Bad problem with jerky steering - any feedback?

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Old 04 May 2005, 09:34 pm   #1 (permalink)
M. Hamill
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Default Bad problem with jerky steering - any feedback?

I hope some people reading this will have helpful advice on what may be
causing a long-standing problem on my 1986 Camry.

On 3/19/04, my engine had stopped on me, and I had it towed to a shop
for repair. On 3/23, the shop worked on it and replaced the timing belt,
an idler pulley and tensioner. I was able to drive the car again, and did.

However, on the day after the repair, I noticed a new problem: the car
would now suddenly and abruptly jerk to the left on increasing speed for
just an instant; and it on increasing speed, it would, with a little less
force,
abruptly jerk to the right on falling speed. It was most noticeable in the
60-70 mph range (not surprising because friction with the road is less at
higher speeds), but also at lower speed ranges, too.

I suspected something was wrong with the power steering; however,
othing was really apparent. I thought perhaps the shop had
inadvertently done some damage to the pump during the timing belt
replacement somehow; the pump has to be either swiveled aside and
"unbelted" (for lack of a better word) or removed to replace the timing
belt. However, I did nothing about the problem. There was and never has
been any sign of power steering fluid leaking anywhere.

Last spring or summer, I posted a message here explaining my problem,
and I was told that "torque steer", a frequent problem on front wheel
drive cars, might be my problem. The responses I got at that time, and
the literature I found on the Web on the subject of torque steer said
that it often occurs when suspension is worn, and is often manifested by
problems at the wheel diagonally opposite the corner where suspension is
bad. I knew by this time that the shock on my right rear corner was a
goner, and that the steering jerk problem I was having seemed to be
occurring primarily at the left front wheel. But I didn't use the car a
lot during the last half of 2004.

Finally, 3 months ago I had the damper parts of the MacPherson struts on
this car replaced; a 4-wheel alignment was also done. I had hopes that
this would fix my jerky steering problem. It did not; it's as bad as it
ever was. This car is also very hard to keep in alignment, too. A shop
will align it and in no time flat it is out of alignment and pulling to
the left (it's been a pretty chronic problem on this car.) The front
tires are wearing very fast.

I had the idea to detach the power steering belt and drive around for a
while without power steering. My reasoning was that if the jerky
steering did not happen with the power steering out of service, that I
could be sure the power steering was causing my problem. I talked it
over with a mechanic, and he advised against it. He said it was
potentially dangerous to drive this car without power steering.
And he also said that there is sometimes wear in the "rack" which can
cause a problem like mine. This car has rack and pinion steering, and
the rack is moved by the steering wheel, with, of course, power
assistance.

I pondered what the mechanic said, and came to discount his theory of
rack wear. For one thing, ever since I first noticed the jerky steering
in March `04, actual manual steering on this car has worked fine.
Whether I am turning the wheels slightly or a lot, it has been very
responsive, with no feeling of looseness or wander in steering. So I
don't think there is any significant wear or mechanical hangup in either
the steering mechanism or the power-assisted rack.

I read recently that most power steering pumps have a built-in
recirculation valve that open should pump discharge pressure get too
high. And I got to thinking that maybe there's a problem with my power
steering pump's recirculation valve. For there definitely seems to be
both a bump-up and bump-down in pressure now that wasn't there 14 months
ago.

The problem with that argument, though, is that an abrupt change in
power steering pump pressure would not necessarily result rack motion,
because with the steering mechanism in a neutral position, an increase
or decrease in output pressure would be felt simultaneously on opposite
ends of the hydraulic cylinder which moves the rack, and cancel out. Or
so I think - perhaps incorrectly.

And for what it's worth, I also see a lot of wear on the rubber cushions
where the ends of the stabilizer bar join the control arms. The wear is
particularly bad on the passenger (right) side. (Per my Haynes manual,
these cushions are inserted to adjust caster during alignment.)
Evidently the stabilizer bar is taking quite a beating.

Anyway, this problem has been frustrating me for a long time, and I'm
putting it out to the newsgroup for input and suggestions. If I was
pretty sure that replacing the power steering pump would fix my problem,
I'd do it, but I'm not there yet.

