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54BuickDoc

Disk Brake Conversion

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Having recently acquired a car with wire wheels, the very first thought I had was, "Boy, I'm glad I have drum brakes so I dont have to clean brake dust off those wire wheels every few days."

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Many claim the newer ceramic disc brake pads "don't dust", but they do.  Just that the dust isn't darker, so its lighter beige color doesn't show up nearly as easily on wheels and such.  But it's still there and would show on wire wheel spokes.

 

The issue with the wheel/caliper clearance is the shape of the backside of the wheel rim.  NOT just the wheel diameter itself.

 

Disc brakes have their benefits and their ultimate installation costs might be less than different sheet metal on the car.  BUT . . . most panic stops only happen once and in those cases, it's "tire rubber/pavement friction interfaces" that can be more important than what kind of brakes are on the car.  NOT the same as driving in the mountains where added fade resistance can be important.  OR the same as trying to slow down enough to make that turn at the end of a 1/4 mile drag strip.

 

The question might be "Why are you driving something with K-H wires on it in tight city traffic or on a drag strip?  Might driving style be a better change, to allow for more following distance between other cars on the road?

 

Respectfully,

NTX5467

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More to the point of drum vs disc brakes . . . I was talking to a performance enthusiast at a cruise event two years ago.  We were talking about the Wilwood brake kits.  He thought a bit and said that he actually thought that large drum brakes actually stopped "better" than the Wilwoods he put on one vehicle.  BUT the Wilwoods would stop the same all day long and the drums wouldn't do that.  Driving non-abs cars with drum brakes, usually easier to "lock 'em up" and leave skid marks with power drum brakes.

 

NTX5467

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 This is a bit off of your topic, but, perhaps relevant. The type of lining is very important to stopping power. The modern lining type tends to be too hard, and doesn't stop as well as the older, softer kind. Which often contains asbestos, so that is a hazard to be aware of when servicing.

 There are places that will bond modern Kevlar material the the old cores, and this is supposed to be very effective. I plan to try this route on my '56 Roadmaster later this year. This is a bit more costly, but so is converting to disk.

 Keith

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Approximately 15 years ago there was a documentary on TV that compared ABS and regular brakes on a closed circuit track.  Some of the professional racing drivers were able to beat the ABS by a considerable margin.  The one thing that several drivers mentioned was that in a panic you should not put the brakes on gradually because this often causes a skid because the brakes are no adjusted exactly evenly.  The consensus was to stomp on the brakes as hard and fast as you could so you would lock up all four wheels at the same time.

As was mentioned by NTX5467  in post #4 the only advantage to disc brakes is they don't fade.

I have never had a problem driving my 1930 mechanically operated brakes on the highway.  I am just thankful these days for the right hand truck lane.  In the mountains I always remember the information given when I first drove trucks on the highway in the 60's.  Always use the same gear downhill that you used going up the hill.  It doesn't mean I drive my car down in second very often but always make sure not to exceed the speed limit or use "Mexican overdrive".

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Back in the late 1960s, a FMVSS regulation allegedly came online which put a maximum brake pedal pressure to be used for max-effort stops.  I seem to recall that some disc/drum cars still had stellar stopping performance with bias-belted tires.  One car stood out, a '69 Olds 442 W-30, which pulled more than 1G stopping power in a CAR LIFE road test.  When I researched the brake pads on that car, they were normal GM-spec linings which fit a multitude of vehicles and nothing special or "HP" on the rear drum linings either.  The reason was that the braking of my '77 Camaro was not nearly what it should have been, in my estimation.  On the Camaro, they put an organic pad on the outside and a metallic pad on the inside, to decrease brake dusting on the wheels.

