hold-off valve or proportioning valve or both??

[cougs]

I'm converting to front disc brakes from drums all around and need to know of I need to use both a proportioning valve and a hold-off valve or if I can get away with one or the other.  Brake line bending and fitting is new to me so I'd like to take the simplest route.  Car is a 68 charger with manual drums all around (going to manual front disc)

Thanks.

[resq302]

The only thing you will need to install, aside from the correct master cylinder, is a hold off valve that is shaped like a brass t that goes on the line between the distribution block and the rear brakes.  Beware of the repros that In Line tube sells as they were known for having problems.  I experienced it twice with them and ended up finding an original one and rebuilt it myself.

[cougs]

How hard is this to install?  Do I need to flare brake lines?

[resq302]

It is not hard at all if you get new lines.  If you do reuse your original line, you will need to cut and double flare it.  Might be easier just to get the front to back line.

[John_Kunkel]

The only thing you will need to install, aside from the correct master cylinder, is a hold off valve that is shaped like a brass t that goes on the line between the distribution block and the rear brakes.

There is a difference between the hold-off valve that goes in the front brake circuit and the proportioning valve that goes in the rear brake circuit. The hold-off valve delays brake application until a specified pressure builds in the front circuit, the prop valve limits the pressure in the rear circuit.

I don't think anybody uses the hold-off valve in a retrofit, it's a factory thing.

[Hard Charger]

hold off block for back brakes only on old (factory?) systems.

metering block for the front brakes only on some systems.

and the proportioning / distribution block block all the time.

[John_Kunkel]

A difference in terminology, the correct term for the rear brake valve is Residual Pressure Valve (RPV), the metering valve (correct terminology) for the front discs is often called the hold-off valve.

[cougs]

I'm confused again.  I'm converting my manual/drum car to manual w/ front disc.  What do I need?  What do I need to do to install?

[Hard Charger]

i researched the hell out of the conversion. everyone you talk to has an opinion and every vendor has an idea on what need to be done. what blocks need to be used etc. i researched the old threads and pictures on this forum and i saw block that were being used in one and another saying it would never work and still another looking for a fix for using the same block.

in the end i bought the disc conversion and then the power booster and MC all from the same supplier and followed what they said. hopefully that works.

[John_Kunkel]

For a disc/drum setup the RPV in the factory MC is all you need, no need for an inline RPV.

If you're worried about the front metering valve, just get a factory-style combo valve and you won't need to do a lot of extra line bending/flaring.

[cougs]

So there is a residual pressure valve in the master cylinder?  How do I get a factory style combo valve?  Not many wrecking yards around me so i'd like to be able to buy it online...