Suggestions for making my F53 a little easier to drive

[kmb1966]

I have a 2001 Itasca Suncruiser built on a 2000 Ford F53. Just got back from a long trip. Overall it did fine, but am looking for suggestions on what to make it a little easier to drive. I have Koni FSD shocks, and I am overall ok with the ride. The problem the driving. I get blown all over the road when a truck passes by. If I encounter an uneven piece of pavement, the coach swings from side to side very easily. I'm not sure if anything can be done to help, but I'd appreciate any suggestions or success stories.

[Blackdiamond]

JUst FYI,

I had a shop tell me that my bushing for the anti-sway bar were shot, they wanted around $450.00 to replace. I told them no.

I ordered the Polyurethane ones off ebay and decided to do it myself. The old ones were almost none existant, the left one was almost completely gone the right one was a big mess of gooey sticky rubber. The hardest part of replacing them was cleaning the brackets and the bars of all the sticky old bushings.

While I was down there I did the CHF on the anti-sway bars, took about 15 minutes.

Road test, took the coach on a 1 hour drive to a park we had reservations at and then the drive home. What a difference, the drive was so much more pleasant. There was no stomach turning moments that use to happen if I hit a big bump and a curve at the same time. The drive was just so much more stable. So glad I did this.

[427435]

Lot's of technical stuff above but, the bottom line, is that more caster provides better directional stability----------------and reduces wandering and the need to be constantly moving the steering wheel back and forth.

[Wes_Tausend]

wolfe10 wrote:
Bump steer most commonly occurs when the axle is inadequately located/attached to the chassis.

So, one front wheel hits a bump. It drives that side of the axle back causing it to steer in that direction.

Particularly common on Safari coaches with Torsilastic suspension, as there is only ONE forward link (driver's side). So, if right wheel hits a bump that side of the axle is driven rearward, which IS a steering input. Easy fix is to add a forward link on the right side. Created quite a cottage industry for Ralph Andrews/Pioneer Metals in WA state.

Bump-steer is not officially defined as "steering because one has hit a bump which directly forces the wheel out of desired alignment", although this is often the intuitive interpretation.

"Bump" is defined, in engineering terms, as any vertical compression of the sprung suspension and is the opposite of "droop" which any decompression of the sprung suspension. "Bump", the wheel goes up, "droop", the wheel goes down. The important difference is bump-steer is when the swing of the wheel going-up swings in a different arc than does the "tie-rod" link (so to speak). If the tie-rod arc does not track the wheel arc, the tie-rod seemingly gets shorter or longer and adds indirect unwanted steering input. The unwanted steering input is often a toe-in/toe-out change.

Thanks for the tip on Safari coaches with Torsilastic suspension!
-------

427435 wrote:
It's apples and oranges, but I recently had the suspension components all replaced on my 67 Corvette. It steered like **** when I got it back-------all over the road. This was after the shop that replaced the suspension parts had it aligned. The shop that aligned it, used standard 67 alignment specs. Those were set up for bias tires back in the day. It now has (and has had) radial tires. I took it to another shop that increased the caster as is normal for cars with radial tires. The car now steers nicely.

As a downside, radial tires act like a normal bias tire that is running separate within a stiff steel hoop that actually touches the pavement. The stiff hoop can tend to wander on it's own depending on road tilt and/or varying lateral cornering forces. Greater caster muscle-guides the hoop a bit more to follow the aimed wheel direction (the wheel always remains dead center on it's own caster). The hoop is, of course, the steel belt.

The plus is that the hoop/belt better avoids conflict losses of tire tread squirm, delivering much less wear and maximum uniform traction over the face of the tread.

Wes
...

[427435]

It's apples and oranges, but I recently had the suspension components all replaced on my 67 Corvette. It steered like **** when I got it back-------all over the road. This was after the shop that replaced the suspension parts had it aligned. The shop that aligned it, used standard 67 alignment specs. Those were set up for bias tires back in the day. It now has (and has had) radial tires. I took it to another shop that increased the caster as is normal for cars with radial tires. The car now steers nicely.

[wolfe10]

Bump steer most commonly occurs when the axle is inadequately located/attached to the chassis.

So, one front wheel hits a bump. It drives that side of the axle back causing it to steer in that direction.

