Slant Six Forum
https://slantsix.org/forum/

Are finned 9 inch brakes adequate for "normal" dr
https://slantsix.org/forum/viewtopic.php?t=26589		 Page 3 of 4
Author:  HyperValiant [ Sat Jan 12, 2008 2:59 pm ]
Post subject: 
OK Fellas,Ive just been letting this thread hang out and collect opinions and I guess that I will check into the Scarebird setup or find a set of K-H disks and go from there.
Thanks for the opinions
HyperValiant
Author:  Sam Powell [ Mon Jan 14, 2008 4:48 am ]
Post subject: 
How big is your daughter? This Dart was originaly purchased for my older daugher when whe was 16. She could NOT stop the car. She is a small girl, and had trouble reaching the brake pedal and seeing over the steering wheel at the same time. She drove the car once and it was determined this was MY car, and we gave her my minivan. My wife tried moving the car in the driveway once, and almost drove the car out into the road because it did not stop as fast as she thought it would. She has never driven it again.

This car came with 9" brakes, and 13" wheels and tires. Driving it was a frightening experience, not for the faint of heart. Not only did it have a mind of its own about which direction it wanted to go when you hit the brakes, when you changed lanes you never were sure which lane you were going to be in when it stppped changing. White knuckles does not begin to explain it. That being said, I did drive it for a year before I converted it. Just changing to 14" wheels was a big improvement. But I was an experienced adult driver, familiar with older cars.

If, as Dan says we push whatever vehicle to the limit of our acceptable danger, or risk level, which I believe is true, then I could be driving this car at 95 most of the time and not approach the risk involved with the stock parts.

I would never put MY daughter in a car with 9" drums. They MIGHT be fine for an experienced older driver, but not my kid.

Sam
Author:  Dart270 [ Mon Jan 14, 2008 6:37 am ]
Post subject: 
Hyper,

I would seriously go for the 73-up discs. The KH's work fine, but are expensive and the newly made pads for them are hard and make for stiff pedal. I have them on my 68 Dart and will likely pull them and swap to later model stuff, partly cause I want BBP too.

BTW, I just saw a 73-up Dart near Pembroke, VA in the backwoods that could be a good donor car for brakes. Email me if you want to know where it is.

Lou
Author:  emsvitil [ Tue Jan 15, 2008 5:21 pm ]
Post subject: 
The advantage of larger diameter brakes isn't really in the swept area.........

It's in leverage. The farther you are away from the axle (or the closer to the tire tread) the more leverage you have.

All else being equal (same wheel cylinder size, same master cylinder size, same shoe area, same swept area), a 10" drum would be (10/9) or 111% the effectiveness of a 9" drum.... (11% better)

(For disks use the avg radius (distance to center of pad))
Author:  Romeo Furio [ Wed Jan 16, 2008 2:31 pm ]
Post subject: 
For any one that wants to stay with 9" drums I found this guy at Carlisle ( he is there every year) that has NOS brake shoes that are riveted that work better than any auto parts stores have now. I have had 4 sets of Carquest bonded shoes that have come apart. Anyway back to this guy,, Moblie Parts " The Antique Automotive King " Covering 1941 to 1970.
Craig Studnick 516-485-1935 I think that's NY. I have bought many brake parts and suspension parts for a great price. I needed 11"x3" riveted shoes for a 67 R/T and he had them for $35 bucks a set new in Mopar boxes. Just something to think about.
Author:  Valleyant [ Wed Jan 16, 2008 4:28 pm ]
Post subject: 
That is good news Romeo! Thanks for the info...My '72 daily driver will be keeping the 9 inch brakes all around...I went through and replaced almost everything and they work just fine for me...they did take some getting used to as I was accustomed to my '03 PT GT Cruiser that has 4 wheel disc....no comparison :shock: , I commute to work a total of 20 miles and since the Valiant will not have much more power than stock and has only 45,000 original miles I can live with the 9" brakes. I do plan to open the exhaust a little and get some insight on recurving the distributor for some extra grunt but that is about it, it's turning out to be a fun and practical package...the news about the source for NOS shoes is great... will get a couple sets if possible...My '70 Duster however will get a hopped up Slant Six and it has 10'ers all around so I will upgrade them...maybe muscle car brakes stuff...I have just heard about them....Thanks again, Romeo, for the news and do you still have DustYa? Thanks, Nico
Author:  Valleyant [ Wed Jan 16, 2008 4:31 pm ]
Post subject: 
OOPS did I say That? The 70 Duster has 10 inch drums all around :oops:
Nico
Author:  dakight [ Wed Jan 16, 2008 4:36 pm ]
Post subject: 
For what it's worth, swept area on a 10 x 2.5 drum is 78.54 sq in, rounded to 2 decimal places. Swept area for a 9 x 2.5 drum is 70.69 sq in, a difference of more than 10% which I would judge to be significant.
Author:  Romeo Furio [ Wed Jan 16, 2008 6:20 pm ]
Post subject: 
Dust'ya now belongs to Reggie Jackson. Sold it in '04.
Author:  dlthomas [ Thu Jan 17, 2008 2:57 pm ]
Post subject:  9"drums
I have driven both a 318 and a 360 v8 powered '64 dart around Memphis in traffic with 9" stock drum brakes. I currently have a slant 6 dart with the same brakes. I tend to agree with most that has been said above.