Thanks in advance,

Mike


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Old 05 May 2005, 12:01 pm   #2 (permalink)
Jason James
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Default Re: Bad problem with jerky steering - any feedback?


"M. Hamill" <mhamill@fuse.net> wrote in message
news:b7f76$42798651$d8442641$9680@FUSE.NET...
> I hope some people reading this will have helpful advice on what may be
> causing a long-standing problem on my 1986 Camry.


[. . .]


> And for what it's worth, I also see a lot of wear on the rubber cushions
> where the ends of the stabilizer bar join the control arms. The wear is
> particularly bad on the passenger (right) side. (Per my Haynes manual,
> these cushions are inserted to adjust caster during alignment.)
> Evidently the stabilizer bar is taking quite a beating.
>
> Anyway, this problem has been frustrating me for a long time, and I'm
> putting it out to the newsgroup for input and suggestions. If I was
> pretty sure that replacing the power steering pump would fix my problem,
> I'd do it, but I'm not there yet.
>
> Thanks in advance,
>
> Mike


Mike, you need to understand that older vehicles will get less stable if the
front and rear suspension/steering gear is not kept in reasonable condition.

There are *many* points in the suspension/steering which can cause the
tracking problems you have and as such a proper inspection will pick-up any
bushes/balljoint/tie-rod end/ strut/ strut mount which has increased
movement,..especially if only one side is worn more than the other. as this
also increases torque-steer on that side.

If your steering rack has lots of play or movement, then this can allow
small tracking probs simply because your hands are not holding the car
on-line. As to torque steer,..a worn rack would not contribute to that, only
reduce the driver's response in correcting any pulling.

The alignment parameters: castor and camber are particularly relevant to TS
and tracking problems. If castor is less on one side, then the car will pull
to that side on both rear and front WD cars. Too much neg camber on one side
will cause pulling to that side. The road wheel's tendency to TS will be
worsened by these same parameters being out of tolerance.

Car manufacturers try to cancel the effect of TS by keeping both sides TS
equal.

Often when a steering alignment shop has an old car, they will ignore any
play or movement in the steerin/suspension and just make adjustments as the
car is sitting. The car isn't moving of course, so any wear is not
considered.

In the final analysis, a proper inspection is the only answer.

Jason


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Old 08 May 2005, 02:42 pm   #3 (permalink)
davidj92
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Default Re: Bad problem with jerky steering - any feedback?

