disc brake conversion

[billybobmopar]

does anybody know if a disc brake set up off of a 1976 volare' roadrunner will fit on a 1970 GTX?

thanks
billy

[dwc43]

AS far as I can tell, the Volare' never came with a rear disc set up. I can get you a rear disc for a good price though.

[cutting torch]

DW, you're reading and posting too fast again. He never said rear. As for the swap, I think I've heard of using the spindles, rotors, and calipers, but don't take that as gospel. I'm not really sure. Wait for some more posts, I'm sure someone knows.

torch

[dwc43]

You are correct. I don't know where I THOUGHT I saw that it said rears.

The spindles off of an F,M, or J body (Volare') will NOT fit. The rest of the parts will. The spindles are too tall for a B body. This causes over angled ball joints, a change in axis inclination, an increase in A arm angle that will keep your from getting a propper front end alignment. It also causes a change in caster as the wheel moves through it's travel. Several posts on this board alone that will agree that you can't use F,M, and J spindles on anything other than an F,M, or J car.

[cageman]

Whatever
Last month one of the mopar mags had an extensive myth buster article, and it stated that these spindles do indeed work, and actually show no signs of bad angles or over angled control arms. they set up a front end and went thru the spindles and the Volare spindles work fine.

[cutting torch]

OK, I'm right, wrong, and/or otherwise. I'll sit back and let you two hash it out, and maybe learn something in the process!

torch

[dave571]

I saw that article too.

I'll say this.

1)Lots of guys have used the F spindles without problems.
2)some have done it with problems(I have seen them first hand)
3)There is no argument that the spindles are not the same for an F body and a B body. The F body ones are taller.


I don't think the question on the spindles is whether they are wrong, it's just whether they are so wrong that they will cause a problem.

Obviously this is where the difference of opinion is.

Personally, I feel that the 73-76 A body spindle (which is exactly the same dimensions as the early B spindle) is not so rare, that it's worth going to the F body stuff.

To get the part that is known to be right, or the one that is probably right. Seems like an easy choice to me.

To each thier own.

[4406RR]

I have them on my 71 Road Runner clone they were the same hight as the ones I took off and mached so well when I took the car to be aligned it was dead on . The spindles I used came from a 76 Volare I used the caliper brackets and roters from a 79 St. Regis and now have 11.5" disks on the front with no problems

[4406RR]

I also have used the 73 b-body spindles on the earlyer b's with little problems on some cars I have had to swap them sides so I could huck up the swaybar.
but other than that they worked fine

[George G. Leverette]

dwc check the Hollander exchange manual the spindles for the F, M, J, R are exactly the same and were used for years across the car lines. The conversion is not recommended for racing applications, but is used extensively in street driven machines without adverse effects. Rather than look for the getting rare 73-76 A-body spindles, a set of the spindles, rotors and other parts can be pulled from a New Yorker (R) and the set will be a complete bolt on.

[cageman]

It works real good for racing, I was able to get the camber gain I wanted on my 68 coronet. I had abody spindles on it first, then I went to the Gran fury spindles. I put a set of Dodge pickup ones on and that was way to much, Never ran it that way tho.
Now I am wondering where the A body set went when I moved, Ill have to look.

[charger_dan]

most have seen this article, but in case you haven't:

http://www.moparaction.com/Tech/archive/disc-main.html

[dwc43]

Originally Posted by George G. Leverette

dwc check the Hollander exchange manual the spindles for the F, M, J, R are exactly the same and were used for years across the car lines. The conversion is not recommended for racing applications, but is used extensively in street driven machines without adverse effects. Rather than look for the getting rare 73-76 A-body spindles, a set of the spindles, rotors and other parts can be pulled from a New Yorker (R) and the set will be a complete bolt on.

Like cageman said, it can be great for racing with proper set up, but NOT on the street. What the article did not do was check the A arms over angling, axis inclination, the change in the caster camber curves, ackerman and bumpsteer. The F,M, and J's just wont work on the B bodies without major problems period. It wont handle right, it wont align correctly, and it over angle the ball joints and it's just palin dangerous on the street. Street cars have softer suspension and use up more than the 2 to 3" of travel that a racecar uses and that works on the ball joint angles. I've got a busted lower ball joint somewhere where a friend of mine tried it after he was told it wont work.

[DartGT66]

I believe, the B-body and E-body spindles are different? 73&up A-bodies use the same spindles, but I have never heard of anyone referring that htey should bolt on to B-bodies, or that you couls use B-body parts in converting an A-body to discs. Anyway, here is information about the wheel alignment changes using the newer spindles in A bodies. http://www.bigblockdart.com/tech/spindles.shtml

[rumblefish360]

Ya seemed a might out gunned on this DW even though some have said they are currently making use of the parts.

