Advice on Bouncy Ride?

[Papa Rick]

I need your help and advice again. I had posted this question once before, and tried many things, but so far nothing has helped.

I have a 1985 Freightliner Day Cab, Spring Ride, the only shocks are on the front.

When going down the road at 43-50 & 62-70 my Truck has a bounce in it, not a vibration, but a bounce up and down in it.

You can not feel it in the Steering Wheel, the shifter shows no sign of going crazy at this time.

I put new steers on 20,000 miles ago, new shocks 10,000 miles ago, New brake drums on the front just last week.

Driveshaft redone completly.

The bounce gets worse the longer in the day I drive it. I haul logs for a living and when I first start out in the morning it still does this, but nothing compared to 12 hours later in the afternoon????

When I am coming to a stop it will buck and bounce like maybe I ran over something, not always, but more so later in the day.

I Noticed the Left front steer tire has what looks like a bouncing pattern in it where you can feel it with your hand just slightly?

The other steer tires were on the Truck when I bought it Sept 06, and had them replaced only 2 months later. They still looked brand new?? Took it to a Front End Shop to find out about the Vibration (VERY SMALL then compared to now)

The guy jacked up the front end and put it on a machine that spinned the wheel and man did it jump around.

He didn't know what caused this, but said that I needed new steer tires. They only do 3 axle alignment, no tire selling, so he was not just trying to make a buck.

Got the new steer tires put on, and no improvement?

After all of this, I am at a loss and really discouraged about finding the problem.

I have had some people tell me it could be a harmonic balancing problem, and I might agree with this, but it only had a small bounce when I first bought it, but now it is like riding a horse?

Any suggestions would be greatly appreciated, and if you know of anyone close to where I could take it, I am only 40 miles south of Chattanooga TN off of I 59 I would love to know, because I have had it in 6 different shops and most Mechanics look at this as a piece of Junk and don't really want to mess with it, but have no problem when it comes time to pay the bill.

It is an old truck, but has been took good care of, as I am the 4th Owner this Truck has had. It still has the Original Motor (Rebuilt of Course), and I would love to figure this out.

Sorry for the long post everyone, but this has really worn my endurance down much.

[cabbie313]

regarding bouncy ride on freightliner,had a problem like yours on a peterbilt.it would bounce like crazy when loaded,when empty was fine.did about all the things you did still had a bounce when loaded. finally got smart and checked fifth wheel for movement,had all kinds of up and down play in bushings. changed fifth wheel saddle and problem was cured. hope this helps you.

[Papa Rick]

Forgot to post, but this only does it empty. When loaded it rides very smooth, no bounce at all.

I have the same problem that I'm dealing with right now on my Western Star. It starts to happen after the truck has been driven a while. Sort of like maybe some rubber part needs to heat up before it starts. I also have replaced the drive shaft. I replaced my steers and all 6 shocks and no luck.

My problem happens at 55 to 60 but when loaded, doesn't happen till 70 or 75. I'll bet your problem is the same if you went faster when loaded.

I bought a cheap USB camera and already filmed the rear end but didn't see anything. As soon as I get the chance I'm going to film each front end part so I can at least narrow it down.

[Papa Rick]

Steve, could you explain in detail how to do the USB Camera, as I know very little about this, but would love to try this. It only does the bounce when empty. I have had it up to 80 loaded and it rides smooth.

If you have a laptop you can buy a cheap USB camera at Walmart. You will then need a USB extension cable from Radio Shack to reach into the engine compartment or rear of truck.

Tie wrap the camera to something so it's pointing at what you want to video.
The USB camera comes with video software. Bring up the video application and get it ready to go then start driving. When your ready, click on record with your laptop being in the passenger seat or have someone do it.

When you have recorded enough click stop then pull over and view the video to see if you can see the problem.

I would say keep doing this until you narrow down the area then start to focus on that area and get close it need be with the camera. They are cheap and worth destroying if it finds your problem.

[heavyhaulerss]

keep the bounce. it will keep you awake & alert.

[furbis]

I know you said the front shocks were fairley new but they could still be bad, when you park the truck at night after running all day feel each shock and see what the temp is if it is cold or very hot the shock is bad it should be warm, it sounds like your steers are starting to cup and I am pretty sure that is a sign of bad shocks. you might also grab a bar and see how much up and down play is in your 5th wheel.

My shocks were replaced and no difference. Although, that's a good point. Maybe the shocks aren't heavy enough for my truck? That would explain why it doesn't happen until things heat up like the oil in the shock. Something for me to think about and keep an eye on. Maybe time for some gas shocks if that's the problem.

[Bobby]

Rick,

If this truck has a heavy front axel (16K +) and Hendricson or rubber pad rear suspension ? what you are experiancing might be normal.

[Papa Rick]

Whew what a Day!

Started out getting the steer tire took off and used wheel and steer tire put on to see if this would help, and it did not.

