OT - '91 F150 ride quality

[1990notch]

Could really use some help on this...

My father had a stroke last year and can no longer drive, so he gave me his 91 F150. It's got a little rust underneath, but is otherwise almost like new. When I got it late last year, it only had 28,000 miles on the odometer. He bought it with the towing package, I'm not sure what that's made up of but maybe stronger leaf springs. It's both a super cab and a long bed, so it has a long wheelbase.

The problem though, is that it's a extremely bouncy ride on the freeways here in Los Angeles. So much so that it's unbearable. It seems that the freeways here are made up of small sections of concrete, and the sections are either warped or they're made that way. The truck is bounces the most at 60-70mph, but much less at 50 or 85mph. I'm thinking the problem is either due to the truck frame flexing (since the frame is so long) or the shocks are insufficient for the springs. I replaced the shocks yesterday, it didn't help at all.

I noticed it doesn't seem to be a problem when the truck is loaded with a few hundred pounds. Is this just an inherent problem with a long pickup or does it sound like a spring/shock tuning problem? What about the frame flexing?

Any ideas?

[thinkharderchri]

There is not much that I know to do about tough springs. But you could check the tire pressure. It might have heavy duty tires on it that fill up to aroung 75 psi max to give more load capacity. The thing is if you do not regularly haul a lot of weight you do not need to have them aired up all the way. This gives the tires much more flexability and they will absorb some of the shock you are feeling. I think the norm is about 20 psi under the max psi limit or something like that. Just something to check out.

[1990notch]

Thanks for the reply. It has Wrangler light truck tires on it. I think they're only 35-40 psi.

I guess another idea would be to carry some ballast in the back somehow, but I think that would reduce mileage. Keeping both gas tanks full doesn't do much in this regard. Not enough weight.

[Winger Ed.]

The trailer towing package normally has tougher springs, the larger of the radiators offered that year, the stouter rear bumper with the hitch points on it instead of a pretty chrome one, and maybe 'heavy duty' shocks.

If bounce is the main problem-- it sounds like the shocks are just too 'soft' . I'd put a set of 'heavy duty' shocks on it. They take much more energy to get them to travel 'in & out' I guess you'd say.

Adding 500 or so pounds isn't a big deal. It like having two big ole' husky buddys in the truck--- surely that won't hurt it or kill the gas mileage..

I used to have a pile of junk in my toolbox on a Chevy 1/2 ton. It rode great!! I emptyed it out when I sold the truck to a buddy, who never puts anything in the truck or toolbox. The first time I rode anywhere like that with him, I thought, 'gosh, this thing rides awful'.... 'what'd he do to it'? The only difference was all the junk I took out of the tool box. And it had fresh, heavy duty shocks too.


If your frame was flexing any abnormal amount, you'd see where the top of the bed was crushing against the back of the cab. Or, you could look at the top of the bed, and the bottom of the rear window, and see that the truck was sort of twisted. They do flex some,,, ask anyone that's ever stuck thier hand between the bed & cab to hold on as they rode across a field.......

Something that just dawned on me: I had a truck one time that had a harmonic vibration between 35 and 45 mph. It drove me crazy..hopping around like a low-rider or something... until I had the tires re-balanced, and found one that was 'out of round'. RE-balance and rotate your tires--- it may fix it, but if not- it don't cost much.

All this is also figuring that your roads aren't like some are in New Jersy.
They got roads up there that whatever shape your car is in---- won't matter.
You'll still bounch enough to get your tires in the air.

.




.

[1990notch]

The trailer towing package normally has tougher springs, the larger of the radiators offered that year, the stouter rear bumper with the hitch points on it instead of a pretty chrome one, and maybe 'heavy duty' shocks.

If bounce is the main problem-- it sounds like the shocks are just too 'soft' . I'd put a set of 'heavy duty' shocks on it. They take much more energy to get them to travel 'in & out' I guess you'd say.

Adding 500 or so pounds isn't a big deal. It like having two big ole' husky buddys in the truck--- surely that won't hurt it or kill the gas mileage..

I used to have a pile of junk in my toolbox on a Chevy 1/2 ton. It rode great!! I emptyed it out when I sold the truck to a buddy, who never puts anything in the truck or toolbox. The first time I rode anywhere like that with him, I thought, 'gosh, this thing rides awful'.... 'what'd he do to it'? The only difference was all the junk I took out of the tool box. And it had fresh, heavy duty shocks too.


If your frame was flexing any abnormal amount, you'd see where the top of the bed was crushing against the back of the cab. Or, you could look at the top of the bed, and the bottom of the rear window, and see that the truck was sort of twisted. They do flex some,,, ask anyone that's ever stuck thier hand between the bed & cab to hold on as they rode across a field.......

Something that just dawned on me: I had a truck one time that had a harmonic vibration between 35 and 45 mph. It drove me crazy..hopping around like a low-rider or something... until I had the tires re-balanced, and found one that was 'out of round'. RE-balance and rotate your tires--- it may fix it, but if not- it don't cost much.

All this is also figuring that your roads aren't like some are in New Jersy.
They got roads up there that whatever shape your car is in---- won't matter.
You'll still bounch enough to get your tires in the air.

So this is not really anything unusual for a pickup then. I've had two other pickups, a Toyota 1/2 ton and a 79 F150 (wish I still had it). I don't remember either one riding like this one though.

I think I'll have to add a tool box. It needs one anyway. Good idea, thanks.

[Winger Ed.]

I think I'll have to add a tool box. It needs one anyway. Good idea, thanks.

