Brake questions

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Rorschach81

Rorschach81

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Hey folks, I've been looking through the forms to see if anyone has already answered this question but I haven't found what I was looking for. I have a 1970 Dodge Dart Swinger with drum brakes all the way around .The car does not have power brakes .I want to upgrade my front brakes to discs. Do I need to install power brakes for that? Also what size would I want and who is a good distributor for something like that?
 
No, they don't have to be power, I do not have power on my 71 demon and they work fine.

IMG_20180912_165856.jpg
 
drum brakes are what they call self-energizing in that when the shoes contact the drum, the spinning motion of the drum tends to decrease the pedal effort required as the car slows down.
Disc brakes do not have this type of behavior. So they often have a booster to compensate for the extra leg-power required.
The power-assist does make it a lil easier to modulate the brake application.
Light-weight A-bodies can get away without a booster, however
personally, I like a small diameter MC with a booster for it's excellent road manners.
 
Something important to note that hasn't been brought up yet. If you have a 4 wheel drum '70 Dart you also have the small bolt pattern, 5x4". If you want to keep that bolt pattern, you have fewer options for front disk brakes. If you're going to upgrade to the large bolt pattern (5x4.5"), then you'll also need to convert the rear brakes and axles.

There are a couple of disk kits out there that allow you to keep the SBP, but even some of those kits won't work with the original small bolt pattern drum brake rims (the center register for those wheels is too small for some kits). So even if you use a SBP disk brake kit you may have to buy new wheels.

It also makes a difference what drum brakes you have now, the 9" drums and 10" drums have different spindles. So depending on which spindle you have your options will be a little different (if you keep your current spindles).

There are a ton of threads on FABO about disk brake conversions and the different kits available. First you should decide if you want to keep the SBP or upgrade to LBP, then do a search on disk brake conversions.
 
AJ/FormS said:
drum brakes are what they call self-energizing in that when the shoes contact the drum, the spinning motion of the drum tends to decrease the pedal effort required as the car slows down.
Click to expand...
Which gets to a very important point @Rorschach81
When you say you would like to upgrade, what is it you don't like about the brakes now?
If it relates to braking effort, then switching to disks of a similar diameter and braking area will require more effort than the current drum set up.
 
72bluNblu said:
Something important to note that hasn't been brought up yet. If you have a 4 wheel drum '70 Dart you also have the small bolt pattern, 5x4". If you want to keep that bolt pattern, you have fewer options for front disk brakes. If you're going to upgrade to the large bolt pattern (5x4.5"), then you'll also need to convert the rear brakes and axles.

There are a couple of disk kits out there that allow you to keep the SBP, but even some of those kits won't work with the original small bolt pattern drum brake rims (the center register for those wheels is too small for some kits). So even if you use a SBP disk brake kit you may have to buy new wheels.

It also makes a difference what drum brakes you have now, the 9" drums and 10" drums have different spindles. So depending on which spindle you have your options will be a little different (if you keep your current spindles).

There are a ton of threads on FABO about disk brake conversions and the different kits available. First you should decide if you want to keep the SBP or upgrade to LBP, then do a search on disk brake conversions.
Click to expand...
Those are very important things to consider that I hadn't thought of. Thank you very much! I obviously need to do more research.
 
Mattax said:
Which gets to a very important point @Rorschach81
When you say you would like to upgrade, what is it you don't like about the brakes now?
If it relates to braking effort, then switching to disks of a similar diameter and braking area will require more effort than the current drum set up.
Click to expand...
it's not so much the braking effort as it is constantly having to adjust the brakes. I also like the look and ease of maintenance of discs.
 
