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Disk brake conversion front of 73 Javelin

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billd View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Topic: Disk brake conversion front of 73 Javelin
    Posted: Nov/18/2017 at 12:03am
I gave away the front brakes and spindles from my 73 Javelin as I plan on a disk brake swap. 
I will be using the parts from a donor car - a 1980 Concord for the disk brake parts and spindles, etc.
In attempting to determine what I will need for brake lines and hoses (knowing this car, it's getting all new lines and hoses, front, rear and in between)
The question?
In ordering lines and hoses it's a bit of a situation because anything I order would assume the sort of disk brakes the car would have had in 73 IF AMC had put disk brakes on THIS car. But it will have the 1980 style of calipers. 
Has anyone made a similar swap that can tell me what hoses to buy - and would a set of steel brake lines for a 73 with disk brakes work out ok on this car?  I know not to order for front drums because I'll be adding the combo valve on the frame rail up front and since front drum doesn't have that it would mean the front steel lines would be wrong, and missing a piece or two. 

So if I order steel line SET for a 73 Javelin with front disks would the lines up front work out "ok"?

What hoses would be required - would new hoses for a later car work out on the Javelin since they'd have to mate up with the 1980 calipers from the Concord?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Samuelsc360 Quote  Post ReplyReply Direct Link To This Post Posted: Nov/18/2017 at 3:13pm
I did this conversion on my Sportabout. I used the 80 master cylinder and firewall lines from the Concord. Everything under the car fit as is. The hard lines to the calipers came from the Concord but the rubber hoses were for 1975 Hornet. I don't know if any of this will help with a Javelin.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Nov/18/2017 at 3:17pm
I had a 73 Javelin with KH discs. Was going to do the swap and got down to parts, but never done it before selling.

You need the spindle, rotor, caliper and it's mount with hardware, dust shield, proportioning valve and the soft lines for the newer brakes. The hard lines will work fine, but you will need to swap out the proportioning valve as it is valved for front disc brakes.

If you had disc brakes, some of the items are not swapped out... like proportioning valve, and master cylinder.

My 71 with drums have the same line fittings my 73 with disc brakes, but the hard lines are routed differently.
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 73hornut Quote  Post ReplyReply Direct Link To This Post Posted: Nov/18/2017 at 3:31pm
I did this swap on our 71 Javelin, from non-power drum to power disk(KH). APD has new front lines, didn't need rear, and I mounted a factory prop valve in the stock location. Everything mounted up nicely, the rear line mounted right up to the new prop valve. Depending on the year brakes, you may also need new front soft lines to the calipers.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Nov/18/2017 at 9:30pm
Originally posted by 304-dude 304-dude wrote:

I had a 73 Javelin with KH discs. Was going to do the swap and got down to parts, but never done it before selling.

You need the spindle, rotor, caliper and it's mount with hardware, dust shield, proportioning valve and the soft lines for the newer brakes. The hard lines will work fine, but you will need to swap out the proportioning valve as it is valved for front disc brakes.

If you had disc brakes, some of the items are not swapped out... like proportioning valve, and master cylinder.

My 71 with drums have the same line fittings my 73 with disc brakes, but the hard lines are routed differently.


I know all the parts needed - and I have a full donor car sitting about 30 feet from the Javelin. 
The Javelin is a 73 so used a combo valve - and I found a nice looking used one. That mounts on the FRONT of the car, right side engine bay on the inner side of the front frame rail between right wheel and firewall on frame rail. I tried to leave a clue with "....if AMC had put disk brakes on this car....." - it was a power DRUM car. 
I gave away the front drum brakes - spindles and all as I noted. 