Particularly common on Safari coaches with Torsilastic suspension, as there is only ONE forward link (driver's side). So, if right wheel hits a bump that side of the axle is driven rearward, which IS a steering input. Easy fix is to add a forward link on the right side. Created quite a cottage industry for Ralph Andrews/Pioneer Metals in WA state.

[Wes_Tausend]

wildmanbaker wrote:

Wes Tausend wrote:
...

Some thoughts on suspension...

I like the descriptive phrase of "saw steering" that Mark (427435) brought up. Good way put it.

The F-53, with an I-beam axle, must be similar to smaller, older 4X4 trucks with a live front axle..........

...........Increasing sway bar tension can also cover up a problem with bump-steer if it exists. Bump-steer is a condition whereby the toe-in changes with suspension spring compression/decompression. This appears when the truck leans during a sway maneuver and the spring compression change affects geometry of the steering tie-rod, which in turn pulls the toe-in setting out of alignment. This can cause a darting reaction that makes the sway escalate much worse and demands a frantic correction, or series of corrections, from the driver as though he is walking a tightrope. Very tiring and worse, hard to intuitively recognize the precise root source from steering feel. The truck just plain steers bad, that is the unsophisticated overall feeling.

Wes
...

What? Apples to oranges.... Bump-steer with a I bean axle? You probably have a usable though, but I am having trouble sorting it out.

wildmanbaker,

Good catch. You are quite correct that classical "toe-in" bump-steer will not occur with a solid I-Beam axle. I started to speak in general terms, but should have left it out of this discussion.

Bump-steer doesn't normally occur on a 4X4 F-250 either for example, because there is a single tie-rod from spindle-to-spindle and we could assume this is also true of the F-53 (Of note, F-250-350 4X4's use a pan-hard bar). Some very minor steering variation may take place during bump (spring compression) in that the drag link swings in an arc rather than perfectly moving vertically.

True bump-steer could more easily occur on an independently sprung smaller twin-I-beam 2wd truck though, since the tie rod is split. I'm not sure if some F-350 mini-homes use the twin-I-beam. Bump-steer should not be a major problem for either drive configuration unless some smaller truck is jacked up for off-road, with an extreme drag link angle.

Wes
...

[wildmanbaker]

Wes Tausend wrote:
...

Some thoughts on suspension...

I like the descriptive phrase of "saw steering" that Mark (427435) brought up. Good way put it.

The F-53, with an I-beam axle, must be similar to smaller, older 4X4 trucks with a live front axle.

First a preliminary look at experiences I had with a couple of 2000 Ford trucks I owned that should have steered identically:

I still own a 4X4 Excursion which still has the original, non-greasable ball-joints (no zerks). The passenger joint has some minor play but the truck steers well for now in spite of worn joints and shocks. In contrast I also later bought a 2000 4X4 F-250 that I pre-noted already had new aftermarket greasable ball-joints, which I thought was a plus, since heavier diesel trucks are noted for wearing ball joints.

Unfortunately the F-250 greasable, after-market ball-joints were steel-on-steel and they did not turn as easy as the slippery OEM Excursion joints which are permanently pre-greased and purposely have a durable plastic cup in them to do so (design allows no zerks). The result was that the F-250 never did steer as well for me as the OEM equipped Excursion. The F-250 steering was slightly sticky resulting in subtle "steer sawing" that Mark (427435) mentioned above, which kept it from naturally going straight. I actually measured a steering effort difference between the two trucks, while tires were off the ground, using a scale to operate the steering wheels dead-engine.

The problem is that sticky steering does not return to center properly, the sole function of having caster settings at all... tuned to forward motion of course. Such a "sticky" truck steers as though it wanders easily and requires constant attention to correct any road surface change at all. This can be very stressful to the driver which is fatiguing.

In conclusion, if I replace Ford ball-joints on the Excursion, they will be the factory engineered OEM joints. Even without zerks, OEM parts are good for another 100k. They all self-center as they wear, maintaining alignment and many are changed out prematurely because of yet-acceptable minor play. If slipperier ball-joints (or better lube) are available for the F-53 chassis, that would then be my choice also.

-------------------------------------
FYI, I note that one fix given here is to increase caster settings from 3 degrees to 4+ degrees. While this fixes automatic steering centering by overpowering the stiction, it will make steering in reverse harder since the caster wants to flip the steering around more aggressively while backing, just like a grocery cart. This is usually a small price to pay, but could make it harder to back a longer distance should one need to back out of a long, narrow road. Ideally the steering would flat-out have very little stiction and, while at high forward speed, a very mild caster would be enough to assist moving straight in ones own lane... without being detrimental to backing up.

