joe_padavano

Well, the kit APPEARS to use the same caliper brackets and calipers as stock. In fact, their listing for the caliper bracket alone says that it is a "stock height bracket". It's not the rotors that hit the wheels, it's the calipers. If the calipers are in the stock location, 14" disc brake wheels will clear (despite what the disclaimer says in the ad). By the way, many people round off 10.75" to 11". Keep in mind that the difference is only 1/8" on the radius - 0.125".

Here's the link.

bowtiebrad

I have power drums on my cutlass and just replaced the M/C last year-the old one and the new one both r a double bowl M/C. Will it work with the parts from speedway to where i dont have to purchase another? just need a proportion valve for a 71-72? Also-do i have to remove the distribution block off the frame when i install prop valve or does it not matter-would hate to have to mess with rerouting all those lines. Car is covered up dont know part number of new M/C may have to dig n there n find it. Might just go buy new M/C at parts store n return later if its the same as what I just installed. Thanks guys

joe_padavano

Drum brake M/C:



Disk brake M/C:



The correct disk brake M/C runs about $22 at RockAuto. They are different for a reason.

txrob779

Joe,

Quick question please. So, did I read that, say on my 66, that has power drums AND a single bowl master cylinder if I use 1967 (or whatever) front discs I need to change both the booster and the M/C...and use an inline P vlve which is the simplest cost effective route?

joe_padavano

The single bowl M/C is not suitable for disc/drum systems, and more importantly doesn't have the extra safety margin of a split system. Unfortunately, you'll need a 1967-up booster as the length of the pushrod between the booster and M/C is different from 66 to 67.

Tedisthebestkingintheworl

Once again, within minutes I received like 30 replies. Y'all have began to make my search efforts for this truly exceptional care almost effort free and 99% of y'all's information turns out to be very accurate. I am very grateful for y'all and this forum. Thanks again.

Alex72cutty

Joe, I Have a proportion valve from a 72 cutlass that came with factory disc brakes. Will I still be able to mount this along the frame with my current factory plumbing lines?

joe_padavano

Please refresh my memory. What's your car and are you converting from drums? If you are asking about using the drum brake lines with a 1972 combo valve, you will likely need to do some minor rebending, as the ports on the combo valve are not at exactly the same locations as on the distribution block. Also, you may find that one or two of the ports will require an adapter due to different thread size.

boese1978

Curious why no comments about the Scarebird kits......I installed on my '68 but have yet to get it on the road....

joe_padavano

Well, because this thread is about the factory-style disc brakes. Parts for these are plentiful and frankly, I remain worried about aftermarket caliper mounts that are simply a plate without the ears that the factory brackets have to prevent the caliper from getting cocked on the rotor. If all you can find for a car is an aftermarket kit, that's one thing, but A-body disc parts pretty much grow on trees (sometimes it's good to have commonality with Chevies).

I also don't understand the need for a different kit for use with 14" wheels. Once again, the factory 10.75" rotors came with 14" wheels. I assume these 14" aftermarket kits are designed to clear the non-disk 14" wheels, but they use Honda-sized rotors and calipers with smaller pistons than the factory disks. Why even bother?

boese1978

Thanks for the informative reply!

Alex72cutty

Its a 72 cutlass that came with factory drums brakes.

txrob779

Hey Joe,

Will first generation F body spindles, backing plates, calipers, rotors and so on fit a 64-66 A Body?

I found the complete front disc parts and cannot seem to find what will fit and what wont?

It seems that SW kit 4642 says it will NOT work with 14# wheels.....hmm I guess I need to read the thread closer as I said before, I have 1970 SSI disc wheels....BUT it does say it will fit 67-69 F Body. (I read where you said this might work despite what the sales add says)

I am sure I will need to ask later about brake lines. Heck I have never made brake lines before so I am sure that will be a PIA.


Oh, 1 more question. Can you define using the combo/proportioning valve setup? I am confused about using the "early style" in-line valve w/stock distribution block or using the later combo valve. I am thinking the combo valve is the simplest setup is for me LOL....I mean I am searching and reading all over but man I cannot get my head around this as well as I had hoped. Embarrassing for sure but crap, I got no choice but to ask.
The way I see it I can just use the combo valve and mount it say, under the master and re plumb the lines from the master to the combo to the front flex lines? I have seen this done on a 67 Camaro recently. Is that about right?
Thanks

txrob779

but for the price of that Speedway Kit #4642 it makes no sense to use old cheap Camaro parts.

It also helps to READ closer LOL.....crikey

joe_padavano

Rob,

I don't know if this means that you got your answers or not, but all 1964-72 A-body, all 1967-69 F-body, and all 1968-74 X-body cars use spindles that interchange. There are a a few minor differences over the years, mainly the size of the bolts used to hold the steering arms to the spindles, but they are essentially the same and will swap. The A-body cars use different bolt-on steering arms than do the F- and X-body cars, but those can be swapped. The "won't fit 14" wheels" is another footnote like "headers won't fit Supremes". Obviously these cars came with disc brakes and 14" wheels from the factory. I quizzed one disc brake vendor about this and the response was that it was easier to use this footnote than to try to educate people about the difference between disc-brake wheels and drum-only wheels.

