[font size="1" color="#FF0000"]LAST EDITED ON 02-May-01 AT 02:10*AM (EST)[/font][p][font size="1" color="#FF0000"]LAST EDITED ON 02-May-01 AT 02:06*AM (EST)[/font]
>I have a 2001 F-250 v-10
>and i have the same
>problem, so it cant
>be the hydroboost brake thing?
>
>Billy
(on edits - first out then back in)
Just to clarify: Gassers come with vacuum boost power assist brakes. Diesels come with hydro-boost.
And to provide another data point here, I tried to reproduce the problem tonight in my 350 (diesel). My truck does not exhibit this problem - maybe because of the hydro-boost?
Hope this helps.
'01 350 PSD CC 4X4 LARIAT / '00 LAND ROVER DISCO II CCP SRP ACE
There are two separate problems with the steering of the late model SD's.
One is hard steering when the truck is stationary with the brakes applied. This is usually on the 4x4's and is due to the larger scrub radius over previous model years and the 4x2's. This can occur with vacuum boost and hydroboost trucks; but not every one. A little variance in scrub radius goes a long way.
The second hard steering problem is on vehicles with hydroboost during hard braking applications. This can occur at all speeds, and is more noticeable at low engine rpm. This problem on the 4x4's can be worse when the vehicle is stationary, because of the added scrub radius problem. This problem may be caused by low pump flow, fluid contamination, or defective pumps, gears, or hydroboost units.
The hydroboost is on all SD diesels, and F450/550's with gasoline engines.
Autotech - I have a new F350, 4x4, SC, V10, build date 7/00, with 1000 miles on it. The problem is not hard steering when parked, that is a normal condition with any vehicle - remember the days before power steering? Most cars had to be moving at least slightly to be able to easily turn the steering wwheel.
The problem with the Superduties is different. Here's how I tested mine. While parked and no pressure on the brakes, the steering wheel turns easily with approx. three turns lock to lock. When I apply substantiaal pressure to the brakes, the steering wheel will make approx. one full turn with ease, then it bloody locks. The condition is repeatable and consistant; try it.
I have a theory that this is intentional, that some yuppie puke involved in the design decided we're so stupid that we might have difficulty controlling the vehicle if we were to turn sharply while braking hard. So, the vehicle was designed in such a way that when brake pressure exceeds a threshold value the steering goes out to lunch.
I looked but could not find any mechanical connection between the steering and braking systems, but I suspect there might be an electronic connection. Since I don't have the manuals to properly research this, I can't check it out. Like I said, its only a theory, maybe just a wild-#####-guess. If anybody has the manuals, look for a sensor in the brake hydralics with a connection to a an electronic modulee as well as some similar connection between the power steering and an electronic module.
You may be onto something - I don't know. But there need not be a direct electrical connection between the brake and steering systems. Going out on a limb here, but I think I am correct in assuming that these trucks have a digital network between the various system controllers and there is probably one primary controller. The primary controller could be the (information) link between the brake and steering systems. Just a guess.
Regarding the yuppie puke designing the controller - since 4 wheel ABS is now standard, I doubt anyone would intentionally disable steering upon heavy braking. The idea being that you can still steer while braking with ABS. I am sure these vehicle designs are thoroughly proven on test tracks. However, out onto that limb again, ABS may not allow high brake line pressure since it will pulsate. The "steering while hard-braking" scenario, perhaps better defined as "steering with high brake line pressure", might not be a possible scenario with ABS - and thus nothing to be concerned with. I dunno. Just another guess.
'01 350 PSD CC 4X4 LARIAT / '00 LAND ROVER DISCO II CCP SRP ACE
hears what im gonna do one of these weekends,
jack up the front of the truck take off both tires
apply a piece of masking tape on both sides of the caliber (laterally with the caliper or vertically on the rotor)
start the truck stomp on the breaks and turn the wheel
if the masking tape is bunched up on either side it proves my therory
which is:
Because the center point of the axle isnt at 90 degrees, more like 88 degrees(look at the front pumpkin, its raked up torward the transfer case)
that when u turn the steering wheel the rotors want to spin opisite of the turn
if turning right the rotors will spin counter clockwise or if turning left then clockwise.
so with the breaks applied hard the rotor cant spin so the steering locks up.
Jacking the front wheels up is a great idea - it should help isolate the source of the problem. As for my own theory, I really believe it is too far out to be given any credence, it may, however, provide food for thought.
I really love my truck though I had to accomplish the final assembly. Yes, there were dozens of loose bolts, and extra bolts resting inside various crevices plus the windshild cleaning container had never been filled, etc. I discovered mine was made in Tiajuana, or some such place in Mexico, instead of in Louisville. At any rate, the quality control guy must have been taking a siesta when my truck rolled off the assembly line.
well,niner1,if you are towing a 15000 lb trlr I'm not surprised
you have a problem. The 250/350 SD's are not rated to pull anything over 13-13.5K. You don't have enough brakes to handle
15K on a consistent basis.
I did double-check trailer weight and it is 12k. Here is the problem specifically that I have : when the truck is not even hooked up to the trailer, I have resistance in Park when turning the wheel, resistance turning the wheels while moving with low speed, and when light pressure applied to brake (parralell parking or hooked up trying to park the trailer) NOT ABLE TO TURN THE WHEELS WITH EASE = MAJOR RESISTANCE. The NHTSA has proceeded with a formal investigation today after 41 crashes and 13 injuries from lack of steering control. They note that fractures in the steering gear sector shaft, which makes the front wheels turn when the driver moves the steering wheel, have contributed to the problem. I absolutley love my Ford truck, however, my concerns for safety in the need to steer the beast are valid.
>as long as your moving u
>can turn your wheel,
>its not that big of
>a thing. if your
>moving your breaks and turning
>wheel work fine, if
>your stopped u have to
>not push the break pedal
>to the floor, ease up
>on it a bit so
>the rotor can spin when
>your turning your wheel.
It is a very big deal if you are trying to park on the street and that street has an incline. Most local governments want you to turn your front wheels either to the left or to the right as a safety issue.
All I can say is try parking your truck on a 30 degree incline road in SF and see what happens--other than a citation for not turning your wheels in/out.
