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Front axle (2WD) disc brake conversion
Posted: Sat Feb 04, 2023 1:53 pm
by PickupPete65
Hi to all and Happy New Year...
I would like to covert my 1965 D100 front drum brakes to disc brakes. Any and all feedback, recommendations, experiences, etc., are welcome. I really love driving it. The single stage brake master cylinder often leaves me feeling like I'm always a split second from a potential braking mishap...that may not end well. Thanks, and have a nice day.
Re: Front axle (2WD) disc brake conversion
Posted: Sat Feb 04, 2023 6:25 pm
by BigBlockTrucks
Check with scarebird for brackets to build your own,or the ram man for a complete kit.
Re: Front axle (2WD) disc brake conversion
Posted: Sat Feb 04, 2023 8:49 pm
by my5thmopar
Do your research before buying either and there are several posts here. Search function is your friend. I have Scarebird and I had no issues with the drums. I think they actually worked better than the disk. If you hit the brakes hard, it would about throw me through windshield. If the dropped axle I got from a friend didn't already have Scarebird, I probably wouldn't have done the swap. Craig
Re: Front axle (2WD) disc brake conversion
Posted: Sun Feb 05, 2023 8:58 am
by chilort
Scarebird says they're going out of business. I've got the older setup that doesn't use the metric caliper. Wish I had the newer setup since there are so many more caliper (Wilwood) and pad options. Best bet is going to be trying to find the backing plates used if you want to go that route.
I did the conversion years ago. My biggest complaint was the crummy master cylinder I bought. It never seemed right and the pushrod length (even though a Dodge master cylinder) was wrong. I've recently converted to a Wilwood aluminum MC, rebuilt my lines with nickel copper tube, and worked to get the pushrod length correct. I've yet to drive it but the pedal feel is better just sitting in the garage
Re: Front axle (2WD) disc brake conversion
Posted: Sun Feb 05, 2023 3:28 pm
by martincom
I'm still running the stock drums on my '71 D100 and they perform great. So, I'm of the same thought as my5thmopar, that you really don't need to migrate to disc brakes. Moreover, drum brakes actually have more braking power due to their much larger contact area and the self-energizing action. Where disc brakes shine over drum brakes is heat fade. The rotor can dissipate heat much faster than a drum.
I salute you on your move a dual master cylinder. It is one of the best safety improvements you can make. As you'll be replacing the master cylinder no matter what you choose, I'd add the vacuum booster at the same time. However, this gets complicated if you have a hydraulic clutch, which I'm going to guess you likely do. I'm pretty sure the Ram Man has the offset brackets and everything you would need for either a drum or disc brake master cylinder.
Of course, at this point, you hate to expend dollars on a drum brake master cylinder if you decide to add discs later, not to mention the brake line work. Just how deep you want to dive into you wallet will probably be the deciding factor.
Re: Front axle (2WD) disc brake conversion
Posted: Mon Feb 06, 2023 6:22 am
by Series1Utiline
chilort wrote: ↑Sun Feb 05, 2023 8:58 am
Scarebird says they're going out of business. I've got the older setup that doesn't use the metric caliper. Wish I had the newer setup since there are so many more caliper (Wilwood) and pad options. Best bet is going to be trying to find the backing plates used if you want to go that route.
I did the conversion years ago. My biggest complaint was the crummy master cylinder I bought. It never seemed right and the pushrod length (even though a Dodge master cylinder) was wrong. I've recently converted to a Wilwood aluminum MC, rebuilt my lines with nickel copper tube, and worked to get the pushrod length correct. I've yet to drive it but the pedal feel is better just sitting in the garage
Are they selling anything now or are they just "planning" to stop the business in the future? You mentioned finding "backing plates". Do you mean caliper brackets?
