Weird Baffling Crabbing Problem - I need HELP

I have a 1980 Nissan Patrol (4X4) that I have been restoring for the past 6 years. I thought I was done when I completed the paint job las month. Two days ago when I left for the airport it seemed to me that the car was crabbing down the road - going straight but pointed to the left (notably!) The car does not pull nor does it dive when I hit the brakes. I can’t find anything odd looking in the suspension although the steering wheel is suddenly out of true. I have never had this sort of problem with any car before and don’t even know where to start. I am thinking to take it to an alignment shop.

Has anyone run into this sort of thing before?

Any help would be appreciated.

I am located in Cali, Colombia

Have you had the frame checked for accident damage?

Have you checked the rear axle to be sure that it and its suspension mounts are exactly as they should be?

Those would be my prime suspects for a crabbing problem.

Somewhere over the years, through some action, your rear axle has become misaligned relative to your frame. You can verify this by measuring the centers of the end of each axle to diagonal corresponding points on the frame, the hypotenuse of the triangles. I’ll bet they’re different.

This is not as unusual as one would think. Especially in a 29 year old vehicle that’s been subjected to who-knows-what.

Take it to a chassis shop and tell them the problem. They should be able to get everything lined up properly again.

If there is such a thing as a chassis shop in Cali, Columbia, they should be able to put things right with the rear axle. But, is there such a thing as a chassis shop in that part of the world? Articteach–is there such a thing in your environs?

Excellent point.
If not, by making sure everything is in good shape and secure (good spring brackets, sound frame, good busings etc) the OP could perhaps equalize the hypoteneus measurements himself. It’s not rocket science, but it does take some elbow grease.

Something is bent in the suspension, worn out, or quite possibly the alignment is out quite a bit.
Crabbing (or track) can be corrected even during a 4-wheel alignment or even a 2-wheel alignment depending on the machine. It’s simply a matter of equalizing the tie rod adjustment.

Measure the tie rod threads that are visible and make sure the same amount of thread is showing on each side.

I should have added that the steering wheel out of true can be caused by something bent or the tie rods seriously out of adjustment.

I could be wrong, but I think this has a solid rear axle.

I am also pretty sure that an '80s-vintage Nissan 4x4 would have a solid rear axle.

My point about the 2 or 4 wheel alignment is not so much that a solid rear axle may be sitting out of whack. It’s just that the track can be altered by adjusting the front tie rods.
The rear wheels are only used as references.

Matter of fact, every 2-wheel front alignment always got the track checked and adjusted as part of the job. The process was carried out a bit further than the usual front toe, camber, and caster specs.

I suggest that you find a straight wooden board of a lightweight size. You can do a very good job of evaluating the board or slat for what you need with your eye. Look along both sides and from both ends while judging the straightness.

Align the slat or board along each of your rear tires to see how they line up with the front tires. You can use a tape measure to compare the wheelbase on both sides of the vehicle.

Another thing that you can do is to park the vehicle on a level surface and roughly judge the camber settings on each wheel with a torpedo level against the wheel rim provided the rim is not bent or distorted.

If you parked the vehicle on the level pad while driving into place while steering straight ahead, you can use your straight edge along the front wheels to evaluate front wheel toe.

This will give you a rough idea of what you have regarding some aspects of wheel alignment and is not intended as a substitute for professional wheel alignment equipment.

Keep in mind that road levelness can affect pull as well as a dragging brake, a low pressured tire or defective tires although I have never encountered that; consider that rare.

I had a car a few years back that pulled to one side. That problem was traced to unequal caster settings, not easy to check as the items above.

Maybe the eye bolt in the leaf spring is missing or the u-bolts are loose.

I think you will find that when a vehicle is crabbing, its always in the rear. The rear tires are not parallel with the vehicles centerline. With a solid axle, that means the axle is not anchored correctly. It could be a lot of things that cause this, simple as a bushing to a bent frame. If its a bent frame, it would have been nice to know before starting the six year restoration.

This easy to check, find a long straight edge, 8 feet long or longer if possible. A piece of angle iron or channel iron should work. Place it along the edge of the tire with most of it pointed to the front tire. Do this on each side, you will see that the straight edge will point outboard to one front tire, inboard on the other.

If during your restoration you had the rear springs off, you might have put one on backwards.

Except for the fact the OP states the vehicle has a steering wheel that is suddenly out of true and that’s a sign of something in the front either bent or seriously out of adjustment.

It really needs to go on the alignment rack and have the suspension inspected.

If you have leaf springs in the rear it is possible that a leaf is broken. Some of us remember Firebirds,Camaros, Novas,etc., crabbing down the road, it was always a broken leaf.

After a few years, all of the Novas crabbed down the road. I believe that those “monoplate” rear springs became deformed over a period of time, leading to a “swung axle”.

There is a problem, as mentioned previously the problem is probably that the rear axle has slipped . Fix it now!

Waterboy is right on it. You probably have a broken spring center bolt thats allowed the axle to move. To be sure measure from the center line of your frontspring hanger to the center of the spring bolt where it shows at the axle.