Patrol/Safari bits for Sani

[davidvdm]

Sorry guys, I can't keep up posting on three forums, even though I think this forum is probably going to be giving me the most info in the long run with the entire drive train and suspension being converted to Patrol/Safari..

So as far as I can figure, we got our hands on a 83(or there abouts) Safari/Patrol MQ. Runs on a C200 diff on the front and the H260 on the rear.

We stuffed a one tonner hardbody set of leaf springs under the front end in the same orientation it would be found on the rear of the Hardbody. Fixed mounting facing forward and the shackles facing rear. This setup seemed to make sense as it brought the diff forward slightly (100mm) and gave us good castor angle.

But the leafs were too soft and went inverted the first time we dropped the Sani onto his wheels. Our compression was too much and settled with only 30mm between the diff and the sump. We are running with a SOA so that we can keep the front spring mounts tight against the original chassis. With the orientation of the springs as we had it, the short end of the springs facing to the front of the car also made our extension past the front of the chassis a mere 120mm or so.

But the leafs were at there limit and very hard at this point. Trying to bounce the car reminded me of my SJ410 bare chassis bounce (there was just about nothing).

While changing ideas with Ricster, he managed to find a set of Patrol springs. Thanks to Dirk on the forum for the donation of said springs front and rear coils.

So off the bat we knew the two spring packs were going to be to hard (or so we and many other forum member thought). We removed two of the blades from the spring spring pack immediately and shoved the coils in place. Amazingly everything was much softer. The car bounced (nearly uncontrollably). What we had done was lift the leafs into a softer segment of there movement arc. Dropped the car by about 100mm to get back to a stiffer place and constructed coil buckets.

Continued next post, having power problems and just lost me previous post.....

[davidvdm]

After all was in, we managed to keep the lift from original IFS hight to a mere 130mm. Our one problem that has now haunted us, is that our Castor has gone to 7.5deg. With the backside still running standard height (130mm down), the Castor is as 9,3deg.

Yesterday it looked like we were nearing our goal. We got our brake lines extended, and steering arm off the top kingpin position built and a steering arm from a new Pitman arm off the steering box.

A set of second hand Landy D2 shocks was donated by a community forum member, but we realised we were not going to have time to get that installed last night. But as the excitement of having a car that could actually steer and brake, we could not contain ourselves to take it around the block.

With the backside hanging it feels nothing but weird. It's a boat at the moment without shocks (I am hoping the shocks sorts some of the rocking out), but what caught me out, is the death wobble that started before I even got to second gear.

I believe we have some bearing and seals issues on the new diff. The Birfield on the left wheel is leaking diff oil, which means the seal between the tube and the Birfield knuckle is shot. The diff oil will be washing the grease in the Birfield by now.

I think a total recon of the Birfield/wheel bearings and seals is in order.

We are busy with shock mounts as we speak, to get the D2 shocks mounted and see if it in any way fixes the DW I experienced last night. I can't imagine our geometry can be so stuffed up that we have built a DW machine.

I will post some pictures later..

[ricster]

Dave, besides the caster causing DW, the king pin bearings can also play a HUGE role in DW. Check the play in those bearings, remove a shim and reassemble and check the play. This may help. Looking forward to seeing the final Safani on the road !!!

[davidvdm]

Something I found in the manual..

Seems the Kingpin angle which I thought was the Castor angle is not the same thing. Off the top of the Kingpin I am presently at 7,5Deg which seems to equate to around 1,5deg Castor.

castor camber.jpg (79.22 KiB) Viewed 5552 times

I am going to copy and paste my posts off the community forum so that the info is the same on all the sites and the guys can see the process we have been through and where we are at.

[davidvdm]

Backend got 100mm lift and second hand set of D2 shocks.

Kingpib bearings got a shim removed on each bearing and things tightened up nicely. But our leaf springs seem to weak to do the job of holding the diff in place. We have lateral movement and looks like we need a Panhard rod to secure it.

60Km/h is still the top end at which time things get scary.

