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65 valiant drum brakes
https://slantsix.org/forum/viewtopic.php?t=55409		 Page 1 of 2
Author:  nashvegas99 [ Wed May 21, 2014 8:41 am ]
Post subject:  65 valiant drum brakes
Hey everybody. New here. I've got to go on and put an introduction post up. But, I have a question about my drum brakes. I have a 65 valiant and I've ordered, cleaned, and replaced all the parts all the way around. I did not reattach the parking brake b/c the cable is broke. So, I removed the cable links from the backing plates. My question is this....is the flat strut bar needed now since I've removed the links and also the actuator arm? any help would be appreciated greatly. thnx
Author:  Doc [ Wed May 21, 2014 10:51 am ]
Post subject: 
The PB strut should also be removed.
Please tell me that you have a dual master cylinder on thes vehicle...
DD
Author:  nashvegas99 [ Wed May 21, 2014 11:17 am ]
Post subject: 
its all stock. what came on it. it has 5/16 line running to a junction block and then splits the lines to front and back
Author:  Danarchy [ Wed May 21, 2014 12:56 pm ]
Post subject: 
You should read this. http://www.earlycuda.org/tech/dualmaster.htm

and be Safe.
Author:  nashvegas99 [ Thu May 22, 2014 2:24 pm ]
Post subject: 
ok, until I can get that going....is the standard size for the line coming from the master cylinder to the junction block 5/16?
Author:  nashvegas99 [ Fri May 23, 2014 7:08 am ]
Post subject: 
well,i got everything buttoned up and drove around the block. she stops pretty well. I need to readjust the shoes, but I have a question...I think I read somewhere that the "shorter" shoe pad goes forward towards the front of the vehicle. Is that correct and is it that way front and rear?
Author:  WagonsRcool [ Sat May 31, 2014 6:35 pm ]
Post subject: 
Like most cars of the time, Mopar uses a style of Bendix "self-energizing" drum brake. Force from the smaller "primary" shoe is transferred through the adjuster to incease apply force on the larger "secondary" shoe. So the smaller brake shoe is towards the front on both front & rear axles.

If the shoes are reversed you'll end up with uncontrollable wheel lockup on braking once the shoes wear in. If you don't have enough shoe-to-drum "toe-heel" clearance, you'll get lockup. If things are perfect you'll have brakes that were adequate- 40 years ago. (most folk will reccomend some sort of disc brake conversion).
Author:  63Valiant [ Sat May 31, 2014 8:15 pm ]
Post subject: 
Drum brakes are under-rated. When in proper repair and maintained they stop the car fine. Otherwise, as Dan eloquently pointed out once, all the front ends of all of our old cars would be all smashed in.

As already confirmed, yes, the shorter shoe is the primary and goes towards the front of the car on all four corners.
Author:  AndyZ [ Thu Jun 19, 2014 10:00 pm ]
Post subject: 
My drums worked great until I went through a deep enough puddle. Then they dont work. :shock:
Author:  Rug_Trucker [ Sat Jun 21, 2014 4:18 pm ]
Post subject: 
My Dart has 10" drum all around. I had an issue with one of the front brakes on one side and fixed it. I don't remember what. Still not enough brake.

If you are interested I have spindles rotors and other paraphenalia if you are interested, cheap.
Author:  wjajr [ Sat Jun 21, 2014 5:35 pm ]
Post subject: 
Drum brakes are under-rated. When in proper repair and maintained they stop the car fine. Otherwise, as Dan eloquently pointed out once, all the front ends of all of our old cars would be all smashed in.

Dan has a point to a point. When all cars had drum brakes, all cars sort of had stopping distances in the same ball park. Today the average modern car will stop in a 20% plus shorter distance than the cars of the sixties, and in a straight line.

Just remember to keep back several extra car lengths over the normal distance in a modern car, and hope the guy in front doesn’t clamp on the binders real hard because you will eat all that extra space real fast. Also don’t expect the next hard stop to be as short as the first if the brakes are still hot, stopping distances will increase drastically.
Author:  63Valiant [ Sat Jun 21, 2014 6:39 pm ]
Post subject: 
Quote:
Dan has a point to a point. When all cars had drum brakes, all cars sort of had stopping distances in the same ball park. Today the average modern car will stop in a 20% plus shorter distance than the cars of the sixties, and in a straight line.

