Power Brake Booster

[jim_ss409]

I've installed front disc brakes on a 62 with a high-perf. 409. I now need a power brake booster. As we already know it has to be offset like the factory setup in order to clear the valve cover. There is one available from the aftermarket that moves the booster both up and out. http://www.ecihotrodbrakes.com/55-62-Chevy-offset-power-booster.html I was thinking about getting it but I'm not sure I've got enough vacuum to run it. It's pretty expensive and I don't want to have to get a vacuum pump as well. I didn't run my new engine long but when I did I only had about 8in. of vacume at an idle. I might get 10in. with some tuning but that would be about it with the cam I've got. Does anybody know if that would be enough? Also has anybody run disc brakes without a booster? I was thinking about using a hydraulic setup from a wrecking yard but there's not alot of room at the power steering pump to add extra hoses so I'm thinking the offset booster would be the quickest solution. If it'll work.

[MRHP]

Why is your vac. reading so low? Does the motor have a massive cam or somthing? You may do some tuning and find your vac. reading will go up. Unless your engine is a race only design I would think you would have a reading of 15 to 24 inches. Just curious

[pg409]

I posted this two weeks ago on the engine forum. Ihave a 63 Impala
with a 340 hp 409/glide.
I used a stock 63 booster(cause I had a parts car) with a 72 Impala
M.cyl. ( deep cup)
Simple deal.........Used Chevelle discs. and rotors.

Check the thread.....has parts numbers and all....

Keith

[jim_ss409]

Keith, I did read your post (good info) but I've got droped spindles so I had to use Camaro rotors and Monte Carlo callipers. I even bid on a stock 62 booster on E-bay tonight but it went pretty high, $263
MRHP, I only idled the engine for a couple of minutes because I just wanted to test run it in the chassis, it's not hooked up to run now. With some tuning time I will get some improvement on the 8in. of vacuum that I got but I wasn't expecting to get anywhere near 15 to 24in. at an idle. My cam's not that big but it does have a fair bit of overlap due to the 110deg. LSA. It's a hydraulic roller with 238-248 @.050 This is in a 476ci. stroker. The 1" open carb spacers I'm running would also hurt the idle vacuum a bit. I do intend to take a few degrees of advance out of the distributor so that I can run more initial timing I know that'll help. But still I wasn't counting on more than about 10in. at an idle.

[dq409]

If you still have low vacc you might try a simple vacc canister. Might be just enough to make it work,,,dq

[jim_ss409]

yes! A vacuum canister might just be enough to do it if it's close.

[fatride]

I have a booster from Stainless Steel brakes inc. I run with the Moon aluminum valve covers. The booster clears the covers with about 1/4" to spare. I think you have to have at least 15" of vacuum to power your brakes. With the right master cylinder bore size you could have your Disc brakes without boost. There is a ratio formula that would have to be adhered to. But you can have power brakes without boost. I'll look and see if I can find the specs. Look at this and you will see that you can run disc without boost!

http://www.ssbrakes.com/tech/

[jim_ss409]

Thanks PDR. Manual brakes might be the easiest way to go. A friend of mine had a 70 340 Swinger that had manual disk brakes and it stoped all right. I wimped out and went with power steering but I don't mind having to push hard on the binders. I might give SS Brakes a call.

[Gus68]

Hey Guys!!! I recently installed disk brakes on my 68 Chevelle, I robbed the spindles, calipers and everything off of a 72 Chevelle, BUT I wanted a manual master cyl. BUT chevelles never came with manual disk brakes, so I ended up using a master intended for a mid seventys camaro with manual disk brakes. After driving the car for years with manual drums, I would have to say the car now stops on a dime!!!! It was the most simple swap I have ever done, I simply removed the drum master cyl and installed the disk master cyl. I used the original drum proportioning valve and everything!!!! Now I know that your car is NOT a chevelle but I would imagine that the manual camaro or possibly a different aplication would work pretty good for you.