The Stovebolt Site Forums The Shop Area Driveline Truck steers left or right when braking

I have a 54 3600 completely rebuilt with new parts from ground up. it has no worn or old parts. It is a daily driver. sometimes it will steer right or left when braking. Other times straight ahead. Hard braking may make it worse. I've checked the adjustment several times. This has been going on for 2 years. I'm pulling my hair out because it can be dangerous.
Thanks Sharon

Any suspension modifications such as raised or lowered, or non-stock wheel offset? It sounds like you're dealing with a bump steer problem or something suspension-related, rather than a brake problem.
Jerry

the ride height is stock. I did put 1/4" spacers on the front wheels to clear tie rods because I put new 16" wheels all around

Hy Sharon Danella, Is the truck stock or modified? Have you bled the front brakes since this started?

I have bled the brakes. I have installed a CPP power booster 2 weeks ago.
Rest of system is stock.

Jerry, could a steering stabilizer help with the bump steer. also I have added a front sway bar kit to the truck. Sorry to get this jnfo out in a jumbled mess.

Bump steer is caused by a mismatch of steering components, such as when a vehice is raised or lowered, and the drag link from the Pitman arm at the steering gear to the spindle is not level with the ground. Another possibility is a mis-adjusted sector gear preload that allows the steering gear to wander when the vehicle is traveling straight ahead. If there is a good wheel alignment shop in your area with someone who is familiar with straight axle steering geometry, have them do a detailed analysis of the steering system. A steering stabilizer is just a band-aid fix that attempts to hide other problems. Be sure the stabilizer is free to travel up and down without binding or putting an unwanted input into the tie rods.
Jerry

Edit: If your new wheels are noticeably wider than original, or the tread centerline has changed more than an inch or two, the extra leverage on the spindle can create a pull while braking.
Jerry

Recheck the steering box adjustment. Recheck the toe in. Look for any loose bits and follow the advise from Hotrod. He knows some stuff.

In addition to what Jerry and Steve mention, you may want to check the preload on the tie rods, if they are still the original type.

quite a lot of items still to check. The tie rods are new. Have adjusted the steering box per manuals specs.LT 235/85/16 tires.Toe in was set after truck was finished, but I don't have a lot of faith because they didn't catch the caster shims missing. they said I was good to go. Need to find a good alignment shop in Tucson.

Are the tie rods original style? Or are they the new style? The original style do require preloading after an overhaul. Otherwise, they will not hold a toe setting when the truck is driven.

I have a 54 3600 and have rebuilt the tie rods. jerry mentioned the preload may be off. How do you set the preload? I cant find it in the manual.

The process itself is pretty straightforward, but you will need the special drag ling socket to do it properly. They look similar to a very large slotted screwdriver, usually with a 3/8" square drive on the drive end. Napa should have them, and you can also get them from the major tool companies, like Snap-On.
To make the adjustment, you'll need to turn the slotted plug in until the spring compresses solid. Then you back it off to the first cotter pin hole. The toe will need to be reset afterwards, as it will change.

Longbox55 thank you. I did bring one of those tools with me when I retired. this weekend I will get started on more front end work. Thanks to everyone, Sharon

No problem. I had a similar problem with mine, turned out to be the tie rods.

The sector gear preload is what I'm talking about. It's the adjusting bolt on the engine side of the steering gear with a lock nut. Loosen the locknut, and tighten the slotted screw until there is a slight drag as the steering rolls over the center point. This needs to be done with the Pitman arm disconnected from the drag link. The turning torque on the steering shaft, measured with an inch/lb torque wrench at the steering shaft nut should increase 10 inch pounds as the center point is passed. For instance, if it takes 10 in/lbs to keep the steering shaft turning, as the center point is passed the torque should increase to 20 in/lbs, then drop back to 10. If there is an increase/decrease/increase in torque with a free spot in the middle, the steering worm gear is worn out and must be replaced. There is also a way to check center point preload with a spring scale and a string attached to the steering wheel. The inch/lb torque wrench is more accurate. Have fun!
Jerry

Sounds like a
lot of work then a lot of beer drinking. Thanks Jerry

LOL! Be sure you get the work and the beer in the right sequence. I've never been able to do a good job of working or drinking if I try them both at once! I have been known to empty a Budweiser can when I needed a few connecting rod shims for a 216, though!
Jerry

Also make sure that you have the steering centered when you start making adjustments to steering gear.