The Stovebolt Site Forums The Shop Area Driveline severe front end vibration

Help, my 41 pickup developed a severe vibration if I hit a bump doing more than 25 MPH. So bad I have to almost come to a complete stop to regain control of truck. Any tips on where to start

I'd check and see if the shocks are low on fluid. By vibration do you mean the truck starts bouncing uncontrollably when you hit the bump? To test it I would unhook the shock link going down to the springs and move the arm up and down to try and feel resistance. If they are covered in grease and you haven't touched them they might be leaking. You can fill them up with hydraulic oil until the level reaches the fill hole but they might leak out again. (I'm assuming you have the lever action shocks)

Thanks for the reply. Bouncing uncontrollably is exactly what it does. I will check fluid level in the shocks as you said. Will let you know.

Is it bouncing up and down, or feel like the wheels shaking back and forth? If the wheels are shaking back and forth check all the tie rods and the kingpins/bushing for slack some where.

If it's bouncing up and down after a bump then checking the shoks is a good idea.

Thank you...I will check those also.

If they are bone dry and give you no resistance when you tug on them make sure you get all the air in the shock body out by working the shock arm all the way up and all the way down. I did this on my lever shocks and I was able to add a decent amount of fluid on top of what it showed as "full".

I had the same issue with my 66 c30 turned out to be a bad tire.

If it's a bad tire it should get worse with speed, and shouldn't only be when you hit a bump. It sounds like what he's got isn't a vibration, but a shock issue.

Not necessarily. I've had cars come in the shop with a low speed vibration from a bad tire that would smooth out with increased speed.

Nope if I hit a bump with mine or pothole it would get an uncontrollable vibration/shimmy would have to come to a complete stop to get back to normal once i changed the tire and wheel it never did this again.The funny thing is that it drove with no problems unless I hit a bad bump these were 7.50x16 bias tires.

This looks like an old discussion. Apparently no solution was found. It's 2020 now and I have the hard shimmy problem with my 53 3/4 T pickup. I swapped the pumpkin for a 4:10 from a 71 C 20. It now cruises quite well at 60-65 MPH, but if I hit a pot hole at speeds above 50-55 it shimmy's wildly. It stops when I slow to 40-45. This has happened since the pumpkin was changed...of course it wouldn't go that fast before the swap. So, any comments? Has anybody tried a front end stabilizer? I'm running with a freshly rebuild 1955 235 engine, so speed isn't an issue.

The bump induced shimmy ........is classic loose king pins.

Needs to be put on an alignment rack to see what you have and where to adjust. Before any adjustments are made, be sure all front end parts are like new or are new. If it's loose, nothing will help. While checking, be sure the steering box is adjusted correctly and is in the correct location when in straight ahead position. https://www.flickr.com/photos/advance-design_parts_co/sets/72157632210242370/

Stabilizers just cover up the real problem.