M. Hamill wrote:
> I hope some people reading this will have helpful advice on what may
> be causing a long-standing problem on my 1986 Camry.
>
> On 3/19/04, my engine had stopped on me, and I had it towed to a shop
> for repair. On 3/23, the shop worked on it and replaced the timing
> belt, an idler pulley and tensioner. I was able to drive the car
> again, and did.
> However, on the day after the repair, I noticed a new problem: the car
> would now suddenly and abruptly jerk to the left on increasing speed
> for just an instant; and it on increasing speed, it would, with a
> little less force,
> abruptly jerk to the right on falling speed. It was most noticeable
> in the 60-70 mph range (not surprising because friction with the road
> is less at higher speeds), but also at lower speed ranges, too.
>
> I suspected something was wrong with the power steering; however,
> othing was really apparent. I thought perhaps the shop had
> inadvertently done some damage to the pump during the timing belt
> replacement somehow; the pump has to be either swiveled aside and
> "unbelted" (for lack of a better word) or removed to replace the
> timing belt. However, I did nothing about the problem. There was and
> never has been any sign of power steering fluid leaking anywhere.
>
> Last spring or summer, I posted a message here explaining my problem,
> and I was told that "torque steer", a frequent problem on front wheel
> drive cars, might be my problem. The responses I got at that time, and
> the literature I found on the Web on the subject of torque steer said
> that it often occurs when suspension is worn, and is often manifested
> by problems at the wheel diagonally opposite the corner where
> suspension is bad. I knew by this time that the shock on my right
> rear corner was a goner, and that the steering jerk problem I was
> having seemed to be occurring primarily at the left front wheel. But
> I didn't use the car a lot during the last half of 2004.
>
> Finally, 3 months ago I had the damper parts of the MacPherson struts
> on this car replaced; a 4-wheel alignment was also done. I had hopes
> that this would fix my jerky steering problem. It did not; it's as
> bad as it ever was. This car is also very hard to keep in alignment,
> too. A shop will align it and in no time flat it is out of alignment
> and pulling to the left (it's been a pretty chronic problem on this
> car.) The front tires are wearing very fast.
>
> I had the idea to detach the power steering belt and drive around for
> a while without power steering. My reasoning was that if the jerky
> steering did not happen with the power steering out of service, that I
> could be sure the power steering was causing my problem. I talked it
> over with a mechanic, and he advised against it. He said it was
> potentially dangerous to drive this car without power steering.
> And he also said that there is sometimes wear in the "rack" which can
> cause a problem like mine. This car has rack and pinion steering, and
> the rack is moved by the steering wheel, with, of course, power
> assistance.
>
> I pondered what the mechanic said, and came to discount his theory of
> rack wear. For one thing, ever since I first noticed the jerky
> steering in March `04, actual manual steering on this car has worked fine.
> Whether I am turning the wheels slightly or a lot, it has been very
> responsive, with no feeling of looseness or wander in steering. So I
> don't think there is any significant wear or mechanical hangup in
> either the steering mechanism or the power-assisted rack.
>
> I read recently that most power steering pumps have a built-in
> recirculation valve that open should pump discharge pressure get too
> high. And I got to thinking that maybe there's a problem with my power
> steering pump's recirculation valve. For there definitely seems to be
> both a bump-up and bump-down in pressure now that wasn't there 14
> months ago.
>
> The problem with that argument, though, is that an abrupt change in
> power steering pump pressure would not necessarily result rack motion,
> because with the steering mechanism in a neutral position, an increase
> or decrease in output pressure would be felt simultaneously on
> opposite ends of the hydraulic cylinder which moves the rack, and
> cancel out. Or so I think - perhaps incorrectly.
>
> And for what it's worth, I also see a lot of wear on the rubber
> cushions where the ends of the stabilizer bar join the control arms.
> The wear is particularly bad on the passenger (right) side. (Per my
> Haynes manual, these cushions are inserted to adjust caster during
> alignment.) Evidently the stabilizer bar is taking quite a beating.
>
> Anyway, this problem has been frustrating me for a long time, and I'm
> putting it out to the newsgroup for input and suggestions. If I was
> pretty sure that replacing the power steering pump would fix my
> problem, I'd do it, but I'm not there yet.
>
> Thanks in advance,
>
> Mike


I agree with Jason and would suggest you check steering soon just in case a
steering component or the rack and pinion assembly is loose which could
cause steering failure. One other thing is motor/transmission mounts. If one
or more of these are bad the engine/trans can move, causing jerking.
HTH, davidj92


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Old 08 May 2005, 08:39 pm   #4 (permalink)
M. Hamill
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Default Re: Bad problem with jerky steering - any feedback?


"Jason James" <associate@dodo.comzapspam.au> wrote in message
news:427a5164@news.comindico.com.au...
>
> "M. Hamill" <mhamill@fuse.net> wrote in message
> news:b7f76$42798651$d8442641$9680@FUSE.NET...
>> I hope some people reading this will have helpful advice on what may be
>> causing a long-standing problem on my 1986 Camry.

>
> [. . .]
>
>
>> And for what it's worth, I also see a lot of wear on the rubber cushions
>> where the ends of the stabilizer bar join the control arms. The wear is
>> particularly bad on the passenger (right) side. (Per my Haynes manual,
>> these cushions are inserted to adjust caster during alignment.)
>> Evidently the stabilizer bar is taking quite a beating.
>>
>> Anyway, this problem has been frustrating me for a long time, and I'm
>> putting it out to the newsgroup for input and suggestions. If I was
>> pretty sure that replacing the power steering pump would fix my problem,
>> I'd do it, but I'm not there yet.
>>
>> Thanks in advance,
>>
>> Mike

