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Baffling suspension issue

5K views 57 replies 9 participants last post by  Joe G 
#1 ·
Hi guys. It's been a while since I've posed but I still follow threads. I have a problem that is baffling us. This is a bit long so please bear with me.

Car is a 69 with a ZZ430 (350), TKO 600, Baer 13" Track discs on all 4. I've gone through a few suspension changes over the years and am pretty familiar with how things work. Current front setup is Ride Tech upper and lower control arms and coilovers, L&H Customs tall spindles and steering arms (no longer in business, I think). Lee Engineering steering box. Hotchkis lowering springs rear. Wheels are 8 x 17 Billet Specialties with 235/50x17 Bridgestone Potenza S-04 Pole Position tires all around. Nice sticky tire.
This setup has been on the car for several years now with no issues. Handles well, pretty neutral. Sits pretty low so I have to be real careful on speed bumps. My headers show flat spots from that.

My issue: a few weeks ago I put the car on my rack and changed the oil and lubed the fittings. All normal. But when I lowered the. car back down and took it for a drive, the toe-in had changed drastically. There was so much toe-in that the tires squealed and smoked going in a straight line! I measured the tire temps with a pyrometer and the outside edge of the fronts were over 180F anfter a short drive. I could smell the rubber burning. Also the car sat a bit higher in the front (maybe 1/2 inch). I put it back up onto track and tried to find something that moved. Nada, nothing. Put a 3 foot pry bar on everything to try and find some movement. Nothing. Tightened everything I could find but nothing was loose. I re-adjusted the toe-in just to see what would happen. The adjustment needed to go from severe toe-in to somewhat straight is less that a turn on the sleeves so it doesn't take much. I lowered the car back down and drove it. All is well again. Drives great. Oh boy! Car is still about 1/4 inch higher that before 9measuring from grade to the front fender lips) but still ok.I scratch my head and leave it alone and just drive it. Still can't figure out how raising the car on the lift would affect anything. It's been on that lift dozens of times.

Driving it around all seemed normal again until yesterday. I pulled out of our local grocery store parking lot turned left with light acceleration. I felt the car kinda twitch a bit and it felt like the front end lifted a bit. The toe-in changed back to severe toe-in, the tires are stealing again and the self-centering for the steering went away. I
drove it home and in the garage the toe-in was quite visible and the ride height increase was evident. (1/2 inch at the fender lips). So I put it back on the rack again. This time I loosened everything up. Lowered the spring adjusters so the springs were loose and re-centered them. I retightened everything again and reset the toe-in. Again it is now driving great. But what is changing? I don't have confidence to take it anywhere and I drive this car to load distance events.

I've bought new tie rod ends and new idler arm just out of frustration. The existing ones are only 7-8 years old but I'm out of ideas of what to change. When it changes it is not subtle. It is either good or very bad; no in between. The fact that the ride height increases when this happens is a clue, but not sure of what. I have looked closely at the springs pockets, frame welds, and anything else that is connected.

I've got the new parts so I'll be putting them in this week but I have zero confidence that that will change what's happening.

Any thoughts?

Thanks for taking the time!!

Joe
 
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#2 ·
I would take a long hard look at those spindles and steering arms. Those guys are out of business for good reason imho.

Don
 
#5 ·
I have has 2 cars that had their shocks stick after raising them on a lift. Both needed new shocks. Both has absolutely no suspension movement, the ride height was much higher.
My first thought was a tie rod adjuster is stripped.
 
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#6 ·
Good suggestions on the shocks and I wouldn't have thought about a stripped tie rod sleeve until I looked under the and could tell it had moved.

I'd be looking at the upper control arm mounting bolts and nuts to be sure they are tight and no shims fell out. Check the upper and lower bushings too. I doubt it has anything to do with the spindles but check the nuts on those as well.