Keep the added weight close to the middle of the truck, it helps more there. Or, you get a better benifit from it being there than near one end or the other.

It might be a good experiment to get 5-6 of those $2-3 bags of cement from Home Depot or someplace, and move them around. Try them lined up on the floor behind the front seat, in the front end of the bed, etc. and go from there.

.

[greywynd]

With the low mileage on the truck, any chance they are the original tires? If they are, being 15 years old, they won't help the ride either, I'm sure the rubber has hardened and stiffened a lot. Also look and see, are they LT's, or P rated tires? 1/2 tons can have either, LT's being a stiffer tire, but better for loads.

Mark

[Bob S2]

Those tires are way old, and have taken a 'set'. Sitting so much has created flat spots on the tires that first give you a horrible ride from not being round, and then also are way out of balance as a result, increasing the effect further. Dump the tires and get new ones, balanced and everything. Makes a huge difference. You can also have a shop take out one of the leafs to make it ride closer to a non-heavy-duty truck. Do all this, then throw a couple sand bags in the rear. Makes all the difference in the world.
--Bob

[1990notch]

Thanks for all the replies. I was starting to consider selling the truck if I couldn't resolve this. It rides worse than anything I've ever had.

Replacing the tires is the first thing I did when I got it last year. It's riding on Goodyear Wrangler LT's.

I don't know why it didn't occur to me before starting the thread, but I think the toolbox is the best idea.

[ol smuggler]

I dont think theres anything wrong with that truck other than it drives like a truck.I see it all the time customers complaining they just spent $40,000 on a new dodge ram 2500 and it dont drive right,Well,i see alot of complaints from bouncy over bumps to slight pull to creaky noises.alot of times il notice a problem quickly on the test drive.But when it comes down to it a 2500 ram aint gonna drive like a soccer moms minivan.there just two different vehicles,also try filling the gas tank ALL THE WAY, i know it is expensive but it may give you a better feel/

[calweld]

I've had almost exclusively Ford trucks over the last thirty years or so, all of them rode better with some kind of a load in back.

If the ride is that important to you, sell it and buy a Chevy . . . and no, this isn't a joke, this is serious advice :rolleyes: ;) :cool: :cool:

[1990notch]

I've noticed the chevy trucks do ride much better than fords. It's been that way for a few years it seems.

Normally I've never had a problem living with a truck that rides like a truck. But I've had some sort of medical problems for almost a year now with chronic nausea and other digestive problems. I've been to Kaiser at least 12 times so far trying to get some answers and it's going very slow. The good news is that they did find something, abnormal blood amylase level and slightly abnormal liver protein. The bad news is that they don't know why. All I know is that I feel awful most of the time and it seems to be getting worse. So a bouncy ride is rough when I'm already having nausea on a daily basis.

[MAC702]

I've noticed the chevy trucks do ride much better than fords. ....

Yeah, but the Chebbies cause more nausea for other reasons.

[chevyman_de]

Yeah, but the Chebbies cause more nausea for other reasons.
I've heard that!;)

[Blacksmith]

Monroe Reflex Shocks. Should be available for your truck. I put them on my 99 F150 and improved both the handling and the ride. They are stiffer, to get rid of bounce and sawy, but soften for a few milliseconds on a really harsh (fast suspension travel) bump. About $60 each. Or if you want the best, go for Edelbrock IAS shocks, about $80-90 each.

[whateg0]

I guess when you say bounce, you mean it sort of oscillates with the surface? I found out that Ford had a problem with the AOD that would cause a vibration at about 60MPH. It was due to deterioration of one of the check *****. As far as bouncing, I have had shocks that were so worn out that they did not want to move. The shaft on one actually broke. That will cause a truck to bounce as well, but it's much harsher than a boingy-boingy-boingy thing.

Dave

[Teeps]

Try driving a medium duty truck with no weight on the back and a shorter wheel base, bounce you to death literally.

I'm talking a 36000 lbs GVW medium duty, like an International.

The chassis and suspension are built to haul and operate in certain load conditions.

The suspension will be right at home when it's operating in it's "designed for" normal usage.

I'm sure the stock shock valving leaves alot to be desired, ultimately you could do something custom with strong shock valving, especially if you get any numbers on your spring specs.

Definately the toolbox, and 500 lbs will help alot.

That torquey engine won't wince at 500 lbs at all (HUGE straight six crank, just like the old Combines the farmers use :P well not exactly, but similar).

[1990notch]

I guess when you say bounce, you mean it sort of oscillates with the surface? I found out that Ford had a problem with the AOD that would cause a vibration at about 60MPH. It was due to deterioration of one of the check *****. As far as bouncing, I have had shocks that were so worn out that they did not want to move. The shaft on one actually broke. That will cause a truck to bounce as well, but it's much harsher than a boingy-boingy-boingy thing.

Dave

In my opinion, it's exactly like a resonance problem. It's the worst at about 75mph, but really only happens between 60-80. There's no problem at all at 50 on the same roads that I have trouble with. There's also no problem at 75mph when the road is smooth. It just so happens that about 90% of the freeways here have the undulations that cause the resonance.

[whateg0]

Gotcha! Well good luck with that. There is a bridge on the way home from work here that is exactly the same way. The speed limit is 45 and if you are anywhere near that - well, it's kinda entertaining to have somebody with a weak stomach in the truck.:eek: Seems that no matter what vehicle I've ridden across that bridge in, it gets to bouncing, so I wonder if there aren't some roads for which there is just no hope.

Dave

[weld_13]

thats not unusuall at all my ford with the towing package ( 01' crew cab long bed) does the same thing just the springs i believe.