kelsey hayes vs f/m/j swap

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Supertrooper455

Supertrooper455

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I have a couple of questions that i hope someone might have some answers to.

First off, on my demon i have what i believe to be the kelsey hayes disk brakes on the front, and stock drums on the rear. Are this brakes adequate enough to stop this car? My uncle always complained how they were not up to par with his standards

Can i get more braking power out of the f/m/j swap, or is the kelsey hayes about as good as i can get?

I dont really want to look at the expensive conversion kits for the drum spindles because i plan on eventually getting the alterkation k member, so cost efficiency is definitely a factor.
So in short, should i just rebuild the kelsey hayes system or go the the f/m/j spindles and calipers
 
Cost to rebuild the KH ain't cheap. The BBP setup is pretty cheap to do plus if you are going rms down the line you'll need BBP anyway.
All that said you can just rebuild what you have and sell the KH later when you get your rms stuff.
 
Cant you get moser rear axles to have a matching bolt pattern front to back if you do the f/m/j swap
 
Yes moser strange Yukon all sell BBP axle in a body length, you'll also want to upgrade to b body brakes. The biggest is think a 11x3 but you'll find 11x2.5 easier to find.
 
The K-H disk brakes are great. They were used on high-end Mustangs the same years too. The fixed 4-piston calipers is considered better than sliding calipers, and preferred by racers. A member here (near me) rebuilds the K-H brake systems as a sideline. You can also get rebuilt calipers from rockauto and new disks are now very reasonable (Centric brand).

I don't understand why your uncle thought those brakes couldn't stop the car. The ultimate limit is when the tires skid and even 9" drum brakes can easily skid the tires. The advantage of bigger drums is they can absorb more heat, so can handle higher-speed braking better. The advantage of disks is that they cool faster, especially those w/ internal passages and fins that act like a fan. That allows quicker recovery for things like constant braking in road-course racing. Front disks were mandated by the feds ~1973 because too many drivers didn't understand how to use the engine to brake the car on downhill runs, thus overheating the brakes and going off cliffs. Disks can give more even braking because drum brakes are more sensitive to changes in friction such as from oil or leaking brake fluid. Disks don't have the amplifying effect of drum shoes, so take more force on the pedal, thus vacuum boosters are more common though many A owners say they aren't necessary.
 
BillGrissom said:
The K-H disk brakes are great. They were used on high-end Mustangs the same years too. The fixed 4-piston calipers is considered better than sliding calipers, and preferred by racers. A member here (near me) rebuilds the K-H brake systems as a sideline. You can also get rebuilt calipers from rockauto and new disks are now very reasonable (Centric brand).

I don't understand why your uncle thought those brakes couldn't stop the car. The ultimate limit is when the tires skid and even 9" drum brakes can easily skid the tires. The advantage of bigger drums is they can absorb more heat, so can handle higher-speed braking better. The advantage of disks is that they cool faster, especially those w/ internal passages and fins that act like a fan. That allows quicker recovery for things like constant braking in road-course racing. Front disks were mandated by the feds ~1973 because too many drivers didn't understand how to use the engine to brake the car on downhill runs, thus overheating the brakes and going off cliffs. Disks can give more even braking because drum brakes are more sensitive to changes in friction such as from oil or leaking brake fluid. Disks don't have the amplifying effect of drum shoes, so take more force on the pedal, thus vacuum boosters are more common though many A owners say they aren't necessary.
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Dang, im thinking that just made my decision a whole lot easier. Kelsey Hayes rebuild it is, thanks man
 
Yep, I agree with Bill Grissom. The K-H brakes were a quality piece. Four-piston fixed calipers beat single-piston sliding calipers any day of the week. Rebuilt K-H calipers aren't that expensive when you have a core to exchange.
 
I'll second that. K-H brakes in good condition are good enough for track days. A couple tips: Summit Racing sells made-in-USA slotted crossdrilled rotors cheaper than the OEM replacement ones from who-knows-where. They also sell ceramic pads that really work great -- don't need to be warmed up like metallic pads.
 
:happy1:

This is great info-I have a set of KH stuff from a seller on here, and have been debating whether or not I want to go with the BB pattern...I think you may very well have added some weight to me keeping/rebuilding my KH stuff...I know I need new discs; they look heavily worn.
 
I have to disagree. While the KH brakes work well when they are working, over time, the pistons give trouble. They can get cocked in the bores and get stuck. Chrysler knew they were troublesome. That's why they went to a single piston setup. Nine times out of ten, if you jump to something newer, it's also better. Yup, you can make the K/H brakes work great. I've had them myself. I have a set of FMJ police brakes I plan on putting on my 63 now. No way in the world would I look for some 40 plus year old designs to stop my car with now.
 
RustyRatRod said:
I have to disagree. While the KH brakes work well when they are working, over time, the pistons give trouble. They can get cocked in the bores and get stuck. Chrysler knew they were troublesome. That's why they went to a single piston setup. Nine times out of ten, if you jump to something newer, it's also better. Yup, you can make the K/H brakes work great. I've had them myself. I have a set of FMJ police brakes I plan on putting on my 63 now. No way in the world would I look for some 40 plus year old designs to stop my car with now.
Click to expand...

Does you know if this problem would still persist if i went and got entirely new calipers from rock auto?
 
