63 SWC: Advice on Brake Changes
12-15-2014, 06:57 PM
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63 SWC: Advice on Brake Changes
I own a ‘63 SWC and will be going through the front and rear brakes soon. My car currently has the original 4-wheel drums on the car. I want to convert to a Dual Master Cylinder system, as the car has had one system failure with the single reservoir system before – and I’m also contemplating a change to front disc brakes while I’m at it. My dilemma is this – whether to go with the “stock” 1963 parts versus upgrading to discs while I’m doing this. Looking at the 60-0 stopping distances in road tests from the period are more impressive than I would have thought – 60mph stops in 130’ on the original bias-plys. Consider a NEW 2014 Challenger 5.7L RT with 4-wheel disks also does a 60-0 in the 130’ range (I know, it’s 50% heavier).
Let me first say make these disclaimers/explanations:
The car will never be a track car. Nor may it ever be an NCRS-type restored car as it has a non-numbers matching engine block, and I have run into dead ends being able to get the original paperwork for the car. What I can say is everything points to it originally being a 340hp Hi-Po. While I try to put “correct” parts on the car as I replace different things, I am willing to do deviate from original to improve drivability or durability (examples I’m considering – dual master cylinder change, front disk conversion, stainless exhaust). I also am willing to do things that would move it into what I would call a “Day-2” car (examples – ET Sebring wheels that look like the Halibrand racing wheels GM used in the period, and 670-15 Coker radial reproduction tires that look like period bias-plys).
With all that said……..here finally are my questions for the group:
1) As I note above, the car will not be a track car. The stopping distances on the stock parts aren’t as bad as you’d think from a 50-year old car. Should I bother with a front disk swap, or keep it simple and just do the Dual Master Cylinder swap for safety and leave things at that?
2) If I DO swap to front disks – will I also need a power assist booster? I know the 65’s and 66’s had disks at all 4 corners, and yet, power assist was an option. I’d like to avoid adding the booster because it (I believe) will require me to drill into my firewall so the booster’s 2 upper “legs” can be attached. Also, my understanding is my ’63 hood may require notching to allow for both a booster and dual master.
3) If I JUST go with the Dual Master conversion – I see the master cylinder most kits include is a 1” bore part. My understanding is my original non-power drum cylinder is 7/8” – will my brake pedal effort be affected significantly if I do this, and DON’T add the booster?
4) I see some of the Dual Master kits offer a proportioning valve, other don’t…….some kits offer residual pressure valves, and others don’t. Any insights on this?
Let me first say make these disclaimers/explanations:
The car will never be a track car. Nor may it ever be an NCRS-type restored car as it has a non-numbers matching engine block, and I have run into dead ends being able to get the original paperwork for the car. What I can say is everything points to it originally being a 340hp Hi-Po. While I try to put “correct” parts on the car as I replace different things, I am willing to do deviate from original to improve drivability or durability (examples I’m considering – dual master cylinder change, front disk conversion, stainless exhaust). I also am willing to do things that would move it into what I would call a “Day-2” car (examples – ET Sebring wheels that look like the Halibrand racing wheels GM used in the period, and 670-15 Coker radial reproduction tires that look like period bias-plys).
With all that said……..here finally are my questions for the group:
1) As I note above, the car will not be a track car. The stopping distances on the stock parts aren’t as bad as you’d think from a 50-year old car. Should I bother with a front disk swap, or keep it simple and just do the Dual Master Cylinder swap for safety and leave things at that?
2) If I DO swap to front disks – will I also need a power assist booster? I know the 65’s and 66’s had disks at all 4 corners, and yet, power assist was an option. I’d like to avoid adding the booster because it (I believe) will require me to drill into my firewall so the booster’s 2 upper “legs” can be attached. Also, my understanding is my ’63 hood may require notching to allow for both a booster and dual master.
3) If I JUST go with the Dual Master conversion – I see the master cylinder most kits include is a 1” bore part. My understanding is my original non-power drum cylinder is 7/8” – will my brake pedal effort be affected significantly if I do this, and DON’T add the booster?
4) I see some of the Dual Master kits offer a proportioning valve, other don’t…….some kits offer residual pressure valves, and others don’t. Any insights on this?
