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New hydroboost still no brakes c10

Landon730

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After I got done changing the motor in my 83 the hydrobooster finally crapped out completely. It always poured PS fluid but still worked. It got to the point where it just went all the way to the floor and the brakes would barely work. I put a new one on it but the pedal still goes to the floor. It comes back up like normal but brakes still don't work right. If you work them just right the brakes work like normal. Occasionally they will work for 1-10 pushes. Im stumped with it at this point
 
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I can't see your instructions but IIRC you should put it on jack stands and then (with the engine running) turn the steering wheel slowly from lock to lock while depressing the brake pedal (the brake pedal should be depressed several times as well but not pumped). If thats not it then something failed in your brake system failed which is highly likely since you indicated that soft pedal before the change.
 

Landon730

Active Member
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Greenwood Arkansas
I can't see your instructions but IIRC you should put it on jack stands and then (with the engine running) turn the steering wheel slowly from lock to lock while depressing the brake pedal. If thats not it then something failed in your brake system failed which is highly likely since you indicated that soft pedal before the change.
I went lock to lock but it wasn’t jacked up I’ll try that tomorrow and the old booster couldn’t build pressure because it just absolutely poured PS fluid out I’ll try it with jacks and let you know how it goes
 

WarWagon

Well it hits on 7 of 8...
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I assume you changed the push rod on the hydro booster into the master cylinder as replacements don't come with the rod installed. You still have the core, right?

A restricted return line comes to mind from the hydrobooster.

Soft brakes to the floor... Blew a wheel cylinder out, air in brake system, bad master cylinder, rear linings out of adjustment... What is brake fluid level? You can test this engine off. @ak diesel driver beat me to post it, but, I agree.
 

Landon730

Active Member
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Location
Greenwood Arkansas
I assume you changed the push rod on the hydro booster into the master cylinder as replacements don't come with the rod installed. You still have the core, right?

A restricted return line comes to mind from the hydrobooster.

Soft brakes to the floor... Blew a wheel cylinder out, air in brake system, bad master cylinder, rear linings out of adjustment... What is brake fluid level? You can test this engine off. @ak diesel driver beat me to post it, but, I agree.
Yes I changed the retainer and push rod and I took the old one in as a core for the new one. No brake fluids leaking from the rear brakes, fluid is full (brown) but full. What I don't undertstand is sometimes they work for 20 minutes or so then gone, then 3 days later they are back... for 20 minutes or so
 

Will L.

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If there is enough contamination to turn the fluid dark- flush it. Then bleed again. It sounds like there is trapped air, but in old contaminated fluid, it is much easier to get the fluid to a state of aeration.
 

Will L.

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Switching to DOT?

The brakefluid should be DOT3
The powersteering and hydrboost system should have either dextron3 atf or power steering fluid in it.

What are you using now?
 

Will L.

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I see nothing wrong with DOT 3. That is what the system was designed for.

switching to dot4, (which I believe is compatible) I will step down from that question. With one caviat: Could be best or worst move available. When having a problem, making unnecessary changes can complicate things. Perhaps the dot4 would work, but maybe has seal swelling or shrinking issues once in a great while. And if a normal flush would fix it but you introduce a new variable...?

So for now, I would not. I would say stick with an unopened bottle of 3 and flush the whole system so it is all new and zero contamination. Then later if you need to step up the game and dot4 sounds like the helper- then do it.

If someone else here knows of big advantages that may help him To use 4, please speak up.
 

Landon730

Active Member
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Location
Greenwood Arkansas
I see nothing wrong with DOT 3. That is what the system was designed for.

switching to dot4, (which I believe is compatible) I will step down from that question. With one caviat: Could be best or worst move available. When having a problem, making unnecessary changes can complicate things. Perhaps the dot4 would work, but maybe has seal swelling or shrinking issues once in a great while. And if a normal flush would fix it but you introduce a new variable...?