>
> Mike, you need to understand that older vehicles will get less stable if
> the
> front and rear suspension/steering gear is not kept in reasonable
> condition.
>
> There are *many* points in the suspension/steering which can cause the
> tracking problems you have and as such a proper inspection will pick-up
> any
> bushes/balljoint/tie-rod end/ strut/ strut mount which has increased
> movement,..especially if only one side is worn more than the other. as
> this
> also increases torque-steer on that side.
>
> If your steering rack has lots of play or movement, then this can allow
> small tracking probs simply because your hands are not holding the car
> on-line. As to torque steer,..a worn rack would not contribute to that,
> only
> reduce the driver's response in correcting any pulling.
>
> The alignment parameters: castor and camber are particularly relevant to
> TS
> and tracking problems. If castor is less on one side, then the car will
> pull
> to that side on both rear and front WD cars. Too much neg camber on one
> side
> will cause pulling to that side. The road wheel's tendency to TS will be
> worsened by these same parameters being out of tolerance.
>
> Car manufacturers try to cancel the effect of TS by keeping both sides TS
> equal.
>
> Often when a steering alignment shop has an old car, they will ignore any
> play or movement in the steerin/suspension and just make adjustments as
> the
> car is sitting. The car isn't moving of course, so any wear is not
> considered.
>
> In the final analysis, a proper inspection is the only answer.
>
> Jason
>

----
I really appreciate the replies.

My lead candidate hypothesis for what's causing my difficulty is a problem
with the power steering pump's built-in recirculation valve. My best guess
is that this valve used to modulate, but now for some reason, it tends to
act like an open-closed valve. Here's what I suspect:

- Because the car is out of alignment, usually steering to the left, I must
turn the steering wheel slightly to the right to counteract this tendency.
So the mechanism which divides power steering fluid pressure to opposite
ends of the rack's piston is out of neutral position.
- When I do this, the divider in the steering gear mechanism that apportions
hydraulic pressure to the power-assist cylinder for the rack puts slightly
higher pressure on the left side of the rack's piston than the right.
- As road speed increases, and pump output pressure increases to a certain
point, the recirculation valve opens abruptly, and pressure falls
noticeably. Because the port to the left side of the cylinder is open
further than the right side's port, the suddenly reduced pressure from the
pump feeds through to the piston's left side before the right side, and it
falls below the pressure on the right side. So, momentarily, the piston
pushes on the left tie rod and pulls the right one.
- The reverse occurs when road speed and pump speed are reduced, and the
recirculation valve closes, and output pressure spikes upward for an
instant.

I tried to test this hypothesis on the highway today, by letting the car
drift to the extent I could when no other cars were near me, so that the
divider (operated by the steering mechanism) would be in a neutral position,
and then increasing & reducing road speed. My thought was, if this divider
were in a neutral position, a bump up or down in fluid pressure would be
canceled out, and that would implicate the recirc valve in the pump. But I
couldn't successfully do the test.

A new thought: one or more of the support plates - or backing plates (pick
your terminology) of the MacPherson struts was acting like a Belleville
spring. I often hear odd klunk sounds on this vehicle, hence my suspicion.
The support plates are between the body and the top of each MacPherson
strut. A Belleville spring acts like a two-position spring, unlike than a
conventional spring. Now, when my struts were replaced 3 months back it
wasn't necessary to replace any of these plates, but I still wonder if maybe
one of them has the snap-action of a Belleville spring. That could change
alignment a little, methinks.

For what it's worth, today I jacked up my car so no weight was on the
wheels, and checked for tightness of the tie rods. They seemed OK.

I'd love to hear back from someone on this. Damn, some of you guys who post
here are really sharp people.

Mike


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Old 09 May 2005, 12:28 pm   #5 (permalink)
Jason James
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Default Re: Bad problem with jerky steering - any feedback?