Jeff
 
#7 · (Edited)
#8 ·
Thanks. I had read your post about the failure shortly after I bought these spindles from L & H. I added a larger washer on the top ball joint that covers the insert to prevent just that event. I did remove the spindles and arms to inspect them closely. They still look like new with no play anywhere.
The spindles were my first "suspect". I didn't state this in my original post but during the process I replaced the LH spindles with Ride Tech's 2 inch dropped tall spindles. They didn't work out on my car. Too low. Springs cranked up all the way to get it off the ground. And the tie rod ends hit the tires. Ride Tech said my tires were too wide! 235 is too wide?
Anyway that experiment didn't fix it either so the LH went back on. They do not seem to be the cause anyway.

Might put the stock spindles back on as a test.....

Thanks again
 
#9 ·
I've checked the tie rod sleeve. It's good. It's the Hotchkis billet one so it's pretty beefy. And it's solidly on the tie rod ends.
Shocks were on my suspect list as well but they move freely? That would explain a lot if they are sticking intermittently I guess? I'll check them again off the car.

Control arms have been tightened and retightened. Nothing there either.

Thanks for the tips!

Keep them coming please.

Joe
 
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#11 ·
I wasn't real clear in my post but the bolts I was referring to are the frame to control arm where the shims go. They are easier to tighten with the weight off. I can't remember a failure from tightening them with weight off that I could attribute to the method. Most of the cars I did alignments on with set ups like the first gen Camaro were tightened with the weight on the wheels. None of the GM trucks were ever tightened with the weight on. I've had shim packs fall out of both but figured it was from leaving the bolts loose. IMO it doesn't matter as long as you get them tight.

Jeff
 
#15 ·
Ok, so just to be clear, the prevailing theory here is that a 1/2 inch change in ride height due to a stuck shock introduced so much bump steer induced toe that the tires were burning. That’s some crazy high bump steer right there imho. I thought those spindles and steering arms were bump steer optimized....

Did you trim the shock towers/spring pockets to accommodate the Ridetech coilovers? Clearance is very tight and the springs may now be rubbing or getting hung up.

Don
 
#16 ·
thanks Don.
I agree that 1/2 inch shouldn't have that much affect on toe-in. I have adjusted the ride height many times much more than that over the years with no affect on toe-in. The reason for the coil overs was to adjust the ride height and it's worked very well. The LH steering arms do mount the tie rod ends a bit lower which helps the dumpster effects (a little). I have adjusted the ride height many times over the years with no toe-in changes. I did trim the towers per their instructions when I installed them years ago. I also reinforced the towers by welding gussets since that area was not designed to support the weight of the car. That's still all good.
I'll be taking it all apart (again) to inspect each piece of the puzzle. Something is definitely changing more than it should.

Joe
 
#21 ·
Thanks for the response David. You are our resident expert!

The spindles have only one set of holes. And I have had this set up on the car for years with no issues. This is crazy.

So today I replaced all tie rod ends, the idler arm and the pitman arm just for something to do. All Moog parts. The center link looks good and tight. The steering is pretty stiff now but I think it's because of all the new stuff. Adjusted toe -in (again). Camber and ride height unchanged. Went for a drive and did some fairly hard cornering on our back road. Checked tire temperatures and the fronts are running what I think is normal. About 115 on the outside edge and 125 on the inside edge. Drove it about 20 miles and other than the stiff steering it seems OK and drives well. For now.

Time will tell..

If it changes again I'm going to bare subframe and starting over.

Joe
 
#22 ·
Another possible issue is the new pitman arm does not seat up against the box. It will only go on about an inch leaving an inch or so of spline showing. That's with an air impact gun. Moog K6582.

Hmmmm.

Joe
 
#25 ·
Today's update:

1)We removed the brakes, spindles, upper and lower a arms and the coil-over springs. We're down to the subframe again. Inspected the frame closely. Tried to get something to flex with a 3 foot pry bar. Nothing.
2)The ball joints are tight in both uppers and lowers. The bushings are tight. I removed the lower a arm bushings just to look (plus they come out easy). They are like new.
3)The upper arm bushings are tight. I can't remove them without some special tools but there is no need.
4)Spindles look good; steering arms look good.

