94 Body Height

[BadTrak]

Does anyone out there have a manuel that will tell you the correct height measurement from the top of the wheel well to the ground for the front and rear of the vehicle? It was probably the same back a few years from '94. Along with sagging springs and removal of components it does not sit the same. I want to get this riding in the proper position for alignment.

Thanks!

[old_master]

Chassis ride height is typically calculated from a point on the lower ball joint or steering knuckle in relationship to a certain point on the frame, for each side of the vehicle. The whole purpose of checking/adjusting chassis ride height is to make sure the SUSPENSION is at the correct height. By measuring fender height you are checking the body and therefore bypassing, or covering up incorrect chassis ride height. 4WD chassis ride height is adjustable using the torsion bars. 2WD is changed only by replacing the springs if ride height is too low. The specifications may be different year to year, and are definitely different for 4WD and 2WD. A Chilton, Haynes or Alldata shop manual will show where the measurements are taken. Specs are rather hard to come by though; you may have to consult a front end shop or the dealer. Rear ride height is measured from the top of the axle housing to the under side of the bump stop bracket. Hope this helps.

[BadTrak]

Wow, a lot more complicated than I thought. It's 4wd with torsion, so I filled the air shocks with 50psi that lifted the rear a little (I tow a boat so the air shocks will come in handy for that too). Took measurement from the ground to the top of the wheel well and also top of the wheel well to the top of the tire rim. The rear ended up at 10.5" (rim to wheel well) and then I adjusted the front down to 10.5" also (front end was pointing up). Putting a level on the bottom of the rocker resulted in a slight downhill rake to the front. Measured the distance from the bump stop to lower A arm on the front, side to side and it was equal although small in my opinion. It came into alignment fine, so I'll leave it there for now.

Thanks!

[old_master]

You didn’t mention you have air shocks. Here’s an interesting tid-bit for you to ponder:
Any time you raise or lower the rear end of a vehicle, there is a substantial weight transfer. That transfer of weight affects ALL front end alignment angles! The alignment you just paid for to save those expensive tires goes right out the window as soon as the air pressure changes in the air shocks. There are certain vehicles that specify placing a weight, (simulating a driver) in the driver seat while doing the alignment. Yes, alignment is that sensitive! 150 pounds of driver is not even close to the weight transfer that air shocks can easily induce. Shock absorbers are designed to dampen the action of the springs. Springs are designed to hold the vehicle at the specified ride height. If the ride height is not within specifications, replacing the springs is the proper way to do it. Air shocks are a “band-aid” at best. Usually you can have a spring shop add a leaf for about the same money you spend on air shocks. My advice, get rid of them if you're concerned at all about excessive tire wear.

[ericn1300]

OM is right. getting the leaf springs re-arched is not very expensive and will probably solve your problem. and they can add an over weight leaf that has a different arch and that only comes into use when you have excessive weight on the rear of the vehicle. my 92 stock towing package is rated at 750/6000 but i try to balance the trailer to keep the tounge weight under 350 lbs. too little tounge weight will cause bucking and swaying in the trailer, too much will cause the front of the vehicle to float causing steering and braking problems. remember the laws of leverage and be careful where you place that ice chest full of adult beverages.

OM, i never heard of aligning the vehicle with weight in the drivers seat before. i'm going to have the pontiac aligned in the next week or two and will try an experiment. i'll have them align it and before it comes off the rack i'll plant my 225lb bum in the drivers seat and have them recheck the settings. might even take my load leveler along and have her sit in the passenger seat too. between the two of us we can add almost a quarter ton (metric) to the vehicle.

[old_master]

Hey Eric,
Not sure if they still do, but a few years back BMW called for that along with 10 gallons of fuel onboard. Normally auto manufacturers “Ball Park” in approximately 150 pounds and claim more than that can be an issue. I recall a situation in that a "rather large" customer complained of a pull after an alignment. I knew the adjustments were correct and went down the avenue of rotating tires, etc, the whole nine yards. I asked him in a way not to offend him, if he would mind sitting in the car while I realigned it. This was several years ago and I don't remember the difference in degrees for camber, caster and toe in, but after making some changes, the car went straight. I don’t know how familiar you are with alignment angles and what they do, but his pull was induced by excessive cross camber. It's not a bad idea, especially with "larger" occupants, to have ride height checked and the alignment done with the vehicle loaded the way it normally is when most of the driving is done. I guess it depends how particular the owner is. I can tell you first hand though, it DOES make a difference.

[ericn1300]

yeah, i can see where camber and body height could be effected by a lateral weight shift. especialy with large tires with soft sidewalls. maybe that explains the shift to oversized wheels and low profile tires on many cars, keeping the aspect ratio to the body height the same but lessening the effect on the alignment. i noticed my dad parked partialy on the curb and the goodyears he was running held their form and lifted off the road surface. tire quality makes a big difference too.

kinda like balancing the tires on the car instead of the standard method, gotta take in all the variables like an unbalanced brake drum.