12-15-2014, 07:10 PM
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12-15-2014, 07:14 PM
#3
Le Mans Master
I own a ‘63 SWC and will be going through the front and rear brakes soon. My car currently has the original 4-wheel drums on the car. I want to convert to a Dual Master Cylinder system, as the car has had one system failure with the single reservoir system before – and I’m also contemplating a change to front disc brakes while I’m at it. My dilemma is this – whether to go with the “stock” 1963 parts versus upgrading to discs while I’m doing this. Looking at the 60-0 stopping distances in road tests from the period are more impressive than I would have thought – 60mph stops in 130’ on the original bias-plys. Consider a NEW 2014 Challenger 5.7L RT with 4-wheel disks also does a 60-0 in the 130’ range (I know, it’s 50% heavier).
Let me first say make these disclaimers/explanations:
The car will never be a track car. Nor may it ever be an NCRS-type restored car as it has a non-numbers matching engine block, and I have run into dead ends being able to get the original paperwork for the car. What I can say is everything points to it originally being a 340hp Hi-Po. While I try to put “correct” parts on the car as I replace different things, I am willing to do deviate from original to improve drivability or durability (examples I’m considering – dual master cylinder change, front disk conversion, stainless exhaust). I also am willing to do things that would move it into what I would call a “Day-2” car (examples – ET Sebring wheels that look like the Halibrand racing wheels GM used in the period, and 670-15 Coker radial reproduction tires that look like period bias-plys).
With all that said……..here finally are my questions for the group:
1) As I note above, the car will not be a track car. The stopping distances on the stock parts aren’t as bad as you’d think from a 50-year old car. Should I bother with a front disk swap, or keep it simple and just do the Dual Master Cylinder swap for safety and leave things at that?
2) If I DO swap to front disks – will I also need a power assist booster? I know the 65’s and 66’s had disks at all 4 corners, and yet, power assist was an option. I’d like to avoid adding the booster because it (I believe) will require me to drill into my firewall so the booster’s 2 upper “legs” can be attached. Also, my understanding is my ’63 hood may require notching to allow for both a booster and dual master.
3) If I JUST go with the Dual Master conversion – I see the master cylinder most kits include is a 1” bore part. My understanding is my original non-power drum cylinder is 7/8” – will my brake pedal effort be affected significantly if I do this, and DON’T add the booster?
4) I see some of the Dual Master kits offer a proportioning valve, other don’t…….some kits offer residual pressure valves, and others don’t. Any insights on this?
Let me first say make these disclaimers/explanations:
The car will never be a track car. Nor may it ever be an NCRS-type restored car as it has a non-numbers matching engine block, and I have run into dead ends being able to get the original paperwork for the car. What I can say is everything points to it originally being a 340hp Hi-Po. While I try to put “correct” parts on the car as I replace different things, I am willing to do deviate from original to improve drivability or durability (examples I’m considering – dual master cylinder change, front disk conversion, stainless exhaust). I also am willing to do things that would move it into what I would call a “Day-2” car (examples – ET Sebring wheels that look like the Halibrand racing wheels GM used in the period, and 670-15 Coker radial reproduction tires that look like period bias-plys).
With all that said……..here finally are my questions for the group:
1) As I note above, the car will not be a track car. The stopping distances on the stock parts aren’t as bad as you’d think from a 50-year old car. Should I bother with a front disk swap, or keep it simple and just do the Dual Master Cylinder swap for safety and leave things at that?
2) If I DO swap to front disks – will I also need a power assist booster? I know the 65’s and 66’s had disks at all 4 corners, and yet, power assist was an option. I’d like to avoid adding the booster because it (I believe) will require me to drill into my firewall so the booster’s 2 upper “legs” can be attached. Also, my understanding is my ’63 hood may require notching to allow for both a booster and dual master.
3) If I JUST go with the Dual Master conversion – I see the master cylinder most kits include is a 1” bore part. My understanding is my original non-power drum cylinder is 7/8” – will my brake pedal effort be affected significantly if I do this, and DON’T add the booster?
4) I see some of the Dual Master kits offer a proportioning valve, other don’t…….some kits offer residual pressure valves, and others don’t. Any insights on this?
I suggest that you use the 'search" function because there are many threads on this subject. I would recommend that you (IF your car is a driver, and not a trailer queen):
A) upgrade to a dual master cylinder for safety reasons, and
B) that you upgrade to disc brakes for consistency, reliability, and repeatability (unless you only plan to stop once).
HOWEVER, I have commented and been crucified (on this Forum) SO MANY times that I have lost count, So............wait for others to weigh in and decide for yourself.
NOTE: SAME answer for your questions on suspension changes!
Last edited by 63Corvette; 12-15-2014 at 07:17 PM.
12-15-2014, 07:26 PM
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Suspension changes, Exhaust changes, Brakes changes. Lots of changes. I am going to guess here. You have owned the car less than a month? It does not sound like there is really very much about the car that you are happy with, except perhaps that split rear window?