They are perfectly comfortable for me provided the driver knows their limitations and drives defensively or otherwise like a sane person! Just because the one Dart had a 360 didn't mean I tried to race in traffic like some!

I insist that they are adequate, but I, like many persons above,have and will always upgrade when the opportunity arises.

The issue of other drivers darting in front of you and then braking suddenly is probably the most serious issue. Some idiot did this on one of those low slung Jap motorcycles- jumped in front of my 4000 lb '57 Desoto (with stock 10'drums and no power booster) and was lucky I could veer into the road shoulder!
Author:  DionR [ Thu Jan 17, 2008 4:37 pm ]
Post subject: 
Quote:
Dust'ya now belongs to Reggie Jackson. Sold it in '04.
Does he have an orange '71 340 Duster with an Airgrabber hood and strobe stripes as well? Seems like that is the guy that bought my brothers Duster, but don't remember for sure. Must like Dusters if he is.

Sorry, back to the topic at hand.
Author:  AnotherSix [ Thu Jan 17, 2008 11:19 pm ]
Post subject: 
The 9" brakes don't really work that great. Not having crashed with them is not braking performance data. They do not become wonderful in the hands of an "expert driver". Even if they did, imagine how great a good disk setup would be with the same driver.

If it takes 20 more feet to stop from 60 mph, then someday it just might make a huge difference. I suspect the spread between a disk setup and a 9" drum setup might be more than that.

My 65 Dart had a 273 with 10" drums and 13" wheels. There was no air tight seal between the wheels and drums. Stopping was night and day better than our Swinger was with 9" drums. No amount of misunderstanding or supposing will put the 9" drums on par with the 10" drums.

Now the Swinger has a BBP disk setup and it stops FAST.

Yes you can drive any of these setups. The drums are no match for the stopping distance and control that disks provide. They simply can stop much quicker without locking up. They work better when wet too.

With drum brakes, I would make sure they are in very good condition, and avoid heavy freeway traffic. No matter how careful you are, you can't keep the idiots from doing what they do.
Author:  66aCUDA [ Fri Jan 18, 2008 7:57 am ]
Post subject: 
I guess my big deal with this is being complacent. Even my truck now has 4 wheel discs. So the reaction time you are used to needing is WAY different. When I first drove and older drum car for the first time in years, I thought the brakes were bad. After driving a friends 100% restored a body I realized that there was no problem with the brakes condition. Makes you stop and think and I like that.
Frank
PS I too am going disc on my DD
But not on the race cars
Author:  slantzilla [ Fri Jan 18, 2008 8:15 am ]
Post subject: 
When I was still driving the '66 on the street with 9" drums I learned to leave myself an "appropriate" amount of space on the tollway. New cars can stop a lot faster than old cars. :lol:
Author:  AnotherSix [ Fri Jan 18, 2008 8:29 am ]
Post subject: 
On a drag only car I would keep the 9' drums and use the softest (cheap) shoes available. They hold best when cold for launching. It is also a common trick to remove the adjusters so you can set the shoes so they do not drag at all, and live with more pedal travel. It's not a big deal on a drag car to adjust the brakes every now and then. Of course I am not talking about a 3500 lb car that runs well over 100 in the quarter.

I wanted to weigh the 9" setup with spindles and upper a-arms to compare it to the weight of the BBP setup, but ended up not having a scale where I did the work. The 9" setup did weigh more, by feel, than I expected.
Page 3 of 4 All times are UTC-08:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/