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Disc Brake Upgrade for '64 Skylark


Machine Gun
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I'm planning a couple of upgrades to my Skylark to make it a bit safer, and more comfortable for my wife. I plan to convert the front brakes to disc, primarily because I live in a pretty hilly area here in NJ and I'm tired of dealing with brake fade on a few of our roads. I drove drum brake vehicles for years and I know to avoid riding them on hills, but the terrain here is a bit much. That'll be a Winter project after my garage heater gets installed, but that's a subject for another thread.

 

Edited by Machine Gun (see edit history)
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19 minutes ago, 60FlatTop said:

Just a thought from a skeptic, how old are the shoes. And if you roll back the edge of the wheel cylinder dust cap do you see a hint of brown mud?

I replaced the entire brake system in 2019, including shoes, wheel cylinders, drums, master cylinder (converted to dual circuit), booster, brake hoses, and lines. I did my 3,000+ mile trip along Route 66 back in June with no problem. The drum brake system works just as it should, which is the problem on long, steep, downhill grades.

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Something may be defeating the self energizing feature of the drum brakes. Possibly a check valve to maintain residual pressure in the system some oversight like that. Even the lining material if the shoes were an off the shelf set. My drum brakes get relined with a choice of three grades of non-asbestos material. It would be a shame to toss out all that new stuff.

 

A hundred bucks would get you a few fittings and single bore master cylinder to kind of undo the mod. Just for a test.

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18 hours ago, 60FlatTop said:

Something may be defeating the self energizing feature of the drum brakes. Possibly a check valve to maintain residual pressure in the system some oversight like that. Even the lining material if the shoes were an off the shelf set. My drum brakes get relined with a choice of three grades of non-asbestos material. It would be a shame to toss out all that new stuff.

 

A hundred bucks would get you a few fittings and single bore master cylinder to kind of undo the mod. Just for a test.

Hi Bernie:

 

Considering that there has been no noticeable deficiency in brake system performance over the course of thousands of miles that included a few panic stops, I seriously doubt that there's anything amiss with it. It would just be nice to not have to deal with brake fade on those occasions when I travel down very long, steep grades around here.

 

There's no question, at least in my mind, that disc brakes are superior to drums in areas that are important to me. However, I will throttle back on my immediate plan to do the conversion and consider your suggestions. One thing isn't clear though: why go back to a single-bore MC for the test? What will that tell me? Regardless, there's no way I'm going back to single-bore permanently. And how will your suggestions, even if they improve performance somewhat, significantly reduce the tendency for the brakes to fade, which is what drum brakes are wont to do? Is the secret in the lining material? To be honest, I don't know the composition of the shoes that I used.

 

Edited by Machine Gun (see edit history)
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ONE thing to be cautious of when doing such a brake upgrade is to make a parts list of what was used, where it came from, and such for future reference AND any possible future owners . . . even if the car might be inherited several decades into the future.  Which can be a compelling reason to use Wilwood products.  Yet the one possible issue I might have with their stuff is that their heritage began in drag racing, where weight was not friendly, so many of their earlier products were designed to be light weight in nature, but still worked to slow/stop high speed drag race cars.  "Light weight" when compared to the more robust factory items, by comparison.

 

To me, an "ideal" front set-up would be a kit with adapter brackets to mount a common GM mid-1970s caliper which uses the D52 (industry part number for aftermarket pads) front brake pads.  Which would greatly simplify future pad replacements with common parts, BUT also with a high degree of availability of HD pads (either aftermarket or OEM, as the old 1979 Nova COPO 9C1 police pads, which were really Cadillac limo pads with a high metallic content, orig PN 12300192, IIRC).

 

For the rear, possibly the easiest thing might be to find a kit which would use 1992+ Caprice rear disc brakes.  BUT those cars used the Chevy 10-bolt rear axle, which gives those parts LOTS of possible places to be used, but would need different brackets to mate them to your Buick rear axle housing.   OR, if you could find a Buick mid-'70s Regal mid-size car which used rear 11x2" rear drums whose backing plate would match the pattern on your car.

 

Now, these particular OEM systems would probably be a bit powerful for your weight of car, possibly, BUT might well also last forever due to their "reserve" power.