IMG-20141221-WA0002.jpg (118.86 KiB) Viewed 5552 times

20141221_105402.jpg (836.89 KiB) Viewed 5552 times

Stupidity also contributes, we found the steering arm mounted to the kingpin had play on it. Like we had not tightened the bolts. when we took it all apart, I found we had forgotten to remove the burring where we had drilled the holes through the plate. As the burring collapsed, the bolts were no longer holding it all tight. Stoopid mistake and oversight that aggravated the situation.

OK, so I know a panhard does not go onto a leaf sprung setup, but I am going to build on to see if it sorts the problem. The leaf springs are are bending from side to side allowing the diff to move under the car. This can be seen by just playing with the steering wheel from side to side. The car rocks as you see the diff shift.

[Peter Connan]

If the leaf packs are quite bowed (in order to get the required lift), then there will indeed be sideways flex.

Panhard rods are not unknown on leaf-spring setups, the current ford F250 has such a setup on the front axle as standard, using parabolic springs.

But you need to be very careful of two things, and I would strongly suggest either some serious drawing beforehand, or some accurate model building.

You need to make sure of three things here:
1) That the panhard rod works in conjunction with the drag link in order not to generate bump-steer.
2) That the angle of the panhard rod remains level enough such that it does not introduce too much sideways movement itself, so that it doesn't introduce excessive loading to the leaf springs (looking at the angle of your draglink and the amount of lift you have, I think you may be in trouble here).
3) That the mounting point of the panhard rod is strong enough without obstructing anything or reducing your approach angle.

[davidvdm]

Thanks Peter. You make me feel better about the Panhard.

Here is my problem http://youtu.be/E64fBqAnjXU

We are on our way to put the other two blades back into the pack. If it gets the front stiff enough side ways, I can live a bumpier suspension. It would be a shame though, as the ride is actually softer than the IFS was.

I have been on the drawing board. I know I need to contain axle wrap as well, so was looking to do diff location (panhard) at the same time with the same arm.

I have the forward leaf perches in place that offer wide mounting for two of the four link arms needed to come together on the diff for sideways location as well as contain axle wrap. Then the remaining rear mounts for the radius arms to locate diff from front to rear..

This is what I have in mind...
.

Sani SAS link.jpg (27.52 KiB) Viewed 5544 times

[Peter Connan]

This, in conjunction with the existing steering linkage will give you SERIOUS bump steer, and contriving a steering linkage that will prevent that will be very tricky.

To prevent bump steer with the existing steering linkage, the axle needs to move sideways a little bit as the body moves up and down. Effectively, this requires a panhard rod of almost exactly the same length and agle as the drag link.

If a linkage like this is used (and I reckon you can just use a single tri-angular link at the top, as the leaf springs will take care of the bottom), then you need a steering linkage that does not move the hub ends sideways as the axle moves up and down. The only such I have ever seen was fitted to a live-axled racing buggy, and consisted of a bell-crank mounted on top of the axle tube, which relaid the steering backwards to a steering box which was turned through 90 degrees so that the pitman armed moved forwards and backwards.

Furthermore, the linkage you have drawn will have a very strange effect on caster angle, and odd stresses on the springs.

Hope this makes sense?

[davidvdm]

Back up to 4 blades in the spring pack and the Patrol coil spring, and the DW is still there. It feels somewhat more composed to just over 60 and then a slow wobble starts. Feels like the axle is rowing and the feedback into the steering wheel shows that the diff is moving from side to side.

I'll get it to wheel alignment first thing and see if that helps any. But now the front end is hard.but the car gets upset by the slightest irregularities in the road.

[Peter Connan]

David, why leafs and coils? Using both would seem to leave you with the worst characteristics of each?

Also, I am wondering whether there is not a substantial element of bump steer in your death wobble? Is there any way you can drop the pitman arm's end to reduce the drag link's downward angle without fouling the springs?

I also reckonyou need to get the wheel alignment pretty accurate before you do too much else. Adding caster should tend to alleviate DW, but with increased steering effect. Remember in an emergency you need to be able to man-handle the system should the power steering fail, so probably no more than about 3 degrees?
also, are you not running too much offset? A line drawn through the kingpin bearings should meet the road within 20mm or so of tire centreline, and in fact preferably slightly outside of tire centreline?