While I had it apart the first time I installed new brake pads (PowerStop Z23) and had the 4 rotors turned, just because. 13" Baer drilled/slotted.

I am really frustrated. Can't find ANYTHING wrong. I was actually hoping to find a frame crack or arm crack. At least then I would have something to repair.

Joe
 
#26 · (Edited)
For the latest test, I'm planning to put it back together using the Ride Tech arms, stock spindles and steering arms. I am going to install new ball joints in the Ride Tech arms. Tall upper ball joints and the tall out tie rod ends as recommended. There are two tall ball joints. .5 inch and .9 inch from Pro Forged.

I've read David Pozzi's ball joint test and it appears the .5 inch does give a decent camber gain. The .9 would probably give a bit more, but neither would give the same gain as the 1 1/2 taller spindle. Am I assuming correctly?

I should add that these are an earlier version of Ride Techs arms from 2013. The uppers do not have the removable "pills" to change caster. Just what is built in.

I would really prefer to actually find something broken so I could fix it. :(

Joe
 
#32 ·
I'd use the .5" tall upper ball joints with .5" tall outer steering arms. The .9" tall uppers have better camber gain but increase bump steer too much unless you go and bend your steering arms down. The .9" MIGHT work ok if you set a large amount of positive caster, like 7 or 8 degrees. I haven't tested at that setting.
I'm wondering if your tie rod adjuster sleeves slipped, or one of them. Are your adjuster sleeves stock or aftermarket? The threads on the tie rod ends are not very deep and I've seen old adjuster sleeves slip. I've also seen loose aftermarket adjusters that fit tight on some brands of tie rods, and loose on others.
 
#27 ·
Joe, If you want to go through the extra work you could assemble the suspension without
the coilovers installed. Then cycle the control arms through their arc with a jack just to see
if there is a bind anywhere. You'll have to be creative with supporting the car without the
coilovers but you might find something due to the combination of parts you're using. The
control arm angles, pivot points and the ball joint pivots all have to work in unison.
 
#28 ·
I forgot to mention tha tI have attempted to get some advice from Ride Tech but have not heard back.
 
#29 ·
Good idea Al. I think I will try that. I have a lift so supporting the car is easy (it's on it now). Just use a floor jack and 4x4 to lift the arms through their arc.

Thank you
 
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#33 ·
Thank you David.

I have ordered the .5 inch tall ball joints and the tall out tie rods ends. New lower ball joints too. I don't see anything wrong with the existing ball joints but this is the last thing to change.
I have the Hotchkis adjuster sleeves. They aren't slipping as far as I can tell. I have cleaned and lubed the threads and screwed the tie rod ends in and out to ensure the threads were good. Maybe I should get sone new ones just in case. These are about 12 years old.

This is the strangest suspension issue I have ever seen.

As an aside, I refer to your web page frequently for advice (and general knowledge). I appreciate al the work you have done. I would not assume you would remember but we met many years ago at a Good Guys event in Pleasanton watching Mary autocross. She is FAST. Your cars are awesome!

Thanks again for your advice.

Joe
 
#34 ·
Latest find (maybe)

I was looking closely at the subframe mounting holes for the lower control arms. On the drivers side rear hole there is about 1/16 of play where the bolts comes through. I can wiggle the bolt around when I slide it in. There doesn't seem to be that kind of clearance on the front holes. The bolt is much tighter there. On the passenger side there is a little git of play but not as much.

It doesn't seem like that could allow much movement but it's the only thing I have found.

My thoughts: Reassemble the suspension with some thick washers on the outside of the holes. Ensure the washers are a very tight fit around the bolt. Once it is together and at ride height, run a weld bead around the thick washers to hold then in place permanently.

Thoughts?

If this is indeed the fix, I owe Jeff some virtual ice cream out there.

Joe
 
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#36 ·
Thanks David. Drilling out a washer to fit was my thought. Or I could weld the nut directly onto the frame. Sounds unlikely but it's all I have found.

Joe
 
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