hydroboost system ????

[Chatmanboy]

I need to figure out how this system actually work. im having problem getting hard brakes. they just got to the floor. I changed the MC and it still does the same thing when i try do bleed the system. As if im not getting pressure. I hear hissing noise from the PS pump when i apply the brakes. Can the PS pump be bad and can cause no brake pressure? Or could it be the hydroboost need to be change. Is there a way to diagnose the hydroboost?

 

[TurboBuRick]

Is it a new system? Just installed?

 

[Chatmanboy]

no isnt new, but one day my brakes went to the floor on me. took a look at the system and noticed build up by the PS pump and hoses. So i took it off and cleaned it up and made sure everything was tight. put and back on and tried bleeding the system and the brakes went to the floor. So i changed the master cylinder and still does the same thing. cant even bleed the brakes

 

[GNRick]

I've heard that noise from the PS pump is normal at first, then goes away when the air is all out. What HB system do you have?

 

[Chatmanboy]

hyrdoboost system not the powermaster or vac.

 

[GNRick]

Ok I just noticed in your sig that you have an 85 GN. So you have the original HB that came on the car? The one I just bought comes with a vacuum canister so if the engine or power steering pump dies the brakes still work.

 

[Chatmanboy]

Ok well maybe I got a new faulty master cylinder or the hydroboost is bad. I'm goin to put the master cylinder I replaced back on and see what happen

 

[TurboBuRick]

Did you take the brake lines loose or the power steering lines? Sounds like the master needs to be bled.

 

[TurboBuRick]

Are you bench bleeding the master?

 

[Chatmanboy]

No didn't do that. How that process go? I'm not a mechanic I just know the bleendinf process with the brake pedal

 

[Chatmanboy]

And I took both a loose

 

[TurboBuRick]

The picture is self explanatory but you need a set of hoses and fittings. Looks like advance sells a nice kit. http://shop.advanceautoparts.com/we...s-Dorman---Help_22142388-P_N3378_T|GRP2007___

The hose ends need to be under the fluid. Slowly pump the brakes until no more bubbles. Again go slow. It will shoot fluid out if you go fast. When it's good hook up the lines and bleed the rest of the system.

HTH

RL

 

[novaderrik]

you always - ALWAYS- bench bleed a master cylinder before putting it on the car.. it's not that hard and only takes a couple of minutes to do. they used to put a bench bleeding kit in the box with every new and reman master cylinder, but they decided that it's better to save 50 cents on each one and not include them any more. but they should still have an instruction sheet in the box that tells how to do it, and i'm sure there are more than a few youtube videos out there that demonstrate how it's done.
of course now that you've pushed all that air into the rest of the brake system, you will need to not only take hte master cylinder out and bench bleed it, but also bleed the rest of the system really thoroughly before driving the car any more.

 

[TurboTnZ06]

Yep, bleed the master, when the bubbles stop, keep going for 15 more minutes, more bubbles will appear in my experience.

 

[Chatmanboy]

Man I sure didn't kno that. So what's that on number 2? A rod you use to push? Or can I this with it still hooked to the booster and pump the brakes. Or does it have to be off?

 

[novaderrik]

you could do it in the car- if you jack up the back of the car to get the master cylinder perfectly level and if you have a way to slowly push the pedal down while watching for bubbles... but it's so much easier with it clamped in a bench vise using a large philips screwdriver to push the piston in..

 

[TexasT]

I bled mine on the car. Just have to be gentle, I was told not to stroke the pedal all the way down. I stood at the master cylinder while I had my daughter ease the pedal down until I told her to stop and hold it. Then when I saw the bubbles stop I had her release it to go back up. Safety glasses, very important if you have helper that doesn't follow directions well or you could get squirted with fluid. We bled for at least 15-20 min. Then moved on to the wheel cylinders.

 

[Chatmanboy]

Brakes works fine now. Thanks for the help. Now I know u have to bench bleed b4 putting it on the car