I will be replacing all brake lines because, well, the original master was full of mud and the car has had a questionable past -the springs so rusty they SAG on all corners, so I assume with the mud in the master and the rust on the outside of the brake lines I'd be a fool to take a 400 hp racer and not replace brake lines on it while swapping to disk brakes.  I replaced the master over a year ago with a stock drum master cylinder so will likely run that for a while instead of swapping master cylinders AGAIN. If I recall the piston size was the same but the portion of the reservoir for the disk brake part was larger (as is typical). If the piston size is indeed the same drum vs disk then no problem - just remember to check brake fluid at every oil change or more frequently. (there were NO residual check valves in the old or new so that's not an issue, weird, but not an issue)

The rear will be simple - that will remain stock so stock replacement lines and hose will work.

The front - I have the combo valve to mount on the frame up front. I assume I'd need a line set for a Javelin with disk brakes since that valve is there but not on cars with drum - like mine was. 
So the disk brake line sets for the Javelin should work  maybe - will they end up in the same BRACKETS as drum lines do - in other words, compare a 73 drum car to a 73 disk car, do the front steel lines go to the same frame-mounted brackets where they join the rubber hoses?
If I get rubber hoses for a 1980 Concord - I know the hoses will fit the calipers (that's a duh, right?) but will the rubber hoses go to the frame-mounted brackets and connect up with the steel lines, or will I be moving things around, bending or making brackets, and re-bending the FRONT steel lines to mate with Concord disk brake hoses?
What about the later Javelins - did they use K-H brakes or did they use a single piston like the Concord? (wondering as maybe the hoses would be different?
OR - does someone know - will Concord disk brake HOSES fit seventy-three Javelin disk brake steel lines and brackets?
I'd rather not mess with making steel lines so want to buy the full kit - and I'd rather not have to remake the brackets that hold the line end of the hoses to the frame.
the car is scary quick and I want to be able to stop it...........
I'm not one to sink several grand into hundreds of HP to make a car go from 0 to 60 in a couple of seconds but not be willing to spend or do what's needed to make it stop in short order, too. Think of the HP needed to go fast - how many HP does it take to stop the same car in a fraction of that quarter mile?

Edited by billd - Nov/18/2017 at 9:33pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Nov/18/2017 at 9:40pm
Originally posted by 73hornut 73hornut wrote:

I did this swap on our 71 Javelin, from non-power drum to power disk(KH). APD has new front lines, didn't need rear, and I mounted a factory prop valve in the stock location. Everything mounted up nicely, the rear line mounted right up to the new prop valve. Depending on the year brakes, you may also need new front soft lines to the calipers.


Hmmm will have to compare APD lines COSTS to the ones I see on ebait. Maybe I should give APD a look for lines, forgot all about them. DUH.

The Javelin is 73 power drum. I gave the front drum setup, including spindles and all, away to a neighbor. He wanted "10" drum brakes from the front of an AMC, the whole setup"......... so I gave them to him on the condition he took it all off my car.
The 73 Javelin has the combination valve mounted up front on the front right frame rail just ahead of the firewall (toward the engine)
So it's a different setup than earlier as far as valves - it's got the large combo valve. 
I have a good used valve I'll mount on the right frame where AMC put them.

The Concord is a car I have sitting next to my shop (I'm parting it out for the 4.0, transmission, differential, and other goodies).
It's a 1980 and of course has disk. It should be a good donor for the brake swap - calipers, rotors, spindles, plates and so on but I won't trust 37 year old rubber lines from the brackets to the calipers. 
I'll either rebuild the calipers myself or buy new. 
Don't know the condition of the master cylinder on the concord - and not sure it would even fit a 73 Javelin. I don't have 1980 parts books so can't do part number compares.

The lines need to be swapped - if I showed you the undercarriage of the car, or the original master cylinder, you'd understand - AND, you'd call me stupid for driving it so long that way!  Embarrassed
(But dam that car is FUN!!)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Nov/18/2017 at 10:07pm
It's been some time... from what I understand 74 or late 74 was a bendix year, so depending on how late your 73 is, it may have had the bendix caliper if optioned. Both look the same as for having a single piston.

The wee tab for mounting the brake line to soft brake line is the same, and as long as you use the new hardware (caliper setup) the lines associated for fitment, everything should connect on the hard line and mounting tab.