Just remember to keep back several extra car lengths over the normal distance in a modern car, and hope the guy in front doesn’t clamp on the binders real hard because you will eat all that extra space real fast. Also don’t expect the next hard stop to be as short as the first if the brakes are still hot, stopping distances will increase drastically.
That actually helps make my point, you're selling the idea that drum brakes have inferior stopping power and cannot stop in a straight line. A vehicle that cannot stop in a straight line has faults in the brake system regardless if it is drum or disc. The improved stopping power of today's cars can be contributed to power assist and anti-lock being standard equipment.

If you could improve your stopping power by switching to discs the DOT would have mandated disc brakes on our semis long ago. But it not only didn't happen, disc brakes were tried sometime back in the '90s have been mostly phased out since they offered no improvement. The new trucks we buy today have pretty much the same brake system that was revised/mandated in 1975, air chamber S cam with drum brakes. Of course they've added anti-lock as well now.

I'm not trying to sell anyone on drum brakes over discs, just that there is nothing wrong with drums in good working order. The only real issues with drums are:

1) They are a PITB to work on.
2) Not many know how to work on them.
3) Like RT pointed out, they do not like water, good driving practices will keep you out of trouble here.
4) They do not cool off very quickly, so again good driving practices come into play. However they're not going to overheat by making a high speed panic stop or two, it takes riding the brakes and/or hauling a heavy load to cause serious brake fade.

I have two Ford F250s, one is a '69 with 4 way power drum. The other is an '85 F250 with power disc/drums. The '85 is a diesel, the rear drums are huge, the front discs are sporting dual piston calipers.

Both trucks stop almost equally well, with or without a load. (Usually a travel trailer or loaded equipment trailer. And over Buckhorn summit no less.) If anything the '69 stops better, but I contribute that to it being a slightly lighter truck than the '85.







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Author:  slantzilla [ Sat Jun 21, 2014 7:29 pm ]
Post subject: 
The fact remains, the OP NEEDS a dual master cylinder. I have been in the position of blowing a brake line with a single pot and even with a working "emergency" brake it was just blind luck I didn't crash. Besides, the hand brake isn't designed to stop the car, it is for holding it while parked.

Disc brakes were mandated on cars for a very good reason. Having owned a drum brake 1966 Valiant and a 1976 Duster at the same time, the Duster stopped better hands down.

I raced the '66 with 9" front drums and 11" rear drums and it was a thrill ride getting it stopped after it started going aster than 90 in the 1/4. With 10"/11" it got better, but still nowhere as good as a disc brake car.

For driving around town at low/moderate speeds drum brakes are still very adequate. But out on the expressway they can tend to be a white-knuckle ride.

Yes, the disc brakes on big trucks in the '80's/90's were a dismal failure, mainly because it was impossible to control an air applied caliper, and keep them from corroding and sticking the pistons.
Author:  63Valiant [ Sat Jun 21, 2014 8:14 pm ]
Post subject: 
You'll get no argument from me there, the dual chamber master cylinder is a win/win no matter what brakes you have, and too easy an upgrade not to do.

That upgrade is high on my 'to do' list on the '63.
Author:  AndyZ [ Sat Jun 21, 2014 9:27 pm ]
Post subject: 
I have had a total brake fade and failure in a 66 Barracuda with 9" drums and it was almost the end of me and the car. I agree that good driving habits need to be practiced according to the car you are running. As time goes on, drums are more archaic and dangerous on the highway, especially in denser traffic areas. I think that 20% stopping distance figure is probably a generous number, especially when you add in avoidance swerving, adverse road conditon, rain etc.
Back in the 60's, drums were fine and the Dart, Valiant Barracudas were great performers, especially compared to the Chevy II and the Falcons, but today, if I were planning on building a daily driver, I would upgrade my brakes first to protect my investment.
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