 

Also be prepared to buy new wheels which will clear the disc brake calipers.  Which also might give you the opportunity to go to a 17" wheel size and "modern rubber", rather 15" wheels and BFG Radial T/As, for example.  Or even some of the 15" whitewall Hankook Kinergy ST tires in a 15" size.

 

Scarebird also sells kits, usually based on currently-available auto supply reman parts, which can be good.  But, as they are based on currently available items, that also means they might become unobtainium in 20 years ro so, too.  Which, in the long run broad spectrum of things, make the Wilwood kit a better, one-stop source, deal.

 

In general, disc brakes need a larger capacity power booster to work well.  The earlier systems used a dual-diaphram unit, which is longer than the normal single-diaphram unit.  Later systems used a single diaphram unit of a larger diameter.  In ANY event, the build length of the dual-diaphram booster and the dual master cyl can take up a LOT of underhood real estate on the lh side of the engine compartment, IF that might matter.  Which might also make a set of Iridium spark plugs a necessity.  Then there's the necessary plumbing for the combination valve/divider block and related tubing, hopefully available from somebody like Fine Lines or similar, pre-bent.  End result might be that what might first seem like a simple upgrade CAN become a serious re-engineering operation, all things considered.

 

You might also check some of the Olds F-85 forums on the earlier cars as yours, for ideas and such, too.  Not that an Olds was exactly the same car in all respectss, but possibly similar enough in the needed areas.

 

You might also look around in some of the brake websites (Raybestos and such) for "HD Towing/Police" brake linings, in the needed size.  There is also a place www.musclecarbrakes.com which specializes in drum brake linings pre-1972 muscle cars, also, which might have some better linings you could bolt on and go with.  This MIGHT be the best option as GM used that 9.5" drum on even the early 1970s big block hot rods.

 

Just some thoughts,

NTX5467

Edited by NTX5467 (see edit history)
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Pinpointing the deficiency can be hard when changes to the original system have been made. It was designed as a system more than an assembly of components. What you describe as fade in my mind would be a lack of braking ability on a long decline. Do the brakes fail to grip at the end of the slope? Or is it the lack of being able to give it gentle braking through the slope? You didn't write that the car would not stop after the grade so I'm thinking you are getting a careening feeling through the slope. That led me to think the primary shoe wasn't bringing in the dynamic braking effect. You have to "put too much foot into it" through the slope. That could be the check valve or possibly due to the line size differences required to adapt the master cylinder.

 

It is hard to diagnose remotely, only speculate and be sure no options are overlooked.

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The only time I had brake troubles while driving in the mountains was with 3 yr old car with disc brakes.  The brake fluid degraded to a lower boiling point (another reason to flush every 2 yrs).  Boiling fluid in the calipers is ineffective....first one side and then both and smoke from the rear shoes.

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Brake fade, from my experience, comes about due to drum expansion.  As the drum heats up from use the metal expands, the shoes do not.  Brakes are now "out of adjustment" so to speak.  Completely preventable by driving properly.  Actually, stabbing the brakes, by that I mean,  short moderate use of the brake rather than constant light drag, seems to work.   Discs do not have the expansion problem. 

 

  Ben

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Guys, I appreciate your comments and suggestions on the disc brake conversion topic. Some additional information.

 

@NTX5467I have yet to select a vendor for the conversion, if I decide to do it after all. Wilwood concerns me mostly because they seem to be the only source for replacement parts like pads, rotors, and calipers. If that's the case they're off my list. Sure, Wilwood has been around for a long time, but then again so was Sears. As for currently available parts from auto parts sources being unobtainium in 20 years or so, it's quite likely that I will be unobtainium by then, so that's not a big concern for me.

 

@60FlatTopBernie, just to be clear, the deficiency was there prior to me converting to a dual-circuit system, and did not suddenly appear after the conversion. I've had the car for seven years and it's always behaved this way on long, steep slopes. It's no different than I remember from driving all-drum brake cars back in the '70s. Gentle braking through the slope works fine, but braking effectiveness gradually decreases the farther down the grade I go, which I attribute to increasing temperatures on the drums and linings. I need "too much foot" only as I approach the bottom.

 

@Ben Bruce aka First BornBen, I was taught to "stab" the brakes back when I learned to drive as a teenager. That practice, in addition to taking some grades in a lower gear, helped keep me alive through the years.