Another popular fix besides increased caster, is to increase the sway bar setting. First of all, the greater nuisance of frequent sway may be caused by "saw steering" in some instances, so in these cases, increased caster is really a cover-up of the root problem. The downside to increased sway bar settings is that ideal soft ride suffers some. This occurs because if one front wheel hits a bump, part of the impact is transferred to the other front wheel making the absorption of the bump compress double the springs instead of one. Result... stiffer ride.

One way to heuristically imagine this is to imagine that the sway bar is absolutely solid. If the right front tire hits a 3" rise, the solid bar forces both the right and the left front spring to compress equally, about 3". Both springs transfer the jolt to the chassis. In turn the chassis transfers the impact to the passengers twice as stiffly. Since sway bars are not typically solid, transfer to the other spring lies somewhere between no transfer at all (no sway bar) to partial, a function of the sway bar travel stiffness proportional to suspension spring. But any sway bar always decreases suspension ride compliance; i.e. rides rougher.

Increasing sway bar tension can also cover up a problem with bump-steer if it exists. Bump-steer is a condition whereby the toe-in changes with suspension spring compression/decompression. This appears when the truck leans during a sway maneuver and the spring compression change affects geometry of the steering tie-rod, which in turn pulls the toe-in setting out of alignment. This can cause a darting reaction that makes the sway escalate much worse and demands a frantic correction, or series of corrections, from the driver as though he is walking a tightrope. Very tiring and worse, hard to intuitively recognize the precise root source from steering feel. The truck just plain steers bad, that is the unsophisticated overall feeling.

Wes
...

What? Apples to oranges.... Bump-steer with a I bean axle? You probably have a usable though, but I am having trouble sorting it out.

[Wes_Tausend]

...

Some thoughts on suspension...

I like the descriptive phrase of "saw steering" that Mark (427435) brought up. Good way put it.

The F-53, with an I-beam axle, must be similar to smaller, older 4X4 trucks with a live front axle.

First a preliminary look at experiences I had with a couple of 2000 Ford trucks I owned that should have steered identically:

I still own a 4X4 Excursion which still has the original, non-greasable ball-joints (no zerks). The passenger joint has some minor play but the truck steers well for now in spite of worn joints and shocks. In contrast I also later bought a 2000 4X4 F-250 that I pre-noted already had new aftermarket greasable ball-joints, which I thought was a plus, since heavier diesel trucks are noted for wearing ball joints.

Unfortunately the F-250 greasable, after-market ball-joints were steel-on-steel and they did not turn as easy as the slippery OEM Excursion joints which are permanently pre-greased and purposely have a durable plastic cup in them to do so (design allows no zerks). The result was that the F-250 never did steer as well for me as the OEM equipped Excursion. The F-250 steering was slightly sticky resulting in subtle "steer sawing" that Mark (427435) mentioned above, which kept it from naturally going straight. I actually measured a steering effort difference between the two trucks, while tires were off the ground, using a scale to operate the steering wheels dead-engine.

The problem is that sticky steering does not return to center properly, the sole function of having caster settings at all... tuned to forward motion of course. Such a "sticky" truck steers as though it wanders easily and requires constant attention to correct any road surface change at all. This can be very stressful to the driver which is fatiguing.

In conclusion, if I replace Ford ball-joints on the Excursion, they will be the factory engineered OEM joints. Even without zerks, OEM parts are good for another 100k. They all self-center as they wear, maintaining alignment and many are changed out prematurely because of yet-acceptable minor play. If slipperier ball-joints (or better lube) are available for the F-53 chassis, that would then be my choice also.

-------------------------------------
FYI, I note that one fix given here is to increase caster settings from 3 degrees to 4+ degrees. While this fixes automatic steering centering by overpowering the stiction, it will make steering in reverse harder since the caster wants to flip the steering around more aggressively while backing, just like a grocery cart. This is usually a small price to pay, but could make it harder to back a longer distance should one need to back out of a long, narrow road. Ideally the steering would flat-out have very little stiction and, while at high forward speed, a very mild caster would be enough to assist moving straight in ones own lane... without being detrimental to backing up.

