To convert to discs or not convert? That is the question!

-
M

Maniacmama

Member
Joined
Sep 6, 2013
Messages
8
Reaction score
0
Location
Texas
My vehicle is a '74 Dodge Dart Swinger with drum brakes all around.

I couldn't afford to convert to discs at this point of the mechanical fixes and spent a month finding a brake booster/master cylinder for all drums and subsequently replacement drums for the front

My original intention was to upgrade in 7 months when more funds become available, but while talking to Austin Texas' guru of brakes (as recommended to me by area mechanics) he advised against it because the replacement parts for kits are 'purt near impossible to find.

If it weren't for the discovery of this forum I would have never located the drums, the car would have been shelved for 7 months or sold loosing a good deal more than I would like$$$ Most buyers enjoy stopping.

I need direction and reasons in terms a non-mechanic could understand. Upgrade to discs or keep all drums?
 
im not sure if I understand this correctly but parts are not that hard to find for disc brakes there are complete setups in the for sale adds on here quite often and it is well worth the money.
 
I assume the "brakes guru" is referring to the '72 and earlier Kelsey Hayes disc brakes, which have historically been difficult and expensive to find parts for, but even finding parts for these brakes is no longer difficult. And certainly '73 and up disk brake parts are widely available, as are aftermarket kits.

I think your "guru" might be misinformed, or using dating information.
 
Use '73 up spindles and upper control arms from a car with disc brakes, and the calipers and brackets also, swap your master cylinder, and you have discs. Might need the proportioning valve also. Cheap and plentiful.
 
I almost totalled my 61 Cadillac 2dr HT in stop and go traffic when I made a legal left hand turn and a yahoo ran a red light due to my brake fade. I immediately parked and ordered a kit, stops on a dime. I am doing the same to my 63 Valiant Convt as well. The price of the swap is so small in comparison to an accident.
 
Disc are a great upgrade and 4 wheel disc even better!
 
You can buy new "kits", which are just the factory 1973+ disk brake parts, ~$750 ebay. The kits the guru was talking about were likely after-market Wilwood, SSBC, etc. You can get parts for those now, but might be harder to find than factory parts in 20 years. Don't even consider the early K-H disks for your car, since not original.

One other thing to consider is wheels. I think all drum brake cars, even 1973+ had the early 5 x 4" pattern (SBP), whereas 1973+ disk cars were 5 x 4.5" (BBP). If your wheels are SBP and you want to keep them, that narrows the choice. Wilwood makes kits for both 9" & 10" drums. Before that, look at Scarebird's kits. Much cheaper and use Toyota and GM parts, which will be the easiest to find in 20 years.

As far as stopping ability. Well-maintained drum brakes will stop a car fine. Can't they skid the tires? Can brakes brake any more than that? You will only experience brake fade from continual braking (not enough time to cool) or one-time braking from very high speed (say >90 mph). The guy who claims his Cadillac shoes "faded" when braking during a turn had some other problem going on, unless he was taking the turn at 90 mph.
 
I can see the brake fade even more so in a big barge Cad. Driving around town for a 1/2 hour and a panic stop after JUST stopping can have this result.

Mama, OE parts are easy enough to come by. Stay with the factory parts for ease of installation and replacement parts. There are a bunch of tricks out there but I think you want to use the KISS method. (Keep It Silly Simple)

The job can be done by yourself
 
"To convert to discs or not convert? That is the question!"

And that is an excellent question I might add! When these cars were new, drums were certainly adequate. Even the big boat cars, which had big drums, stopped just fine in normal driving conditions. But, just take a look at all the performance modifications guys on here are doing. We're talking major performance improvements in horsepower and handling. Naturally you would want to upgrade your brakes to discs if you were doing the other upgrades.

But, in my opinion, drums should be fine for lots of weekend cruising, or even as a daily driver. Just keep them fresh and maintained. There is no argument, discs have more stopping power when subjected to prolonged, performance use, etc.

Subscribed...
 
Maniacmama said:
I need direction and reasons in terms a non-mechanic could understand. Upgrade to discs or keep all drums?
Click to expand...

The primary advantages of the disk brakes:
1. They are less likely to overheat the lining material.
2. It's usually easier and requres less skill for a mechanic to change pads than change shoes.

Details:
Heat can be an issue if the brakes are undersized (they're not), if your making rapid repeated stops from over 60 mph, carrying heavy loads or have many steep hills. With these duo servo drums fade is extra noticible because there is less self-assist. But (a) your car has power brakes, so that would help some, (b) you can do a lot to prevent overheating.

If you live in a place with lots of steep grades, will be towing,etc. then down shift so you're not riding the brakes and make sure the shoes have linings good for higher temperatures.*

It's true that as long as the brake calipers don't hang up, pistons retract as they should, then changing disk brake pads is easier than installing shoes for drums. Find a good mechanic and this really isn't a problem.

Advantage to keeping your drum system is that it works, was pretty well designed and implemented by the factory, and all you need to do is maintain it.

Very little in the aftermarket is plug and chug. There's always something that doesn't fit, or needs tweaking, or has a domino effect. If you are hot rodding, then that's part of the adventure. For the average guy, collector, just get good shoes, new hardware if needed, adjust 'em, and fresh fluid. You're good to go.

*The side or back of most brake shoes will have a material code with two letters at the end. Those letters roughly indicate the friction. The first letter is friction rating at lower temperatures, then second one at higher temperatures. EE is pretty typical for shoes. If you don't like the parts store shoe offerings, then you might want to consider Rochester Brake (NY) or Porterfield Brake.
 