"M. Hamill" <mhamill@fuse.net> wrote in message
news:eff50$427ebfce$d8442b7f$6036@FUSE.NET...
> ----
> I really appreciate the replies.
>
> My lead candidate hypothesis for what's causing my difficulty is a problem
> with the power steering pump's built-in recirculation valve. My best guess
> is that this valve used to modulate, but now for some reason, it tends to
> act like an open-closed valve. Here's what I suspect:
>
> - Because the car is out of alignment, usually steering to the left, I

must
> turn the steering wheel slightly to the right to counteract this tendency.
> So the mechanism which divides power steering fluid pressure to opposite
> ends of the rack's piston is out of neutral position.


I see your reasoning,...but it's a very long-shot. If your PS was applying
more effort (thru its hydraulics) to one side relative to the other,..then
you would see this effect demonstrated by raising the front wheels off the
ground,..start the engine and slowly move the steering from one lock to the
other. If there is an unatural bias,.your wheels should move by themselves
to the side which the vehicle is pulling to.



> - When I do this, the divider in the steering gear mechanism that

apportions
> hydraulic pressure to the power-assist cylinder for the rack puts slightly
> higher pressure on the left side of the rack's piston than the right.
> - As road speed increases, and pump output pressure increases to a certain
> point, the recirculation valve opens abruptly, and pressure falls
> noticeably.


The pressure regulator valve will keep pressures from going too high,..but I
suspect its action is subtle, not sudden.


Because the port to the left side of the cylinder is open
> further than the right side's port, the suddenly reduced pressure from the
> pump feeds through to the piston's left side before the right side, and it
> falls below the pressure on the right side. So, momentarily, the piston
> pushes on the left tie rod and pulls the right one.
> - The reverse occurs when road speed and pump speed are reduced, and the
> recirculation valve closes, and output pressure spikes upward for an
> instant.


The test I mentioned should demonstrate this, if its occuring.


> I tried to test this hypothesis on the highway today, by letting the car
> drift to the extent I could when no other cars were near me, so that the
> divider (operated by the steering mechanism) would be in a neutral

position,
> and then increasing & reducing road speed. My thought was, if this divider
> were in a neutral position, a bump up or down in fluid pressure would be
> canceled out, and that would implicate the recirc valve in the pump. But I
> couldn't successfully do the test.
>
> A new thought: one or more of the support plates - or backing plates (pick
> your terminology) of the MacPherson struts was acting like a Belleville
> spring. I often hear odd klunk sounds on this vehicle, hence my suspicion.
> The support plates are between the body and the top of each MacPherson
> strut. A Belleville spring acts like a two-position spring, unlike than a
> conventional spring. Now, when my struts were replaced 3 months back it
> wasn't necessary to replace any of these plates, but I still wonder if

maybe
> one of them has the snap-action of a Belleville spring. That could change
> alignment a little, methinks.
>
> For what it's worth, today I jacked up my car so no weight was on the
> wheels, and checked for tightness of the tie rods. They seemed OK.
>
> I'd love to hear back from someone on this. Damn, some of you guys who

post
> here are really sharp people.
>
> Mike


I think you are over analysing your problem. As I said there are many
things which will cause wandering or pulling,..everything from tire
anomolies to an acumulation of alignment errors and /or wear. The Camry IME
is a very stable car, tracking-wise. In light of this your problem should be
fairly obvious to the trained steering specialist.

NB

Some causes of steering probs I've experienced:

My old Ford V8 had a front tire which was delaminating on one shoulder so
thet the tire had a slightly wider diameter on the outside shoulder to the
inside,..this caused dramatic pulling away from that tire's side/

Chrysler has a different brand tire on one rear wheel,..

Too little castor,..one side caused pulling to that side (Chrysler)

Badly worn idler-arm (recirc ball steering) caused toe-problems that side
and pulling

High crown roads (not flat) caused pulling to verge. Normally castor is set
slightly heavier on the kerb-side to counter this.

Brake drag one side = pulling (VW Passat,..heap of shit car)

Too positive camber caused severe tracking instability (Chrysler had its
torsion bars raised on front)

Too wide a tire on rear caused dangerous instability when moderate steering
corrections were made (Chrysler again)

Sudden changes in cornering radius caused by badly worn strut top mounts
(tire would go positive during cornering,..Passat)

And probably more I cant recall right now//

Jason


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