Welcome to the classic corvette hobby, and the corvette forum.
Welcome to the classic corvette hobby, and the corvette forum.
12-15-2014, 07:58 PM
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No, I actually am quite in love with the car altogether. I have owned it - believe it or not - since around 2005. But it's been sitting for quite awhile - and not much had been done to it for about 25 yrs before I got it. So.....with that said, I'm finally getting around to trying to get the car more road-and presentation-worthy. Unfortunately the last 10 years has been full of "family events" that have kept me from uncovering the car.....until now. Trying to make up for lost time, I suppose......
12-16-2014, 07:13 AM
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Motor Trend 1967 Corvette 427, disc brakes, (coupe but non SWC), 7.75X15 tires. 60-0 131 feet.
Looks like keeping a safe distance between vehicles would be more important than what kind of brakes you have?
12-16-2014, 07:41 AM
#7
Team Owner
Yes, if you use an original booster you will have to drill two holes in the upper firewall below the driver's side cowl vent for the bracket and install a readily available reinforcement "nut plate"...that took me all of about 20 minutes. You will not have to notch the hood if you use an original booster or a converted passenger car booster that looks original. You will also have to change the master cylinder-to-frame "hard" brake line and plumb for manifold vacuum and move the pedal push rod into the lower hole and install the "tab" in the OTHER (uppwe) hole to make the brake light work.
If I had it to do over again I prob wouldn't have done it -- a lot of work and expense.
I also think a dual master cylinder might be a problem but I think its possible.
I've had two single master cylinder failures in my entire life on two used cars traded in on my Dad's car lot. There were plenty of warning signs of pending failure which the owners ignored and I could have prevented if it were my car. Depending on the M/C failure and partial disc brake conversion you could be trying to stop on just the rear drums sorta like the emergency brake you already have.
Do go completely through the existing brakes at a minimum; on my '63 I replaced everything but the backing plates and drums...that means new fluid, rubber hoses, shoes, spring kit, wheel cylinders, etc.. NAPA has it all and I think the total cost was about $235.
If I had it to do over again I prob wouldn't have done it -- a lot of work and expense.
I also think a dual master cylinder might be a problem but I think its possible.
I've had two single master cylinder failures in my entire life on two used cars traded in on my Dad's car lot. There were plenty of warning signs of pending failure which the owners ignored and I could have prevented if it were my car. Depending on the M/C failure and partial disc brake conversion you could be trying to stop on just the rear drums sorta like the emergency brake you already have.
Do go completely through the existing brakes at a minimum; on my '63 I replaced everything but the backing plates and drums...that means new fluid, rubber hoses, shoes, spring kit, wheel cylinders, etc.. NAPA has it all and I think the total cost was about $235.
12-16-2014, 03:48 PM
#8
Burning Brakes
Good brakes
I was lucky went I purchased my SWC 18 months ago. The owner had someone do the brake that knew exactly what they were doing. I pulled each drum just check and found new parts all the way around.
I think the biggest issue people have with these old drums is that if they are not adjusted perfectly the car "walks" around when stopping. My '63 stops straight every time and because of that I don't give the brakes a second thought.
As a matter of fact I was leading a group of Vettes to a car show a couple of weeks ago and had a chance to show off these old drums. We were traveling in a 55 mph zone (we may have been going somewhat faster than that
), we got a "short" yellow traffic light and I jumped on the brakes because I didn't want to lose any of the guys. When we got the show one of the guys came up and asked if I had converted to disc brakes. He was very surprised what quickly and smoothly the old girl ate off the speed.
Drums will never be as good as disc but properly maintained drums will stop you pretty darn good (at least the first time).
I think the biggest issue people have with these old drums is that if they are not adjusted perfectly the car "walks" around when stopping. My '63 stops straight every time and because of that I don't give the brakes a second thought.
As a matter of fact I was leading a group of Vettes to a car show a couple of weeks ago and had a chance to show off these old drums. We were traveling in a 55 mph zone (we may have been going somewhat faster than that
), we got a "short" yellow traffic light and I jumped on the brakes because I didn't want to lose any of the guys. When we got the show one of the guys came up and asked if I had converted to disc brakes. He was very surprised what quickly and smoothly the old girl ate off the speed.Drums will never be as good as disc but properly maintained drums will stop you pretty darn good (at least the first time).
12-16-2014, 04:22 PM
#9
Le Mans Master
I was lucky went I purchased my SWC 18 months ago. The owner had someone do the brake that knew exactly what they were doing. I pulled each drum just check and found new parts all the way around.
