A Cars forum. AutoBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AutoBanter forum » Auto newsgroups » Technology
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Alignment/Measurement Question - Caster of Front Wheels



 
 
Thread Tools Display Modes
  #11  
Old June 6th 05, 05:27 PM
Martin
external usenet poster
 
Posts: n/a
Default

If the tire's contact patch is BEHIND the point where the "kingpin
axis" would be projected onto the pavement, is this positive or
negative caster?

Since I (luckily) have one side where the caster/camber is presumably
correct, can I fine-tune the match using driving characteristics? In
other words, if the vehicle pulls/drifts to the driver's side, which
side needs positive caster reduced (assuming equal camber and level
pavement)?

Thanks,

Martin

Martin wrote:
> I recently replaced upper ball joints on a '96 Dodge 3500 (1-ton) van.
> This vehicle uses pressed-in ball joints, and I replaced them with a
> standard C-frame tool. After a few months, one of the ball joints
> backed itself out (this is a poor design, IMO). I pressed it back in,
> and tack-welded it in a few spots. So far, it's holding just fine.
>
> In order to do the weld, I removed the upper A-frame. Of course, I
> didn't think to mark it's position (uses no shims, just slotted bolt
> holes to adjust caster/camber) until I'd already loosened the bolts and
> let things shift.
>
> I'd like to get the truck properly in alignment. If that's not
> possible, at least driveably close until I buy new tires and have a
> shop fine-tune it.
>
> I think I can measure camber with a plumb bob, and toe-in's a
> no-brainer, but how in the devil can I measure caster?
>
> Also, is there an online reference where I can find the alignment specs
> for my vehicle?
>
> best regards,
>
> Martin


Ads
  #12  
Old June 6th 05, 05:33 PM
Martin
external usenet poster
 
Posts: n/a
Default

It's best to arrive at the shop with alignment in the ballpark.
Caster and camber are highly interactive on this vehicle, ie you loosen
the upper A-frame mounts and wiggle everthing around to change both
settings. If they are 'way off, you're far less likely to get a
satisfactory result from some guy who's used to just setting the
toe-in.

Do you change your own oil? Some of us have curiousity that goes a
little further

Martin

JR North wrote:
> Geezus Christ, go get it aligned, cheapskate
> JR
> Dweller in the cellar
> and next time, buy a Ford
>
> Martin wrote:
> > I recently replaced upper ball joints on a '96 Dodge 3500 (1-ton) van.
> > This vehicle uses pressed-in ball joints, and I replaced them with a
> > standard C-frame tool. After a few months, one of the ball joints
> > backed itself out (this is a poor design, IMO). I pressed it back in,
> > and tack-welded it in a few spots. So far, it's holding just fine.
> >
> > In order to do the weld, I removed the upper A-frame. Of course, I
> > didn't think to mark it's position (uses no shims, just slotted bolt
> > holes to adjust caster/camber) until I'd already loosened the bolts and
> > let things shift.
> >
> > I'd like to get the truck properly in alignment. If that's not
> > possible, at least driveably close until I buy new tires and have a
> > shop fine-tune it.
> >
> > I think I can measure camber with a plumb bob, and toe-in's a
> > no-brainer, but how in the devil can I measure caster?
> >
> > Also, is there an online reference where I can find the alignment specs
> > for my vehicle?
> >
> > best regards,
> >
> > Martin
> >

>
>
> --
> --------------------------------------------------------------
> Home Page: http://www.seanet.com/~jasonrnorth
> If you're not the lead dog, the view never changes
> Doubt yourself, and the real world will eat you alive
> The world doesn't revolve around you, it revolves around me
> No skeletons in the closet; just decomposing corpses
> --------------------------------------------------------------
> Dependence is Vulnerability:
> --------------------------------------------------------------
> "Open the Pod Bay Doors please, Hal"
> "I'm sorry, Dave, I'm afraid I can't do that.."


  #13  
Old June 6th 05, 06:59 PM
JR North
external usenet poster
 
Posts: n/a
Default

I guess you didn't visit my webpage...
JR
Dweller in the cellar

Martin wrote:

