Alignment Help

[Atomic440]

Okay, here goes:

FINALLY finished a front end rebuild, '70.  Nothing fancy, all new Moog components all around including offset UCA bushings.  Firm-feel stage II PS box, KYB shocks, new torsion bars, and I also weld re-inforced the K-member and LCA's.  Took it to alignment shop Saturday, and asked for non-stock specs: 1.5" ride height (as measured per FSM), -0.5° Camber, 2.5 - 3.5° Caster, 1/16" toe-in.  The shop gave me confidence, worked on old cars before, two techs that have aligned these cars longer than I've been alive, etc...

Pick it up and they claim they can't meet those specs.  Leave me with +0.5° Camber and around 1.7° Caster.  They assure me that's all they can get, but it will run true, no tire wear.  Took the car, and immediately noticed it pulling to the right, especially at highway speed.  Took it back to them, and they spent all day on it today.  They put it back to stock specs (+0.5° Camber and 1.2° Caster) - and say the pull is better, but still there.  Plus, they claim the wheels/steering wheel won't return back to center in a corner (left or right turn, though I didn't notice it).  The readings are the same left to right, and cross camber is within 0.1.  They can't explain the pull.

I haven't driven it at the stock specs yet as I left it there overnight.  They want to check out the frame and maybe try to align it with the wheels off (they have adapters that bolt directly to hub I guess).

Any ideas?  Can't wait to get it back on the road, and feeling like this is pretty ridiculous.  Not a brake drag issue, tire pressures are good...  what am I missing?   

[Atomic440]

Oh, BTW, anybody have frame dimensions for a '70 Charger?  I left my FSM at the shop, assume they're in there, but don't have faith in the shop to find them!

[bobs66440]

I just had mine aligned (stock suspension). I gave him the specs I wanted: -.5deg camber, +1.5 to 2.5deg caster, 1/16 toe-in. He was only able to get a max of +1.25deg caster but met the others. The car drives fine, no issues. It seems to me that your car should drive ok based on the specs you have (except that the positive number on the caster will make it a little less responsive in cornering, but I wouldn't think that it would cause a pull.) The less positive caster you have, the less the wheel will want to snap back to center after turning and the less stable it will be in a straight line. Also it will steer easier.

With the mods done to the suspension, there may be something tweaked while welding the control arms or K-member? It seems that they should be able to get to the specs you want with the offset bushings...after all, that's why they're there. Measuring the chassis at the critical points and diagonally at critical points will tell you if the car is straight, but there may be something going on with the control arms.

Thais is a pretty good article

http://www.allpar.com/history/mopar/front-end-alignment.html

[Highbanked Hauler]

  I have run mine with  0 camber  1/8 toe in  and I think caster is 1.2 on the right and 1.7 on the left. It goes down the road fine but after I save up my allowance I want to get a set of adjustable uppers and cure the problem.  If your car has power steering it might be the box itself. I grabbed a PS box out of the pile when I put mine together and with the car idling  and sitting still the thing would give off little jerks in the steering and after a couple of minutes  the wheels would turn all the way to the right. I put in another box and no problem.
  Have you been driving the car all along or did you just get it on the road?

[b5blue]

Strut rod bent? Strut rod bushing soft or loose/worn? My 70 had a slight bend in one strut rod and you couldn't tell until I had it off the car. I replaced it. Keep in mind if you lower the front end it does affect alignment. Also check rear spring bushings. 

[Atomic440]

Thanks guys, all good stuff.

"With the mods done to the suspension, there may be something tweaked while welding the control arms or K-member"
This has crossed my mind, but trying not to think about it as I don't like the consequences
The shop found the frame specs, and said the frame is very straight, max difference is less than 1/8" on any measurement.  How could I tell if I jacked the K-member or LCA's up when I welded them?

