Need some advice

[75chev4x4]

Hey guys I'm sure a few have seen my posts before about the steering on my 75 k20, but I'm kinda at a loss right now with what to do with this truck. I need some advice on a project point of view on this thing. I have had it for about 5 years now and done lots of work to it about $8k worth and it has steered bad from day one. Anyway aside from all the money and time I have put into this truck I never get to drive it or use it much except short trips in town because of how horrible it usually drives. I say usually because sometimes it can be ok and sometimes like tonight it is just down right scary to drive. I have replaced EVERYTHING in the front end of this truck: new steering box, sway bar bushings, steering box brace(no cracks around frame), borgeson steering shaft, new tie rods, new center link, drop pitman arm(2" lift), new drag link, new ball joints, wheel bearings repacked, tires are good and have had them balanced many times. I even found an old school alignment shop and after taking the truck there it drove the best it ever had which was ok, but is now back to scary again. I'm to the point where I don't have anything else that I know of that will fix the way it drives; have to correct it back and forth to go straight and then it will kinda dart if you correct it wrong and scare you to death, it just kinda wonders. You have to pay close attention while driving it because your not sure how it will react to the next bump or corner. Anyone had a project like this? Is it best to stop chasing it and sell it or leave it alone for a few years or... ? I really love these trucks and I would almost like to just go buy a 2wd(thinking it would handle better than my 4wd) of this generation and swap all my stuff over to it but not sure how the 2wd ones drive either. Almost thinking of going and test driving one or two similar to mine on craigslist and seeing if its just mine that drives this way or what? OK, well any advice would be nice guys, hope this didn't sound like a "poor me" rant but I'm frustrated with this thing, thanks!

[meter swinger]

Kinda sounds like my 59. If it werent for bumb steer it wouldn't steer. both my squares ( one SWB one CCDRW) are 2wd and drive great. Have you done the wheel bearings? Its more common on the 50's trucks but when my 59 had worn bearings it would follow the grooves in the road. The wider the tire the worse it was.
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[75chev4x4]

No havent replaced the wheel bearings I did repack them and they looked ok, that's an idea though.

[Keith Seymore]

No bump steer on these trucks, since they have the solid (beam) front axle. You do get some feedback into the steering wheel as a result of axle rotation during braking, because of the fore/aft drag link (if the front springs are soft enough to allow axle windup - usually more of a problem on the 1/2 tons).

When you went to the alignment shop did they say what your caster setting was?

We had good success in the past cranking the caster way up (like to 10 degrees) through the use of tapered shims.

K

[jjzepplin]

I had the same problem with my 72 blazer. Hit a bump and she was all over the place. I found that my steel wheels were flexing at the bolt pattern so I switched to aluminum. It was better...Then I put on a double cylinder stabilizer. It was a lot better.. Then I found that the tires were the next issue as I replaced them with 10ply swampers. Now it was like I was on rails! I would hit bumps and no problem at all. 70mph on the freeway not an issue. Got about 50,000 out of them tires so when I win the lottery I am going to buy another set!

[75chev4x4]

Hi keith, I remember talking to u about the caster before I took it in. The guy at the shop said it was fine. I asked him about adding more he said it was about perfect.

[75chev4x4]

Ive wondered about these tires they are les schwab dean mud terrains I don't think they make them anymore. Tread is good but I don't know if they are causeing the problem. Couldn't ever find any info of people having problems with these tires.

[Ski-me]

What kind of lift do you have and how tall? What size tires and rim size?

I've done a ton of work on my K5 because of similar experiences as you. Mine is now very minimal and is certainly predictable when hitting large bumps on the freeway. I have 35" tires with a 2.5" lift on 15" rims. A little bubbly with that much rubber but managable. If I had more rim, I think it would handle even better.

The first thing I would check is the toe alignment. That can have a lot of effect on the truck feeling squirly. If you said the truck drove great right after the alignment but now worse, it's worth looking into. You can check this yourself as well.

Take some tape and place it on the front two tires in the center. If you are looking at the driver's side tire, the tape would be located at the 9 o'clock position. Draw a vertical line on each piece of tape and then measure the distance from the two tires. Then, back the truck up so the tape is now at the 3 o'clock position and re-measure. The difference needs to be at least 1/8" to 1/4" narrower at the 9'oclock postion. You want to be slightly "toe in".

This would be at least a free check on your part. All the other adjustments are quite extensive and most alignment shops don't really address (adjust) those without charging you a lot of extra cash (caster/camber).

[75chev4x4]

The lift is a tuff country easy ride 2 inch lift. I honestly wish I kept my stock springs so I could go back and see if the lift was the problem. 265/75/16 tires. The alignment guy was really good I might just take it in have it done again but I'm sure it will go right back to its old tricks.

[75chev4x4]

I always wonder if I put the lift on wrong cause the instructions were not great. Said something about having the longer end of the spring face forward or back but they seemed to be equal both ways to the center. It drove similar to this when I bought it with no lift but all original worn components, same tires though hmm

[Ski-me]

You might be sure your u-bolts are tightened as well. You need to probably check those about 2-3 times after installing the lift as they tend to settle a bit.

Because it wasn't clear in the installation, you should check the measurement of each spring to be sure that they are equal. In other words, if the length from one eye to the centerpin is slightly longer on one end, be sure that both are facing the correct way. I don't recall if one is longer on one side or not.

[75chev4x4]

Yea I have retorqued u bolts. Everything measures out center just weird the instructions said this.

[Ski-me]

Maybe it's just a more "universal" instruction manual. I looked up the dimensions on my 2.5" BDS, and it looks like the "eye to center pin-rear" and the "eye to center pin-front" are the same at 23.25". Also, isn't the front eye larger than the rear (1.5"/1.125")....so I don't think you could mix them up. I did see that the 4" lift had different "eye to center pin dimensions" from front to back so maybe that's where the "universal" instructions came from.

So, after all that, it sounds like the springs are probably OK. Also, your tires aren't too big so getting any "bouncy" feedback is also not too likely.

One more thought....how are your front axle u-joints? I've heard similar, bizzare driving conditions when one or both are going bad.

[75chev4x4]

Not sure about those axle joints I bet they are original, I will look when I get home and maybe just change them its worth a shot. Thank you, good idea

[75chev4x4]

Only thing is I don't thing they spin when in 2wd cause I have a part time kit and locking hubs not 100% if they could still affect this.