The man wants MORE caster. How about this idea?

[Garrett Ellison]

Not trying to be controversial, but is any modification DOT approved on anybody’s car here?

Top A arm is a pretty low tech piece of stamped steel. Given some reasonable welding skills and a little bit of reinforcing, this seems like a great idea for us cheapskates. Like just about anything, a skilled guy can make it work and an unskilled guy can’t.

That’s also a valid point. And it depends on which inspection station you use. If you go to the places who do it “the mostly right way” that put a Jack under your lower control arm and lift the front end and check parts for slop, they’re probably going to have questions about seeing welds on the upper control arm. I will agree that it shouldn’t be an issue if done properly. Those same shops here get a lot of business plating frames and rebuilding front ends, too! My friend who’s a former commission mechanic was licensed to do state inspections was usually on the frame repairs. If you watch “just rolled in”, he was usually living the nightmare. That and the mine and gas well service trucks with a wheelbarrow of dried mud caked on underneath them.

 

[72bluNblu]

That’s also a valid point. And it depends on which inspection station you use. If you go to the places who do it “the mostly right way” that put a Jack under your lower control arm and lift the front end and check parts for slop, they’re probably going to have questions about seeing welds on the upper control arm. I will agree that it shouldn’t be an issue if done properly. Those same shops here get a lot of business plating frames and rebuilding front ends, too! My friend who’s a former commission mechanic was licensed to do state inspections was usually on the frame repairs. If you watch “just rolled in”, he was usually living the nightmare. That and the mine and gas well service trucks with a wheelbarrow of dried mud caked on underneath them.

Given some of the "repairs" I've seen myself I can totally understand why anyone doing inspections would want to really scrutinize any welds on a factory control arm, because I would bet a lot of the repairs they see at those places would be pretty marginal.

That said, the factory control arms are just stamped mild steel, so, a modification done thoughtfully and with good welds could easily mean the arm was improved in its strength compared to factory.

How about this?
How about cutting the UCA on the forward leg, spread it 1/4" and welding in another section?

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Properly welded, it wouldn't fail. The slight change in angle will affect the rear bushing slightly but not enough to matter. This can be done for next to nothing. The 1/4" piece sectioned in could come from small ball joint UCAs that are not as valuable to some people. By welding in an extension, you'd still be able to use any type of bushing, offset or stock so there would still be the same range of adjustment.
Opinions?

Here's the article with the picture on the modified TransAm car UCA's. They were modified at the ball joint mount, which was tipped at an angle as well as replaced with a larger ball joint (larger than the standard B/E stuff).

Building the AAR ‘Cuda Trans-Am

The modification was done for the larger ball joint and to change the angle because of the amount the cars were lowered, not sure if it also increased caster but there's no reason it couldn't. I don't think they cut the arm of the UCA at all.

Doing the modification at the ball joint would be stronger, the area in the arm will have more flex than at the area around the ball joint. Plus the bushing ends remain aligned, so you run less risk of adding some binding into the travel.

The other thing is that lengthening the arm will also push the ball joint out some, so, you'd lose camber and potentially widen the track a little.

 

[moparlvr166]

I think the spindles are symmetric, and it's really unlikely the mounting holes for the steering arms are off a 1/4" on a machined part since the tolerances for that stuff is in thousandths.

When you change or adjust the upper control arm all you are doing is moving the spindle to the specs you want so if you can move the lower portion of the spindle forward would that not help with more caster?

 

[Kern Dog]

