65-66 Impala Ackermann Issue Repair

[kwhizz]

The Story continues..........Just to go back in time.......the 66 Impala has a complete RideTech suspension front and rear (Coil-overs)......since completion the car has had a Ackermann issue.......driving straight it was a slot car.......turning was a different story.......Pull into the garage and the tires would leave black marks on the driveway, and sharp turns were pretty nasty.........so.....not being a suspension guy and the car driving normal when not turning.....I just accepted it as some nuance with the Ridetech suspension with slightly wider rims.........Keep in mind this car was finished 5 years ago...We drove the car on two Power Tours without any issues.......Then the Chevelle came into the picture and the Impala sat in the garage for two years
After driving the Chevelle during that time (no steering issues) and then getting back into driving the Impala.......I was determined to find out what was going on here.....At Barrett-Jackson last January I happened to stop at the RideTech display and talked to the people there and explained my concerns about the Ackermann issues..........To make a long story short, if this issue was going to get resolved I was going to have to do it myself........So, In talking with Mark Webster, he informed me that GM changed the 65-66 "B" body steering geometry to a new configuration in 67.........Hummmm !!!!
What changed and why???.............After a lot of research and asking stupid questions on a lot of web sites.......I found out that GM knew there were issues with the 65-66 models with wider rims such as Police cars and in Sept of 66 there was a Service Bulletin to address these issues.......This Bulletin basically gave the part numbers of all the new 67 design parts and the position and templates for the mounting holes for the repositioning of the 67 design Idler Arm assy........The Biggest difference is the mounting location of the Idler Arm .......In the 65-66 model years, the Idler arm was mounted thru a hole inside the frame rail.........67 and up it was mounted inside the frame rail and forward of the thru frame position.....












It's pretty obvious by this picture the differences............Here's a picture of the difference in the spindle steering arms....







Pictures of the supplied templates provided in the 1966 Service Bulletin.......











So........What I did was make the required steering arm spacer with tapped holes......got it in position .....and welded it in......









After installing the new Pitman Arm , centerlink, and Idler Arm.......It was apparent that there was something wrong as the centerlink went up on an angle and back towards the rear of the car........Hummmm!!!!..........After thinking about it and looking at what could be the problem.....I noticed that the 67 Pitman arm was about a 1/2" lower than the 66.........The Template must have been made with the 66 arm...........I made the centerlink parallel to the frame and the front crossmember.........Drilled new holes for the Idler arm (which corresponded to the lower 67 arm...........Makes perfect sense now ) and bolted everything in........Installed new Tie Rod ends.........Now everything is new.......Adjusted the toe roughly and when I pulled out of the garage to go to the alignment shop..........I knew right away there was a major difference as there wasn't any tire squeeling or scrubbing...........after alignment.........It is now the complete package.....Ackermann issue solved.........drives and steer's perfectly...............

[Bill71]

Great detective work!

[Josh@Ridetech]

Glad you got to the bottom of it! Alot of good information here. I think I remember you saying that finding some of the parts weren't the easiest?

[kwhizz]

The learning curve continues.......In swapping the parts over originally, I was so ecstatic with the steering corrections that I just accepted everything as is was.........and after driving the car on the Good Guys Road Tour this year and driving thru a highway construction zone and after hitting a dipped area at highway speed....I heard a scraping sound........Hummmm!!!.....When we got home I put the car up on the lift to change the oil and I noticed the center link had a scraped area on it.........so.....I then really looked at the install closer and noticed the center link was below the front cross member (remember that on the initial install I had to add additional mounting holes in the frame to accommodate the 67 Pitman Arm which was 3/4" lower than the 66 unit) See Pictures.....So.....I re-installed the 66 Pitman to raise the center link up.......and I installed the idler arm in the original holes which were set for the 66 Pitman arm......Perfect......Center link is now even with the bottom of the cross member......took the car today and got the front end aligned again......Drives perfect......So....If you are doing this swap I would just basically change the Idler arm assy and the center link......You can get by with the 66 steering arms.....(someone else did the swap with the stock arms and there are no problems doing it that way)........

[RKROEGER]

Ken, great info. Where can I get a copy of the service bulletin? I would like the dimensions for the mounting plate and the template for mounting it. Already found a used center link and have a new idler arm ordered.

Thanks, Rick