15 replies to this topic

[Davis]

Can some one tell me the difference between the rear drum brakes on a (drum/drum) setup as opposed to a (disc/drum) setup.

 

My car was originally drum/drum but I will be converting to a disc/drum setup, I know that some minor changes need to be made to the rear drums so they work correctly with the disc front.

 

Here are a couple pics of a new diff I picked up, hoping its off a disc brake front torana....if not what parts do I need to correct it?

 

Thanks in advance

Attached Files

•  IMG_3961a.jpg   180.17K   5 downloads
•  IMG_3962a.jpg   178.76K   7 downloads

[sibhs]

Hi Davis,
It'll be the rear slave cylinders that need changing. I'd just by new ones and ask for the disk brake versions.
I don't know numbers or sizes but going through this at the moment.

[S pack]

The only thing you need to do is ensure the wheel cylinders are 9/16" bore.

[dattoman]

Thats technically right

But also the shoes are different for a disc brake car

Your drum ones will have pushrods that go from cyl to shoe

The disc ones have a button on the end of the piston that the shoes (of a different shape) pushes directly on

 

So change shoes and cyls to disc front spec and your golden

 

 

Attached Files

•  P1020875.jpg   146.48K   6 downloads

[Davis]

Thanks guys, u've been extremely helpful

[Davis]

Just had a closer look at the drums on the diff I just picked up, and it appears it was from a car with a disc front, correct cylinder and shoes....happy days.

[dattoman]

Those shoes look very thick

Check the drums aren't too far oversize

Your drums will swap onto the other diff if you find they are better

And make sure if you buy shoes they are radius ground to suit the drum diameter... not just off the shelf 

STD is 228.6mm

1st oversize is 230.1mm

[sibhs]

Bit of a hijack here.
My drums are just under 229mm so my shoes should be ok?
Datto, were my shoes radius ground? Or do I need to get that done?
Cheers
Marty

[Davis]

All good Marty....

My drums are 229 also, but look like they have been sitting a while, so a first oversize grind will prob be a good idea.

What would be the maximum oversize limit for an radius grind?

[dattoman]

Shoes are radius ground as part of the relining process

Its the last step before they are blown off and go in the bag

 

So sounds like your both good to go 

[sibhs]

Your rear drums will activate too early and could cause rear lock-up and spin out.

[S pack]

My bad... Had a proper look at the cylinders, they are the button style version. And same problem with sibhs, when a heap of pressure on pedal I can still turn rear wheels.

Hi Dave

 

From what I've learned in the past few months over Marty's brake problem there is no problem to be solved. They are working as they are designed to.