Yes, it is mandatory to change out the front drum hard brake lines for the disc hard line setup. I mentioned fittings, as if you had good lines, the fittings would not keep you from connecting the newer soft lines.

As for master cylinder... i figured you would change out with new 71 to 76 big car master cylinder, and being your a stickler for correctness, the disc master cylinder would not be a question. Yes, your right, I should not second guess your thoughts.

No your not stupid for driving with messed up breaks... I drove my freshly bought 71 with non power drums and standard steering home on a 230 mile stretch. Yes my brakes were about gone as well.

Sounds like everything is in order... changing out all the lines would be a given, just because of the previous care.

All in all the soft lines will be of correct length, as all the mounting tabs for front lines are located in the same proximity about one inch from the suspension hump seem, for all bodies. The suspensions are about the same in wheel placement, so the lines will be of proper length.

Having the disc combo valve, which I called proportioning valve, will be swapped in place of the original drum version, as you already have thought of it in plans.

Mainly I just refreshed in my 1st reply, about what I gathered would be needed for anyone checking in that may want to do an upgrade. Better to have more info than find out the soft lines are just the tip of the iceberg.
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Red Devil Quote  Post ReplyReply Direct Link To This Post Posted: Nov/19/2017 at 12:39pm
'73 (and '74) Javelin had Kelsey Hayes slide-pin type floating calipers.   '80 used the steel-on-steel Bendix floating calipers.  Different flex hoses.   Not sure about length?

Personally, I hated the later Bendix as they always seemed to rust and stop sliding after a winter of salted roads so needed to pull apart in the spring, sand, file and grease.   Pads wore unevenly, didn't last as long, pistons would stick and didn't stop as well as the KH.   More frequent maintenance and fluid changes helped. 

But if you have a donor handy, use what's available.  I did swap a '78 Concord Bendix set onto a '73 Hornet power drum car and used everything from the Concord including booster, master and combination valve.  Did need to drill a new hole in pedal arm to match the Concord pushrod location and made all new hard lines.

Hope this helps, RD  


Edited by Red Devil - Nov/19/2017 at 12:44pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Nov/20/2017 at 4:18pm
Found out something interesting........yeah, the 80 Concord has the calipers held in by the wedge and that slide on the support bracket BUT........1981 had the calipers that slide on pins. I know - I was going to use 81 brakes on my 82 Eagle but they are very different. The Concord has the flat head recessed socket bolt to remove then drive that wedge out while because my 81 had the pins that's what I expected on the Concord!
Anyway, it's so bloody rusted very little is usable except the spindles, hubs, and caliper supports.
The splash shields are GONE, just piles of rust after I simply touched and wiggled them. They literally crumbled in my fingers.
So I guess I need a good pair of shields for an 80 with the wedged-in type calipers.
BUMMER.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Nov/20/2017 at 4:28pm
Originally posted by billd billd wrote:

Found out something interesting........yeah, the 80 Concord has the calipers held in by the wedge and that slide on the support bracket BUT........1981 had the calipers that slide on pins. I know - I was going to use 81 brakes on my 82 Eagle but they are very different. The Concord has the flat head recessed socket bolt to remove then drive that wedge out while because my 81 had the pins that's what I expected on the Concord!
Anyway, it's so bloody rusted very little is usable except the spindles, hubs, and caliper supports.
The splash shields are GONE, just piles of rust after I simply touched and wiggled them. They literally crumbled in my fingers.
So I guess I need a good pair of shields for an 80 with the wedged-in type calipers.
BUMMER.


Ah, i had no idea about such differences... maybe the 81 setup with pins would be better and more easier to obtain? At least you got spindles and hubs. I think finding calipers and if wanting pin type setup, with supports, should not be so difficult.

I may have gotten 79 stuff, or forgotten exactly what I had, but I assume it was not the pin version, just had an odd bracket is all I can recall now. We are talking early 90'90 ' when I pulled everything and boxed it.
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
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