Rorschach81 said:
it's not so much the braking effort as it is constantly having to adjust the brakes. I also like the look and ease of maintenance of discs.
Click to expand...
Truth is they all can be a PIA. 4 piston calipers, sliders, drums all have their hangups. Drums are just a bit more complicated and I agree, changing pads is usually a lot easier than changing shoes.
You should not have to do much adjusting on the drum brakes if everything is working right. The self adjusters should do most of it. So while you're looking into front calipers, you might see what can be done to improve the drum self adjusting. It will still apply to the rear brakes even when you do switch. The rear brakes are most important early, before weight shifts forward. So they effect initial feel and response more than many people realize.
This is a pretty good pamphlet for the '69 up style shoes and adjusters.
Drum Brake Service Highlights (Session 260) from the Master Technician's Service Conference

The ref to early adusters in the above pamphlet still refers to the '69 up system. TSB for the change is here:
The 1970 Hamtramck Registry "1969 DODGE MODEL TSBs Index" Page

This booklet covers the Kelsey Hayes 4 piston (fixed caliper) system used on A-bodies through 1972. I think it provides a pretty good overview which is useful even if you don't go with the factory system.
1967 Imperial & Chrysler Disc Brake System - Session 233
 
Mattax said:
Truth is they all can be a PIA. 4 piston calipers, sliders, drums all have their hangups. Drums are just a bit more complicated and I agree, changing pads is usually a lot easier than changing shoes.
You should not have to do much adjusting on the drum brakes if everything is working right. The self adjusters should do most of it. So while you're looking into front calipers, you might see what can be done to improve the drum self adjusting. It will still apply to the rear brakes even when you do switch. The rear brakes are most important early, before weight shifts forward. So they effect initial feel and response more than many people realize.
This is a pretty good pamphlet for the '69 up style shoes and adjusters.
Drum Brake Service Highlights (Session 260) from the Master Technician's Service Conference

The ref to early adusters in the above pamphlet still refers to the '69 up system. TSB for the change is here:
The 1970 Hamtramck Registry "1969 DODGE MODEL TSBs Index" Page

This booklet covers the Kelsey Hayes 4 piston (fixed caliper) system used on A-bodies through 1972. I think it provides a pretty good overview which is useful even if you don't go with the factory system.
1967 Imperial & Chrysler Disc Brake System - Session 233
Click to expand...
your awesome! Thank you very much! The information links you sent will come in handy.
 
AJ/FormS said:
Fix the automatic self adjusters?
Click to expand...
I've replaced the auto adjusters and everything in the brakes a few times, it still won't adjust correctly and still pulls hard to the left when I brake. With the engine I have in it now, I need more breaking power. And I'm sick of dealing with the drums.
 
I am a streeter and
I have had great success with the KH 4 piston set-up, and silicon fluid. Zero maintenance since 1999 when I installed them.
I run 235/60-14s up front on 7.5" aluminum rims. and I run the 10x2 rear drum brakes,with 295/50-15s on 10" rims,and with NO brake proportioning.
The drums are also zero maintenance. The rear brakes do a lot more work now with zero proportioning, and the car has excellent stopping manners.
I run a manual trans and with nearly 11/1 Scr, she has a lotta compression braking.
________________
In 125,000 miles I have replaced the rear shoes exactly once, and the fronts not at all.
By running the front wheel bearings on the loose side of the spec, I get just enough knock-back to be able to coast nearly a mile from 65 to 25, in neutral. From 25 to zero is also a very long distance,but putting it into first gear gets me 3400 rpm, and at closed throttle,it slows down in a hurry. Then I brake for a couple of feet.
I live in the country, so not a lotta brake action going on, until I get to the City. And in the City, the speed limit is 30mph, and there is rarely traffic, so again very little brake useage. And in the City, I usually behave myself.
Gosh, I haven't even looked at the brakes for maybe a decade or more. Hmmmmmmmm
 