As for the combo valve vs. metering valve question, they are equivalent. The combo valve simply takes the metering valve and incorporates it into a common housing with the distribution block. They are functionally equivalent, the only reason for the change was to reduce the number of parts to minimize potential leak points and reduce assembly line labor.

txrob779

Well I will dig into the 68 Camaro parts I can get on the cheap and go from there Joe.
Thanks deciphering my rambling.

txrob779

Hey Joe,

I have seen some resto modded 4 wheel disk mods that that the 4WD master cylinder and that combo valve mounted on a bracket to the booster. You follow me? And pics or run down on where to mount that combo valve on a front disc/back drum power system?
Do you know of any lots that supply the valve and brake lines both?
Or and suggestions on how to learn to bend and flange my own lines? I have never attempted it but willing to experiment for sure?

txrob779

joe_padavano

Lots of aftermarket kits mount the combo valve under the M/C to avoid problems with headers. Right Stuff is one of many vendors who sell hard line kits for this also. Flaring your own brake lines is easy, so long as you have a correct double-flare kit.

68442Convertible

So has anyone tried to install the new Speedway kit, and do 14 inch wheels clear (14x6 SS III)?

Deluxe 1964-74 GM car front disc brake kit
new part number 91031958 still $240
Now listing the rotor as 11" instead of the old 10.75"

joe_padavano

From the photos, the caliper brackets look exactly like the stock ones. Most vendors round up 10.75" to 11". When I've asked about the fact that factory cars came with 14" wheels, I get the answer that it's easier to specify 15" wheels rather than try to educate buyers about the different types of 14" wheels. In your case, ALL SSII/III wheels clear stock (and repro stock) disk brakes. I can guarantee that Speedway didn't tool up new caliper brackets that are further outboard than the old ones. It's the caliper that hits the wheel, not the rotor.

wcwhite

What is the diameter that I need to clear this disc brake setup? I have 14" after market wheels that I would like to use with a disc brake conversion. Any information on this would be appreciated.

joe_padavano

Well, you will find the info you need if you actually read this whole thread.

One more time: STOCK A-body disc brakes came from the factory with 14" wheels. Exact repros of stock brakes will clear 14" wheels also.

The problem is that there are two different styles of 14" wheels for GM cars, those that only clear drums and those that clear discs also. You will need to determine what type of aftermarket wheels you have, but pretty much any wheels made since 1970 will clear stock disc brakes. This photo shows the difference. Disc wheels are on the left. Note how the backside is contoured to clear the caliper. The dark blue arrow is where the drum-only wheels will hit the calipers.

wcwhite

Thanks, Joe. The pictures helped me understand.

Co.D62dPA

Hi Joe, redoing the brakes on my 1967 Visa Cruiser. Keeping the power brake 4 drums for now but considering your "cheap" disc in the future. I need a new master cylinder presently, my original is 1" bore but is corroded. You suggested the Raybestos MC36306 with the 1 1/8 bore for the disc job. If I install the MC36306 now but keep everything else the same...am I going to have complications?

joe_padavano

Two things. One, the larger bore will require more pedal force for the same stopping force with the current drum wheel cylinders. Two, the front part of the new M/C won't have a residual pressure valve, which is really needed for drum brakes. To tell you the truth, the correct drum brake M/C is about $30 from RockAuto. It really isn't worth using the wrong one.

Co.D62dPA

Thanks for the quick reply. I appreciate your guidance and I will install a Raybestos MC36235 with the original 1" bore. Along the same line, I had a little difficulty locally finding the correct 3/4" bore rear wheel cylinders. They were eventually located at www.inlinetube.com. Rock Auto offers 1" bore rear wheel cylinders as replacements, not 3/4". Fusick did not have them but did refer me to inlinetube.

Harty360

I've got a 72 olds CS convert. I see a lot on here about going from power drums to disc. My question is, should one do this? The power drum brakes scare me, if disc brakes will work more like a modern car and make it more fun to drive, I'm in.

Thoughts?

joe_padavano

Why do the drum brakes "scare you"?

As for should you do it, your call. It's a pretty straightforward swap.

68442Convertible

I recently converted to front discs, and they work great - my car stops better than it ever did. My drum brakes probably never worked as well as they should - they were serviced by local shops that may not have known what they were doing.

I modified my spindles to accept the caliper brackets without removing them from the car. I also retained my drum/drum master cylinder after discovering that the front port doesn't have a check valve.

I will post info on what I did when I have time - hopefully in a week or so.

joe_padavano

Time to update this thread. Attached is a parts list with prices and sources for a low-cost conversion. This list assumes using a brass combo valve under the M/C. If you want to go a different route, parts and prices change. The wheel bearings and grease seals for any 64-72 A-body fit these rotors, so if you need new ones, just get the ones for your car with drum brakes. I did not include them here.

