Minor brake issues on Midlife

[Midlife]

When doing a hard, nearly panic stop, Midlife stops at first straight, and about 2/3rds the way through the braking, the rear end slews to the right.  The steering wheel stays straight, so I suspect the rear breaks.  AZPete found a minor issue with my rear brakes a few weeks ago, and we adjusted the drums by hand using the star adjuster.  Since I found the problem, I backed up in reverse hard several times, and I found the problem diminished some, but not entirely.  I suspect one drum is still over-tightened, probably the left.  Does this sound right?

Also, I found the car on the highway now tends to veer right if I don't have my hands on the steering wheel.  Our roads are not entirely level, and I suspect the crown may be causing the problem.  Generally, I have to keep a slight amount of left control on the wheel while driving, but it is barely noticeable.  Could the two problems be related?

[Fast68back]

Better your left hand than right since thats the one that goes onthe passengers knee  ~dk

[daveSanborn]

Could the two problems be related?

They could be....  Do you still have your paper copy from the alignment rack?  What were the caster specs for L & R sides?

[napaguy]

Have the alignment checked first and see what happens.

[Sluggo]

The alignment would really have to be whacked to pull as described.

Make sure your brake hoses are not collapsed. You can force fluid through one way but it don't want to come back.

Post you specs

[daveSanborn]

The alignment would really have to be whacked to pull as described.

I agree.  I was focusing on his tracking issue while driving straight w/o braking.

[Midlife]

Caster 2-3, toe 1/8-1/4, and camber 1.5 (I can't remember and I'm on the road).  We replaced a driver's side UCA, and rechecked alignment, and it was still good (but didn't check toe).  The pull is slight, and feels more like the road crown than anything else.  When i get back home, I'll try and find a better road and recheck the pull.

[daveSanborn]

The pull is slight, and feels more like the road crown than anything else.

Well, I'm not ruling out a dragging brake, but you should have a cross caster setting on the alignment to overcome the road crown.

Your camber is negative 1.5 right?

[Sluggo]

The pull is slight, and feels more like the road crown than anything else.

but you should have a cross caster setting on the alignment to overcome the road crown.

WTF! Somebody on a board actually knows alignment lingo? And what cross caster is?
I'm impressed Dave.

[daveSanborn]

Somebody on a board actually knows alignment lingo?

Well if the local yocal alignment rack guy (one of my beer drinking buddies) didn't expect the alignment to take 40 minutes from start to finish for every model of car on the road, I probably wouldn't know what cross caster was.

I was forced to learn because he threw the towel in after the first hour and said "this is the best I can get it".  Really?  Go get yourself a beer and roll your tool box over here for me, I've got plenty of time.

Now, I just schedule rack time and do it myself.

Piece of cake jake!

[Sluggo]

Somebody on a board actually knows alignment lingo?

I was forced to learn because he threw the towel in after the first hour and said "this is the best I can get it". 

What a nancy boy. "best I can get it" I'da kicked his ass.

This is how a pro does it.

[daveSanborn]

This is how a pro does it....

.... on his GrandMas' car.

What's up with the positive Camber?

Due to the design geometry of the suspension system, as the outside tire/wheel moves upwards (suspension compression) while in a sharp turn/cornering, the component geometry induces positive camber,  This positive camber places less tire surface area onto the road.  The more positive camber you have initially, the more you'll have while in a sharp turn.  Since the weight of the vehicle will shift to the outside tire/wheel while cornering, most of your steering traction is on this outside tire surface.

Look closely at road race cars.  Their static camber settings are usually in the -3 to -4 range.  The tires look awkwardly "tilted" inwards at the top.  Once these cars are at speed and cornering, the induced positive camber reduces the static negative camber placing the full contact patch of the outside tire onto the roads surface while cornering.

While camber settings of -3 to -4 are not practical for street use (due to increased tire wear) on a daily driver, this same daily driver can benefit greatly from having some static negative camber.  Usually in the -1 to -2 range.

I run -1.5 camber on my '66 and love the hell out of it.

Sluggo, you're probably aware of all of this, but it's good reading for the under-informed.  Do you test drive after initial settings and then re-check the specs?  Due to "settling" (as I like to call it), rarely will I get the exact same specs twice in a row.

[Midlife]

OK...I'm beginning to remember.  I'm on the road and don't have my stats online.  Yes, camber was negative, but one was nearly zero (-0.5?) and the other about -1.2???  Shit...too much YJ.  I'll be back home on Monday and will dig out the stats.

So what is cross camber?  Should it be set up that the car, if truly on level ground, has a slight left tendency to counteract the crown?

The guy who aligned my car is an old-timer, using straight edges and a simple caster/camber device.  He doesn't blink at these old cars, and did the whole alignment in about 30 minutes, and charged $45.  Nothing difficult on these old Mustangs, but you do have to know about the shims and what order to put them in.  Since then, I obtained my own caster/camber device and rechecked his work: dead on his numbers.  Like I said, I didn't re-check toe. 