So for now, I would not. I would say stick with an unopened bottle of 3 and flush the whole system so it is all new and zero contamination. Then later if you need to step up the game and dot4 sounds like the helper- then do it.

If someone else here knows of big advantages that may help him To use 4, please speak up.
Ok I’ve heard that dot 4 doesn’t draw moisture like 3. For now I’ll keep 3 to keep thinking’s constant. Power steering/ hydro boost have clean dexron/power steering fluid mix. Another possibility I thought of was maybe a weak pump? When the brakes do work it whines
 

Will L.

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That is incorrect. Dot 5 is the one that repels moisture. But DO NOT switch to it. It has it’s own host of problems. The first of which is it is not compatible at all with dot2,3,or 4. The seals have soaked in 3 and will come apart quickly if you swap to dot 5. You have to have all brand new unused components to run 5.

You should flush the steering and booster system now too since they are mixed. From now on ONLY use dextron3 in it. They are compatible in that one will not destroy the other or damage the seals, other than the dextron will slightly swell the seals. Once vacant of it they will try returning to original size and will allow bypass. But they do pressurize at different rates and handle temps slightly different. That in itself could be part of the issue.

So buy UNOPENED DOT3 to flush and bleed the brake fluid. Then buy dextron 3 and flush the power boosting system and bleed it of air.

Do both before trying any other parts, fixes, or adjustments.
 

WarWagon

Well it hits on 7 of 8...
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The hydrobooster just helps you push the brakes. If the pedal goes to the floor the wheels should be locking up. If not something in brake system is wrong.

Whining is the pump at full pressure against a load like full lock on the steering wheel or working brake system.

A non working brake system is not building pressure before the master cylinder bottoms out. So air, leaks including leaks internally in master cylinder...

The pedal hitting the floor at times with poor braking... Wet brake fluid boils easy. Dragging brake caliper can heat it up and steam is air.
 

WarWagon

Well it hits on 7 of 8...
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Ok so replace (or not likely rebuild) the rust pitted 35 year old (36 model year) master cylinder, replace/rebuild the calipers as you can't flush them out well and same rust pitting, and replace the wheel cylinders. Brake hoses are also 35+ years old so then can stand to be new while you are there. Check all brake lines for rusting trough. Just a PIA - not much in parts. Frictions are your call, but, get the expensive ones if you do change them like Raybestos or Wagner. You would be surprised at what top of the line shoes can do with well adjusted rear drums. CHEAPEST brake frictions add stopping distance and CHEAP on brake systems is one area even my Frugal ass doesn't do. Parts Store house brands are not top of the line - there is better out there. @RockAutoLLC Rock Auto is a very good option for saving money on top of the line frictions like I mentioned.

And since you are staring at them the rear axle seals could be a ticking leak bomb ready to ruin your brake frictions.
 
Last edited:

Landon730

Active Member
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Location
Greenwood Arkansas
Ok so replace (or not likely rebuild) the rust pitted 35 year old (36 model year) master cylinder, replace/rebuild the calipers as you can't flush them out well and same rust pitting, and replace the wheel cylinders. Brake hoses are also 35+ years old so then can stand to be new while you are there. Check all brake lines for rusting trough. Just a PIA - not much in parts. Frictions are your call, but, get the expensive ones if you do change them like Raybestos or Wagner. You would be surprised at what top of the line shoes can do with well adjusted rear drums. CHEAPEST brake frictions add stopping distance and CHEAP on brake systems is one area even my Frugal ass doesn't do. Parts Store house brands are not top of the line - there is better out there. @RockAutoLLC Rock Auto is a very good option for saving money on top of the line frictions like I mentioned.

And since you are staring at them the rear axle seals could be a ticking leak bomb ready to ruin your brake frictions.
Turns out the master wasn't pushing no pressure. My dad wanted to try bleeding the brakes out so I got under it and fluid was at the bleeders but wouldn't even dribble out when the pedal was pushed. But a new to me master cylinder on it and now it shoots fluid all the way up to the fender well.
 
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