Back in 1998-99, I made a home video with car stunts, jumps and collisions. I used free cars that were given to me along with a 75 Dart 4 door, a 74 Dart Sport 360, a 74 Dart Sport 225 and a 73 Duster. I jumped the 75 Dart 4 times, the 74 Dart Sport 360 got jumped 6 times, the other cars were used for various other scenes. The 73 Duster was the hero car that never was jumped, just driven on dirt roads like them Duke boys...
The 74 DS 360 was a total loss insurance job so I wasn't destroying a valuable car. I patched it back together for use as a stunt car. The biggest jump that I did went over 10 feet of clear air under it and 77 feet in length. This of course destroyed it but that was the last jump of SIX.
After the 3rd jump, the K member lost much of its arch. Doing the jumps, the flattened K member pushed the frame rails apart and pushed the UCA mounts in toward the engine. Negative camber was extreme! I changed the K member and right then realized the damage that the jumps did to the structure. I used ratchet straps to pull the rails back closer together to fit the replacement K member but the UCA mounts???
I welded extensions to the mounting tabs on the car. I left the UCAs alone. Those mounts were welded with an old school arc welder in absolutely unprofessional conditions. (by me...I didn't own a MIG at the time) I was able to get the alignment reasonably safe to aim it straight for 3 more jumps and nothing broke off, it was intact and bent when I cut the car up for scrap.
I had to cut a hole in the firewall behind the distributor cap because it made contact during jumps causing a horrible misfire.
I know, this all sounds bonkers but I enjoyed the whole process of the hobby movie.

 

[72bluNblu]

When you change or adjust the upper control arm all you are doing is moving the spindle to the specs you want so if you can move the lower portion of the spindle forward would that not help with more caster?

When you're adjusting the upper control arm you're just tipping the spindle at a different angle, you're not significantly changing the location of the wheels. If you drill the spindle to move it back a 1/4" with respect to the lower ball joint you're changing the wheel base of the car. Not to mention the caster, and drilling the spindle so it slides backward to gain tire clearance at the front corner would make the caster more negative, which is exactly the opposite of what you want. These cars already can't get enough positive caster with the factory control arms and bushings.

The spindles are symmetric. The issue with the tire clearance is because of something else that changed when the spindles were swapped.

 

[HemiDenny]

I think the spindles are symmetric, and it's really unlikely the mounting holes for the steering arms are off a 1/4" on a machined part since the tolerances for that stuff is in thousandths.

for the most part they are.....EXCEPT the OEM small ball joint / 4" bolt circle drum brake spindle where the top is offset to the front.

 

[Garrett Ellison]

Thank You for the pictures of the modifications on the trans am control arms. I wonder if the 1972-1993 D or B Series (truck or van) UCS’s would be a good starting point for a modified setup.

 

[72bluNblu]

for the most part they are.....EXCEPT the OEM small ball joint / 4" bolt circle drum brake spindle where the top is offset to the front.

But we're talking about '73+ disk spindles that are symmetric and can be swapped side for side without changing anything other than the position of the caliper.

Thank You for the pictures of the modifications on the trans am control arms. I wonder if the 1972-1993 D or B Series (truck or van) UCS’s would be a good starting point for a modified setup.

The Chrysler Kit cars had a D300 spindle option...

"D300 truck front wheel spindles with larger wheel bearings, front disc brakes with 3.10" dia. pistons."

 

[HemiDenny]

When you change or adjust the upper control arm all you are doing is moving the spindle to the specs you want so if you can move the lower portion of the spindle forward would that not help with more caster?

sure it would. Remember, where the pin in the spindle is located up/ down dictates how much movement you actually get top vs bottom.

 

[72bluNblu]

sure it would. Remember, where the pin in the spindle is located up/ down dictates how much movement you actually get top vs bottom.

Right, but doing that to add caster would also decrease tire clearance to the front corner of the fender too, which was the problem that @RLF Cuda was having to start with.

 

[HemiDenny]

Right, but doing that to add caster would also decrease tire clearance to the front corner of the fender too, which was the problem that @RLF Cuda was having to start with.

if the UCA remains the same.....if the bottom of the spindle was moved forward, it would increase caster and decrease front fender clearance. If the bottom was moved rearward it would decrease caster but gain fender clearance.

 

[72bluNblu]

if the UCA remains the same.....if the bottom of the spindle was moved forward, it would increase caster and decrease front fender clearance. If the bottom was moved rearward it would decrease caster but gain fender clearance.

Exactly, and this was brought up to increase clearance at the fender, so the caster effect would be to make the caster more negative. Leaving the spindle symmetric and finding the actual source of the lost clearance is the better solution.

