70.... Drum to PDB conversion. Rear brake lines...

[Fourdman]

The proportioning valve / dist block on 70 with manual drum brakes is positioned differently than typical power disk brake cars in 1970. The rear brake lines enter the bottom of the proportioning valve on the power disk brake cars and enter the rear of the distribution block on the manual drum cars. I got my parts of an identical donor car that had pdb.

Complete brake line kits for what $150.00? If I have to replace all the lines to make this work then i'll go that route but I was wanting to avoid that and only replace the front lines. I have so much other work to do (in the middle of a complete front end build) as well as pedal, etc.

 

[Hack]

If you need new lines just buy the universal lines at the local auto parts store and bend them yourself. You'll be surprised at how easy it is.

 

[Fourdman]

I guess I have a few options...

attempting to bend the rear brake line so I can replace the dist block with the portioning valve and have it enter the unit at the right place. using an extenstion might make this possible??

I could keep the dist blick in and just and cut into the rear brake line and put a proportioning valve in line.

mold new rear brake lines? What tool? about how long is the rear line from dist/proportionign valve to the rear drums? will this be available in a pre cut length.

I need to get under there in my collllld garage and see what it's gonna take to remove the rear brake lines. I wish they used the same brake lines for drum cars in 70.

 

[bdepedro]

Are the brake lines different because of the disc/drum difference or the manual/power difference?

I currently have a '70 with manual brakes and front discs. I'm planning on converting to power brakes but also thinking about changing the rear drums to discs at the same time if it's not too much a PITA.

If you wind up changing your rear lines, let me know how it goes. I would do the rear disc conv mostly for maintenance ease so If it's too much work than I'll just do the power conv.

 

[mfp4073]

I think its the same as my 67

 

[Fourdman]

you wont have problems like me as there is no difference in the hydraulic system, only in the brake pedal and the addition of the booster, however... the rear end, etc. you using 9 inch rear?

I'll let ya know on the lines, shouldnt be too hard.

Regarding the post about the 67's system...

Thats what was used up untill 70 which is a two unit distribution block and proportioning valve. Although yours looks like an aftermarket adjustable proportioning valve it's still the same idea. Thanks for posting that, it's giving me ideas.

Are the brake lines different because of the disc/drum difference or the manual/power difference?

I currently have a '70 with manual brakes and front discs. I'm planning on converting to power brakes but also thinking about changing the rear drums to discs at the same time if it's not too much a PITA.

If you wind up changing your rear lines, let me know how it goes. I would do the rear disc conv mostly for maintenance ease so If it's too much work than I'll just do the power conv.

 

[Fourdman]

I posted this in another thread but here it is here too.

picture of the distribution block installed in my 70 drum system

proportioning valve off a 70 that i will be installing.

Notice how the rear line enters the dist block on the bottom on the drum system and the rear on the disk system.

 

[mfp4073]

Yeah, thats what I used when I went to front disk. I have a larger one if need be, just let me know.

 

[Edbert]

There's the unit on the fenderwell near the master cylinder, it is a distribution block AND a proportion valve (not adjustable), then there's another unit on the rear axle...sometimes they are cylindrical sometimes squared brass. I have heard these called proportion valves too, but they are sometimes called residual-pressure vavles. I don't claim to know the right answer for use of terms. I put 4-wheel discs on mine so all I needed was two "T" connections for splitting left & right from the front circuit and the rear, then an adjustable prop valve like in MFP's picture.

Also wanted to chime in on the "making your own lines" thought...if you use standard aluminum lines they are VERY easy to work with using a hand-tool you can get at Autozone for under $20. But if you are using stainless steel lines it is quite a bit harder, not out of the ability of a patient shadetree mechaninic, but definitely harder to work with. You'll also want a flaring tool to DIY, I bent mine, put the fittings in place and took them to a brake shop to have flares made professionally...not wanting to risk failures on brakes and all. Brake Check only charged me $20 to make about 10 flares.

 

[Fourdman]

OK, the picture is making sense now.

I would still have to do some routing and mod to that rear line and since i got the prop/dist valve combo already it still might be best to mend my own brake lines and go with the stock dist/prop valve.

It's certainly an option, at least i'd know how to run it. makes sense. I'll let ya know about that bigger prop valve you got. Would i have to do anything with the residual pressure valves in the rear lines? I thought 70 did all of it in the one unit for PDB.

 

[bdepedro]

you wont have problems like me as there is no difference in the hydraulic system, only in the brake pedal and the addition of the booster, however... the rear end, etc. you using 9 inch rear?

I'll let ya know on the lines, shouldnt be too hard.

Regarding the post about the 67's system...

Thats what was used up untill 70 which is a two unit distribution block and proportioning valve. Although yours looks like an aftermarket adjustable proportioning valve it's still the same idea. Thanks for posting that, it's giving me ideas.

Yep, 9" rear w/ drums; front discs (Granada conv). I've seen some booster conversions that say they don't require a pedal change. That would be nice!

 

[jayer]

what is pdb.?

 

[Justin01]

what is pdb.?

Power Disc Brakes