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Lock up brakes

Tiny
ALEX JANE VILLAR
  • MEMBER
  • 2000 ISUZU ELF
  • 4 CYL
  • 2WD
  • MANUAL
  • 10,000 MILES
Brake master already replaced and the wheel cylinder too. If I test the brakes without running the engine, the brakes does not lock up but if I put the engine and test the brakes, it will lock up though I released the brake pedal already.
Saturday, December 14th, 2019 AT 1:58 AM

11 Replies

Tiny
ALEX JANE VILLAR
  • MEMBER
  • 7 POSTS
I will wait for the answer and I am glad to be here.
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Saturday, December 14th, 2019 AT 2:05 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,867 POSTS
Hi,

I'm not familiar with this vehicle. However, I'll try my best to help.

When you say it locks up when you start the engine, does it require you to first apply the brake or does it happen automatically? Also, what type of power brake assist does this vehicle have? Is it vacuum actuated?

Let me know.

Take care,
Joe
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Saturday, December 14th, 2019 AT 9:08 PM
Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,005 POSTS
I have no information specific to your vehicle.

It does sound as though that maybe the adjustment rod/ screw found in between the vacuum booster and the master cylinder may be "adjusted out" a little too far.

Sometimes getting it just right may require a few times of trial and error.

You might even try to find a better procedure from a local source that may make this easier for you.

Although this is "not" your vehicle at all in my pic, it may explain what I'm suggesting. I say again, this pic is just a generic one.

The Medic
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Saturday, December 14th, 2019 AT 9:15 PM
Tiny
ALEX JANE VILLAR
  • MEMBER
  • 7 POSTS
How will I adjust the rod? Is it inward or outward?
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Saturday, December 14th, 2019 AT 9:39 PM
Tiny
ALEX JANE VILLAR
  • MEMBER
  • 7 POSTS
CJ MEDEVAC, how will I adjust the rod? Is it inward or outward?
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Saturday, December 14th, 2019 AT 9:41 PM
Tiny
ALEX JANE VILLAR
  • MEMBER
  • 7 POSTS
Joe, it happens when I apply the brakes.
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Saturday, December 14th, 2019 AT 9:42 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,867 POSTS
Does it have a vacuum assist brake booster? If you disconnect the booster, does it happen? As far as the rod CJ is referring to, if adjustable, it would need turned in slightly. If you try that, make sure the brakes are working properly before driving it.
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Saturday, December 14th, 2019 AT 10:53 PM
Tiny
ALEX JANE VILLAR
  • MEMBER
  • 7 POSTS
Joe, when I disconnect the hose from the booster the brake don't lock up. Then I connect again and the brake lock up.
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Sunday, December 15th, 2019 AT 2:33 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,867 POSTS
Is it a vacuum assist brake boost system? Also, do you know if there is an adjustable push rod?
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Sunday, December 15th, 2019 AT 5:17 PM
Tiny
ALEX JANE VILLAR
  • MEMBER
  • 7 POSTS
Joe, it's vacuum assisted brake system.
I saw an adjustable push rod in the booster.
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Monday, December 16th, 2019 AT 12:10 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,867 POSTS
Hi,

Please understand I don't have technical info on this vehicle, but it sounds like the push rod needs retracted a bit. When the assist is actuated (vacuum), it sounds like the travel for the push rod isn't there any longer.
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Monday, December 16th, 2019 AT 12:24 PM

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