I think the biggest issue people have with these old drums is that if they are not adjusted perfectly the car "walks" around when stopping. My '63 stops straight every time and because of that I don't give the brakes a second thought.
As a matter of fact I was leading a group of Vettes to a car show a couple of weeks ago and had a chance to show off these old drums. We were traveling in a 55 mph zone (we may have been going somewhat faster than that), we got a "short" yellow traffic light and I jumped on the brakes because I didn't want to lose any of the guys. When we got the show one of the guys came up and asked if I had converted to disc brakes. He was very surprised what quickly and smoothly the old girl ate off the speed.
Drums will never be as good as disc but properly maintained drums will stop you pretty darn good (at least the first time).
I think the biggest issue people have with these old drums is that if they are not adjusted perfectly the car "walks" around when stopping. My '63 stops straight every time and because of that I don't give the brakes a second thought.
As a matter of fact I was leading a group of Vettes to a car show a couple of weeks ago and had a chance to show off these old drums. We were traveling in a 55 mph zone (we may have been going somewhat faster than that
), we got a "short" yellow traffic light and I jumped on the brakes because I didn't want to lose any of the guys. When we got the show one of the guys came up and asked if I had converted to disc brakes. He was very surprised what quickly and smoothly the old girl ate off the speed.Drums will never be as good as disc but properly maintained drums will stop you pretty darn good (at least the first time).
12-16-2014, 04:35 PM
#10
Team Owner
Since this topic is open, and I have read it with interest, I'll ask a related question for you and Frankie and others- just rebuilt my stock drums on the 64 and it brakes very straight now. New cylinders hoses linings and springs. Adjusters cleaned and lubed and the system is bled "to death." Since I never owned a New car with drum all around- how firm should my pedal be? My brake pedal sits properly at rest, and is soft compared to modern rides- getting progressively harder from 7/8 from top (about) and will lock up the drums pretty close to the floor only (about an inch and half). Should my pedal be firmer at the onset? I set the drums up snug and have backed the self adjusters in reverse a dozen times or so with sharp stops. I'm a little confused as to how firm a non antilock and all drum old car pedal should feel. I'm confident I have no air in the system and am holding steady fluid. Thanks!
12-16-2014, 04:46 PM
#11
Le Mans Master
Thanks for the feedback Frankie, as always! I've surmised that "in the old days" a more shall I say progressive pedal is probably intentional... I can see where a modern power/abs pedal feel in one of these cars would lend itself toward locking up with little input. So I guess I'm satisfied it's set up properly and I'll join the ranks of folks considering if it needs changed to be truly happy. But again- my thanks!
12-16-2014, 04:49 PM
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Since this topic is open, and I have read it with interest, I'll ask a related question for you and Frankie and others- just rebuilt my stock drums on the 64 and it brakes very straight now. New cylinders hoses linings and springs. Adjusters cleaned and lubed and the system is bled "to death." Since I never owned a New car with drum all around- how firm should my pedal be? My brake pedal sits properly at rest, and is soft compared to modern rides- getting progressively harder from 7/8 from top (about) and will lock up the drums pretty close to the floor only (about an inch and half). Should my pedal be firmer at the onset? I set the drums up snug and have backed the self adjusters in reverse a dozen times or so with sharp stops. I'm a little confused as to how firm a non antilock and all drum old car pedal should feel. I'm confident I have no air in the system and am holding steady fluid. Thanks!
Sounds like your brakes need to be tightened up. You should have a hard pedal with drum brakes. Maybe not quite as solid as the Corvette disc brakes but hard once shoe contact with the drum is made.
Drum brake shoes have to travel a little further to contact the drums that disc brake pads have to travel getting to the rotors.
Sounds like you have a low pedal and if you do a tighter adjustment will help that.
12-16-2014, 04:55 PM
#13
Le Mans Master
Sounds like your brakes need to be tightened up. You should have a hard pedal with drum brakes. Maybe not quite as solid as the Corvette disc brakes but hard once shoe contact with the drum is made.
Drum brake shoes have to travel a little further to contact the drums that disc brake pads have to travel getting to the rotors.
Sounds like you have a low pedal and if you do a tighter adjustment will help that.
Drum brake shoes have to travel a little further to contact the drums that disc brake pads have to travel getting to the rotors.
Sounds like you have a low pedal and if you do a tighter adjustment will help that.
12-16-2014, 05:40 PM
#14
Team Owner
A "low" pedal is relative in these cars. The 63 shop manual section on power brakes states for an in car check that the pedal should not go closer than 1" to the toeboard when pressed. ONE inch...so 1-1/2" is deemed OK. Close enuf to be scary but within spec.