You have drums now. Do you feel confident in them? driving in Austin traffic?
I sourced out most of the hard parts for the 11.75" disc conversion off of this forum for alot less than a KIT. It is more important to me to be able to stop fast that go fast.
 
Oklacarcollecto said:
Once you go to disc brakes you won't want drum brakes any more.

If you want to stay sbp to match the rear brakes you might want to consider these.

http://www.forabodiesonly.com/mopar/showthread.php?t=249438
Click to expand...

X2

Things to consider:

  1. Since your car has drums, it probably has a 4"x 5 bolt pattern hub. Late model brakes (73 & > ) have a 4½"x5 bolt pattern. If you change over to late model brakes, your existing wheels will not fit the larger bolt pattern on the hub.
  2. You can carry two spares or convert the front to the four piston caliper as in Oklacarcollecto's post link.
  3. You can carry two spares or swap out the rear end for one that has a 4½x5 bolt pattern. If this course is pursued, none of the existing wheels will fit. Fortunately, the aftermarket and used market is full of choices.
  4. You may elect to keep the drums. Obviously, they will stop the vehicle safely. They are not as heat resistant as disk brakes and will lose effectiveness with heavy usage. They do cool down and regain effectiveness, but that's not a good position to be in when a quick stop is needed NOW! Drum brakes are not as moisture resistant as disk brakes. A disk brake recovers much quicker than a drum brake when the friction surface gets wet. Finally, disk brakes continually self-adjust for wear. Drum brakes can also be self-adjusting, but it happens mainly in strong stops from about 10 mph and up in reverse.
I drove a 66 Dart V-8 in Austin with manual drum brakes from 1988-1992. Other than having a mechanic miss the L stamped on the studs on the drivers' side of the car, I had no real problem. I avoided deep water in the roadway like the plague. When I could not avoid it, I dragged the brakes as I went through the water. When I was through the water, I made sure it was safe to try to come to a full stop. The first attempt would be a little darty (pardon the pun) as some drums would be more soaked than others. Once I felt like I had all four wheels more or less working as before, I'd motor on.

The next 66 Dart I had (92-00) was equipped with manual disk brakes. It always came though the water test without any darting about.
 
What engine is in the car? What are your plans with the car? If all you want is a nice street car, drums will work fine as long as they are in good condition. They have been around over 100 years and they are still used on cars and trucks today. Not a thing wrong with drums if they are used within their operating parameters.
 
I agree with RRR. I have driven many A bodys with drum brakes since 1978. They work fine under normal average driving. But with newer cars stopping faster, and people driving more erratically (texting, eating, etc) the need to stop short has become more important.

Like others have said, I would look for a set of used components off of a 73-76 A body and do the work yourself. It's not that hard and there's plenty of help here. They can be found on your local craigslist, eBay or dare I say it?!? Moparts.com

BTW I have four wheel discs with slotted and cross drilled rotors. Is it over kill??? Hell yeah, but I shopped smartly and got everything for a decent price. Now when some kid cuts me off, my front bumper won't crush the bumper on his Mom's Prius.
 
Just opinions so here's mine... I've go a complete 73 power disc brake suspension to put under my 67 fish. About 7 years ago when I bought the fish I said to myself... Someday it will need brake work of some sort. I will not spend one dime on the drum brakes. When it does need linings, master cylinder, anything, the drums come out and the discs go in.
Hasn't happened yet. I guess I don't put enough miles on the car.
 
I second the Scarebird conversion suggestion. Probably the cheapest unless you score another disk setup cheap, and I'd say definitely the easiest to convert to since you don't even have to change the spindles. I did the same thing on my '72, even spent a while looking for what seemed like the last set of front drums sitting in a dusty warehouse in Kansas, and I regret not just upgrading to disks right away.
 
RustyRatRod said:
What engine is in the car? What are your plans with the car? If all you want is a nice street car, drums will work fine as long as they are in good condition. They have been around over 100 years and they are still used on cars and trucks today. Not a thing wrong with drums if they are used within their operating parameters.
Click to expand...

I'm with Rusty here as well....all depends on what you want to do with the car. My car is just a street-driven cruiser, so I'm sticking with the manual drum brakes I currently have. I just have to remember that I have drum brakes and the car isn't going to stop like a Porsche, and drive accordingly.

YMMV....
 
my last Dart had all new drum brakes and i could lock them up in a panic situation easily,you just never knew where you going to end up.
..there is really no question what you should use.
 
Disc without question. My former '69 Barracuda used M body spindles ('80 Diplomat). Went on with no real challenges. Cheap to. Several people use them on B and E bodies as well. Cost effective way to get stopped.

I would not think of sourcing all the parts for a K-H setup. Not worth the coin.
 
ir3333 said:
my last Dart had all new drum brakes and i could lock them up in a panic situation easily,you just never knew where you going to end up.
..there is really no question what you should use.
Click to expand...

I think you can lock up discs too, if you stand on the pedal hard enough....in that case, it's the tires that stop the car, not the brakes.
 
Right you are 65Val. It is indeed possible to lock up a non-ABS disk brake system. But that's the not the objective. The brake/tire combination is most effective at the point just before lock-up. Tires will be screaming at this point, but they'll still be turning. A turning tire is a steerable tire. No turn, no steer.

In setting up the bias on the brakes (balance between front/rear), most agree it is safest if the fronts lock first. This assumes, of course, that both front wheels lock at about the same time. Otherwise, the car is going to turn left or right rather rapidly. The problem with locking the rears first is that the tail wags the dog. Unlike Yaw under power, there is nothing left to bring the tail back into line.
 
Like my auto mechanics instructor in high school used to tell us, "braking is least effective during a slide".
 
You must log in or register to reply here.
-

Back
Top