[old_master]

Originally Posted by ericn1300

yeah, i can see where camber and body height could be effected by weight shift. especialy with large tires and soft sidewalls. maybe that explains the shift to oversized wheels and low profile tires on many cars, keeping the aspect ratio to the body height the same but lessening the effect on the alignment. i noticed my dad parked partialy on the curb and the goodyears he was running held their form and lifted off the road surface.

kinda like balancing the tires on the car, gotta take in all the variables like an unbalanced brake drum.

Exactly right with the brake drum theory. As far as wheels and tires changing alignment or ride height, nope, not at all. Body height yes, but not ride height, (two different things). A wheel alignment more technically should be called a "ball joint alignment". Both camber and caster are measured in degrees, of the position of the upper ball joint in relationship to the lower ball joint. When the upper ball joint is outboard of the lower ball joint, this is called positive camber. When the upper ball joint is behind the lower ball joint, this is called positive caster. Once these angles are set, any wheel with any tire will be in alignment. Ride height will not change due to it being a measurement between two points on the chassis of the vehicle. Different vehicles have different ways of adjusting camber and caster. Some are fully adjustable, some are not. Some are caster only, some are camber only. They all, however, have adjustable toe in. In the case of GM T series (Blazer, Jimmy, Bravada 4WD) they are fully adjustable by means of two cams in the upper control arm.

[Chris Stewart]

Thanks OM, your info makes this is a great thread!!

[ericn1300]

OK O.M. i have another alignment question for the master. i finaly got the pontiac aligned after replacing the passenger side lower control arm and the trailing arm that were bent in the accident. the steering wheel was off center big time to the right before i replaced the control arm, and after the repairs it was right on center and the vehicle tracked perfect, no pulling or wandering. i went ahead and got an alignment anway and now the sterring wheel is off center to the left, enough that the left turn signal doesn't always cancel now. i took it back for a redo and it seems even worse. the alignment seems fine and i got the print out showing it's in spec, it's just the steering wheel off center that really annoys me.

a friend of mine says he can fix it quick since the aligment is good. he says to measure the toe in with a piece of string for reference. then let out the left tie rod, counting the turns, until the steering wheel is centered, then bring in the right tie rod the same amount of turns then check the toe in with the string, adjusting the right tie rod until the toe in is right. will this work?

[old_master]

Eric,
Yes that will work, although it is not very accurate and I certainly wouldn't trust it for any length of time, especially with expensive tires. If camber is out of spec it generally takes 3,000 to 5,000 miles to notice. Camber will wear the tread smoothly and evenly on either the inside or outside edge of the tire. Caster will not cause any tire wear if it is out of spec, only a pull or wander. Toe in will not cause a pull or wander. If it is out of spec, it can make the vehicle handle "squirrely" on wet or snow covered pavement. You have witnessed what it does to the steering wheel, crooked. Toe in that is out of specs can do permanent damage to a tire in very few miles. Excessive toe in will cause an uneven "saw tooth" pattern to form on the outside edge of the tire and once there, the wear will not smooth out. The tire will be noisy while driving, other than that, no problem. Excessive toe out will do the same thing only on the inside edge of the tire. As close as you think you are, using a string, or even a measuring tape, at best it's a crap shoot. The shop that did the alignment should take care of it for you. I would guess that you have a close ratio steering gear box, how am I doing? Close ratio boxes can be a bear to get the wheel straight due to the fact that it takes very little steering wheel movement to correct while driving. There is a secret to it; hopefully your alignment tech knows it. The tech needs to be very patient and follow a certain procedure to get it right. Just as you need to be persistent in returning to them to have them do it right. Talk to them, if they don't have a clue how to do it, PM me and I'll email you how to do it, you can print it out and give it to them. Hope this helps.

[ericn1300]

Originally Posted by old_master

I would guess that you have a close ratio steering gear box, how am I doing?

yep, you got it. i wasn't used to the close ratio steering and when combined with the front wheel drive it put me into a powered four wheel drift when i tried to take evasive action during the accident. i was about to be t-boned and tried to accelerate and flip the rear around like i can do so easy in the mustang and ended up hitting the curb hard with both wheels after getting hit on the drivers side rear quarter. could have been worse i guess, but heck i can be driving straight and just sneeze in the 'tang and the rear will come around on me. i still think a well balanced rear wheel drive vehicle handles better in most evasive situations.

i do plan on taking it back one more time and was checking with you because the alignment tech there seems to be even more clue less than me. if you would be so kind as to email me the "secret" procedure i'll buy you a cold one next time you're in idaho.

[ericn1300]

sorry, Chris, if the previous post was a little off topic, but when you get someone this good online, you've got to milk it.

[Chris Stewart]

Originally Posted by ericn1300

sorry, Chris, if the previous post was a little off topic, but when you get someone this good online, you've got to milk it.

Finally got some time to check in.
I'm not a moderator...I just like Bravada's and Bravada people, we think alike.
There's no harm in going off topic except some very good info can get lost.
OM's most valued info can be offered and kept at the top of the page as a quick reference like Blazee's..

[ericn1300]

Originally Posted by Chris Stewart

Finally got some time to check in.
I'm not a moderator...I just like Bravada's and Bravada people, we think alike.
There's no harm in going off topic except some very good info can get lost.
OM's most valued info can be offered and kept at the top of the page as a quick reference like Blazee's..

i see you got a sticky now too, right above his. way to go.