Steering Stability

The truck is a 74 stepside. It’s been lowered via van LCAs. Been experiencing a wobble at around 35mph and smooths out. Someone along the life of the truck welded some angle iron from the frame in vicinity of the steering box to the core support. Looks like they were trying to address the stress the box puts on the frame. I’m thinking of cutting out that ankle iron bracing and add the correct brace from the steering box to the core support. Also thinking of adding a brace that ties the left and right stub. Anyone else deal with this and what did you do?

That won't cure your death wobble. It's caused by steering geometry being off due to the truck being lowered. Installing the correct brace won't hurt but won't get rid of the wobble. It seems installing a steering shock helps. Do an online search for death wobble fixs.

A steering shock is just a band aid for a geometry problem.

If you haven't aready you need to take the truck to a good reputable alignment guy, not a tire shop and have the alignment checked.

The only vehicle I experienced death wobble in was a Jeep ZJ, there was no way to drive out of it, only slowing down to an almost stop. I recall a ZJ passing me at 65 MPH going into death wobble and I witnessed the left and right tires alternately leaving the road surface completely. The first time that happened to me I needed to go home and change my drawers. It was an extremely violent unpleasant event. Ultimately traced to worn factory and then a cheap aftermarket track bar.Granted the ZJ was 4WD but had a complete front end rebuild including ball joints

I think the 1974 frame is significantly different from a later 70's frame but recall the late seventies frames cracking at the box/frame connection hence the creation of the steering box brace that came with a recall. This defect appeared to be exacerbated by running 7-8" wide wheel and tires on the front of a D100/D150 2 WD truck.

When I was planning a Lil Red and a Warlock restoration my plan was to fully box the front left frame rail at a minimum but I am no mechanical genius.

I know you have posted a lot regarding this truck, is the front end and suspension all new high quality parts? Do you see any cracking in the frame rail?

Good luck!

Red

The front suspension is all fresh MOOG to include the inner tie rods and drag link. Fresh Red Head steering box, fresh shocks. I am running 15x7 slots in the front with 255/60/15. When we had the old box off we checked for cracking. The alignment is dead on. We also did the axle flip replacing the Dana with 8.75. I like your idea of boxing the frame.

What is the caster and camber set at now?

I lowered my 74 D100 using Dakota drop spindles and rear axle flip and the alignment specs were different then stock. I got the specs from one of the Dodge truck sites but it's been a few years so I don't remember which site it was. I had the same wobble problem so I do have some experience with it.

What year spindles did you use, any pics?

I think they were first gen Dakotas form bell tech. Got the complete kit with shocks and all. Ended up 2" drop in front and 4" in the rear. Did have to swap rotors because of bearing sizes. I did this 10 years ago so my memory isn't perfect.

I'd put a little more caster in it...

Agree

That's why I asked the poster to show what it was set to. Without seeing the print out and knowing what it was aligned to its hard to make correct suggestions.

I can do that tomorrow

1974 D200 Club cab long box. We used B van LCA's and we moved the rear springs front hanger up and used drop shackles. This was a net effect of dropping this D200 4 inches all around. My son is running 245/70 16's front and 265/70 16 rear. No wobble at any speed. We set the alignment in the driveway using a level for Camber and a string for toe.

This is the brace I plan on using

That's a good piece and will help keep the frame from breaking. Won't stop the wobble.

Kinda figured that

Is your truck 4wd? If so, inspect the front track bar for slop very carefully.

Track bars did not come out until 1994.

More caster will increase steering feel (harder) less caster will decrease steering feel (less effort) and create steering instability. As the axis inclination angle increased the ability to pivot about that axis becomes easier and more susceptible to road condition influences. Most factory specs are a compromise between optimal and driver effort. More caster reduces road condition influences. Once you modify a suspension factory specs are just a jumping off point with tweaks to follow

Here’s the printout from the alignment shop. Yes, with a modified suspension some tweaks are in order. There’s a guy on the west side of town that does a lot of street rod suspensions as well as lowered vehicles. I’ll give him a shout.

You need more positive caster. I would like to see 3 degrees at least.

3 degrees positive caster from a stock type suspension is pretty hard to get, let alone from a lowered truck. Your numbers don't look bad and from what you describe I would suspect something more like a tire problem. Can you swap some wheels and tires from a known good driver?

I have the front end up and plan to check the front wheel bearings and swap tires. I pretty much ruled out an out of round wheel in that when they were balanced a wheel is sure would of showed up.

Yeah a wheel would have showed up but may still balance OK. Maybe the guy operating the balancer didn't give [censored]. A broken belt in a tire may not have shown up or refer back to the original guy running the balancer.
I seriously doubt that since your issue only manifests at a certain speed ( and a low speed at that) and then clears up that you have an alignment issue.

I agree

Ok, earlier in the week I cut out the angle iron that someone welded to the frame connecting to the core support. Then installed the steering box bracket. Took it out for a drive around side streets the the freeway. Wobble I’d gone. I will pursue adding a little more camber or castor. Also, the going to do some boxing in The vicinity of the box.

power or manual steering? Though all Dodge trucks back then specified too little caster, usually manual steer spec's less because the higher caster goes so does steering effort...
I had a 79 years ago back when I was an alignment guy, that was manual steer. One day we were slow at work so the boss let me throw my truck up there on the rack and "hang the heads on it"... I planned on "doing" an alignment, though it drove fine and the tires were not wearing... all stock suspension, though I had replaced the springs a while earlier since I had 1 break on me (the result of it originally being a /6 truck that I swapped a smallblock V8 into) They had been on plenty of months and miles that they had settled as much was to be expected.... I was quite surprised when I saw how bad the alignment was as compared to factory specs.... I decided to just do a "toe and go" on it and call it good, because it surprisingly drove so well.... its been years/ but as I remember, everything was in negative territory, with a big "spread" side to side (which is ultimately where most "pulls" come from) I couldn't believe it drove as well as it did/ so that was one (of very few) that I left alone and didn't make any adjustments to (other than setting toe)