Converting 10 bolt drums to 9" ford rear disk , do you have to run a hose at the end of the line or can you run stainless all the way connecting to the disk brakes. 1987 Camaro

 

Best to use hose at the ends. The calipers move, therefore the lines need to be able to as well. (the one side of the old crappy Delco-Moraine system notwithstanding... since those never did much of anything anyway, probably wasn't much of an issue)

 

The caliper moves but not the part that the hose connects to, that's how it looks to me. tell me if you think I'm wrong. I just don't really know. It would be easier if I can use the existing brake line.

 

A fixed caliper you can, a floating caliper you can't or shouldn't .

 

the piston housing is fixed, Thank you.

 

There should also be a flex-line from the Body to the Rear Differential.

 

The piston housing aka caliper in that system is NOT fixed. It floats. Same as the fronts.

Best to use hose at the ends. The calipers move, therefore the lines need to be able to as well. (the one side of the old crappy Delco-Moraine system notwithstanding... since those never did much of anything anyway, probably wasn't much of an issue)

 

Yes I have that thank you much. So do you think I should have hose at the disk side also, The Piston housing is fixed/

 

Maybe it's the terminology , Everything above my finger which is the piston housing is bolted solidly to the axle, only the part under my finger moves at all. So above my finger Where the banjo bolt is, is solid to the axle,


This is what I have.

 

Can someone nail this down for me please.

 

Your caliper looks to be the floating design. It slides on the those pins

 

^^^ This ^^^

 

I'm putting on a new 9" ford axle , look at the point that my finger is pointing at ,it is pointing at the shaft the brakes slides on, the finger side of the shaft has threads that are threaded through and into the plate on my finger side of the pads, it doesn't slide at that end , it slides at the other end where there is no threads. I'm not trying to argue here , I'm asking this in a few forums and I'm running about 50 50 on the answers
This is a floating caliper it does move and needs hose, it doesn't seem to be what I have.


Anyone want to add to this.

 

Floating and non floating both apply the pads with hyd psi. The nonfloating are bolted solid to the bracket without slider bolts or studs. You have calipers that slide on the bolts.

You have sliding/floating calipers and if that is a pic of your driver side, the caliper needs to go on the pass side so the bleeder screw is on the top. Hose connection should be on the bottom, bleeder on top.

No need to get to hung up on the wording, your caliper will move on those studs, put a rubber hose on the caliper and be done.

 

The caliper actually does slide with that set up. When you press the brakes, the pad on the piston side engages first, then that pad continuing to be pressed against the rotor is what makes the whole caliper slide back on those pins to engage the other pad. Since the brake master cylinder is fixed to the body, and the rear axle where the brakes are mounted moves relative to the body, you should have a flexible line. Otherwise when you go over bumps while driving you'll just be bending the solid steel line back and forth over and over again until it breaks.

 

To keep things very simple...

The Disk-Brakes will need to either have a "Floating-Rotor" or a "Floating-Caliper".
It is easy enough to see of the Rotor is "Floating" or not...
and will determine of the Caliper is "Floating".

 

It would be helpful to know the brand and model of the OP's brake setup.
FWIW, I swapped to PBR calipers on my 86 when I installed the D44 rear axle. The caliper mount/backing plate bolts directly to the axle tube end with the standard 4 t-bolts. To that, the caliper is mounted with two bolts. The caliper is fixed in position and does not move relative to axle. For this to work, the caliper needs to be shimmed so it's centred over the rotor.
That said, I still used flex to connect the caliper to the hard line. Not necessarily necessary but it eased the installation somewhat.
What brand and model of caliper is involved here?

 

The PBR caliper is also floating. The "caliper abutment bracket" contains pins that the caliper is bolted to and that can slide in and out of a hole drilled in the bracket, and because the caliper is mounted to these pins, it is allowed to "float".

The OP's photo clearly shows the Delco-Moraine pins, with the threads right behind the head, and cast-iron calipers. There is no doubt in my mind that it's someone's mounting kit, made of flat-stock brackets, to install those old crappy things onto a foreign rear that isn't otherwise equipped for them.

Virtually all modern brake systems including the PBR setup, locate the pads in the "caliper abutment bracket". The caliper then clamps the pads together around the rotor, but the pads, being restrained in the abutment bracket, transfer the actual brake torque force to the abutment bracket, which is bolted to the spindle. (or the rear axle housing in the case of rears). In that design, which is EXTREMELY TYPICAL of modern stock brakes, the caliper ONLY provides clamping force; the actual braking force is not applied to it, as it was in the old Delco-Moraine system.. If one pad wears more than the other, the caliper HAS TO move, to keep the clamping pressure equal on both sides of the rotor.

The old Delco-Moraine brake system had the pins screw into the backing plate, and the caliper could then slide along them as necessary. In that system, the pads fastened onto the caliper, and the force of slowing the rotor down was transmitted to the spindle through the caliper and pins. Very much Stone Age. We can do better than that now.

jbander, your cute diagram there DOESN'T EVEN SHOW the pins or the brackets. It's devoted pretty much entirely to THE HYDRAULICS. I don't know where it came from, but while it's not "wrong" or anything, it's also FAR FROM complete.

The only systems that DO NOT float the calipers are those with pistons on BOTH sides of the caliper. Obviously to make this happen, the caliper has to be 2-piece; a SERIOUS long-term reliability liability The pistons themselves in such aa system can then take up whatever spacing the pads dictate as they wear. There aren't many stock systems like that anymore, if any. While potentially A Good Idea for racing and such, it typically doesn't work too well on the street, with long intervals between service, corrosion, etc. Just ask anybody that's had to deal with the rear brakes on C2 & C3 Vettes.

Bottom line, the D-M cast-iron rear brakes ARE FLOATERS. They need a rubber hose to take up the movement of the caliper along the pins, the factory's effff-up on the driver's side notwithstanding.

 

I can not compute as to how some people do not know how the Disc-Brakes on their Vehicle operate.

Yes the Abutment-Bracket is fixed in-place...
However the Caliper moves one the Guide-Pins separate from the Abutment-Bracket that is fixed in-place.

The purpose of the Guide-Pins, is to guide the Caliper as it moves back-and-forth.

A quick and simple cheat for any of you that do not grasp this concept is...
If you see a one-piece Brake-Rotor; there is a 99% chance that the Calipers are floating.



...Ugh! C3 Corvette Disk-Brakes...
Horrible!

 

If the caliper must slide on pins, it IS floating. Period.

 

Understanding is one thing, remembering how my brake installation went together over ten years ago is another....
And I used flex lines.

 

Visuals help a lot. It's not this dramatic on the car though. And it'll keep creeping towards the axle as the outside pad wears (gets thinner).

 

That vid is an excellent demonstration of why a solid brake line cannot be run directly to the caliper; if it were to be plumbed that way, even that small amount of movement will fatigue and then break the line.

As far as 'fixed' calipers are concerned, the only cars I've ever worked on equipped that way were '65, '66, and '67 Corvettes. Others may have been similarly equipped, but those years are the extent of my own experience. I can say that while fixed calipers have definite performance advantages (greatly increased clamping force on the disc spread over a larger area of the pads), they also have definite drawbacks, namely, two-piece construction and a greatly increased number of wear-components. Those old cast iron Corvette calipers were subject to wear and rust in the piston bores, necessitating either complete replacement, or else overboring and sleeving with stainless steel inserts.

 

Piston on one side only = floating caliper.
Pistons on each side = fixed caliper.
Then you have radial mounted vs std mounting, but that's a horse of another color.

 

Thank You all.