[daveSanborn]

So what is cross camber?  Should it be set up that the car, if truly on level ground, has a slight left tendency to counteract the crown?

Yes, but it's cross caster that accomplishes this, not the camber.

[Midlife]

First I've ever heard of this.  Tell me more!

[Starfury]

Wow Dave, that's a LOT of negative camber to be running on a street car.  I bet your front tires don't last too long, heh.  I run -.5* and I like it, but it still eats up the inside tread.  Then again, mine's a daily driver and sees a fair amount of freeway miles.

[daveSanborn]

I've put on maybe 200 miles and most of that is doing donuts.

[daveSanborn]

the ole blacktop road in front of my house looks like an accident scene with all of the rubber on the road

[Starfury]

lol...yeah, I've put 200 miles on in the last 2 months:P  I'm at like 12k on the new motor, which was something like 4 years ago.

[Sluggo]

OK...I'm beginning to remember.  I'm on the road and don't have my stats online.  Yes, camber was negative, but one was nearly zero (-0.5?) and the other about -1.2???  chit...too much YJ.  I'll be back home on Monday and will dig out the stats.

So what is cross camber?  Should it be set up that the car, if truly on level ground, has a slight left tendency to counteract the crown?

The guy who aligned my car is an old-timer, using straight edges and a simple caster/camber device.  He doesn't blink at these old cars, and did the whole alignment in about 30 minutes, and charged $45.  Nothing difficult on these old Mustangs, but you do have to know about the shims and what order to put them in.  Since then, I obtained my own caster/camber device and rechecked his work: dead on his numbers.  Like I said, I didn't re-check toe. 

I have never seen a car even after a short drive read the same.
I'm running a little positive trying to get away from the bumpsteer until I get a kit. (it does not help) I ran 1.5 neg for a while but it looked like about 3 degrees-.

I'll probably go 1.2 with the bumpsteer kit and the steering converted to manual. The control valve is not too condusive to handling.

[Midlife]

Caster 2-3, toe 1/8-1/4, and camber 1.5 (I can't remember and I'm on the road).  We replaced a driver's side UCA, and rechecked alignment, and it was still good (but didn't check toe).  The pull is slight, and feels more like the road crown than anything else.  When i get back home, I'll try and find a better road and recheck the pull.

Got home, and here are the specs: Toe: 1/8" in, Caster 3* positive, and 1/4* negative camber.  No details for each side. 

Still looking for a definition of cross-caster.

[Sluggo]

Caster 2-3, toe 1/8-1/4, and camber 1.5 (I can't remember and I'm on the road).  We replaced a driver's side UCA, and rechecked alignment, and it was still good (but didn't check toe).  The pull is slight, and feels more like the road crown than anything else.  When i get back home, I'll try and find a better road and recheck the pull.

Got home, and here are the specs: Toe: 1/8" in, Caster 3* positive, and 1/4* negative camber.  No details for each side. 

Still looking for a definition of cross-caster.

Cross caster is the difference from side to side. say your left side is +3.2 and right is 2.8+ your cross caster is .4+

Your left wheel is actually leading the right by .4 degrees. .5 degrees is the most any reputable alignment guy will allow
regardless of what the spec is.

Using the above numbers 3.2+ left and 2.8+ right, the car will have a tendency to want to go right. This is because your wheel
base is actually shorter on the right side. This setup would probably pull pretty hard anywhere where roads are crowned.

The most cross caster I allow is .3 right leading left (right more +) to correct for crown yet not be far enough ahead to cause a pull.

That's the short answer. Want the long one?

[Midlife]

That's sort of what I expected: you want the caster to be smaller (if there is to be a difference) on the left side to compensate for the crown of the road.  I can understand that, and why measuring each wheel is so crucial. 

Now that I have my own measuring tools, I'll drag AZPete over here again, and re-measure, and perhaps add or subtract a shim or two.  But first, I'll try the car on a different road that may not have so prominent a crown.

As an aside, in 8 years of reading every post on TOF (That Other Forum), this is the first time I have heard of cross-camber and what advantages or disadvantages it can create.  Thank you, kind Sir!

[Midlife]

I took my '06 Mustang along the same stretch of roadway that I saw a fair amount of veering to the right without braking.  The newer 'Stang definitely had a crown issue.  We have sand as a base under the asphalt, and most of our roads have two ruts and three crowns.  With the newer car, the car would veer left or right easily once one got out of the ruts.  Therefore, I conclude that I do not have a major problem, but will continue to find a better road for testing, if I can find true concrete anywhere...

[AzPete]

You may actually have to drive that car more than 45 mins. lol I suggest trying to check it on one of the longer bridges around here. Much better surface.

Let me know when and I will bring the big hammers. We WILL get it adjusted.......