Another popular fix besides increased caster, is to increase the sway bar setting. First of all, the greater nuisance of frequent sway may be caused by "saw steering" in some instances, so in these cases, increased caster is really a cover-up of the root problem. The downside to increased sway bar settings is that ideal soft ride suffers some. This occurs because if one front wheel hits a bump, part of the impact is transferred to the other front wheel making the absorption of the bump compress double the springs instead of one. Result... stiffer ride.

One way to heuristically imagine this is to imagine that the sway bar is absolutely solid. If the right front tire hits a 3" rise, the solid bar forces both the right and the left front spring to compress equally, about 3". Both springs transfer the jolt to the chassis. In turn the chassis transfers the impact to the passengers twice as stiffly. Since sway bars are not typically solid, transfer to the other spring lies somewhere between no transfer at all (no sway bar) to partial, a function of the sway bar travel stiffness proportional to suspension spring. But any sway bar always decreases suspension ride compliance; i.e. rides rougher.

Increasing sway bar tension can also cover up a problem with bump-steer if it exists. Bump-steer is a condition whereby the toe-in changes with suspension spring compression/decompression. This appears when the truck leans during a sway maneuver and the spring compression change affects geometry of the steering tie-rod, which in turn pulls the toe-in setting out of alignment. This can cause a darting reaction that makes the sway escalate much worse and demands a frantic correction, or series of corrections, from the driver as though he is walking a tightrope. Very tiring and worse, hard to intuitively recognize the precise root source from steering feel. The truck just plain steers bad, that is the unsophisticated overall feeling.

Wes
...

[Raloma]

Did the Cheap Handling Fix on our 2008. Made a world of difference, the wife even likes driving now.

[NAUTIQUE]

Dale.Traveling wrote:
Correct tire pressure, CHF and the rear track bar has the greatest effect on sway, wander and general straight line performance. Koni shocks helped with taming poor road surfaces. The coach is still a general purpose truck chassis but much better than the day I drove it home for the first time. I'm pretty much done with suspension mods.

Very good summation of our wonderful F-53's! :B

[Dale_Traveling]

Philip.Saran wrote:
,,, I was told the Cheap quick fix "can" break the links, has anyone had that problem?

25,000 miles in four years up and down the eastern sea board and excursions west to the Mississippi and no problems related to the CHF.

Coach weight and tire pressures set accordingly, alignment checked and set, rear poly sway bar bushings, CHF, Koni shocks on all four corners and a rear track bar, installed in listed order. Also replaced the front axle frame bumpers not for any potential improvement but because the originals were crumbling. Installed air bags on all four corners but the improvement was marginal for the cost and effort.

Correct tire pressure, CHF and the rear track bar has the greatest effect on sway, wander and general straight line performance. Koni shocks helped with taming poor road surfaces. The coach is still a general purpose truck chassis but much better than the day I drove it home for the first time. I'm pretty much done with suspension mods.

[427435]

wildmanbaker wrote:

Philip.Saran wrote:
I have a Safe-T-Steer stabilizer on the front end and a track bar added to the rear of my MH. Keep the front tire pressure at 95psi and the rear at 100psi.

I was told the Cheap quick fix "can" break the links, has anyone had that problem?

I don't know of anyone coming forward with having problems with the sway bar end links breaking or bending. Shocks, sway bars will help with side to side rock, alignment will help with straight ahead steering, but the "tail wagging the dog" will require a track bar on the rear, and possibly the front also.

Tail wagging is often caused by "sawing" at the steering wheel to keep the MH in its lane. Adequate caster greatly reduces the need to be constantly turning the steering wheel back and forth.

To put it another way, my 35' MH doesn't have either a tail wagging problem or a track bar.

[americanrascal]

Philip.Saran wrote:
....
I was told the Cheap quick fix "can" break the links, has anyone had that problem?

Have run the CHF on the two rigs I've had during the past 3 years -- over 20,000 miles- Florida to Alaska and back- and all over the eastern US. Been on some wicked roads in those journeys. The only thing that happened was I had much better control and safer drive. ---- and I didn't spend a dime making the change.

[TNGW1500SE]

Philip.Saran wrote:
.................I was told the Cheap quick fix "can" break the links, has anyone had that problem?............

I've really research it and never heard of that.

Remember,,, Ford put the holes there.