A shop building my streetrod subframed a 1988 Cutlass Classic front suspension onto our 1939 Olds sedan more than two years ago. The car has always had oversteer and an alignment shop says the caster cannot be brought into spec (1.8-3.8 degrees). Caster is 11.8 degrees.
The alignment technician said this would cause oversteer but not tire wear.
I guess this means the subframe was not welded at the correct angle to allow proper alignment. The shop that did the work is long gone out of business so any corrections are up to me.
Car rides well and tracks nicely, but once past about a 30 degree turn of the steering wheel it doesn't return to center by itself and starts to turn really quick.
The car has the 1988 stock front stablizer bar, but no rear stablizer bar. Rear has been converted to coil overs with adjustable upper control arms for setting pinion angle.
Are there any fixes to this problem short of cutting and repositioning the front subframe -- such as some aftermarket front suspension replacements or modification of some mounting points or rods?
My apologies not getting you a picture sooner - I actually forgot when I was in the barn, but looked through my old pics and found a front suspension shot from this spring:
Changing the uppers isn't a big deal, but treat the springs with A LOT of respect. Their is a lot of energy their waiting to seriously hurt someone if you aren't paying attention. I agree with Chopt48 on how to do it - if the engine is in the car you shouldn't have a problem jacking up the lower control arm to compress the spring. In those pics it looked like the upper balljoints were still riveted in (meaning they are OEM) - why not install new ball joints while you have the arms off? New Moog's are only about $18 per side.
If you have any problems with the front suspension just ask - I've played with my stock car A LOT in the last two years and I'm sure a lot of people on here know a lot more then me about the stuff too!
Yep, sure looks like mine are reversed from yours. Your ball joint appears to be closer to the front while mine is closer to the rear.
The springs shouldn't be a hazard should they since they stay contained between the lower CA and the frame?
But what happens when the upper ball joint is pushed out of the steering knuckle --won't the wheel assembly tend to fall over because it is just held by the lower ball joint?
But what happens when the upper ball joint is pushed out of the steering knuckle --won't the wheel assembly tend to fall over because it is just held by the lower ball joint?
Yes it will, not a big deal though. It is not too difficult to get the spindle and ball joint lined up again.
Position your jack on the lower arm as far outboard as possible. This way, if you are having some trouble getting the joint into the spindle, you can jack the lower arm up to meet the upper. There is more leverage at the end of the arm than at, let's say, just under the coil pocket.
They shouldn't be a hazard, but I was thinking more along the lines of if your jack slips from under the control arm allowing the lower to rapidly unload the spring could come flying out. You will still have the shock mounted in through the center of the spring so that should catch it in case you have a jack failure.
They shouldn't be a hazard, but I was thinking more along the lines of if your jack slips from under the control arm allowing the lower to rapidly unload the spring could come flying out. You will still have the shock mounted in through the center of the spring so that should catch it in case you have a jack failure.
The springs won't be a hazzard unless the shocks are removed. The shocks keep the Lower A arm from dropping down and releasing the spring.
If it is sitting static as it shows in the photo of the drivers with the wrong A arm I don't think you will have any problem.
Just be very carefull as to where you put the stands under the lowers.
I usually put them just inside of the ball joint and don't extend them any higher than you have to.
And as I mentioned earlier put somthing under the frame to act as a safety in case it does try to drop. I would use rims laying flat or solid wood blocks with an inch or so clearance.
The spindle is going to be easier to hook to the ball joint simply because it will be lined up as it should be.
the ball on the stud in the ball joint should be tight and the stud should be very hard to wiggle If it is easy to wiggle around with your fingers replace the ball joints.
They are easy to change even though knocking the rivits out takes a bit of work.
The lower ball joints have to be pressed out and in with a ball joint press that looks somthing like a heavy duty C-clamp with attatchments.
An easy job with the tool, near impossible with out it.
You can check the lower ball joint when you have the car jacked up by the A frame. Just use a long bar under the tire to see if you can lift it an see noticable slack open up between the spindle and lower control arm. You may get a little but anything over 1/8 of an inch of movement calls for replacement. (Note, on Mopars refer the manual as they have extra clearance from the factory).
Just wanted to bring to light something that I'm aware of that I think could make a difference with the line of thinking about JohnTNs' clip situation. The engine and transmission were set back in the car apparently by welding the motor mounts rearward of the engine cradle after the clip was installed. It appears the drive line has been welded in place in perfect alignment in the car with the clip askew. If he were to try to reposition the clip, he would bring the drive line out of alignment.
Chopt 48- I'm real interested in your input on these next questions. They are beyond my experience and could really use your expertise and input.
1.) Would the use of specially made solid greasable bushings with the mounting holes bored appropriately offset in the lower control arms be a viable option to bring the .8125 (13/16") lower ball joint mis-alignment back to proper alignment? Each side could be offset bored so as to compensate for a .40625 change at the ball joint.
2.) If that were done, would any change to the upper A-arms beyond shimming and perhaps longer bolts be required? Is there enough range of motion at the ball joint?
