I gave up on the rebuilding the original master cylinder/power booster for my '62 Invicta and I have decided to convert to a dual system. Why?... MUCH SAFER! I wanted to convert it to the most common, cheapest setup I could find and I figured a 76/77 Chevy Caprice Classic was about the right displacement tonnage. I was told that a 1977 Buick Estate Wagon shared the same MC/PB that the 77 Caprice did so, I went out and bought the power booster with the master cylinder attached ($100 from Autozone, A-1 CARDONE Part # 501002). The bolt pattern looked the same but the booster housing was bigger so I was worried that it wouldn't fit. <a href="http://www.v8buick.com/attachment.php?attachmentid=94595&stc=1&d=1180989818"> <img src="http://www.v8buick.com/attachment.php?attachmentid=94595&stc=1&d=1180989818" width="250" align="center"></a> The GOOD NEWS is that (62 Buick Guys, are you paying attention?) the PB/MC bolted right in with NO MODIFICATIONS! It fit like a charm! <a href="http://www.v8buick.com/attachment.php?attachmentid=94596&stc=1&d=1180989987"> <img src="http://www.v8buick.com/attachment.php?attachmentid=94596&stc=1&d=1180989987" width="250" align="center"></a>
The project hasn't progressed because I'm still looking for a proportioning valve... It seems that proportioning valves don't go bad so they are all dealer items (READ: overly expensive). A friend of mine has a Suburban that is wrecked that he's going to give me the valve from. AMCer...YOU RULE!!!:bglasses: I will be saving this info for use on my 62 Electra. I know. BTW, Here's my Invicta- <img src="http://www.v8buick.com/vbgarage.php?do=getimage&id=372">
Excellent thread! Thanks so much for posting this AMCer! And you brought up something I've been wondering about.... proportioning valves. The 73 Century wagon we're parting out has such a valve. I know cause I've seen it. lol Should I keep this and use it on our 60 Invicta? The Invicta has drums all the way around so is it necessary - beneficial - pointless?
I'd have to disagree with that, especially when running a rear drum/front disc MC on a four-wheel drum car. The original four wheel drum MC usually had equal metering in the front & rear pistons, but still required the valve to set the front to rear brake bias due to weight distribution (less pressure to the rear). Adding the late model disc/drum MC to a four wheel drum car may make the bias even worse depending on what mix of part you use. The easy way to make it right is to use an adjustable proportioning valve and dial it right in. Good stuff here. Devon
Yea, right. Forgot about using the disc brake master. Guess I should pay more ATTENTION when reading posts. Me bad!!!!
Should you keep the proportioning valve??? HELL YES! The proportioning valve is a block the you connect both the front and rear brake lines to. It has a sliding piston in it that moves to [somewhat] equalize the pressure AND sense a brake failure (it drives the BRAKE dash light). These things never fail and thus, they are not sold as off-the-shelf replacement parts. You can only get them from the dealer or a junked car. You can buy new after market ones for race cars for way-too-much $$$. I'm having a bitch of a time finding one (for less than an obscene amount). I am to understand that if you are running full drums or full discs, you don't need a another valve (the adjustable one mention above). You may need to add and adjustable valve if you are running a disc/drum setup. I don't know, I'm running all drums.
If you run all disc/all drums with an all disc/all drum MC, an all disc/all drum valve might do it. If you run a frt disc/rear drum MC on all disc/all drum, you may need an adjustable valve rather than the OEM type. The best setup is to use the adjustable valve from the start. Those OEM parts were designed and calibrated for specific brake bias due to weight distribution. If you're swapping parts around that were never meant to be together, the valving & bias may not be appropriate between the MC and proportioning valve you've installed. By using an adjustable valve and setting it up per the article, you're in good shape for your specific combination and have the luxury of tuning it as you change the car in other ways...even changing tire width can affect bias. Braking is something you just don't wanna mess up. Devon P.S. For what it's worth, I'm a fuel/brake design engineer...at least at work, anyway.
Thanks for explaining it the way you did Devon. What you are saying makes sense, but(don't ya just hate it when people say that?) if you don't mind could you maybe answer a couple other questions for me? How do I determine the set-up on the pro valve I have on the 73 wagon? It might be right it might be totally off.... how do I know for sure? Is there a way to utlize the current pro valve that is on my 60 Invicta with a newer 2 line master cylinder? Maybe I could find another pro valve from a 60 Invicta plug the rear output on one and front on the other? Even if I get an adjustable pro valve I'd have no idea how to go about setting it? Thanks for your time.
The link I pasted in post #9 does a good job of explaining...sorry if it was hard to catch the link, here it is: http://www.chevyhiperformance.com/techarticles/71398_install_brake_proportioning_valve/ Basically with whatever setup you've got, you always want to keep the rear brakes from locking up before the front...that keeps the rear of the car behind you where it belongs. :grin: Devon