Re: Front axle (2WD) disc brake conversion
Posted: Mon Feb 06, 2023 6:34 am
by chilort
Yes, brackets. I tried to get the updated brackets and they said they're going out of business and no longer have them
Re: Front axle (2WD) disc brake conversion
Posted: Mon Feb 06, 2023 1:19 pm
by Wildergarten
martincom wrote: ↑Sun Feb 05, 2023 3:28 pm
I'm still running the stock drums on my '71 D100 and they perform great. So, I'm of the same thought as my5thmopar, that you really don't need to migrate to disc brakes.
It only takes one experienceof brake fade due to heat carrying a really heavy load to bring doubt to this conclusion. I could have died towing a pavement roller because the rental trailer had surge brakes and I didn't have enough braking left in the truck to actuate them. I'll never forget as long as I live that experience, heading downhill at over 40mph screaming at the roadway ahead hoping nobody would cross below me. And that wasn't the only near thing I experienced in that truck due to brake fade. Yet for the record, the vacuum booster on that truck was inoperable.
Never again. You may be right, but I'm not taking that chance in the build I'm doing now.
Re: Front axle (2WD) disc brake conversion
Posted: Wed Feb 08, 2023 1:23 am
by johnah
I have a rebuilt low miles complete front axle from my 1970 d100 that I would let someone have at a good price. Has scarebird disc brakes and the king pins have about 10,000 miles on them. These were road miles traveling back and forth from FL to Co for my summers. I have a post of them on Sweptline Facebook. Check them out, if I can help give me a shout. Just would like to help out.
Re: Front axle (2WD) disc brake conversion
Posted: Fri Feb 10, 2023 7:22 am
by Series1Utiline
It would be nice to be able to get some specs on the new brackets but as mentioned, that would likely only happen when someone is able to get a set and copy them. I wasn't even aware they had come out with a 2nd design that used other caliper assemblies.
The main problem with the earlier Scarebird package (that most of us appear to have), is the use of the GM "low-drag" calipers. This was a design that GM came up with that would cause the pads to retract further away from the disc at rest so as to avoid drag. This was mainly done as a fuel mileage benefit. What was never communicated in using this caliper assembly in an aftermarket application is that the correct master cylinder needs to be used, not just in terms of diameter but more importantly of the correct bore design. A master cylinder designed for the GM low-drag caliper requires a "take-up" cylinder that has a larger diameter step in the bore, created to allow more volume at the initial press of the brake pedal in order to get the pads to move out quickly and meet the disc. Once the pads have med the disc, the master cylinder piston is in the 2nd (smaller) diameter section of the bore and functions normally at that point.
If anyone is wanting to change to a "take-up" master cylinder, an 80s S-10 a match for these calipers.
Re: Front axle (2WD) disc brake conversion
Posted: Fri Feb 10, 2023 8:11 am
by johnah
All good info, the Scarebird kit I installed was purchased from a member on this forum. He had bought it and never installed the kit. It did include Scarebird hubs and as I remember there was a bearing seal missing from the kit by the time I got it. Had to do some figuring to get the right one. Keep in mine, this was 2015 that I did the install. I ran those brake across country at least 3 times. From FL to Co and back, twice to CA from Co. they worked better than the drums but I always thought they could be better. I’m running the Ram man brakes now they do seem to perform a little better.
This is a parts list that works on the Scarebird brackets:
Calipers RC4416 (L) RC 4415(R). Chevy C1500 (1990)
Rotors. 66492R. Ford Crown Vic 11.45”
P.S. at least the kit I’m running
Re: Front axle (2WD) disc brake conversion
Posted: Fri Feb 10, 2023 10:41 am
by mopar
Thanks for posting the chev and ford part numbers.
It did include Scarebird hubs and as I remember ...
are the Scarebird hubs Scarebird manufactored, Scarebird modified, or something else?
Re: Front axle (2WD) disc brake conversion
Posted: Fri Feb 10, 2023 4:52 pm
by BigBlockTrucks
I used the scarebird brackets on my 60 d100. The original hubs fit in the rotors and work fine.
I don’t know what year they started making them differently.