Next the mechanic rode with me to get a better understanding of what it was doing. Still could not pinpoint front or back. When we got back to the shop, the owner came out and rode with me, and thought it was in the back, so he rides on the catwalk and watches the rears and driveshaft, and can't find anything wrong.

They check the tie rod ends, kingpins, spring pins, shackles and hangers, bushings, and find nothing abnormal.

He said the only thing he could suggest was find a place that could balance the wheel, tire, and brake drum on the Truck. Found a place in Chattanooga TN, but were closed today!

Was referred to Lee Smith in Chattanooga TN, and found out about a VIS check, which is awesome, never seen anything like it. It provides a full evaluation of your vehicle's Brake efficiency, Brake response time, steering components, suspension components, drive line components, wheel alighment.

The good news is they told me my Truck was in great shape, and only needed two bushings replaced.

The bad news, still no problem solved.

Tommorow I will go and get a 3 axle alignment and see if this helps.

The fifth wheel has not been checked, but today I bobtailed to the three shops I went to and it was no change from hauling a Trailer.

I will check the shocks and see about that.

Steve Thanks for the advice on the camera, I will try this if the alignment doesn't help.

I appreciate the advice and words of wisdom. I will keep posting when I get something done, and when it is fixed what it was.


Thanks everyone!!!!

This will be interesting to see if you find the problem. I'm going through almost exactly the same experiences. I'm very wary of the mechanics though. They all say, oh it's this or that needs to be replaced. Well, they don't know squat and are just guessing at my expense.

I'm tempted to put some gas shocks on the front of my truck.

[Papa Rick]

Took my Truck in for a 3 Axle Alignment yesterday. Found out the reason my steer tires have some abnormal wear, the drives were out of alignment, not much, but enough to cause this.

One of the U-Bolts on the axle was loose and allowed the back drive axle to move ever so slightly when I made turns. It was not loose enough to feel, but they took a hammer and hit the top of them to see if they would move.

As far as the bounce up and down, they believed it had to be a out of round tire on my drives. They were able to spin my steers up pretty fast and watch them, but no bounce.

I plan on taking it somerwhere and getting the drive tires checked out closer next week.

[Fredog]

Took my Truck in for a 3 Axle Alignment yesterday. Found out the reason my steer tires have some abnormal wear, the drives were out of alignment, not much, but enough to cause this.

One of the U-Bolts on the axle was loose and allowed the back drive axle to move ever so slightly when I made turns. It was not loose enough to feel, but they took a hammer and hit the top of them to see if they would move.

As far as the bounce up and down, they believed it had to be a out of round tire on my drives. They were able to spin my steers up pretty fast and watch them, but no bounce.

I plan on taking it somerwhere and getting the drive tires checked out closer next week.

The Peterbilt dealer in Georgia I-75 exit 348. has one of the best frame shops around, we have our trucks aligned there, its pretty close to you and you usually dont have to wait long.

[Papa Rick]

I believe it is also in my Drive Tires, but now sure which one. The shop that did my 3 axle alignment told me they could spin balance my tires and it should show up then.

Several Questions:


1. Has anyone ever had this done to find an out of round tire? My recaps have 20,000 on them.

My steer tires started to show wear on:

Left Steer Tire: on the inside.
Right Steer Tire: on the outside.

Not very much, but enough for a novice like me to see it. My front end was a little out of line, but not as much as my rears were.

2. My question is this, will the steer tires come back into wearing even? They took them off and flipped them to get them back into even wear?

4. About the 3 axle alignment: I know if I think it is out of alignment, to get this done, but if it seems to be staying in alignment how often would I need to have this done? Remember I haul logs for a living, so I am in and out on dirt roads.

If your tires were out of round or out of balance they bounce the same in the morning and at night. I don't think it has anything to do with your tires.

[Papa Rick]

The longer you drive your tires the hotter they get, and the air pressure goes up in them. I have read that to get a True reading of your Air Pressure you must wait at least 3 hours after driving.

Didn't believe it, but tried it a few times and found out they were right.

I have had everything else checked out with the exception of my power divider.

The reason I beleive it is a out of round tire, is due to the fact that the longer I drive on them the worse the bounce gets.

I will post the results when I find it.

[special k]

An out of round tire can get worse as the day goes on but other drivers should be able to see it as you go down the road. Get someone to follow you to see if a tire starts to actually bounce. Spring ride trucks often have these problems thats half the reason people went to air ride.

[Papa Rick]

I actually had someone ride on the catwalk trying to find it while it was doing it with no luck. I know the spring ride will never ride like a air ride does, but it didn't start doing this until a couple of months after I bought my drive tires.

[Papa Rick]

Just got back from the Tire Shop. I had them take off two tires that were showing real bad abnormal wear for only 20,000. Took it out for a test, and this got 95% of the bounce out of it. The other 5% is due to it being a spring ride.

Boy am I glad this has been solved!!!!!!!!

I appreciate all of the advice and input that everyone gave.