AJ/FormS said:
I am a streeter and
I have had great success with the KH 4 piston set-up, and silicon fluid. Zero maintenance since 1999 when I installed them.
I run 235/60-14s up front on 7.5" aluminum rims. and I run the 10x2 rear drum brakes,with 295/50-15s on 10" rims,and with NO brake proportioning.
The drums are also zero maintenance. The rear brakes do a lot more work now with zero proportioning, and the car has excellent stopping manners.
I run a manual trans and with nearly 11/1 Scr, she has a lotta compression braking.
________________
In 125,000 miles I have replaced the rear shoes exactly once, and the fronts not at all.
By running the front wheel bearings on the loose side of the spec, I get just enough knock-back to be able to coast nearly a mile from 65 to 25, in neutral. From 25 to zero is also a very long distance,but putting it into first gear gets me 3400 rpm, and at closed throttle,it slows down in a hurry. Then I brake for a couple of feet.
I live in the country, so not a lotta brake action going on, until I get to the City. And in the City, the speed limit is 30mph, and there is rarely traffic, so again very little brake useage. And in the City, I usually behave myself.
Gosh, I haven't even looked at the brakes for maybe a decade or more. Hmmmmmmmm
Click to expand...
WOW! Sounds like that's what I need to look into! I live the the Denver metro area (unfortunately) so braking is a constant...
 
The single-piston floating-caliper is much easier to find and therefore to purchase, plus normal-wear parts are still available at the jobber. It just takes a lil longer to replace pads, and the sliders need to be serviced on occasion, plus eventually the slideways will need repairing. Sometimes the calipers stick and wear out the pads in a hurry, so you have to be alert.
The KHers are fixed calipers and do not suffer any of those problems, especially with the non-hydroscopic silicon fluid.
 
AJ/FormS said:
The single-piston floating-caliper is much easier to find and therefore to purchase, plus normal-wear parts are still available at the jobber. It just takes a lil longer to replace pads, and the sliders need to be serviced on occasion, plus eventually the slideways will need repairing. Sometimes the calipers stick and wear out the pads in a hurry, so you have to be alert.
The KHers are fixed calipers and do not suffer any of those problems, especially with the non-hydroscopic silicon fluid.
Click to expand...
The less maintenance, the better. Think I'll go with the KHers. Thanks!
 
I think you can buy "fixed caliper brake kits" now. KHers are getting scarce and pricey.
I still recommend them as they are great street brakes. They have more power than 235s can deal with, which is why I tuned my rear brakes to take up the slack. Now I have a worthy stopper that keeps me out of trouble. And the thing about working rear brakes and 295s is this; I now have sideways brakes too. So if the car is setting up to get away on me and slide into a curb I got an option that doesn't always involve opening my wallet for wheel repairs.
 
Oh really? I didn't realize those were becoming more of a rare find. How would you rate fixed Cali brake kits? Good enough? You are obviously someone with a lot more knowledge than me.
 
Rorschach81 said:
Oh really? I didn't realize those were becoming more of a rare find. How would you rate fixed Cali brake kits? Good enough? You are obviously someone with a lot more knowledge than me.
Click to expand...
I have no personal experience with kits, only with the oem Mopar stuff, which, IMO, is perfectly adequate for a streeter.. I prefer the fixed calipers on account of I've been driving them for a few decades with no problems. All my other Mopars have been floating caliper cars, and they do Ok in their applications. You can retro-fit the 73 up system pretty easily and that system was in production for decades,on all kinds of Mopars,so their are plenty of cars to pluck one from. FMJs and Darts are easy pickings.
 
AJ/FormS said:
I have no personal experience with kits, only with the oem Mopar stuff, which, IMO, is perfectly adequate for a streeter.. I prefer the fixed calipers on account of I've been driving them for a few decades with no problems. All my other Mopars have been floating caliper cars, and they do Ok in their applications. You can retro-fit the 73 up system pretty easily and that system was in production for decades,on all kinds of Mopars,so their are plenty of cars to pluck one from. FMJs and Darts are easy pickings.
Click to expand...
I find quite a few of the old A bodies in the pick and pull lots that I go too. I'll keep an eye out. Thanks again!!
 
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