Thread: Defender, new suspension now has vibration

Originally Posted by LoveMyV8County

I love this forum! I am troubleshooting this exact problem which occurs in exactly the same 80 -> 60km/h speed range.

I believe it is the UJs on the rear prop that are worn and the lift has revealed the problem. When I dropped the rear height an inch or two (air suspension) the vibration reduced noticeably. I know it's not the front because I experienced it with the front prop removed.

Hope to have a definitive answer this weekend after I replace the bearings and spiders.

Chris

My defender has 50mm lift springs and it vibrated,I removed the back ones and fitted standard so it would sit level and the vibration left,lowering the rear should put more angle on the front so it should make it worse but it didn't. Pat

Originally Posted by BigJon

The general concensus seems to be that slotted swivels are a much better method of correcting castor after a suspension lift.

Cranked arms / correction bushes will make the driveline angles worse and castor correction bushes tend to be very hard (limiting suspension flex) and wear out quickly.

I am not a fan at all of castor corrected bushes - never use them now, always corrected arms.

Using the rotated swivels does correct the castor problem, but doesnt necesserily re-align the axle to a position normal to the spring and damper, it also doesnt relieve stress on the rear radius arm bush. To that end the springs can continue to want to pop out of the top holders and extra stress is placed in the bottom damper retaining stud.

I realise that there is always more than one way to skin a cat - each to there own I suspect. I prefer corrected arms as this addresses all issues. Using the correct "corrected arms" does NOT make the drive line (propshaft??) angles worse, exactly the opposite!! Rotated swivels on the otherhand do nothing to correct propshaft angles.

It all sorted thanks for the help

i have flogged out castor correction bush's was wondering if that was causing my wobble when turning right only.

Originally Posted by Yorkshire_Jon

<snip>

Using the correct "corrected arms" does NOT make the drive line (propshaft??) angles worse, exactly the opposite!!

It has to Jon.
If the diff housing is angled to increase caster due to a lift, the pinion angle is altered relative to the driveshaft.

Slotting the swivels is a far more elegant solution for caster correction IMO.

Rotated swivels on the otherhand do nothing to correct propshaft angles.

No they don't, they don't bugger them up in the first place which is what happens when caster corrected bushes or bent arms are utilised.

That's why you adjust the caster at the swivel, so the pinion angle isn't altered.

had same problem NOZ had the tyres balanced a few times, and i will check once i return from here. THanks for the ideas

Originally Posted by rick130

It has to Jon.
If the diff housing is angled to increase caster due to a lift, the pinion angle is altered relative to the driveshaft.

Slotting the swivels is a far more elegant solution for caster correction IMO.

No they don't, they don't bugger them up in the first place which is what happens when caster corrected bushes or bent arms are utilised.

That's why you adjust the caster at the swivel, so the pinion angle isn't altered.

100% correct Rick.

cheers, DL

i have just fitted a very soft 3" lift to mine, so its actuly just under 3",

and now i have a vibration on exactly 55kph, im suspecting the front prop, and i no my props are perfect so there not flogged out, i think its just that there is to much angle now,, and need to fit a double cardon joint,

i have allso noted on mine that there is no prob with the caster as mine dose not wonder at all,, in fact i think it dirves better then befor other then the vib at 55