 

My research indicated that in many aftermarket replacement pads, "they were all the same, from Nova to C-30 trucks".  Then came the '79 Police Nova!  Great stopping performance, compared to other similar cars.  A set of those brake pads and the Camaro stopped better than ever.  Special pads?  The same as on '79 Cadillac limos.  Adding the '81 Z/28 "export" 11x2 rear brakes (same as the later mid-'80s Caprice police cars AND '77 Monte Carlo) and THEN it finally stopped with confidence with a really good pedal feel.  ALL bolt-on, in stock GM items.  On the '90s Caprices, the Chevys and Cadillacs had rear disc brakes with an existing Chevy 10-bolt rear axle.  More bolt-on stuff!  The similar Roadmasters had 11x2 rear drums.

 

Brake frictions are undergoing another issue as the copper in the formulations must be removed by a certain date in the future.  Something about the copper coimponents showing up in river water, which was affecting the fish in the rivers.  

 

As for our vintage vehicles, back in the later '50s, Chrysler was using full-metallic brake linings on their police cars with great results (in continued stopping performance in the CHP  police car tests (www.allpar.com, Chrysler Squads, Curtis Redgap chronicles).  That lining was provided by a small brake rebuilder in Amarillo, TX, as I recall, but it worked better than anything else.  The '61 Chevy Impala SS had segmented metallic linings from the factory, but many removed them for regular linings as they couldn't stage the car at the drag strip with "cold" metallic linings that didn't  grip very well until they were hot.

 

In a long-prior thread on brake linings, Old-Tank mentioned that on his '55 Buick that one "name brand " lining was too hard and didn't stop very well on his car.  The other "name brand" stopped better on his car.

 

In the world of brake pad frictions, there is a "side code" on the side edge of the friction material.  That code has a sequence of letters and numbers to identify the manufacturer, batch number, and cold/hot frictional characteristics of the friction material itself.  I suspect that drum brake linings are similar.  For stopping purposes, the letter codes are significant.  Seems like they start at "C" and end at "F"?  Higher letters are best.  One person was seeking some good linings for an autocross car he was putting brakes on and also driving daily.  Seems that one auto supply chain's "house brand" brake pads had "EE" temperature codes, which is as good as it gets until you get into the race-only higher ratings.  He was surprised and pleased.  You can probably Google "brake friction side codes" to verify which codes are what.  These ratings are separate and apart from the statements by the brake pad/lining vendors of "proper fit and function" for your particular vehicle.  In short, just purchasing a quality brand might not be enough to get the best braking performance.

 

I'm not sure what the brake re-lining industry has for their performance specs.  If the truck materials would work on cars, for example.  It might be good to ask these questions if you might get a set of your drum brake shoes re-lined in the future.

 

So, things aren't quite as generic as we might have perceived.  

 

NTX5467 

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All very interesting, but back to the question "Has anyone tried a disk brake conversion under Kelsey Hayes original wire wheels?   Do the calipers fit?"

 

I wonder this as well. I don't have wires or disc brakes, but if I decide to go that direction, it might be handy information

 

 

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I can't comment on the wire wheels but i will say that i found in my personal experience, the disc brakes were not worth the effort. 

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On 6/9/2018 at 2:53 AM, 54BuickDoc said:

Do the calipers fit?

Looking at my KH wire  wheel on my spare and a regular rim... if a regular rim will not work with calipers then the wires will not work either.

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This is the area you have to look at.  This is a Wheels Vintique  wire rim.  Notice how the back is flat and then there is a sharp curve towards the center?  That flat surface is there to clear a disc brake caliper.  I don't have a Kelsey Hayes rim to compare this to, but on the older steel rims this area is angled from the outside to the center and there won't be a clear step in the center.   Hope that makes sense.

 

IMG_0630.jpg.bf642c842a6b667a004e0178df884761.jpg

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See there you go

 

An answer to the question, not un asked for opinions on the value or not of changing to disc brakes

 

Thank you

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On my '55 Special, the Wilwood discs clear both the wires and the original steel wheels WITH a spacer behind them.  There is no power assist.  A definite improvement in ease of braking.  Also have a dual master cylinder.

 

Steanson

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