> It's best to arrive at the shop with alignment in the ballpark.
> Caster and camber are highly interactive on this vehicle, ie you loosen
> the upper A-frame mounts and wiggle everthing around to change both
> settings. If they are 'way off, you're far less likely to get a
> satisfactory result from some guy who's used to just setting the
> toe-in.
>
> Do you change your own oil? Some of us have curiousity that goes a
> little further
>
> Martin
>
> JR North wrote:
>
>>Geezus Christ, go get it aligned, cheapskate
>>JR
>>Dweller in the cellar
>>and next time, buy a Ford
>>
>>Martin wrote:
>>
>>>I recently replaced upper ball joints on a '96 Dodge 3500 (1-ton) van.
>>>This vehicle uses pressed-in ball joints, and I replaced them with a
>>>standard C-frame tool. After a few months, one of the ball joints
>>>backed itself out (this is a poor design, IMO). I pressed it back in,
>>>and tack-welded it in a few spots. So far, it's holding just fine.
>>>
>>>In order to do the weld, I removed the upper A-frame. Of course, I
>>>didn't think to mark it's position (uses no shims, just slotted bolt
>>>holes to adjust caster/camber) until I'd already loosened the bolts and
>>>let things shift.
>>>
>>>I'd like to get the truck properly in alignment. If that's not
>>>possible, at least driveably close until I buy new tires and have a
>>>shop fine-tune it.
>>>
>>>I think I can measure camber with a plumb bob, and toe-in's a
>>>no-brainer, but how in the devil can I measure caster?
>>>
>>>Also, is there an online reference where I can find the alignment specs
>>>for my vehicle?
>>>
>>>best regards,
>>>
>>>Martin
>>>

>>
>>
>>--
>>--------------------------------------------------------------
>> Home Page: http://www.seanet.com/~jasonrnorth
>> If you're not the lead dog, the view never changes
>> Doubt yourself, and the real world will eat you alive
>> The world doesn't revolve around you, it revolves around me
>> No skeletons in the closet; just decomposing corpses
>>--------------------------------------------------------------
>>Dependence is Vulnerability:
>>--------------------------------------------------------------
>>"Open the Pod Bay Doors please, Hal"
>>"I'm sorry, Dave, I'm afraid I can't do that.."

>
>



--
--------------------------------------------------------------
Home Page: http://www.seanet.com/~jasonrnorth
If you're not the lead dog, the view never changes
Doubt yourself, and the real world will eat you alive
The world doesn't revolve around you, it revolves around me
No skeletons in the closet; just decomposing corpses
--------------------------------------------------------------
Dependence is Vulnerability:
--------------------------------------------------------------
"Open the Pod Bay Doors please, Hal"
"I'm sorry, Dave, I'm afraid I can't do that.."
  #14  
Old June 7th 05, 07:15 PM
Martin
external usenet poster
 
Posts: n/a
Default

OK, I did the homebrew alignment last night, after also replacing two
idler arms and putting the best two tires on front. BTW, thank-you Dan
Saitz for emailing to me the alignment specs for my van!

First, I used my 4' box-beam level to locate a level parking lot. Had
to go to a church about a block from the house. On the way home, I
took the van up to about 50 MPH on several smooth roads. It pulled
very strongly to the left, and I thought I could hear some scrubbing
from the tires.

On the driveway at home, I removed the right front wheel and loosened
the two mounting bolts on the upper A-frame. These bolts ride in
slotted holes in the vehicle frame, so that the front and rear mounting
points can be separately adjusted by pulling/pushing toward or away
from the vehicle centerline. So, you adjust caster and camber
simultaneously.

I pulled the upper A-frame all the way to the outside stops. This
would result in maximum positive camber (top of tire leaning outward)
and an unknown (but hopefully small) amount of caster. Then I slightly
snugged the front A-frame bolt to hold it in place, and pushed the rear
mount toward the vehicle centerline by a "calibrated eyeball" amount to
increase the caster. Then I slightly snugged the rear bolt, loosened
the front bolt, and pushed the front mount of the A-frame toward the
centerline by HALF of the "calibrated eyeball" amount. My idea here
was to achieve a net reduction from max camber while preserving half of
the added caster.

I then repeated the procedure on the left side, re-installed the
wheels, grabbed a flashlight, and headed to my level parking lot for
some measurements. I noticed an immediate improvement in handling.
The pulling seemed to be gone, though it was hard to tell at 30 MPH on
bad roads. There did seem to be a lot of "wandering", though.

With the help of my girlfriend, I made camber measurements straight
forward and turning to the stops (maybe around 45 degrees) on both
sides. By having her steady the vertical 4' level against the fender
while I used the flashlight to watch the bubble and scoot the other end
around on the ground, we were able to come up with a reference that was
"plumb" (at least in the plane perpendicular to the vehicle) and within
about two inches of the wheel. I made distance measurements from the
vertical to the rim at top and bottom, to calculate actual camber.
I calculated camber of +1.6 degrees on the right and +1.2 degrees on
the left. The tops of my tires were still leaning slightly "out".

