Only thing that has helped was fitting the wedges and spacing the centre bearing.
Oh yeah and i hardly feel it now that i've fitted cooper stt's. lol.
Dan

[david allan]

dan

how much lift did you get with the comfort ones for stock standard.
And how much lift you got above stock standard with the heavier ones.

Who fixed the vibration by fitting wedges & spacers

[hiluxdan]

Only got about 20mm with the comforts over stock but went up to about 60mm over stock with the heavier ones.
Local suspension mob on the Gold Coast, PM me if you want some details to give him a call.
Dan

[paynebrody]

Just sharing my learnings. I just installed the Iron Man 'add a leaf' which lifted the rear end of my single cab kun26 slightly, along with a 35mm Lovells lift at the front. I started getting a resonant driveline related vibration at approx 5km/h, i.e. just taking off or just coming to a stop. After a week of faffing about and reading, this is what I found:

- If the input and output flanges (i.e. the trans case output flange and the diff pinion input flange) on a two piece drive shaft are not parallel, then the output flange will have a non constant velocity. I.e. its rotational velocity will be sinusoidal (i.e. it will pulse faster and slower). If the input and output flanges are parallel, and the yokes are correctly phased, then this sin wave velocity profile is cancelled out between the input and output yokes, resulting in a constant rotational output flange velocity
- If the output flange rotational velocity is sinusoidal (or pulsing), then even a well balanced driveshaft may vibrate, hence balancing a driveshaft probably wont totally fix this issue
- Shimming the centre bearing, in theory, will not alleviate this issue either as the parallelism of the input an output flanges will not be affected by the collinearity of the two driveshafts, i.e. even if you make the two drive shafts share the same rotational axis, the input and output flanges will still have a relative angle between them
- Adding leaf spring wedges or angled shims adjusts the pinion flange angle, or rear axle castor, relative to the trans case output flange and is the only (easy) way to make the in/out flanges parallel (you could also adjust the resting position of the trans case but this is much harder than adding leaf shims)
- ALL THAT BEING SAID, I did mess around with packing out the centre bearing because I was going on a trip and didn't have time to order or buy any wedges. I also did measure the relative angle between my input and output flanges and because the angle was as close to 0 as I could measure (i.e as close to parallel), I thought I might be able to get away without wedges (though it is possible the measurement was out by say 1deg, and even this small discrepancy will have an effect apparently)
- I used washers to play around with different centre bearing offsets, starting by packing the bearing down by approx 5mm, then 10mm, then 15mm, 20mm etc
- Only after I added 25mm worth of washers did I notice a significant reduction in vibration, i.e. almost gone. This created a slight angle between the two shafts. There is still the faintest vibration but enough to live with
- Not a good idea to use washers as they will prob allow the bolts to loosen over time so I machined some aluminium spacers of the same dimensions to fit permanently

Not sure what the moral is. I guess check the in/out flanges are parallel first. If they are pretty close, then maybe packing the centre bearing will help but you will need at least 20-25mm spacers. If your in/out flanges are off by 1-5 deg, you will likely need to add angled leaf shims as neither packing the centre bearing nor balancing the driveshafts will help as these are not the root cause/s of the issue.

[paynebrody]

Just realised the last post was 10 years ago lol. Hopefully that still helps someone...

[aandy]

Interesting write up Payne.

Having gone through this years ago and coming to similar conclusions I’ll add my bit.

I first tried lowering the centre bearing and it did help a little but the vibration was still there.

I measured the flange angles with varying loads onboard and varying positions on the flattest slab I could find, I graphed my readings as they were all over the shop and came to a conclusion that I did have at least a few degrees difference.

I adjusted the diff input flange angle in an attempt to match trans output flange angle, not with wedges but by separating the leaf spring pack with a wedge and cutting an amount, 10mm at a time, off the end of one of the leaves.
After the final cut and success with the vibration problem I chamfered and painted the cut leaf.

It would have been interesting to get more measurements after this but I couldn’t be bothered and the reliability of my first measurements was poor anyway. In the end it was basically experimental.

That was 100k smooth kms ago.

[paynebrody]

Thanks aandy. Thats interesting, I didn't consider trimming leafs as an option. Will have a think about that!
Brody