Poor brakes at low RPM
 

I am new to this forum. I just purchased a 71 Chevelle, I am very disappointed with the braking. I've noticed the power brakes are very bad when at idle and low speeds. This is my 2nd 71 Chevelle and never had issue's with power brakes, although this one is not as stock as my previous. It's got a 400 bored out to a 406 with a pretty beefy cam. Any suggestions on what to look for first? Any possibility it's the booster?

Any suggestions would be greatly appreciated.

john

It's not pulling enough vacuum because of the camshaft. Install a vacuum reservoir canister, that will fix your braking issue relatively cheap & easy.

Welcome to the Chevelle forums John.

A couple questions I have for you would be, do you know how much vacuum you have at idle? Did you check your brake hose to the manifold for leaks? Maybe the check valve at the booster is bad or leaking.

We like to see some pics too.

Mike

There is a canister currently installed. I also notice power steering is effected as well when I first start the car. I will check vacuum at idle as that seems most logical at this point. The carb is a "demon" which I am not all that familiar with since i've only had Holley carbs. Can carbs also effect vacuum?

I appreciate your responses! I've got to get this fixed. Makes me nervous driving it!

Sorry Mike, I went to attach a picture but not sure how that's done? never mind- found how to attach

Welcome and I bet the others are right about too little Vacuum as my old chevy truck was just as you described .

Here is a picture.

Welcome John. Looks like a nice car. I had problems with vacuum. Installed a canister like previously suggested and it cured my problem. My problem had more to do with the bigger cam and carb and when I braked I lost a lot of vacuum. Good luck, and just so you know. If you put your pics into an album on your profile page, you will be able to use the BB code and post larger pictures into the threads.

Grumpy, testing the vacuum what is the proper range at idle that brakes require?

WOW ,that yellow really pops ,I like it .You know we want more pics though ,nice car.