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Old 07-17-2010, 11:34 PM   #1
bigdon-70blazer
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Went for a little drive.

Took the Blazer for a little drive this eve. The brakes are HORRIBLE ! I changed everything when I restored her. I rebuilt all the wheel cylinders and the master cylinder myself. Bled the brakes but at regular driving, it was like not having brakes. Any suggestions? Should I start at the master cylinder, replace it with a rebuilt one then the wheel cylinders? I changed all the brake lines also with stainless stuff from inline tube. I think I got my throttle thing worked out, actually got it up to 55 miles per hour, still got some shakedown to do.
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Old 07-17-2010, 11:36 PM   #2
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Re: Went for a little drive.

I'd start by bleeding the system to make sure it doesn't have any air in the lines.
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Old 07-18-2010, 08:35 AM   #3
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Re: Went for a little drive.

Will do!
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Old 07-18-2010, 10:08 AM   #4
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Re: Went for a little drive.

I would also bleed the system again. After that I would look at the MC. If its a rebuilt one I would be suspicious. I went through two bad rebuilt MC's on a vette once before using a brand new one which worked fine. Good luck.
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Old 07-18-2010, 12:56 PM   #5
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Re: Went for a little drive.

Brake booster? It could be leaking vacuum.
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Old 07-18-2010, 02:45 PM   #6
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Re: Went for a little drive.

I also would look at the master cylinder.

If you had one bad wheel cylinder or caliper it would probably be leaking or you would notice one corner of the vehicle not braking properly. Sounds like all 4 corners of yours are equally not working. So after one more good bleeding just to be sure, I would look at the MC. The booster wouldn't cause this problem, it would just cause you to lose the "power" feel, not the braking itself.
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Old 07-18-2010, 03:50 PM   #7
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Re: Went for a little drive.

How does the pedal feel when you step on the brake?
Step on the brake and then start the engine. The pedal should sink a bit when the booster gets vacuum.
Does the emergency brake work right?
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Old 07-18-2010, 04:32 PM   #8
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Re: Went for a little drive.

Does it have drums on all 4 corners?
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Old 07-18-2010, 05:18 PM   #9
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Re: Went for a little drive.

No power for me! It has 4 corner drums. And I rebuilt the master cylinder myself, a job I had never done but it was not that complicated so that could be the problem also. The brakes feel hard enough just not enough braking for the amount of force I seem to be giving. Boy, rebuilding a car is fun!
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Old 07-18-2010, 10:28 PM   #10
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Re: Went for a little drive.

Quote:
Originally Posted by bigdon-70blazer View Post
No power for me! It has 4 corner drums. And I rebuilt the master cylinder myself, a job I had never done but it was not that complicated so that could be the problem also. The brakes feel hard enough just not enough braking for the amount of force I seem to be giving. Boy, rebuilding a car is fun!
Well there's your problem! You need power disk brakes!

I'm kidding but not really. I can't remember, did you drive this blazer before the rebuild? Are you familiar with how non-power drums are supposed to feel??? I'm sure you are.

On my 68 truck with the same setup I had to spend hours adjusting the so called "self adjusters" because they weren't doing their job! Have you tried backing them out a little?
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Old 07-18-2010, 07:48 PM   #11
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Re: Went for a little drive.

Did you "bench bleed" the master cylinder?

Last edited by low'n slow; 07-18-2010 at 07:49 PM.
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Old 07-18-2010, 11:23 PM   #12
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Re: Went for a little drive.

You need to adjust the brakes more. Turn the drums by hand and completely tighten them with the adjusters, then back them off until you can actually hear the shoes with the drums. If your MC is ok, the problem is adjustment.
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Old 07-19-2010, 12:03 AM   #13
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Re: Went for a little drive.

Quote:
Originally Posted by 72Levi View Post
You need to adjust the brakes more. Turn the drums by hand and completely tighten them with the adjusters, then back them off until you can actually hear the shoes with the drums. If your MC is ok, the problem is adjustment.
That's what I was getting at, I'm just a little "longer winded".
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Old 07-19-2010, 08:38 AM   #14
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Re: Went for a little drive.

I will try this...Thanks!
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Old 07-19-2010, 02:08 PM   #15
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Re: Went for a little drive.

x2 on the bench bleeding of the master cylinder. I also highly recommend getting some of those "one man" brake bleeder screws for each of your brake pistons. These prevent backflow of fluid and air into the pistons as you pump the pedal. You don't need a second person to open and close the screw. Can get them in any parts store in the "Help" section for a few bucks.
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