Rear Brakes

[Canuck70Ghia]

Looking for some advice.

I am in the middle of a major rebuild. Took a few years off and am now just finishing the rear end.

IRS is apart and I am just washing, blasting, painting, replacing moving parts and re-assembliing.

While I wait for some seals, I am looking at the old drums. I had thought that the CB Rotohub kit was going to look pretty good back there. But the stock is low and after shipping, well . . . I could use the cash elsewhere.

So I blasted the drums and they look okay. I brought the plate back to life, solid, will look like new with a coat of primer and paint. Question is I have all gear to rebuild and put new shoes in, braided stainless lines etc and I would like to know if there is a real difference in the drum to disc changeover? I am thinking that with my 100 horse injected 1600, the car may be fine with the drums.

That being said I am much more spoiled now, even my truck has 4 wheel discs.

Opinions welcome.

[helowrench]

Install oversize wheel cylinders.
I have 1970 beetle FRONT wheel cylinders in the back of my 71 ghia.
They are a good match for the front discs.
Much better feel, and they are a direct swap in.

You can find much cheaper ways to go disc if you do some research, and can do any fib work yourself.
Somebody sells adapters to put modern sliding calipers from vw on the rears, retaining usage of the parking brake.
I do not remember who.
I have no clue as to the subsequent balance or feel.

[Piledriver]

See...
http://www.shoptalkforums.com/viewtopic ... 6&start=31

[Canuck70Ghia]

Hey Guys thanks.

The replacement cylinders I have are oversized. I also upgraded the Shoes with some Stop fast types.

I am thinking that with the braided lines I should get what I need from the old girl. I have a few weeks to think on this.

[dlamyle]

I copied this guys set up and it works just fine. I orded the calipers w/brackets on amazon for about $100 per side. You will still need the rotors/ conversion brackets and a plan for the brake lines.

http://www.youtube.com/watch?v=csMiH-JN ... xULOuiV-3w

This was a photo of something else but you can see the route I took for the lines...

[FJCamper]

Hi Canuck,

We don't fit the demographic of super brakes add-ons, but we are in the top 2% of heavy brake users. We run 14-hour road races with 2.2 litre engines. Top end on our Bug is 125 mph (measured at Daytona) and more on our Ghias.

We have run disk/drum combos, and disk/disk.

Currently, our 1965 Ghia has a standard front disk brake kit (we use four-lug wheels) with an ATE/VARGA type caliper. That's dual 40mm pistons. The rear is the "large" 1968-up rear drums, drilled for ventilation by http://www.chtopping in California.

The camo-painted Super Bug in the photo above has four wheel disks, all stock VW rotors, and ATE/VARGA calipers.

We do use NAPA DOT 4 brake fluid or Wilwood Racing fluid, and for the front brakes, Porterfield carbon-kevlar brake pads, both the S (street) and hard (endurance race) types.

We have no brake problems. We can bring our cars down from 100 MPH to 30 MPH for hairpins literally all day. No fade. No pull. No drama.

We also use 20.6mm master cylinders, but the stock 19mm cylinders were doing just fine.

Now, if we had twice our power, and we were more concerned about braking from 130 to 75 MPH, we might have to convert to larger front calipers. But as it is, we (by luck) have a really good front to rear brake bias.

We try to keep things simple.

FJC

[Ol'fogasaurus]

Great post FJC

[Canuck70Ghia]

I agree, that is the kind of post that gives confidence to guys like me. I am proceeding to deploy the stock system with upgraded shoes, braided lines and a larger cylinder (not much bigger but it works and was stock). I am also going to refurbish the stock german drums as the replacement ones i ordered (Mexican) are rusted pretty bad all ready after sitting the garage. In fact they are rusted in the pline area where the axle goes through. Not happy about that but given budget concerns . . .

Pictures forthcoming.

[Canuck70Ghia]

Hey I would like to know more about drilling the drums. Can it be done locally?

[FJCamper]

Hi Canuck,

I doubt a shop that has not drilled a drum before would get it right without a lot of practice.

My understanding of CH Topping's technique is to know exactly how to stagger and space out the holes so they don't overlap, and do not induce squealing and cracks when the drum gets hot.

It would probably be too expensive for you to send them your drums, but you could buy a set of drums online and have them delivered to CH Topping.

I learned something about rear drum brakes back in the 1970's when we ran a 1973 Super Bug in the IMSA BF Goodrich Radial Challenge. The rear drum brakes just didn't wear. Even after two seasons. On stock shoes. So I doubt even if you can't get your drums drilled, it's not that serious.

The front brakes do most of the braking.

FJCC

[Canuck70Ghia]

Where is the like button?

Just threw the bearings and backing on today on the left side. It all looks good. I am not having any issues with the plan.

[Ol'fogasaurus]

Canuck70Ghia, I know it is dealing with off-road stuff but if you can find a copy of Baja Bugs & Buggies to borrow and read (the section of brakes specifically), there is a bunch of information on brakes to be found there. It gives info in the changing over to larger wheel cylinders in the rear and the same with Master cylinder for the slave cylinders change in bore. While the book is a bit old and the author has since passed away but what is there might be worth looking into... who knows.

It also talks about type 3 brakes (assuming you can find a set. The backing plates are the hardest to find).

W/o knowing more: you may or may not need to get an adjustable brake proportioning valve (http://www.mooreparts.com/store/search.asp) as you are changing a lot of the front to rear bias... or may end up wanting to.

Boring holes in the backing plates is an old trick but w/o some supporting things done I don't know how much good it does. On discs I have read pros and cons on the drilling of the rotors or machining gas pockets dimples in for cooling. As has been said already, there seems to be good jobs done and not so good jobs done in this area.

I think I would look towards FJC, Piledriver, Marc, Dustymohave and several others who have done quite a bit of racing in different track/street settings; there is a plethora of difference types of experience there alone much less the others here on STF than I am not aware of what they have done.

Lee

[FJCamper]

Hi Canuck,

I don't know that you'd want to do this for street use, but you can drill the brake backing plates for ventilation.

An alternative is to cut a port into the backing plate, and fabricate a flexible air tube to the vent, fed by a screened scoop that gets plenty of air at speed. That keeps the debris out, and if you mount the scoops to the suspension members, all of the rain -- but not spashes from standing water.

I'd love to see someone make finned aluminum brake drum sleeves.

FJC

[Ol'fogasaurus]

Back in the day I seem to remember someone making the scoops for the backing plates but with the movement towards discs much of that stuff stopped. Finned drums are still pretty popular and come to think of it there is/was someone making disc brake covers that gave the impression of the old Buick (I think) finned drums.

Scoops: for example:

http://www.speedwaymotors.com/OTB-Gear- ... 0000024819

http://www.speedwaymotors.com/OTB-Gear- ... 58553.html

http://www.obrientruckers.com/ecom/product/246/2741/

http://www.ace-customs.com/id18.html This is more like what I remember.

Something like this you would want two per backing plate: 1 for intake and the other for evacuating heat and dust.

http://www.ebay.com/itm/Triumph-Preunit ... 43cc022fd6 I wonder if a louver die in a shop press would work.

Anyway, maybe some ideas you could think about.

Lee

[helowrench]

It also talks about type 3 brakes (assuming you can find a set. The backing plates are the hardest to find).



Lee

In a ghia the type3 brakes will push the wheel outboard.
So, research this very carefully against your wheel plans before going down this road.