K H brakes work great. Chrysler went to the single piston because it was cheaper not better. The only pro is the large bolt pattern.
 
Supertrooper455 said:
Does you know if this problem would still persist if i went and got entirely new calipers from rock auto?
Click to expand...

I'm just speaking from experience. What I've actually seen. The original K/H pistons were made from bakelight. Stainless replacements ain't cheap. If you buy reman calipers with stainless replacement pistons they are even more not cheap. For my money, I like the single piston calipers. If you already have the K/H stuff, use it. But if you're contenplating a change to the larger bolt pattern, I would go with something different.

And yes, Chrysler changed to cut costs. But the design is cheaper to make, cheaper to provide parts for, cheaper to service, which makes the single piston caliper a better design.
 
If you want a 4 piston based caliper, buy a set of viper calipers. There isn't a chance in hell I'd ever use a set of KH calipers, but that's just me.
 
I would ask the question as to why do MOST High End Performance Cars , Motorcycles and Aftermarket H.P. Calipers are 4 to 6 Piston Calipers ? Super trooper 455 I would stay with and MY car has K/H Brakes. The only draw back I see and am dealing with now is Wheel selection. Hope my input helps.....:D
 
Nobody's doggin multi piston calipers.
 
RustyRatRod said:
I'm just speaking from experience. What I've actually seen. The original K/H pistons were made from bakelight. Stainless replacements ain't cheap. If you buy reman calipers with stainless replacement pistons they are even more not cheap.
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I'm the guy that member BillGrissom mentioned that rebuilds these Kelsey Hayes 4 piston brake systems to bring them back to operating condition, so other people can put them back into use on their cars.
FYI.
There is no such thing as a bakelight piston, original, to the Kelsey Hayes 4 piston brakes, for the Mopar cars, or the 65-67 Ford Mustangs, which used basically the same 4 piston KH calipers.
All are metal pistons.
Never heard of, never seen a bakelight piston.
Have no idea where that "rumor" ever came from, or started.
Also, the factory Superstock 68 Hemi Darts and Barracudas were equipped with these 4 piston KH disc brakes.
They stopped those cars quite well at the end of the quarter mile, and are very good braking system, even to this day.
The only thing different between the Superstock system, and the "street" cars was the Superstock cars used a rotor, that's for the 4 1/2 inch bolt pattern.
I would like to feel that i know a thing or two about these brakes, as i have been rebuilding them, and then selling them for the past 8 years or more.
I kept track, and i sold 25 of them to the Mopar people, during that time, plus others for the early Mustangs.
Ya, modern brakes have mutiple pistons in the calipers, so maybe technology is going back to the old days, which was wasn't bad to begin with, anyway.
Just my two cents on the subject, this morning.
JV.
 
I don't know if they're stainless or not, but Rock Auto sells replacement steel pistons for $12 a piece...that would make replacing them a little pricey, but at that point in time, just trading in your cores for a loaded set would make WAY more sense.
 
I know and you do some damned fine work too. But honestly, I'm not tryin to cause trouble here. I have seen first hand NON metallic pistons come out of original K/H calipers on many more than one occasion. Maybe they weren't bakelight, but they were not metal. Metal does not chip apart on the edges. These pistons were black and plastic like. I'm not slammin multi piston calipers here. RUn whatever you want. It is simply my own formulated opinion that the later style single piston caliper is better. It's what "I" prefer. That's all.

hemi71x said:
I'm the guy that member BillGrissom mentioned that rebuilds these Kelsey Hayes 4 piston brake systems to bring them back to operating condition, so other people can put them back into use on their cars.
FYI.
There is no such thing as a bakelight piston, original, to the Kelsey Hayes 4 piston brakes, for the Mopar cars, or the 65-67 Ford Mustangs, which used basically the same 4 piston KH calipers.
All are metal pistons.
Never heard of, never seen a bakelight piston.
Have no idea where that "rumor" ever came from, or started.
Also, the factory Superstock 68 Hemi Darts and Barracudas were equipped with these 4 piston KH disc brakes.
They stopped those cars quite well at the end of the quarter mile, and are very good braking system, even to this day.
The only thing different between the Superstock system, and the "street" cars was the Superstock cars used a rotor, that's for the 4 1/2 inch bolt pattern.
I would like to feel that i know a thing or two about these brakes, as i have been rebuilding them, and then selling them for the past 8 years or more.
I kept track, and i sold 25 of them to the Mopar people, during that time, plus others for the early Mustangs.
Ya, modern brakes have mutiple pistons in the calipers, so maybe technology is going back to the old days, which was wasn't bad to begin with, anyway.
Just my two cents on the subject, this morning.
JV.
Click to expand...
 
Again with the KH you'll have more maintaining to do with vs the single or a NEW 4 piston caliper (I'm not talking a reman KH but a new/modern viper caliper).
The more pistons allow more even pressure across the pad (pads a usually longer as a result). However even with the KH, if you don't have a big rotor to back it up, it is just pissing money away.
 
Thanks everyone for the feedback and discussion as it gave me more than enough info for me to base my decision off of. I'm going to just stick with the KH brakes and get the rebuilt caliper with those slotted and cross drilled rotors from summit.

Another question though, will those viper calipers bolt on to the KH caliper brackets?
 
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