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Proportioning valve

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Old 04-14-2019, 08:35 AM
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Default Proportioning valve

I have a 88 dodge dakota 4WD. Has around 124,000 on it. The brake pedal goes about 3/4 of the way down. Before it even thinks about stopping. Pedal is very soft. Returns slow. Also sometimes when I let off of it I hear a squeaking coming from outside the truck. I put new pads and rotors on in the spring of last year. Flushed and bled all 4 corners while I was at it too. Did this manually. Pedal was soft and came back slow then too. But not as soft as it is now. I just recently put new drums and shoes on a couple weeks ago. I had to more/less quit driving it unless I have to. As I can't trust it to stop. Already rear ended two cars. First one was a freak deal where a dog ran into traffic. 2nd I ended up getting a ticket. One or more of the wheels do lock up under heavy braking. Could the p-valve be bad. No light is on. It has the p-valve with adjustable spring on the outside of it.
 
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Old 04-14-2019, 10:24 AM
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Pedal height is controlled by rear brake adjustment. Make sure that is good first. Next, it sounds like you still have air in the system somewhere, or, possibly a failing master cylinder...... Try pumping up the brakes with the engine off, and see if they will, then, hold the pedal, and see if it starts sinking slowly to the floor.
 
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Old 04-14-2019, 01:47 PM
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what he said.
if the rear shoe adjustment is to large...the master cylinder has to move a lot of fluid for the wheel cylinders to move the shoe into contact with the drum. bad set up will also mean a slack ebrake adjustment.

you should have some drag on the drum and shoe. When I set them up; I set a slight drag....apply the service brake several times and then release...this centers the shoes to the drums...and then perform a final adjustment.
 
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Old 04-14-2019, 04:07 PM
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one drum went on a little snug. the other didn't. but the rear is suppose to self adjust when backing up. as far as rear brake adjustment do i just turn the thumb screw?
 
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Old 04-14-2019, 04:48 PM
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The adjusting star wheel? Yep.

Full instructions are on almost any location that describes drum brakes; also, in the factory service manual. Page 5-1 to be specific.

I've attached that page as a 1 page PDF.

RwP
 
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Old 04-14-2019, 06:12 PM
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Originally Posted by DKirkman41
one drum went on a little snug. the other didn't. but the rear is suppose to self adjust when backing up. as far as rear brake adjustment do i just turn the thumb screw?
self adjusting system will not correct for a large gap. you could back up all day. remove the plug and move the star wheel. I like to make it tight, then back it off...takes more time and is a little harder to push off the lock off the star wheel.
 
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Old 04-14-2019, 09:47 PM
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The pedal does get hard. When I pump it with out the engine running. As soon as I crank it. The pedal goes to the floor.
 
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Old 04-14-2019, 10:06 PM
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That might be the brake booster there, DKirkman41.

Typically when a booster fails, it's because the master cylinder seals failed and it's been sucking brake fluid into the booster; I'd be replacing both because of your cousin and mine, Justin Case.

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Old 04-14-2019, 10:56 PM
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your pedal will always sink when engine starts and vacuum applied to booster. but pedal should still be solid and firm not squishy.
on your squeak, that is common with drum brakes. could also be pedal linkage under the dash being a bit dry.
 



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