Castor problem?

[blakesrover]

I've posted on other forums but haven't posted here yet.

2" OME lift on disco 1. before the lift, truck drove great. now that it's lifted, truck drives "tight". No problems with wandering at all, only a VERY responsive steer..so much that any little touch changes the course of the vehicle. theres absolutely no play. a perfect example of the steering is when at a stop making a right hand turn, the truck will not correct itself back to center. I have to manually steer it back to center.

There is a very, very slight vibration upon acceleration but is not felt at constant speed, whether on streets or highway. (It's not bad at all)

so...what to do first? could it just be toe in/out and need adjusting? do i need to look at castor correct rad. arms, re-drilled swivel balls, DC drive shaft, DDC drive shaft?

thanks!

~Blake

 

[ntsqd]

Sounds like Caster to me. Lacxk of Return to Center is very indicative of that. If it were toe-in/out you'd be complaining of 'Dartiness' or excessive tire wear.
Sorry, no idea what the fix is. You can't be the first to run into this. Anything about this posted on Rover forums?

 

[Rovernut]

Normally a 2" lift won't cause that "driving on edge" feeling. 3" and up will, and requires caster correcting arms or caster corrected swivel balls. Try waiting on your springs to settle a bit before changing anything else on the front end. If they settle, and most do, maybe the problem will go away. If not, a good remedy is a TrueTrac limited slip in the front.

The vibration you feel is from the rubber donut at the rear of your rear drive shaft. Replace it with the drive shaft from a Range Rover ( SWB Classic) along with the yoke and spacer from the RR diff. That'll fix the vibes.

 

[MattScott]

The vibration you feel is from the rubber donut at the rear of your rear drive shaft. Replace it with the drive shaft from a Range Rover ( SWB Classic) along with the yoke and spacer from the RR diff. That'll fix the vibes.

The rotoflex would eat the vibes if it is in good shape, as well as the inner rubber bushing. The u-joint wouldn't eat the vibes up.

 

[blakesrover]

it's not that i'm looking for a changed answer. it's actually giving more and more insight when people offer comments/solutions/opinions. Because of more feedback on other forums, i've already concluded a few stock components which aren't causing problems i.e. rotoflex is fine

even your most recent post on

you are used to having caster...now you have almost none

that helps me understand a little bit more about caster in the sense that i must have lost caster with the lift and need to gain some back. how many degrees though? i dont know. all this stuff is brand spankin new to me..so the learning curve is in full affect.

 

[UK4X4]

castor angle, as others have mentioned,

the remedy

New suspension arms castor corrected, Rovertyme will advise on what you need and the large bill to suit

I had a 4" lift on my disco 2- yep never centered on its own- did I care - no

Its a truck, drive it like one with two hands.

As soon as you mess with a vehicles suspension, handling and steering feel changes, thats just a simple factoid

Vibe you also have a front d - shaft

 

[Snagger]

The lack of self centring and feel on the steering is definitely down to the reduction in castor angle. You can get the expensive corrected radius arms, or you could buy corrective bushes with eccentric centres to correct the castor angle while retaining the existing arms.

The vibration could be either prop shaft. The rotoflex used on RRC rear props is only problematic if perished and split/deformed. If it's in good order, it'll absorb vibration because it is made to act as a driveline damper - that's why it was fitted to the LR flagship before it went ontop the Discovery, and why it was never used on the more agricultural Defender. I'd take a close look at the UJs as well as the rotoflex.

 

[dallasrover]

With it being a D1, I assume it has fair milage on it. Has it ever had the motor/trans mounts changed out? This solved about 90% of my vibration concerns.

 

[UnfrozenCaveman]

Be forewarned, if you "fix" the steering feel issue with a Tru-Trac and drive in snow and ice you will not be happy.

been there...done that...still driving the crazy thing.

 

[Mike_rupp]

I drove for years in Chicago and now for the last 3 winters here in WA with a True Trac and have never had any complaints in the snow and ice. I do agree though that the True Trac masks the caster problem. My complaint with the TT is that when you are in a long turn such as an on ramp and don't maintain constant throttle, the steering wheel gets really jumpy.

 

[blakesrover]

if re-drilled swivel, castor corrected arms, and DC shaft upfront cures both castor and vibration, is there a need for a TT? and if so, what is the need?

second, do guys run TT upfront to replace front lockers or is it purely for steering correction (band-aid)?

third, my application came with center diff. what would be more beneficial as a whole; lockers in the rear or upfront?

~Blake

 

[revor]

Here's what I've done. Do the caster corrected arms, If that completely blows your no vibe world put in a DC driveshaft.

In reality a D1 should have come with one from the factory, instead they chose to do some sort of wierd "off phase" arrangement with the single cardon shaft.

Look at the factory alignment of the pinion shaft and the output shaft of the t case. in many cases that I have seen the pinion actually points to a point above the output shaft of the t case. Bringing that down so that the pinion points directly at the output shaft indicates that you'll likely need a DC shaft because you've messed with the factory driveshaft black magic.

Or you can do the caster corrected balls, both have benefits.

 

[Snagger]

Using a locking diff would be masking the problem, not curing it, and could lead to all sorts of odd effects on different surfaces. It may have no help at all in keeping the vehicle straight after a front tyre blow out, which correct castor angle does help with.

Don't elongate the swivel housing bolt holes to do this - it's a terrible botch. Firstly, it's inaccurate, and you'll probably end up with uneven castors from side to side. Secondly, it removes a lot of material from under the bolt head (up to 40% loss) so creates a serious weakness in the joint and will likely end up at some point in the bolts shearing or the swivel flange cracking.

Do the job properly and use either castor corrected radius arms and standard bushes, or standard arms and corrected bushes.

A double cardan jointed front prop will probably be of benefit - the front UJ will have been set to a near straight position by the lift while the rear will be more steeply cranked, which will render the factory UJ phasing out of required spec. The rear is unlikely to be a problem unless you have a worn UJ/rotoflex.

 

[stevenmd]

Do the caster corrected arms, If that completely blows your no vibe world put in a DC driveshaft.

x2 - should fix everything.:costumed-smiley-007

 

[ntsqd]

Even though it might work for 99% of the folks using it, that doesn't make it the correct way to do it. This is analogous to disproving a theory. All it takes is one event that does not behave according to the theory to blow the theory out of the water.

I wouldn't desire to be that 1% for whom it did not work, so I would not put myself in that position nor will I advise others to do so. The potential for a catastrophe is large.

If the change needed was large enough that new holes had to be drilled, and they were far enough away from the existing holes that the bearing area under the bolt heads would not eclipse the existing holes, then I'd say go for it.