The caster calculations were more problematic because of measurement
uncertainty. When the wheel was turned, this resulted in fender
obscuration of the point where I wanted to set the level. So, this
measurement distance was several inches further away, probably adding
error. I was, however, consistent in seeing a decrease in positive
camber (top of wheel tilting relatively inward) of both wheels when
they were on the outside of a turn. This decrease was "maybe" 0.6
degree on one side and 1.0 degree on the other side. So, I felt I at
least had achieved positive caster. Everyone says that caster is a
handling factor but not a wear factor, so I figured I'd fine-tune this
by road testing.

Next we took several toe-in measurements, and found the wheels to be
toed out by about 1/4".

I drove back home (tools and jack were still on the driveway). I
adjusted the toe to zero by shortening the tie rod on the left side
(remembering the earlier drastic left pull, I was thinking about
centering the steering wheel).

Time for a road test - and the van drove like a dream. No pull, all
the way to 65 MPH, and the wandering (probably due to the toe-out) was
also gone. You could take your hands off the wheel and it went
perfectly straight. And, the wheel was centered.

Then I made a mistake. Thinking about the tire wear due to the excess
positive camber, particularly on the right, I decided to make a small
change and take another measurement. Since decreasing right camber
would supposedly make the vehicle pull a little to the left, I thought
I'd simultaneously decrease the caster on that same wheel (several
references indicate that a vehicle pulls to the side with increased
camber or decreased caster) to compensate.

Well, that was just too many variables to deal with when it's after
midnight and the upper A-frame is free to move in two dimensions at
once. My next road test had the vehicle drifting noticeably to the
left. You just can't make a small, precise, "delta" change without
some sort of fixed reference or simultaneous measurement.

Anyway, it took another round of wrenching (and was about 1:15 am)
before I had the driveability back to where I was satisfied.

This weekend I'll try another idea for fine-tuning the camber, which is
still excessive by anyone's account. I'll use a magnetic-base stand
from a dial indicator to position a pointer directly above the grease
fitting of the upper ball joint. That way, I will be able to tell
exactly how much relative shift I've made in the A-frame before
re-tightening the bolts.

Yes, it was a lot of work, but I really feel good about the learning
experience.

best regards,

Martin

Martin wrote:
> I recently replaced upper ball joints on a '96 Dodge 3500 (1-ton) van.
> This vehicle uses pressed-in ball joints, and I replaced them with a
> standard C-frame tool. After a few months, one of the ball joints
> backed itself out (this is a poor design, IMO). I pressed it back in,
> and tack-welded it in a few spots. So far, it's holding just fine.
>
> In order to do the weld, I removed the upper A-frame. Of course, I
> didn't think to mark it's position (uses no shims, just slotted bolt
> holes to adjust caster/camber) until I'd already loosened the bolts and
> let things shift.
>
> I'd like to get the truck properly in alignment. If that's not
> possible, at least driveably close until I buy new tires and have a
> shop fine-tune it.
>
> I think I can measure camber with a plumb bob, and toe-in's a
> no-brainer, but how in the devil can I measure caster?
>
> Also, is there an online reference where I can find the alignment specs
> for my vehicle?
>
> best regards,
>
> Martin


  #15  
Old June 7th 05, 09:46 PM
Martin
external usenet poster
 
Posts: n/a
Default

Nice stuff on the site. You obviously practice do-it-yourself, but
somehow didn't want to preach it (at least not to me, unless you were
joking).

BTW, the Datsun 2000 roadster has always been one of my favorite cars.
One of my best friends from HS had one and it was fast. I'd think
about selling that little 1600, though .... she obviously likes it in
the rear, and that might get you killed one of these days

Martin

JR North wrote:
> I guess you didn't visit my webpage...
> JR
> Dweller in the cellar
>


  #16  
Old June 11th 05, 05:02 PM
Carl Byrns
external usenet poster
 
Posts: n/a
Default


"Martin" > wrote in message
oups.com...
> It's best to arrive at the shop with alignment in the ballpark.


I used to do front end work for a living- if you can drive on the rack, you
can bring it back into alignment.

> Caster and camber are highly interactive on this vehicle, ie you loosen
> the upper A-frame mounts and wiggle everthing around to change both
> settings.


Front end shops have a tool for that...

> If they are 'way off, you're far less likely to get a
> satisfactory result from some guy who's used to just setting the
> toe-in.
>

Bull****- toe is the last operation done.
Vans really need to be thrust angle aligned- not a driveway job.

> Do you change your own oil?


Do you do your own brain surgery?

> Some of us have curiousity that goes a
> little further


Curiosity killed the cat :-(

-Carl


  #17  
Old June 13th 05, 05:10 PM
Martin
external usenet poster
 
Posts: n/a
Default

Carl,

What you "used to do" is not brain surgery. Don't act like it is.

