I have a 1985 FLC 120 day-cab, spring ride, with a 15 speed overdrive transmission. I have had problems with the truck bouncing up and down (That is what it feels like in the drivers seat).

It only does this when it is unloaded or bob tailing at two different speeds 35 - 40 and 62 - 70.

I have had the front end checked, alignment, all tires balanced and rebalanced, wheel bearings checked, and anything else I thought would stop this vibration, and these have helped, but it has not stopped it completely.

I have had this Truck in and out of 6 different garages, and after getting all of this done, everyone was stumped, except for one.

He told me that back in the early 80's that Freight liner came out with a leaf spring support for 13 speed transmission and up, due to the fact they were longer than 10 speed, and freight-liner did this to try and help with the vibration.

And this also would help take out the bouncing, as it would help in the stabilizing the drive axles.

I know a spring ride will not ride anywhere close as air ride, so I know I will not get that smooth of a ride, but do believe this bouncing should be stopped. What do you think?

 

If you have spring ride, it is not going to have as smooth a ride as air ride. It will tend to ride rough unless loaded. It could just be the characteristics of the spring ride suspension on that truck.

 

I had one of those sprigs on the back of the 15 speed in my 1985 KW (my LAST cabover) I had heard it was not nessecery to put it back on when work like a clutch was done, BUT I put it back, figured it was there for a reason.

I suppose if you could find one and put it on it would be worth a try, BUT those short wheelbase trucks with spring ride were ONLY going to ride a certain way and thats it.

My KW was 210" and air-ride, plus air-ride cab, so it rode pretty good, I managed to put a little over 850,000 miles on it, and it was still going around 4 years after I sold it. 8)

 

I found one at the Freightliner place for $68.00. Mine had one on it at one time because the brackets are there for it. I just wanted to hear from someone if it helped a good deal or not.

I understand it will never ride anywhere close as air ride does, but every little bit helps.

I hope to restore it little by little and continue to use it hauling logs. This is my first truck to be an owner-operator, and I am loving it so for.

 

you got a PIC of this truck I really like older trucks when they all where long hoods or cabovers.

 

How old are the shocks? Changing them might help as well.

 

Most sprimg ride trucks didn't use shocks in the rear, another reason they didn't ride well.

 

No picture yet, but hopefully will have in the next couple of weeks. It is a long hood, the first one for me, boy that took some getting used to after driving the short hoods for the past years.

The shocks don't seem to be too old. The guy I purchased it from told me he had changed them about 6 months prior to me buying it (9-18-06).

Is there a way to check the shocks and find out about them?

I am learning as I go on this Truck, so any advice would be greatly appreciated. Just keep in mind, it needs to be explained very simple for me to understand it.

Thanks in advance.

 

If they have oil in them you may see some leakage, however, if they were changed a few months ago they should still be good.

 

Yeah you can pull the shock off and it should be VERY hard to compress and expand.

I had shocks that I thought were good. Then I pulled them off, and they were very easy to expand. They were also not consistant, sometimes there would be a lot of resistance then it would "slip" for about an inch.