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Old 05-25-2012, 03:59 PM   #1
jsdoyle
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Having to stand on them

My new truck has a brake booster, disc up front and drum rears. I've not pulled the tires yet to inspect the brakes but I really have to puts some effort in pressing that brake pedal.

Before I get started do you guys have any suggestions or ideas on what to look for? I know I'll have to pull the tires but are there any adjustments otherwise to try?

Thanks!
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Old 05-25-2012, 04:16 PM   #2
tubbedII
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Re: Having to stand on them

Vacuum leak to the booster would be the 1st thing I'd check.
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Old 05-26-2012, 08:34 AM   #3
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Re: Having to stand on them

Thanks, I did check that and to my surprise the hose end that fits in the valve cover gasket was pulled out. Thinking "shazam!" I put it back in and away I went.

No luck... So much for that! I'll still check to make sure I'm getting vacuum at the boost end.

Thanks!
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Old 05-26-2012, 09:57 AM   #4
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Re: Having to stand on them

The hose from the boster does not go to the valve cover, go's to manifold to gain vacumn
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Old 05-26-2012, 11:51 AM   #5
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Re: Having to stand on them

Yeah. That's right. I had to take the air filter off to find it.

Popped the fluid resevouir lid off and found out it was low on fluid. Should have started there. New fluid makes a hell of a lot of difference!! Now keeping my fingers.crossed theres no leak somewhere.
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Old 05-29-2012, 11:41 AM   #6
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Re: Having to stand on them

Fluid doesn't typically evaporate from the reservior...I'd go through your lines to see where the leak is.
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Old 05-29-2012, 11:48 AM   #7
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Re: Having to stand on them

You are right. It's empty again. So, looks like I've got a leak.
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Old 05-29-2012, 12:48 PM   #8
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Re: Having to stand on them

With it emptying that fast, hopefully it's easy to find at least!
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Old 05-29-2012, 08:52 PM   #9
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Re: Having to stand on them

Do you happen to know what the bore size is in your master ?

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Old 05-30-2012, 12:13 AM   #10
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Re: Having to stand on them

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Do you happen to know what the bore size is in your master ?

Justin
Dont know off the top of my head. How would I measure that?

I checked for leaks tonight and haven't found one. Yet.

So the master cylinder has two chambers. The one toward the booster keeps emptying. There is brake fluid in the engine compartment under the master cylinder.

So is there an issue with the master cylinder and it loosing the fluid due to too much pressure? Brake lines not blead properly?

Scott
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Old 05-30-2012, 10:19 AM   #11
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Re: Having to stand on them

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Dont know off the top of my head. How would I measure that?

I checked for leaks tonight and haven't found one. Yet.

So the master cylinder has two chambers. The one toward the booster keeps emptying. There is brake fluid in the engine compartment under the master cylinder.

So is there an issue with the master cylinder and it loosing the fluid due to too much pressure? Brake lines not blead properly?

Scott
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Measure the opening of your two different ports on your master

Justin
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Old 05-31-2012, 12:51 AM   #12
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Re: Having to stand on them

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Measure the opening of your two different ports on your master

Justin
Well they measure right at 2 inches wide at the top. I'll post a picture in the morning of the master cylinder setup. Thanks!
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Old 05-31-2012, 08:20 AM   #13
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Re: Having to stand on them

Here are a couple pictures of the booster/MC. You can see how some of the brake fluid is on the MC. When I first opened the MC the reservoir closest to the booster was empty. I added brake fluid and after 2 days of driving it was empty again and the MC had brake fluid on it and some was on the wheel well below the MC.

I refilled the MC Monday and after driving last night I see no loss of fluid.

I've not found any leaks other wise but I've not pulled the wheels. I have looked across at each wheel from under the truck and I don't see any signs of a leak. Not that doing that will tell me much.

The truck has disc front and drum rear.
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Old 05-31-2012, 11:57 AM   #14
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Re: Having to stand on them

I would change out the master you have on your truck to a new one

Justin
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Old 05-31-2012, 12:08 PM   #15
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Re: Having to stand on them

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I would change out the master you have on your truck to a new one

Justin
Any recommendations?
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Old 05-31-2012, 12:13 PM   #16
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Re: Having to stand on them

Call us at the shop and we can help you out for sure.You can reach us at (805)485-0382

Justin
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Old 06-07-2012, 07:35 PM   #17
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Re: Having to stand on them

MC may be leaking into the booster? Also that looks like a drum brake MC, disc/drum should be bigger, at least on one side if not both. I agree with Justin, change out the MC
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Old 06-21-2012, 12:32 AM   #18
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Re: Having to stand on them

I may be a little late on this but I've had the same problem before. It turned out to be a hole in the back of my vacuum reservoir. Turns out that it was rubbing against something (can't remember what) and wore a hole right through it back where you couldn't see it; everything was factory stock too. I changed mine out and problem solved.
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Old 06-21-2012, 08:23 AM   #19
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Re: Having to stand on them

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Originally Posted by Lugnutt View Post
I may be a little late on this but I've had the same problem before. It turned out to be a hole in the back of my vacuum reservoir. Turns out that it was rubbing against something (can't remember what) and wore a hole right through it back where you couldn't see it; everything was factory stock too. I changed mine out and problem solved.
Thanks Lugnutt! I ended up fixing them last Saturday. I bought a new master cylinder and brake booster from Autozone for 105 bucks and put those in the truck. I'd never installed those and it's been a while since I had a car/truck I could work on but I got the job done and now my brakes are excellent! I barely have to tap the pedal now. What a difference it made!

I put in a booster and master cylinder for a 74 C10. The only hitch I had was the booster rod to the brake pedal wasn't long enough. I had to make an extension about 2 inches long and that was it!

Lovin' the new brakes!!
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