 

I'm not yet convinced that there's a problem with my braking system to be solved, but instead I'm probably dealing with a characteristic of drum brake systems in general. As I indicated in a prior post, I'm reconsidering doing the conversion. My current thought is to replace the shoes with materials that are more resistant to heat. That may not happen for several weeks as I wait for my garage heater to get installed. I'll keep you guys posted.

 

Again, thank you all for your comments and suggestions.

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1 minute ago, Machine Gun said:

That practice, in addition to taking some grades in a lower gear, helped keep me alive through the years.

Yes - downshifting on a long grade is definitely appropriate.  This is a strategy that most people have either forgotten or never learned.  It's especially important for modern cars that have automatic overdrive transmissions.  Shifting out of overdrive and using engine braking significantly relieves demand on the braking system.

 

That said, I think it's certainly worth looking into new shoes with better friction material.  In the past, there was a trade-off between fade resistance and pedal effort.  The best fade-resistant metallic linings typically required higher pedal effort during normal driving.  Most people would complain about that, so the standard shoe material is formulated for 'average' conditions.  If just changing the shoes gives good performance then you'll save a lot of money and aggravation associated with sorting-out the modified brake system.

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Not sure if front brakes would be the same for the Skylark as an Electra. Probably not.

I have a complete Scarebird setup for a 65 Electra (front) that I removed a few months ago after going back to 100% stock setup.

 

The MC bore was 1/8" larger with the dual MC therefore my pedal was a bit firmer than original.

Mostly flat farm land near me, so less concern for brake fade.

 

Bill

 

 

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Thanks for the additional comments.  When I first discovered "Scarebird" a good while back, I thought it was neat that he was using stuff that could then be found in salvage yards or the auto supplies (as either new or reman items).  I always liked OEM rather than aftermarket in certain areas, personally, as a general rule.  But later on, I noticed that for the same application, HIS parts list had changed as reman items had been depleted, which is why I made those related comments.  Which then might make Wilwood (and their expanded product line) a better alternative, as a result.  BTAIM

 

Disc brakes might have more fade resistance than drum brakes, BUT only if good brake pads are used, from my experience.  On my then-new '77 Camaro Type LT, one of the main concerns with metallic pads was their dusting issues.  So the OEM pads were one metallic pad on the inside, and one organic pad on the outside.  To me, it never did stop "right" and faded far too easily in normal, slightly spirited, driving.  Knowing that it used the "D52" pads, there wre options, all the way to 1-ton pickup trucks.  So I was actively researching this!  Then came the 1979 Police Nova 350 sedans, which "Motor Trend" said would stop repeatedly with very little fade.  So I got into the parts book and ordered some up.  They worked well!  Under normal slowing down, I could tell when they were getting heated up as decel rates increased with a constant pedal pressure.  I was pleased.  THEN I also discovered a 1980 or 1981 Export Z/28 had what I later determined to be 11x2 rear brakes (rather than the normal 9.5" rear brakes).  Further research revealed the parts to make them work were the same as a '77 Monte Carlo rear brakes (only year the Monte Carlo used 11x2 rear brakes), so all of that was installed too.  When done, it stopped better than expected and the pedal was close to the top of the travel, too, which I felt was fantastic.  ALL of this with the stock master cyl, too!  Later . . . same rear brake hardware as the middle 1980s Police Caprices, which also used the Chevy 10-bolt rear axle . . . which then also makes the 1990s rear disc brakes on the later Caprices also a possibility.

 

In doing some research for a drag racer friend, I hsdf discovered earlies that there were some mid-1970s Buick Regals that also had 11" rear brakes, BUT the backing plates were specific to the Buick rear axle they were using, too.  Which raises THAT option from the salvage yard, for a Buick.

 

Then in recent times comes the www.musclecarbrakes.com people.  With a better lining material for better fade resistance and performance.  Probably similar to what Bernie is suggesting from his vendor, I suspect.  Putting better frictions on the existing 9.5" shoes could be the easiest upgrade of that nature.  Expecially has there have been many brake friction formulation changes since those cars were designed.  PLUS the realization that "brake fade" is not JUST about heat dissipation, but that as the lining heats up, it "gasses" from the various components in the linings, which then puts a thin layer of gas between the friction and the drum, decreasing braking performance a bit.  Which then generated the drilled and slotted rotors for HD/HP brake applications (even OEM in many cases).