Martin

Carl Byrns wrote:
> "Martin" > wrote in message
> oups.com...
> > It's best to arrive at the shop with alignment in the ballpark.

>
> I used to do front end work for a living- if you can drive on the rack, you
> can bring it back into alignment.
>
> > Caster and camber are highly interactive on this vehicle, ie you loosen
> > the upper A-frame mounts and wiggle everthing around to change both
> > settings.

>
> Front end shops have a tool for that...
>
> > If they are 'way off, you're far less likely to get a
> > satisfactory result from some guy who's used to just setting the
> > toe-in.
> >

> Bull****- toe is the last operation done.
> Vans really need to be thrust angle aligned- not a driveway job.
>
> > Do you change your own oil?

>
> Do you do your own brain surgery?
>
> > Some of us have curiousity that goes a
> > little further

>
> Curiosity killed the cat :-(
>
> -Carl


  #18  
Old June 13th 05, 06:03 PM
external usenet poster
 
Posts: n/a
Default

I have had shops do front end alignments for me and I get the car home
and end up redoing them in my carport with a tape and string and a
level. I have yet to find a front end shop that know's how to read specs.



Martin wrote:

> Carl,
>
> What you "used to do" is not brain surgery. Don't act like it is.
>
> Martin
>
> Carl Byrns wrote:
>
>>"Martin" > wrote in message
groups.com...
>>
>>>It's best to arrive at the shop with alignment in the ballpark.

>>
>>I used to do front end work for a living- if you can drive on the rack, you
>>can bring it back into alignment.
>>
>>
>>>Caster and camber are highly interactive on this vehicle, ie you loosen
>>>the upper A-frame mounts and wiggle everthing around to change both
>>>settings.

>>
>>Front end shops have a tool for that...
>>
>>
>>>If they are 'way off, you're far less likely to get a
>>>satisfactory result from some guy who's used to just setting the
>>>toe-in.
>>>

>>
>>Bull****- toe is the last operation done.
>>Vans really need to be thrust angle aligned- not a driveway job.
>>
>>
>>>Do you change your own oil?

>>
>>Do you do your own brain surgery?
>>
>>
>>>Some of us have curiousity that goes a
>>>little further

>>
>>Curiosity killed the cat :-(
>>
>>-Carl

>
>


  #19  
Old June 20th 05, 08:01 PM
Martin
external usenet poster
 
Posts: n/a
Default

The pointer and magnetic base trick worked perfectly. I took
measurements, removed the wheel, installed the pointer, and then made
the necessary relative adjustments. The van drives perfectly, no
pulling, no wander, etc. I'm not even going to take it to a shop for
any fine-tuning, as there's no way they could improve on the
driveability, and the current settings should minimize tire wear.

I'd recommend this method to anyone who wants to try a do-it-yourself
alignment.