The other option is to put your original hubs on a lathe and turn them down to fit.
Re: Front axle (2WD) disc brake conversion
Posted: Fri Feb 10, 2023 5:03 pm
by BigBlockTrucks
Series1Utiline wrote: ↑Fri Feb 10, 2023 7:22 am
It would be nice to be able to get some specs on the new brackets but as mentioned, that would likely only happen when someone is able to get a set and copy them. I wasn't even aware they had come out with a 2nd design that used other caliper assemblies.
The main problem with the earlier Scarebird package (that most of us appear to have), is the use of the GM "low-drag" calipers. This was a design that GM came up with that would cause the pads to retract further away from the disc at rest so as to avoid drag. This was mainly done as a fuel mileage benefit. What was never communicated in using this caliper assembly in an aftermarket application is that the correct master cylinder needs to be used, not just in terms of diameter but more importantly of the correct bore design. A master cylinder designed for the GM low-drag caliper requires a "take-up" cylinder that has a larger diameter step in the bore, created to allow more volume at the initial press of the brake pedal in order to get the pads to move out quickly and meet the disc. Once the pads have med the disc, the master cylinder piston is in the 2nd (smaller) diameter section of the bore and functions normally at that point.
If anyone is wanting to change to a "take-up" master cylinder, an 80s S-10 a match for these calipers.
Are there other vehicles Chevy used this “take up” master cylinder on?
The master cylinder and booster I used was from a 93 camaro. And I used an adjustable pressure regulator for the rear discs. The truck stops better than any 60s era vehicles I have driven.
Re: Front axle (2WD) disc brake conversion
Posted: Fri Feb 10, 2023 5:31 pm
by Series1Utiline
Yes there are others although I'm not clear on what other models and years. You can often tell by the external appearance as in the picture below. The cylinder is larger at the firewall (flange) end which is the "take-up" volume.
Re: Front axle (2WD) disc brake conversion
Posted: Tue Feb 14, 2023 4:03 pm
by chilort
Series1Utiline wrote: ↑Fri Feb 10, 2023 7:22 am
It would be nice to be able to get some specs on the new brackets but as mentioned, that would likely only happen when someone is able to get a set and copy them. I wasn't even aware they had come out with a 2nd design that used other caliper assemblies.
The main problem with the earlier Scarebird package (that most of us appear to have), is the use of the GM "low-drag" calipers. This was a design that GM came up with that would cause the pads to retract further away from the disc at rest so as to avoid drag. This was mainly done as a fuel mileage benefit. What was never communicated in using this caliper assembly in an aftermarket application is that the correct master cylinder needs to be used, not just in terms of diameter but more importantly of the correct bore design. A master cylinder designed for the GM low-drag caliper requires a "take-up" cylinder that has a larger diameter step in the bore, created to allow more volume at the initial press of the brake pedal in order to get the pads to move out quickly and meet the disc. Once the pads have med the disc, the master cylinder piston is in the 2nd (smaller) diameter section of the bore and functions normally at that point.
If anyone is wanting to change to a "take-up" master cylinder, an 80s S-10 a match for these calipers.
Wild, I didn't know that about the master cylinder. Would explain part of why I always felt the travel was way too far for these brakes. I nearly bought a MC with a larger bore diameter. Not that it is the same as a take up master cylinder, but might have helped.
The "metric" caliper has a smaller swept area for the pad. So, in some ways, I'm not totally disappointed that I've got the older setup. The option for a 4 piston Willwood caliper, on the other hand, would have been great.
Re: Front axle (2WD) disc brake conversion
Posted: Thu Apr 06, 2023 3:06 pm
by IHWillys
Here's a link to the thread here that I posted in about a pirated version of the RamMan setup:
viewtopic.php?f=20&t=44080
Re: Front axle (2WD) disc brake conversion
Posted: Thu Oct 12, 2023 7:20 pm
by longbed67
I bought the scare bird kit purchased the parts on the list.
So far it’s been great