The rotors and calipers are 69-72 A-body. The M/C is a functional replacement but is the 71-up style. You can get other ones like the dual bale version if you want for optical reasons. Performance won't change. The $4 brake booster pushrod I've included is only needed if you are using a 1964-66 brake booster that originally came with a single circuit M/C. If you already have a dual circuit M/C on your booster, ignore this part.

My total is $441 for everything except the line kit (also not including core charges or shipping). The price of the mini kit seems to have gone up by $50 (or else I got a great show deal). The line kit is $179 for stainless or $155 for steel, your call. Of course, if you choose to go a different route than the combo valve under the M/C, part numbers and prices will vary.

txrob779

Thanks a million Joe for the update and Parts list.

Robert

txrob779

Hey Joe,

On a side note here, since there are dozens of "kits" out there what kit you choose if you chose one? It makes sense for, say, me to just spend the extra couple of hundred and all the parts inclusive. As a example.

http://www.inlinetube.com/_p/prd14/2...-kit---dbk6407
or
This is the one you suggested less spindles from Speedway Motors
http://www.speedwaymotors.com/Speedw...-Kit,4624.html
(I am liking this product the more I look it over)

Or something similar. Also, as I mention in this thread a few years ago, I have a friend who has a 68 Camaro's A Arms w/springs, spindles, calipers and rotors I can pick up cheap and do the clean and restore them. The $64,000 is, after all daid and done is it worth the time and effort for a few hundred bucks?

P.S. Anyone else having trouble with some of these part numbers i.e.

Inline Tube # INL10943? Brake booster pushrod
Inline Tube # ODB66D1? Brake line set?


1 More question. In regards to those Camaro brakes, If I got them uber cheap and went the Speedway kit hypothetically, could I use those parts as cores vs. A body parts (even though they are the same parts so I am assuming YES)

dalilama

This is a great thread and Joe's spreadsheet is very helpful in getting the part list together. I just went through this and IMHO there are a few things that should be added to the spreadsheet:

1. Brake hose bolts (banjo bolts). They don't come with the hose in the spreadsheet.
2. Inner and outer wheel bearings and seal. The rotor does not come with them and you can possibly use the existing ones but you probably want to get these.

Both of these would add about $40.

Finally, as to the wheel fitment/clearance, I have the 14" SS1 rims with the trim ring and after the wheel assembly I had no (repeat NO) issues with clearance.

Thanks for the great info Joe!

pappy

I have a question for anyone that may help. I want to replace my power drums with front disc on my '65 f85. I am running 7" torq thrust wheels with 225/75 tires. I just clear everything with new s/w springs all around. I cannot have any wider stance than stock with this combination without rubbing somewhere. So, do any of these afore mentioned conversions alter the outside tracking width of stock configuration? I could stand to go narrower if anything. Thanks

joe_padavano

Unfortunately the factory rotors push the wheels outboard by about 1/4" per side. Any kit that uses factory rotors and spindles will do the same thing. Part of the problem may be your tire size. You didn't spec wheel diameter, but even a 225/75-14 is about an inch taller than the original tire. 225/70-14 is about the same diameter as original and will likely solve your problem. If you have 225/75-15 tires, those are about 2" taller than original.

pappy

Forgot to mention I am sporting 15" x 225/75 tires and I love the filled in wheel wells. Also remember that I had to change to 6" Torq Thrust in front to get enough clearance. Running 7" wheels in rear on 235/75/15, all the rubber I could stuff under there.

Do the disc brake spindles in these kits accept stock hubs? I know I would have to install longer studs.

Keener

Joe, the spreadsheet has an incorrect part number. The Raybestos master cycliner is MC36306, not MC36036 (looks like the number was transcribed incorrectly). thanks for putting the list together. I'm ordering some parts today!

Phoenix8990

Hi Joe, I am doing the disc brake swap on my 69 Cutlass. I have picked up a set of disc brakes from a 71 Cutlass. I currently have power drum brakes and am wondering if the mc will work. Some threads have left me thinking it won't, but on Speedways site the mc's they show work for both. Is there any way for me to determine if mine is ok? I'm sure it has been changed over the years. It's cheap enough either way. Also just wondering why does the proportional valve need to be changed and how would you determine if it is adjusted correctly?

thanks,
Steve W.

joe_padavano

Steve,

Get a correct disc brake M/C. You can keep the same booster. Optically correct dual bale version run $60 or so, a little more if you want the factory style bleeder screws. Get a 1 1/8" version with power brakes.



If you're on a budget, the 71-up single bale style can be bought for as little as $20 at RockAuto and works exactly the same.




Your drum brake car does not have a proportioning valve. You can use the 67-70 style metering valve that mounts under the M/C and plumbs into the current distribution block. A better choice is to use the 1971-up combo valve that replaces the current distribution block. Depending on how you want the car to look, you can get a M/C and combo valve kit or get a combo valve that mounts in the same location as the current distro block. Location doesn't matter - whichever you prefer works fine.