best regards,

Martin

Martin wrote:
> OK, I did the homebrew alignment last night, after also replacing two
> idler arms and putting the best two tires on front. BTW, thank-you Dan
> Saitz for emailing to me the alignment specs for my van!
>
> First, I used my 4' box-beam level to locate a level parking lot. Had
> to go to a church about a block from the house. On the way home, I
> took the van up to about 50 MPH on several smooth roads. It pulled
> very strongly to the left, and I thought I could hear some scrubbing
> from the tires.
>
> On the driveway at home, I removed the right front wheel and loosened
> the two mounting bolts on the upper A-frame. These bolts ride in
> slotted holes in the vehicle frame, so that the front and rear mounting
> points can be separately adjusted by pulling/pushing toward or away
> from the vehicle centerline. So, you adjust caster and camber
> simultaneously.
>
> I pulled the upper A-frame all the way to the outside stops. This
> would result in maximum positive camber (top of tire leaning outward)
> and an unknown (but hopefully small) amount of caster. Then I slightly
> snugged the front A-frame bolt to hold it in place, and pushed the rear
> mount toward the vehicle centerline by a "calibrated eyeball" amount to
> increase the caster. Then I slightly snugged the rear bolt, loosened
> the front bolt, and pushed the front mount of the A-frame toward the
> centerline by HALF of the "calibrated eyeball" amount. My idea here
> was to achieve a net reduction from max camber while preserving half of
> the added caster.
>
> I then repeated the procedure on the left side, re-installed the
> wheels, grabbed a flashlight, and headed to my level parking lot for
> some measurements. I noticed an immediate improvement in handling.
> The pulling seemed to be gone, though it was hard to tell at 30 MPH on
> bad roads. There did seem to be a lot of "wandering", though.
>
> With the help of my girlfriend, I made camber measurements straight
> forward and turning to the stops (maybe around 45 degrees) on both
> sides. By having her steady the vertical 4' level against the fender
> while I used the flashlight to watch the bubble and scoot the other end
> around on the ground, we were able to come up with a reference that was
> "plumb" (at least in the plane perpendicular to the vehicle) and within
> about two inches of the wheel. I made distance measurements from the
> vertical to the rim at top and bottom, to calculate actual camber.
> I calculated camber of +1.6 degrees on the right and +1.2 degrees on
> the left. The tops of my tires were still leaning slightly "out".
>
> The caster calculations were more problematic because of measurement
> uncertainty. When the wheel was turned, this resulted in fender
> obscuration of the point where I wanted to set the level. So, this
> measurement distance was several inches further away, probably adding
> error. I was, however, consistent in seeing a decrease in positive
> camber (top of wheel tilting relatively inward) of both wheels when
> they were on the outside of a turn. This decrease was "maybe" 0.6
> degree on one side and 1.0 degree on the other side. So, I felt I at
> least had achieved positive caster. Everyone says that caster is a
> handling factor but not a wear factor, so I figured I'd fine-tune this
> by road testing.
>
> Next we took several toe-in measurements, and found the wheels to be
> toed out by about 1/4".
>
> I drove back home (tools and jack were still on the driveway). I
> adjusted the toe to zero by shortening the tie rod on the left side
> (remembering the earlier drastic left pull, I was thinking about
> centering the steering wheel).
>
> Time for a road test - and the van drove like a dream. No pull, all
> the way to 65 MPH, and the wandering (probably due to the toe-out) was
> also gone. You could take your hands off the wheel and it went
> perfectly straight. And, the wheel was centered.
>
> Then I made a mistake. Thinking about the tire wear due to the excess
> positive camber, particularly on the right, I decided to make a small
> change and take another measurement. Since decreasing right camber
> would supposedly make the vehicle pull a little to the left, I thought
> I'd simultaneously decrease the caster on that same wheel (several
> references indicate that a vehicle pulls to the side with increased
> camber or decreased caster) to compensate.
>
> Well, that was just too many variables to deal with when it's after
> midnight and the upper A-frame is free to move in two dimensions at
> once. My next road test had the vehicle drifting noticeably to the
> left. You just can't make a small, precise, "delta" change without
> some sort of fixed reference or simultaneous measurement.
>
> Anyway, it took another round of wrenching (and was about 1:15 am)
> before I had the driveability back to where I was satisfied.
>
> This weekend I'll try another idea for fine-tuning the camber, which is
> still excessive by anyone's account. I'll use a magnetic-base stand
> from a dial indicator to position a pointer directly above the grease
> fitting of the upper ball joint. That way, I will be able to tell
> exactly how much relative shift I've made in the A-frame before
> re-tightening the bolts.
>
> Yes, it was a lot of work, but I really feel good about the learning
> experience.
>
> best regards,
>
> Martin
>
> Martin wrote:
> > I recently replaced upper ball joints on a '96 Dodge 3500 (1-ton) van.
> > This vehicle uses pressed-in ball joints, and I replaced them with a
> > standard C-frame tool. After a few months, one of the ball joints
> > backed itself out (this is a poor design, IMO). I pressed it back in,
> > and tack-welded it in a few spots. So far, it's holding just fine.
> >
> > In order to do the weld, I removed the upper A-frame. Of course, I
> > didn't think to mark it's position (uses no shims, just slotted bolt
> > holes to adjust caster/camber) until I'd already loosened the bolts and
> > let things shift.
> >
> > I'd like to get the truck properly in alignment. If that's not
> > possible, at least driveably close until I buy new tires and have a
> > shop fine-tune it.
> >
> > I think I can measure camber with a plumb bob, and toe-in's a
> > no-brainer, but how in the devil can I measure caster?
> >
> > Also, is there an online reference where I can find the alignment specs
> > for my vehicle?
> >
> > best regards,
> >
> > Martin


 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Jeep Tech: Tips for taking apart a front end. DMaster Jeep 1 March 8th 05 04:00 AM
Bent front axle tube? Dodge 4x4 Steve 4x4 2 February 17th 05 04:49 AM
Another Front Bumper Question Richard Saturn 0 February 14th 05 04:33 AM
99 front brake pads replaced, question on old pads Mikepier Ford Explorer 0 February 4th 05 08:07 PM
Looking for directions to service front hubs (1994 4x4) Chris Ford Explorer 1 November 3rd 04 05:49 PM


All times are GMT +1. The time now is 09:40 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AutoBanter.
The comments are property of their posters.