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Ride height issue
https://slantsix.org/forum/viewtopic.php?t=20667		 Page 1 of 2
Author:  Pierre [ Wed Nov 08, 2006 5:10 pm ]
Post subject:  Ride height issue
About 20k miles ago I rebuilt the entire front end with conversion from drums to KH discs. New ball joints, moog rubber bushings, MP 0.890" diameter bars (stock for an 383?), 4 kyb gas-a-just shocks. I also put in new espo springs/rear bushings. Only things I reused were uca, lca, tierods and strutrods.

Got new tires, alignment and ridehight adjustment. When the adjustment was done All corners of the car were at same height except left rear I believe was different by 1/4" or so.

Now I notice the ride a bit more bouncy then usual. After a quick inspection the whole car front and rear is leaning to the right. Take it to shop that did the alignment - put it on the rack - and indeed it is the car. Right side, both front and rear, is a good 1" or more off the left side. The shop told me its either the bar or bushing.

The right bar has more adjustment in it remaining then the left. Thats how it was when it was first aligned. Also noticed in the right bar is further forward then the left (distance between safety clip in the subframe and the bar is greater on right) - also the same as it was when originally aligned. The right side, whatever is left of the suspension travel, does seem to be a bit softer.

I'm not sure where to start. When the bushing was pressed into the arm / pivot grease was used when the book specifically says not to. Could this have caused the bushing to turn in place? Just seems odd it happened now instead of when it was first put together. Brand new torsion bars wear out? Frame issue?
Author:  Bren67Cuda904 [ Wed Nov 08, 2006 5:22 pm ]
Post subject: 
I am also intrested in the right way to adjust torsion bars after replacing them. Are they adjusted based on ride height only?
It does seem odd that one adjuster is different than the other. Maybe in backwards? Mine too can slide in different amounts.
Author:  slantvaliant [ Wed Nov 08, 2006 6:19 pm ]
Post subject: 
The factory method involves measuring a height difference between points on the LCA's.
You could get fancy, and check/adjust using crossweights - basically putting scales under all four wheels, and tuning how much force each tire puts on the pavement.
There can be quite a bit of variation in the adjuster positions. Tolerances of the LCA sockets and adjuster cutouts, the subframe socket, the bar hexes, threads, etc. all add up. A small variation at near the pivot can mean a lot at the wheel.
Author:  Dart270 [ Wed Nov 08, 2006 7:59 pm ]
Post subject: 
I find that whenever I adjust my Tbars any significant amount, they actually take some time to "settle". I haven't found that just jouncing the car a few times after adjustment and remeasuring works reproducibly. Best to make an adjustment, drive around for 5min, then check again. It's likely your bars (or adjusters?) just settled after driving around. Maybe with new bars it takes longer??

Lou
Author:  Pierre [ Wed Nov 08, 2006 8:19 pm ]
Post subject: 
So just get the adjustment/alignment done again and call it a day?

Also few other things - torsion bar has an arch to it when I had it up in the air on the driveway. Is this normal? I know the original ones that were replaced also had a slight arc to them too.

The arm pivot itself - the stock ones had a bump in them to act as a stop for the bushing. Whomever rebuilt the front end previously replaced them put in ones without a bump, a smooth shaft. Apparently they came with the bushings from moog at that time.
Author:  Dart270 [ Thu Nov 09, 2006 5:15 am ]
Post subject: 
Interesting about the pivots with no bump. I've never noticed any substantial arc, but have seen some that look a bit bent, esp near the ends.

If you can't see anything wrong with the suspension parts, then I say adjust again and drive it. Don't even worry about realigning since that was done at the correct height already. You would probably hear clunks or feel weird handling if something has broken.

Lou
Author:  AnotherSix [ Thu Nov 09, 2006 7:43 am ]
Post subject: 
I had a similar problem with our dart after swapping to big bolt pattern discs. It was with the skinny stock torsion bars and a suspension rebuild with KYB's as well. I did all the work including the alignment myself. It just settled on the right side some. I had to adjust it a couple of times to get it right. The torsion bar being a little forward is not an issue, as long as the one that is back a little is forward of the clip. If everything is intact, it is just going to be the torsion bar adjustment as already pointed out. Remember the engine is offset to the right AND leaning over, there is more weight on that side. Trying to set the suspension with scales will not work to get ride height set. That is a race car tuning thing and they don't all get the same weight anyway. Just get your 3/4 inch socket out and crank up the right bar a bit, you may have to lower the left side some as well. Actually if the rake of the car is right you will end up lowering the left almost as much as you raise the right, but it's not quite in proportion. For reference make a note of the space between the bump stops and the frame so you can check it again later and have a good idea if it is still settling.
Author:  slantvaliant [ Thu Nov 09, 2006 8:11 am ]
Post subject: 
Quote:
Trying to set the suspension with scales will not work to get ride height set. That is a race car tuning thing ...
Hence my preface:
Quote:
You could get fancy ...
I did it per the FSM, and don't worry about corner weights myself. It works well enough.