3.) Would the drag link location being slightly off pose any problems?
4.) Would the bump steer characteristics be any worse than what they already are with the stock metric frame?
5.) If the lower arms were bushed, would a .40625 change cause spring/bucket alignment problems? In other words, would it bow the spring too much and perhaps hit the shock during travel?
I was just curious if this kind of an approach could work out for him and what you thought of the idea. Thank you.
The motor mounts can be seen in the first picture in my photo gallery. The flat plate welded to the rear edge of the front X member is visible on the far side (passenger side). It then makes an L and is welded to the top of the lower A-arm rear mount. On the drivers side, the L part is visible just above the frame rail and behind the upper A-arm.
I described it to Hammerline as being welded to the frame and not bolted to the original location on the X member. Actually both ends of it are welded to the clip now that I look at it again.
After taking a long look at the photo of the subframe install, I don't think that there is any problem with it. the clip and frame appear to be properly aligned.
On the other questions.
1. He is going to swap the Upper arms back to the proper sides and everything should be good. Look at the spindle in the photo of the drivers side of the subframe. you can notice the dramatic angle that it is leaning toward the rear. That is what is giving the excess caster.
If you were to pull the wheel of a stock Cutlass, Chevelle or like car you would see that the spindle should be pretty well vertical.
On the lower ball joints I wasn't referring to misalignment but suggesting that he check for wear in the ball joints while he has it jacked up.
If all the suspension parts have been replaced. = ball joints, bushings, tie rod ends. He doesn't have anything to worry about and should be able to drive the car w/o problems for years.
If any of the parts have excessive wear they will have to be replaced before the car can be aligned properly. I see that the upper bushings have been replaced.
As I stated in a previous post, I am not a fan of "fixes" + off set bushings or shafts, custom offset A arms on street driven cars. Custom parts for "wow" factor yes. Outside of a smooth ride and good handeling, the major reason of installing a clip on an older car is ease of finding replacement parts.
Thank you Chopt. I couldn't agree more when it comes to one off band-aid type fixes. I am not a "Master McGyver" fan either. In 99% of the cases I wouldn't even think about that kind of solution. I've been twisted up by band-aids like that too many times myself. In my mind though, it was shaping up as one of those 1% you need to break the rules deals.
While I know the caster situation is going to be resolved with the upper arm swap, my area of concern was more in reference to the 13/16" difference in the lower ball joints side to side due to the frame skew. I think the last thing any of us want is for him to have to re-do that clip if it could at all be helped.
So just to be 100% sure that I am hearing and understanding you correctly, you do not believe there will be any problem with him running the lower left A-arm ball joint the 13/16" forward of the right lower arm ball joint. The slightly shorter right side wheel base is all John will need to contend with correct? Because if that is the case someone in TN is going to be very happy to hear that news.
Thank you again Chopt. Just goes to show you there is no substitute for experience, good people, and the Hotrodders' Bulletin Board. Happy Thanksgiving everyone. :thumbup:
Ok I went back and read all of John's posts and got to the one that says that the subframe is out of kilter by X amount.
John, if it were me I think I would get the a arms switched and set it down and see how it looks as far as how the wheels fit the wheel wells and if they are positioned evenly from side to side as viewed from the front.
If it looks the way you think it should, get the wheels aligned and drive it.
If it doesn't look right it may be time to resort to plan "B". In your case that would be to take it to a compentent shop to have the problems corrected.
Most chassis on vehicles built up into the mid 80's wern't that perfect from the factory. The stacks of shims to align bumpers an sheet metal testify to that.
Keep us posted on what you decide to do and the progress.
I will swap the A-arms, maybe this weekend, and see how it drives and looks.
If the steering feels safer I will probably leave it as is for right now. The car rides welll except for the oversteer problem --which I can handle in normal driving, but I have been concerned about where I would end up if I made an involuntary quick steering change in an emergency situation.
If the engine ever had to come out of the car, I can consider repositioning the front end at that time.
I really appreciate all the feedback on this situation. If not for the knowledge of you guys, I might be cutting and repositioning the front clip all for naught.
After determining that one of my problems was the upper A-arms were on the wrong sides, I swithched them out. This brought caster down from positive 11.8 degrees to about 0 degrees. They could not be brought into the spec range of 1.8-3.8 degrees without throwing the camber off.
The improvement in steering was less than I expected. The oversteer condition is not as severe but the car still has some oversteer especially to the right. Wheel returns to center slowly, about as before.
I gained about 3/4 inch in wheel base.
Someday when I have to pull the engine I will address the skewness in the front clip.
Thanks for all the imput and especially the suggestions to check the A-arms.
Whne you align the front wheels, you have to do castor first, them the camber, then the toe because the adjustment's affect one another. It's normal for you to lose cambor when agjusting the castor. Just reset it and check toe.
You might not feel a difference becasue it's still out of spec. I would use 3 degree's positive castor and 2 degree's camber, and 1/8 toe.
