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Discussion Starter · #1 ·
So i replaced the rear brake wheel cylinders and i noticed i only get full rear brake power in 4wd but in 2hi they dont get near the amount of brake power. Any idea why
 

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So i replaced the rear brake wheel cylinders and i noticed i only get full rear brake power in 4wd but in 2hi they dont get near the amount of brake power. Any idea why
In 4 hi the front and rear axles are connected together via the t-case which is a part time case and has no differentiation in it. So, basically the front brakes are working to help the rear brakes.

In 2hi, you are getting the correct amount of braking ability because you never want the rears to lock up and it is difficult with a short wheelbase high profile vehicle to make that happen, so they are just barely working in order to keep you safe.

They are only there to stabilize the vehicle in a braking event and little else.
 

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Could you just be feeling more braking when in 4WD because of all 4 wheels are "engine braking" when you let off of the gas?

2WD = Only rear wheels "engine brake"
4WD = Front and Rear "engine brake"

I hope I am explaining this well enough.

Let us know pal.
 

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Discussion Starter · #4 ·
Not a matter of feeling. I was slamming the brakes and in 4wd they would lock up but in 2hi they wouldnt. I just wanted to make sure there wasnt something wrong
 

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did they bleed out ok? or should I say, what does the pedal feel like?

The pedal pressure on the first 1/3 to 1/2 of your pedal push is for rear most of the time. If the first half of your pedal push is spongy, you still have air in the lines and need to bleed 'em again.

If your pedal push is solid right near the top, then your fine and it is working as designed.
 

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Discussion Starter · #6 ·
The pedal is soft til about 1/2 way down so ill re-bleed them. Whats the proper way to do it? Ive heard many differrnt ways. Cap on cap off truck running or off?
 

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The pedal is soft til about 1/2 way down so ill re-bleed them. Whats the proper way to do it? Ive heard many differrnt ways. Cap on cap off truck running or off?
The soft pedal can also be that you don't have the rear shoes adjusted correctly. They need to drag slightly when turn by hand, make it so.

Bleeding is done engine off, start at the furthest point from the master and move progressively closer.

Open bleeder, have helper push pedal down hard and fast and hold at the bottom and tell you when it is down.

You close bleeder and tell them up and let you know when it is up.

Repeat 5-8 times per corner.
 

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The pedal pressure on the first 1/3 to 1/2 of your pedal push is for rear most of the time. If the first half of your pedal push is spongy, you still have air in the lines and need to bleed 'em again.
No, you can't move the pedal without pushing fluid equally out both ports on the master.

There is no delay in how the front pressure builds initially due to the ports between in and out on the combo valve being non valved or restricted for the front brakes.

The rear circuit has proportioning built into it to stop the servo nature of rear drums and to limit pressure once a certain point has been reached to prevent lock-up.
 

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Discussion Starter · #9 ·
Thank you so much for the reply and info! Ill have to re-bleed them tomorrow
 

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a good way to determine if air is present is to pump the pedal two or three times (engine off). if u achieve a higher pedal height on the second or 3rd pump u probably have air in the line.. u can also check adjustment of the rear shoes by setting the E-brake. if it bottoms out with with brake engagement & there is still room left at the top of the lever-set they r properly adjusted...:thumb:
 
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