Because of many factors and tolerance, you'll never get everything exactly right. Even with a perfectly square chassis (if that even exists) and the ride height dead-nuts on the factory spec, who says your fenders and quarter panels are exactly the same left to right? Sometimes you have to accept a little variation in appearance to get the specs right, and vice versa.
Author:  AnotherSix [ Thu Nov 09, 2006 11:37 am ]
Post subject: 
It's a good point about variations from car to car or side to side. I try to go by the suspension or frame and sometimes measure to the centers of the wheel openings to reference changes. Of course there are no factory specs for cross weights, and there is no easy way to adjust the rear rate or pre-load. And I've never seen anyone align a street car with the driver in the drivers seat either. :lol: About the factory ride height specs: I don't pay much attention to them on older cars because the rear springs have usually sagged. Once that nose comes up it just makes the rear worse. All you can do is level it or fix the rear springs first. The fact that we can adjust the front end height of our dodges so easily is really nice compared to what it takes on other makes. New rear leafs in our 71 swinger raised the back about three inchs, pushing the front down about a half inch at the same time. It looked like something was wrong ( it was, the front was now too low ) but that put the rear at the original height. Now I have new hangers that I need to put in there to drop it an inch and get it where I want it. My plan is to get the rear height where I want it first and then not have to mess with it when I swap in new .920 torsion bars. Then I can just do the adjust the front end ritual.
Author:  slantvaliant [ Thu Nov 09, 2006 12:14 pm ]
Post subject: 
Quote:
... we can adjust the front end height of our dodges so easily ...
Dodge? I have a Plymouth, thank you. :wink:
Author:  Pierre [ Thu Nov 09, 2006 3:18 pm ]
Post subject: 
Other then the arc in the torsion bar I didn't notice anything wrong with the parts. The right side seems a bit softer when jouncing the car by hand, for whatever suspension travel is left on that side. This was also evident when he put it on the rack, and lifted the front tires in the air. Stuck a bar under the tire to check for balljoint play. While there was no balljoint play, you can tell the right tire seemed a bit looser, as it would budge before the car lifted, whereas on the left it would move the car right off. Maybe I was just seeing things, but it seems something on the right side is weaker.

There is some slight wear on one edge of the front right tire, and there has been every time I did a rotation. So something funny definitely is happening on that corner.
Author:  AnotherSix [ Thu Nov 09, 2006 6:19 pm ]
Post subject: 
The right side being heavier will make it seem softer. Maybe there is something wrong with your shocks? I had a set of KYB's go bad within a year on my chevelle wagon. they still had pressure in them but leaked oil and would not compress all the way and lost most of their damping. I can only figure that part of the piston assembly broke off inside. One failed shortly after the other. They were replaced under the lifetime warranty. I still have the new pair and they are fine. I have used them on many cars over the years and that is the only problem I have ever had. Just one more thing to check. High pressure gas shocks can affect your ride hight when they go bad. About the outside edge tire wear. Maybe have them try to get 0 - 3/8 degree negative camber when it is aligned, and forget about the "crown of the road" idea. This is still a conservative range. It will handle better and should even out the tire wear, unless something else is wrong. Our dart is running 5/8 degree negative camber.
Author:  Pierre [ Thu Nov 09, 2006 6:49 pm ]
Post subject: 
I cranked on the bolt 4 turns - its closer to even now and could probably use another turn or two. Hard to judge exacts without having a perfectly level surface. I'll drive it for another few days and if it doesn't sag again I'll take it back to the shop and get it aligned once more. There was a slight pull to the right before the adjustment and still is now so if the height holds I'd rather get it re-aligned.

If the height doesn't hold.... hmm, maybe start with new bushings? Or ditch the torsion bars all together and use coil overs? :P Dang frustrating. Figured if I started all new I wouldn't have to go through this business...
Author:  AnotherSix [ Thu Nov 09, 2006 8:01 pm ]
Post subject: 
It really is most likely just that adjustment. The alignment problem could be as simple as the cam bolts slipping a little if they were not tight or the washers (cams) were not seated properly and got bent. I've seen a few like this in the junk yards when looking for disc spindles. If the cam bolts are messed up they are cheap and easy to get replaced when they do the alignment.
Author:  Pierre [ Thu Nov 09, 2006 10:11 pm ]
Post subject: 
Cam bolts were replaced w/new parts when the disc conversion was done. I had to sand the ridges down to fit into the washers. I didn't take barely any material off though, used fine paper and kept sanding little by little until they fit. Shouldn't be of any consequence seeing as they are double-d shafts.

The lock washers are compressed, the bolts look fine the nuts have become a bit rusty probably due to lack of plating. Hopefully its just the bars settling.... I haven't heard of such a thing but apparently they do.
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