 

[remytherat]

The strength of the upper arm shouldn't be a huge concern IMO, since it doesn't bear any of the load of the car. All it does is hold the top of the spindle up and in the correct orientation. That said, if it broke things would get ugly..

 

[72bluNblu]

The strength of the upper arm shouldn't be a huge concern IMO, since it doesn't bear any of the load of the car. All it does is hold the top of the spindle up and in the correct orientation. That said, if it broke things would get ugly..

Uh, it doesn't bear the weight of the car in the vertical plane, but any steering, cornering, or braking loads from the tire that don't go straight up and down are split between the upper and lower control arms.

 

[remytherat]

Uh, it doesn't bear the weight of the car in the vertical plane, but any steering, cornering, or braking loads from the tire that don't go straight up and down are split between the upper and lower control arms.

Good point

 

[moparlvr166]

When I say drilling bolt holes I meant in lower ball joint, it's the least expensive part to replace. I don't think it would take 1/4 in. I just used that as a reference. I'm sure we have an expert here that can figure that out to gain a few degrees.

 

[autoxcuda]

This brings up a question that I have about the 73+ spindles. On my '68 FS FB, I installed 73+ UCA and spindles. Naturally they are wider. But I had sway bar and tire clearance issues with the calipers mounted forward as is stock, so I swapped side to side so the calipers were towards the rear. Worked well but not happy with brake line routing. During restoration, I purchased the Helwig bent sway bar which allowed clearance for the 11.75" rotors and calipers. OK, Happy with that. But the tires moved forward by about 1/4" or a little more. I was running 235-60x15's BFG's before with good clearance. Tight, but no touching. After swapping the spindles back to stock, the tires interfered with the front lower edge of the finder. To get clearance I had to go down 2 sized to 215-60x15's. Not desirable! The wheels are Weld 96-57208 ProStar's with 4.5" Rear Spacing. I am not sure if there are other back spacing options that will give more clearance. Does anyone know if the spindle centerline is offset so that swapping spindles side to side changes effective wheelbase by maybe 1/4" or more?
The 235-60x15 Front photo is of the tires/wheels I ran for 10 years with no issues with the caliper mounted to the rear. With the caliper mounted to the front (see photo), even the 225-60x15's touched the fender (the tire is mounted on a checking rim that is adjustable). So I went with 215-60x15's to clear the fender (but no photo).
Thoughts?

View attachment 1716205701

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I ran rear mounted Pin Calipers on 11.75" rotors with stock LBP UCA from 1993 to 2011. Lots of only car daily driver miles, road course and autocross track time... no issues. You just run a banjo ended brake line. I made up braided steel ones. Dr Diff sells them now.

Personal preference, I would have left yours in the rear and got good brake hoses. Especially since you are running the 67-72 wide sway bar setup.

When I put the Hotchkis TVS upper control arms on, the caliper hit the upper control arm when fully turned. So I had to mount them up front just like you did.

After the spindle swap, the tire clearance did not change. And I'm running real close tire clearance. Of course I changed to adjustable strut rods and UCA's at that same time.

Was not my preference to run them in the front since I want to run brake cooling ducts up there. But I haven't done that yet and will probably upgrade my calipers at the same time.

Most people don't use the Pin Type, so I think it's an under the radar situation. But nonetheless, it can happen. And UCA manufactures should give the customer a heads up.

@HemiDenny Have you checked this not common scenario out with your UCA's ?

 

[HemiDenny]