12-16-2014, 05:47 PM
#15
Le Mans Master
Hopefully mike is right and I can adjust it further. I learned to drive a stick shift on a 53 ford club coupe, and I dimly recall even those brakes feeling at least as firm as what I have now.
12-16-2014, 06:01 PM
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Motor Trend 1963 Corvette 327, Drum brakes, (SWC), 6.70X15 tires. 60-0 130 feet.
Motor Trend 1967 Corvette 427, disc brakes, (coupe but non SWC), 7.75X15 tires. 60-0 131 feet.
Looks like keeping a safe distance between vehicles would be more important than what kind of brakes you have?
Motor Trend 1967 Corvette 427, disc brakes, (coupe but non SWC), 7.75X15 tires. 60-0 131 feet.
Looks like keeping a safe distance between vehicles would be more important than what kind of brakes you have?
Those distances are similar to a brand new R/T Challenger with 4-wheel disks. My 2014 Mustang GT with Track Pack and 14.5" Brembos will do the 60-0 in 105-110' - which were "supercar" numbers just a couple years ago. Keep in mind the difference between the GT/Brembo's numbers and the '63's is only about one car length.
Gets more an more impressive the more I think about it........with 51 years between the two cars......
12-16-2014, 06:07 PM
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Yes, if you use an original booster you will have to drill two holes in the upper firewall below the driver's side cowl vent for the bracket and install a readily available reinforcement "nut plate"...that took me all of about 20 minutes. You will not have to notch the hood if you use an original booster or a converted passenger car booster that looks original. You will also have to change the master cylinder-to-frame "hard" brake line and plumb for manifold vacuum and move the pedal push rod into the lower hole and install the "tab" in the OTHER (uppwe) hole to make the brake light work.
If I had it to do over again I prob wouldn't have done it -- a lot of work and expense.
I also think a dual master cylinder might be a problem but I think its possible.
I've had two single master cylinder failures in my entire life on two used cars traded in on my Dad's car lot. There were plenty of warning signs of pending failure which the owners ignored and I could have prevented if it were my car. Depending on the M/C failure and partial disc brake conversion you could be trying to stop on just the rear drums sorta like the emergency brake you already have.
Do go completely through the existing brakes at a minimum; on my '63 I replaced everything but the backing plates and drums...that means new fluid, rubber hoses, shoes, spring kit, wheel cylinders, etc.. NAPA has it all and I think the total cost was about $235.
If I had it to do over again I prob wouldn't have done it -- a lot of work and expense.
I also think a dual master cylinder might be a problem but I think its possible.
I've had two single master cylinder failures in my entire life on two used cars traded in on my Dad's car lot. There were plenty of warning signs of pending failure which the owners ignored and I could have prevented if it were my car. Depending on the M/C failure and partial disc brake conversion you could be trying to stop on just the rear drums sorta like the emergency brake you already have.
Do go completely through the existing brakes at a minimum; on my '63 I replaced everything but the backing plates and drums...that means new fluid, rubber hoses, shoes, spring kit, wheel cylinders, etc.. NAPA has it all and I think the total cost was about $235.
12-16-2014, 06:19 PM
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I would adjust the brakes manually to the point you can't turn the wheels by hand, step on the brakes hard a couple of times and then go back over them again for a final adjustment that will give you a slight uniform drag on all four wheels.
I've found a manual adjustment on brakes will give you a better pedal than relying on the self adjusters.
Too many brake threads going right now. I forget who is who. A worn MC bore will also give you a low pedal until the piston hits the unworn part.
12-16-2014, 07:02 PM
#19
Le Mans Master
I don't know if you have power brakes or manual. Manual brakes, the pedal should be right up on top of the stroke and firm.
I would adjust the brakes manually to the point you can't turn the wheels by hand, step on the brakes hard a couple of times and then go back over them again for a final adjustment that will give you a slight uniform drag on all four wheels.
I've found a manual adjustment on brakes will give you a better pedal than relying on the self adjusters.
Too many brake threads going right now. I forget who is who. A worn MC bore will also give you a low pedal until the piston hits the unworn part.
I would adjust the brakes manually to the point you can't turn the wheels by hand, step on the brakes hard a couple of times and then go back over them again for a final adjustment that will give you a slight uniform drag on all four wheels.
I've found a manual adjustment on brakes will give you a better pedal than relying on the self adjusters.
Too many brake threads going right now. I forget who is who. A worn MC bore will also give you a low pedal until the piston hits the unworn part.