DLaz70OLDS98

I posted the following on my build thread but felt it would be more appropriate here:

I was out in the garage yesterday and was looking over the brake system. This car was originally drum/drum. At some point someone was kind enough to upgrade the front to disc. . They installed an SSBC master cylinder, unnamed single calipers, unnamed caliper brackets and what I believe to be GM disc spindles. The brake lines are looking a little cruddy so I figured now is the time to swamp them out for a nose new SS set from Inline Tube. All the reading I have done on this conversion indicates that if you originally had the drum/drum system you need to install a proportioning valve directly under the master if you do not have a hold back valve installed in the line. I looked over the entire line and all I have is the D block bolted to the frame under the master cylinder. My question is:
#1 how did the brake system work without the hold back valve? (I thought the back brakes would have been blown out because of this set up)

#2 As I have read, I will be required to either install a proportioning valve or install a new D block with a hold back valve in the system, correct?

My instincts tell me to buy a proportioning valve and the SS conversion break line set and be done but I am curious what I got going on over here! As always I appreciate anyone's and everyone's feedback/insight!

joe_padavano

[QUOTE=DLaz70OLDS98;652772]The BRAKE system probably worked fine - under normal braking activity. Keep in mind that the factory designed the system to work under the extremes of light load/heavy load and light braking/heavy braking. I've unfortunately seen numerous cases of poorly executed disk conversions where the person who did the swap was clueless and did not install a prop valve or metering valve. The previous owner may have just been lucky, or perhaps just learned to live with the brakes locking up prematurely.

Almost. If you have a stock distribution block, you don't need a new one, just the metering valve. Alternately, replace the distribution block with a newer combo valve and kill two birds with one stone.

DLaz70OLDS98

Joe,
Thank you for the clarification and the grammar lesson. Real brain fart on that one

I think I will just get the combo valve and the conversion brake lines. Thanks again.