 

In the early days of NASCAR and road racing, it was somewhat common to see flexible ducts going to the inside of the backing plates, for additional cooling air through the "Swiss-cheesed" backing plates.

 

Getting a RollsRoyce to stop with "authority and presence", rather than hitting something due to braking insufficiencies, is always a good thing.  Especially the optics of such for those who might be watching!

 

Happy Holidays!

NTX5467

Edited by NTX5467 (see edit history)
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1 hour ago, NTX5467 said:

Getting a Rolls Royce to stop with "authority and presence"

Without the presence of of the drip of fluid under the power steering ramp is the key authority. (Talk about a system, the guy said "New motor mounts were part of my brake job?")

 

Rochester Clutch has three grades of non-asbestos friction material from everyday use to stand it on the front bumper. I am not aggressive so I use the standard with them grinding and arching the fit to my drums.

 

I like NTX's references to the rear drums. The combination gives the self energizing benefit from the rear shoes that I mentioned earlier. It all works together.

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@wmsueNo, the Electra setup would not work on a Skylark. However, your decision to return to a stock brake system reinforces my decision to reconsider doing a conversion.

 

@NTX5467I had forgotten about Scarebird. For a variety of reasons I think they'd be neat the top of my list of vendor candidates. 

 

@60FlatTopThanx for suggesting that I contact Rochester Clutch and Brake. I was going to ask you to name your source. And thanx for reminding me of the wisdom of arcing the shoes to match the drums. I knew about that practice years ago but for some reason I had forgotten about it. Making sure that all of the lining material contacts the drum will ensure maximum brake system performance. Do ya think??? How could I have forgotten about that? 

 

OK, here's the plan: I'll contact Rochester C&B and make arrangements to get my shoes relined and matched to the drums. As I indicated earlier that's going to take awhile until I get my garage heated so I can work in relative comfort.

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  • Machine Gun changed the title to Disc Brake Upgrade for '64 Skylark
23 hours ago, Machine Gun said:

Guys, I appreciate your comments and suggestions on the disc brake conversion topic. Some additional information.

 

@NTX5467I have yet to select a vendor for the conversion, if I decide to do it after all. Wilwood concerns me mostly because they seem to be the only source for replacement parts like pads, rotors, and calipers. If that's the case they're off my list. Sure, Wilwood has been around for a long time, but then again so was Sears. As for currently available parts from auto parts sources being unobtainium in 20 years or so, it's quite likely that I will be unobtainium by then, so that's not a big concern for me.

 

@60FlatTopBernie, just to be clear, the deficiency was there prior to me converting to a dual-circuit system, and did not suddenly appear after the conversion. I've had the car for seven years and it's always behaved this way on long, steep slopes. It's no different than I remember from driving all-drum brake cars back in the '70s. Gentle braking through the slope works fine, but braking effectiveness gradually decreases the farther down the grade I go, which I attribute to increasing temperatures on the drums and linings. I need "too much foot" only as I approach the bottom.

 

@Ben Bruce aka First BornBen, I was taught to "stab" the brakes back when I learned to drive as a teenager. That practice, in addition to taking some grades in a lower gear, helped keep me alive through the years.

 

I'm not yet convinced that there's a problem with my braking system to be solved, but instead I'm probably dealing with a characteristic of drum brake systems in general. As I indicated in a prior post, I'm reconsidering doing the conversion. My current thought is to replace the shoes with materials that are more resistant to heat. That may not happen for several weeks as I wait for my garage heater to get installed. I'll keep you guys posted.

 

Again, thank you all for your comments and suggestions.

Greetings, I also have a 64 Buick 'A' body Spec. 2dr sedan/post car. When I started work on the car I was amazed at how small the brakes were! Especially since my car was converted toa 455/turbo400 drive line for power.  Aluminum finned front drums in 1957 helped to reduce Buicks reputation for substandad braking

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On 12/18/2021 at 9:06 AM, NTX5467 said:

ONE thing to be cautious of when doing such a brake upgrade is to make a parts list of what was used, where it came from, and such for future reference AND any possible future owners

This is possibly the most important comment in this thread or on this entire forum.  Don't tell me it's so and so's brake kit, give me replacement numbers that I I can go to the local parts store with.

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