I talked to the FirmFeel guys.  They said that a mis-adjusted spool valve on the steering box could cause a pull (maybe bumped in shipment or during installation).  They recommended jacking car up and going lock to lock with engine running to see if more effort is required to turn one way vs. another.  If so, spool valve needs adjusting.  If not, it's okay.  My guess is not, but I haven't specifically checked it.  The car has been off the road for almost 3 years, I've only driven it a few miles after the rebuild prior to taking it to the alignment shop.  Prior to that I drove it lightly for a while, but the suspension was so bad it was dangerous.

Rear spring bushings - probably original, and probably trashed.  Haven't touched anything in the rear.  With today's fancy 4-wheel alignment racks maybe there's something going on there that affects their front end measurements?

Strut rod - Interesting comment - I re-used the strut rods, but installed new bushings.  One of them (I believe left?) did seem to be bent, but very slightly.  So yes, I cleaned it up and re-used it.  Yes, I'm cheap.  Yes, starting to regret it    Did yours have problems with alignment?  Did replacing it fix it?

BTW, Charger still at the shop - they broke a wheel stud and broke the key to my wheel locks!   

[b5blue]

I had no problems but I went "loaded for bear". New UCA bushings, LCA's reinforced and new bushings, Lower ball joints, new "T" bars and boots, rear springs from Mopar, I found the bent strut at the last moment and got one rush shipped off ebay, shipping cost more than the (used) rod! the only thing I re used was the upper ball joints as they were still good. I also replaced the idler arm, my power steering box and pittman arm have about 20K on them so they are fine as were all my tie rods (I did re boot them with poly ones). I set ride height by the FSM and dialed in everything as close as I could and drove it a few days to get everything "settled in" before alignment. One aspect I wanted was all 4 tires and rims (P205/75-15" with stock junkyard rims) matched. This was to determine the condition of my chassis and relation of the sub frames as close as possible. I had them give me a "dead on" alignment as down here it's common to try and compensate for "road slant" (for road drainage) in the settings, meaning on a true flat surface the car would slightly "drift" left. My axle has fairly new "Green bearings" and was freshly serviced, having had the 8 3/4 chunk pulled, cleaned, checked and replaced. My numbers were great, within 1 to 1/2* of "ideal" settings and has never been better. When I upgrade the brakes to factory type 11 3/4 front rotors with slider calipers I'll install my new UCA's with offset bushings installed to let me lower the front end some and be good to go for a long time.   

[elacruze]

The only two dynamic issues I can think of which could affect a pull are thrust angle (rear axle out of parallel to front spindles) and track alignment (rear wheels out of center with front wheels) Neither of these specs are likely to cause a pull, unless the car has been wrecked hard in the past and they're way out. I'm leaning towards the spool on the steering box, and your near-nothing stock caster angle allowing small pressures to overpower the centering effect.

[68r/t]

I had the same problem with the car pulling to the right after I rebuilt the car and had an alignment done.
I jacked the car up and started the engine and at idle the steering wheel would not move, but if i revved it to 1200+ rpm the wheel would move to the right.
I adjusted the valve on top of the steering box  till the steering wheel did not move when I revved up the engine and now it drives straight,  the valve on the box is sensitive it only takes a slight adjustment to make a lot of difference.

[chargerbr549]

I ran into it several times over the years where taking my car and several friends taking their mopars to an alignment shop and the shop not being able to get it to quit pulling to one side or the other and find out later it was the valve on top of the steering box  that was misadjusted as several people have already stated and as 68 R/T said it is very sensitive so it won't take make much movement of the the valve to cause a pull in one direction or the other.

Kevin

[bobs66440]

I ran into it several times over the years where taking my car and several friends taking their mopars to an alignment shop and the shop not being able to get it to quit pulling to one side or the other and find out later it was the valve on top of the steering box  that was misadjusted as several people have already stated and as 68 R/T said it is very sensitive so it won't take make much movement of the the valve to cause a pull in one direction or the other.

Kevin

That's amazing. Is that just a Mopar thing? I've never heard of that with a Ford or GM...