The alignment was done by an alignment shop. I assume they worked to try and get both camber and caster into spec. I looked at the shims when I got home and it was heavily shimmed one side, I believe it was the side toward the wheel. Looked like the shimming was equal front and back with no shims on the motor side of the mounting arm.
By oversteer, I mean the car starts to turn fast after about 45 degrees of turn of the steering wheel and there is little resistance in the steering wheel to the turn.
What you are describing as over steer sounds more to me like the way a car steers when you have negative caster.
When describing over steer generally it means that the rear of the car will slide before the front, under steer means that even though you turn the wheel the front tires slide and the car doesn't turn. It doesn't have anything to do with how the steering wheel itself turns though.
The biggest problem I can think of having one wheel farther back than the other is a tendency to drift to one side. I'm far from a front end expert though so there may be more problems than just that though.
I am currently fixing the same problem with a g-body IFS that someone else installed. I have installed more of these than I can remember. The easiest way to find the problem is to measure(with a angle finder) the upper control arm angle from front to rear. This is the anti-dive angle & it should be 10 degree's as measured from the pivot shaft w/the front being higher. This is the the angle I measure during installation.
Let us know what your angle is.
Don Meyer-Owner Vintage Streetrods, PhD-Mech Engr.
Without driving my self it will next to imposssible to be sure but it sounds like your steering box may be a variable ratio box. These were 17:1 and then tightened up to 12:1 the further you turn the wheel to make maunervering easier. My truck has the same thing. You can verify this by measure the angle change in the front wheels. Turn the wheel 90 degree's and measure, turn the another 90 and remeasure, keep going till you find the stops. Graph it out and see what you got. You can also diassemble the box to verify. Since you stub was grapted to a smaller wheel base. You will feel the difference because the car react's more with smaller inputs. Racecars have been getting longer for this very reason. Ten years ago a 106" car was norm. Now 112 is often ideal.
The "too easy to turn" wheel could simply be the valving in the pump. Decrease the pressure for more "feel"
It appears that in it's previous life the front clip has settled in somewhat.
Meaning that over time the brackets that the control arms are mounted to have moved in towards the middle of the car. This used to be fairly common on late 60's mid 70's gm intermediate cars. Pontiacs with their heavy engines experienced it quite a bit.
The fix is to have the alignment shop do what is known as "rolling the frame"
The process is = the mechanic chains the outer sections of the crossmenber to the alignment rack and using a large bottle jack and a steel plate under the crossmember pushes the middle of the crossmember up a bit which in turn rolls the frame rails and the brackets that the control arms out to gain positive camber..
I would suggest going to a frame shop and talking to them. The guys who straighten frames on wrecks. The wam bam get it done and out the door guys connected to most tire stores arn't going to be able to do the job or don't know how.
johnsongrass1, Your suggestion of 2 degrees positive camber may work for a circle burner or one of the guys doing autocross but on a street car the tires wouldn't last but a few hundred miles. The outside edges would be worn off
and the inside edge would show no wear.
With his crossmember 1/2 degree positive camber on the drivers side, 1/4 degree positive camber on the passenger side with 1-1/2 to 2 degrees positive caster and 1/8" toe in shoud be a good starting point. Unless he is in an area with excessive or limited crown in the roads it should drive straight and have minimal tire wear with those specs.
The touchy steering at the moment is more likely due to the 0 caster. that and the car probably doesn't want to track that well.
Also, Don Meyers suggestion of checking the dive angle on the control arm is an excellent one. If you don't already own an angle finder you can pick one up at Sears or Harbor Freight. It is an important tool in any car builders tool collection Make sure you have one with a magnetic base.
Here are the alignment readings from the shop, drivers side first:
Camber: +0.8*, +0.8*
Caster: -0.5*, +0.3* (notice one neg, one pos)
Toe-in: +0.03*, +0.05*
Total toe: 0.08*
Steer ahead: -0.01*
Rear total toe: -0.16*
Thrust angle: -0.31*
The car has a slight drift to the left even on roads with a little crown. And it wanders just a little, not bad but evident.
Although the clip came from a Cutlass with 135,000 miles on it, it was lady owned and well cared for.
I have an angle gauge, I've been working to get my driveline angles in good shape. But I just had the car on jack stands two days ago to rotate all the tires and probably won't be jacking it back up to take the tires off to check the control arm mounting angles right now.
The tires were wearing badly on the front. Had 8/32 depth on the inside but only 4/32 depth on the outside edges. Rears were all 8/32 all the way across. These tires only have 2500 miles on them, 460 wear rating.
What Don is referring to is setting the angle finder on the shaft between the bolts that hold it to the frame. You should be able to do this easily with the car sitting on it's wheels. The gage should show that that the shaft is sitting angled 10 degrees higher at the front. from viewing the photo of the control arm that you posted I would belive that it is pretty close to that.
From the computer readings I would have to say that the lack of positive caster is the primary reason that the car is wandering.
There has to be a shop within a reasonable distance that does alignments and frame work where the mechanics know how to deal with such issues.
Check for the shops that work on trucks, motorhomes and such. They are often connected to shops that make or rework springs.
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