Modification of K-member idler arm mount advice

[purplehazenils]

Before you weld that all up you might want to tack it, then jig up the box, pitman and center link, and make sure that height business makes sense. The center link should pretty much be parallel to plumb / level, and you can determine that from the K to frame mounts

Also the pitman shaft and idler bolt should be pretty much parallel, so they swing in the same axis

I think your jig is correct. Notice the lower control arm pin hole on the black k frame. Look at the contour of the top of the k frame in that area in relation to the lower control arm pin hole on both k frames. You can see there's a big difference between the two k frames in these areas and I believe that's where your difference is. I would go ahead and reshape the black idler arm mount where it fits flush on the red k frame all the way around, tack it like Del says and see how close you are. I bet it's right on the money.

It was definitely a good idea to tack it and check before. The idler is way too high, I didn't even need need to check with the centre link. It might be 1 inch too high or a little more

 

[purplehazenils]

My guess is that the steering gear bracket is slightly off on one of the K-members. A little tweak there will equal a lot on the other side and you likely wouldn't be able to tell the difference in driving between the two.

I'm starting to think that this might be the case, I cant see what else it could be.

Since I'm really under time pressure to get the car on four wheels and away to get the chassis straightened I'm thinking about doing the following:

Installing the centrelink to give me the height of the idler arm and then locating it further by measuring out a rectangle like in the photo below. Ill have to check when I'm in the garage but I assume the idler and pitman arm are the same length and their geometry makes a rectangle like in the sketch below.

 

[RustyRatRod]

I'm starting to think that this might be the case, I cant see what else it could be.

Since I'm really under time pressure to get the car on four wheels and away to get the chassis straightened I'm thinking about doing the following:

Installing the centrelink to give me the height of the idler arm and then locating it further by measuring out a rectangle like in the photo below. Ill have to check when I'm in the garage but I assume the idler and pitman arm are the same length and their geometry makes a rectangle like in the sketch below.

View attachment 1716119564

If you look at those two inside steering box bolts, you'll notice the top one is a little offset to the right compared to the bottom. Do you see what I'm talking about? So that's not a good reference to line up by. You somehow need to reference off the pitman arm stud. If that makes sense.

 

[mbaird]

One of the old Chrysler Master Tech training videos on drivability said to look for incorrect idler arms if car is wandering . Said to measure distance from the ground on both pitman and idler arms . should be the same . If they are different your cornering toe will change during bumps or off camber driving

 

[Jim Lusk]

I'm starting to think that this might be the case, I cant see what else it could be.

Since I'm really under time pressure to get the car on four wheels and away to get the chassis straightened I'm thinking about doing the following:

Installing the centrelink to give me the height of the idler arm and then locating it further by measuring out a rectangle like in the photo below. Ill have to check when I'm in the garage but I assume the idler and pitman arm are the same length and their geometry makes a rectangle like in the sketch below.

View attachment 1716119564

Makes sense to me.

 

[purplehazenils]

If you look at those two inside steering box bolts, you'll notice the top one is a little offset to the right compared to the bottom. Do you see what I'm talking about? So that's not a good reference to line up by. You somehow need to reference off the pitman arm stud. If that makes sense.

I'm not sure if its a good reference either. Its that or the k member from the crash is more messed up than I thought, although it looks mostly fine.

One of the old Chrysler Master Tech training videos on drivability said to look for incorrect idler arms if car is wandering . Said to measure distance from the ground on both pitman and idler arms . should be the same . If they are different your cornering toe will change during bumps or off camber driving

I took this into account thank you, got it within a few mm although the idler does have some play in it up and down, might try to remove that in the future.

 

[purplehazenils]

I ended up scrapping the jig and with the help of my dads friend (who has built many many cars) we located the idler arm and mount by carefully taking a of of measurements. We have sure the distance between the pivot points of the idler and pitman were the same along with a bunch of other measurements. The mount is now located in a way that looks totally normal/original.

I'm still not sure exactly what the issue was, maybe the k member that was in the crash was more warped than expected or that using the steering box bolts was not ideal in this case. From measuring, it seems like the tolerances from factory are not that good to start with, hopefully the car will drive well when I get it on the road in a year or two.

Thanks for the help!

 

[RustyRatRod]

That looks more like it! I'm glad you had someone who could come put hands on. Over the internet is difficult at best.

 

[DionR]

Are you going to move the motor mount, too? Or just buy a conversion mount?

 

[mopowers]

None of these cars were perfect from the factory. I bet what you've done is more than adequate. Nice work!

 

[Kern Dog]

My guess is that the steering gear bracket is slightly off on one of the K-members. A little tweak there will equal a lot on the other side and you likely wouldn't be able to tell the difference in driving between the two.

It may be apples and oranges but here are a couple pictures of my '70 Charger. I have standard length idler and Pitman arms and the center link isn't exactly perfectly perpendicular with the engine or car. It aligned great, tracks straight and has zero ill manners.

Not sure is this helps but I know that I get the impression that the cars were all supposed to be square and even everywhere but some stuff was just "imperfect" even when built to spec.

 

[purplehazenils]

That looks more like it! I'm glad you had someone who could come put hands on. Over the internet is difficult at best.

It was lucky to have someone who could go hands on! For stuff like this it can for sure be difficult to explain in text.

Are you going to move the motor mount, too? Or just buy a conversion mount?

I'm doing an engine swap once the car is straightened so I figure I can just weld in something new and remove the old mount down the line.

None of these cars were perfect from the factory. I bet what you've done is more than adequate. Nice work!

After measuring we started to think just that, it might actually be better than factory..!

It may be apples and oranges but here are a couple pictures of my '70 Charger. I have standard length idler and Pitman arms and the center link isn't exactly perfectly perpendicular with the engine or car. It aligned great, tracks straight and has zero ill manners.

Not sure is this helps but I know that I get the impression that the cars were all supposed to be square and even everywhere but some stuff was just "imperfect" even when built to spec.

That is interesting and certainly reassuring. If you take the quality of the welds on the k member you into account then there are probably a few other imperfections on these cars.