[dwc43]

Originally Posted by rumblefish360

Ya seemed a might out gunned on this DW even though some have said they are currently making use of the parts.

You can try it if you like, it's your hide not mine, but you'll pay the price sooner or latter. It wont work. Do a search for past threads and you'll see I aint so out numbered.

[rumblefish360]

Maybe, but i'll not go this route if I cross it. It'll be a nice new set up with disc on all 4 corners, brand spankin new out of the box.

What about the others allready in use? They report no problems.

[4406RR]

I drove this car every day for two summers with no problems back and forth to work 50 mile round trip they work fine

[dwc43]

Originally Posted by rumblefish360

Maybe, but i'll not go this route if I cross it. It'll be a nice new set up with disc on all 4 corners, brand spankin new out of the box.

What about the others allready in use? They report no problems.

There risking there lives and anyone on hte road around them.

[dwc43]

Originally Posted by rumblefish360

Maybe, but i'll not go this route if I cross it. It'll be a nice new set up with disc on all 4 corners, brand spankin new out of the box.

What about the others allready in use? They report no problems.

There risking there lives and anyone on the road around them.

[John Kunkel]

There are no facts on this subject, only opinions.

The Mopar Action article was recently countered by an article in Mopar Muscle that claimed to "end the debate". It didn't.

[cageman]

I thought the article did, but some people are deathly afraid for some reason, even tho the facts are showing no signs of there even being a hint of problem, And for the lower ball joint going out, the lower ball joint is not evn concerned with it being taller, it still rides along thinking it has the old spindle, what would cause it to be stressed, if the spindle is 3/8 taller, and your ride heights are left the same, the lower ball joint would not be an issue, And for stressing the upper, with a bump stop in place, there would be no chance at all at being an issue either. I have no bump stops in my race car, and If it lives in that environment,there is no doubt in my mind from my experience and the article to back me up, that this spindle swap will in no way cause any ones life to be in danger, henny penny!

[dave571]

Originally Posted by DartGT66

I believe, the B-body and E-body spindles are different? 73&up A-bodies use the same spindles, but I have never heard of anyone referring that htey should bolt on to B-bodies, or that you couls use B-body parts in converting an A-body to discs. Anyway, here is information about the wheel alignment changes using the newer spindles in A bodies. http://www.bigblockdart.com/tech/spindles.shtml

Go to the tech archives at www.moparaction.com

There are pictures there with measurements that show the differences in the spindles, and how the 73 to 76 A body spindle has the same dimensions as the early B body spindle.

As John K said, there are only opinions on this.

The facts are that the F, j, m spindles are taller than the original B body spindles. This is a FACT.

What effect it will have is matter of opinion.

I have seen first hand, an E body, with F body spindles installed. There was too much positive camber to adjust out with the cam bolts.

In all fairness to the debate, I'm not sure what the history on the car was (accidents etc) I do know it would not align. I also know that many have installed the f,j,m spindles, and had no problems, with alignment or driveability.

BUT Saying that the spindles have been and installed and driven on isn't a flawless arguement either.

The same can be said for driving with a cracked flex(brake) hose. It's no problem...... till it bursts. If it doesn't burst, does that mean it's safe to do?

What conditions the taller spindle may cause a problem under, may not become evident untill the car is on it's roof (which may be never).

[DartGT66]

Look at the BBD.com charts, they are not an opinion, they are measured information. I had F-body spindles and brakes in my '66 GT that I run for many years in the street and strip. I really saw no difference in how it handled compared to my '73 with stock parts. There was no sign of bump steering whatsoever. I have had that too with "modified" stock parts, and I sure know what it is, and what it does. I would have no trouble doing that swap.

[John Kunkel]

Originally Posted by cageman

I thought the article did, but some people are deathly afraid for some reason, even tho the facts are showing no signs of there even being a hint of problem, And for the lower ball joint going out, the lower ball joint is not evn concerned with it being taller, it still rides along thinking it has the old spindle, what would cause it to be stressed, if the spindle is 3/8 taller, and your ride heights are left the same, the lower ball joint would not be an issue, And for stressing the upper, with a bump stop in place, there would be no chance at all at being an issue either. I have no bump stops in my race car, and If it lives in that environment,there is no doubt in my mind from my experience and the article to back me up, that this spindle swap will in no way cause any ones life to be in danger, henny penny!

The article in MM that claimed to "end the debate" did nothing to disprove the claimed upper ball joint distress, all they did was plot the various geometry and alignment specs within 2.25" of either side of ride height. This disproved in their minds the notion that the caster/camber/bump steer would be excessive with the tall spindle.

I agree that the bump stop is the real issue with the tall spindle, with the bump stop in place it's impossible to bind the upper ball joint at any caster/camber setting within the range of the adjusters, even with the "problem solver" bushing. The picture in one of the old MA issues showing bind was admittedly staged without a bump stop.