This brings up a question that I have about the 73+ spindles. On my '68 FS FB, I installed 73+ UCA and spindles. Naturally they are wider. But I had sway bar and tire clearance issues with the calipers mounted forward as is stock, so I swapped side to side so the calipers were towards the rear. Worked well but not happy with brake line routing. During restoration, I purchased the Helwig bent sway bar which allowed clearance for the 11.75" rotors and calipers. OK, Happy with that. But the tires moved forward by about 1/4" or a little more. I was running 235-60x15's BFG's before with good clearance. Tight, but no touching. After swapping the spindles back to stock, the tires interfered with the front lower edge of the finder. To get clearance I had to go down 2 sized to 215-60x15's. Not desirable! The wheels are Weld 96-57208 ProStar's with 4.5" Rear Spacing. I am not sure if there are other back spacing options that will give more clearance. Does anyone know if the spindle centerline is offset so that swapping spindles side to side changes effective wheelbase by maybe 1/4" or more?
The 235-60x15 Front photo is of the tires/wheels I ran for 10 years with no issues with the caliper mounted to the rear. With the caliper mounted to the front (see photo), even the 225-60x15's touched the fender (the tire is mounted on a checking rim that is adjustable). So I went with 215-60x15's to clear the fender (but no photo).
Thoughts?

View attachment 1716205701

View attachment 1716205706

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On this one.....I will bet dollars to doughnuts the fender issue is because he replaced 9" drum spindles with the later.

 

[72bluNblu]

On this one.....I will bet dollars to doughnuts the fender issue is because he replaced 9" drum spindles with the later.

He literally said he was running the same wheels and tires on the 73+ spindles previously without any issues and just changed them side for side because of the changes he made with the brakes and sway bar.

 

[autoxcuda]

He literally said he was running the same wheels and tires on the 73+ spindles previously without any issues and just changed them side for side because of the changes he made with the brakes and sway bar.

I had to read that a few times. And just read again.

I'm not super clear if there were changes made without tested road time in between them. But it sounded like he ran 11.75 rotor w/calipers mounted in rear with 235/60/15 tires for 10 years.

These deals can be tough to follow.

The odd thing is, you should/can be able to swap spindle side to side without disturbing the UCA alignment cams and not remove the strut rods.

 

[72bluNblu]

I had to read that a few times. And just read again.

I'm not super clear if there were changes made without tested road time in between them. But it sounded like he ran 11.75 rotor w/calipers mounted in rear with 235/60/15 tires for 10 years.

These deals can be tough to follow.

The odd thing is, you should/can be able to swap spindle side to side without disturbing the UCA alignment cams and not remove the strut rods.

Same. It also sounded to me like he had been running the 235's with the 73+ spindles for a long time without issue, and the issues came up when the spindles that had already been on the car for a long time were swapped side for side.

The sway bar was changed as well if I'm following correctly, maybe the change in the sway bar also pulled the LCA's a little bit forward? The end links are bushed so I wouldn't think much would change, but maybe the pull from the new bar took up some slack in the bushings and cheated the LCA's a little farther forward?

 

[Kern Dog]

The odd thing is, you should/can be able to swap spindle side to side without disturbing the UCA alignment cams and not remove the strut rods.

I had the calipers front mounted on my '70 Charger but wanted to run the rear mount and the later FMJ 2.75" single piston caliper so I swapped the knuckles side to side. Of course it all swapped and fit right and the alignment didn't change enough to feel it. It still drove and felt the same to me.

 

[HemiDenny]

He literally said he was running the same wheels and tires on the 73+ spindles previously without any issues and just changed them side for side because of the changes he made with the brakes and sway bar.

Does that make any sense to you? Why would changing symmetrical spindles side to side cause the wheel move forward. Of course with the OEM anti dive UCA mounts, more drop due to sway ar change would have the same effect.

 

[72bluNblu]

Does that make any sense to you? Why would changing symmetrical spindles side to side cause the wheel move forward. Of course with the OEM anti dive UCA mounts, more drop due to sway ar change would have the same effect.

C'mon man. He changed more than one thing at the same time as the spindle side for side swap, and one of the other things he changed caused the wheel interference. It clearly says he was running the 73+ spindles before with the 235's without issue. Literally no where does it say anything about using 9" drum spindles, or changing bolt patterns, or changing wheels.

There's definitely some additional explanation that's missing, and maybe I'm missing something. But the way it reads for me a drum spindle never enters the conversation. Perhaps @RLF Cuda will clarify the timeline

Hell that's not even the point of this thread.

 

[Kern Dog]

Yeah....so how about MORE chatter about welding or modifying this stuff to keep it CHEAP ?