Hydroboost problem???

[laserjock]

Is this normal?

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Pedal is very soft while idling. Push down and when the pedal bottoms out it starts pushing back.

Is it just air?

Thoughts?

 

[F350camper]

Seems like air since you can feel it coming back up. Have you done the old lock to lock to lock with the steering wheel? Running and not running.

 

[laserjock]

I ran it lock to lock while it was running and not. I don't think it was low on fluid. I need to find my qt of fluid.

 

[laserjock]

Steering felt good.

 

[laserjock]

Topped the fluid off. Noise went almost away. I still get a rebound in the pedal especially if I get on it hard. It is a really strange pedal feel but I have never driven a hydroboost truck.

 

[F350camper]

You will get a tiny bit of rebound if you hit it hard like that, But I wonder now if you've got an air bubble or two in the brake side of the system. Cuz what you are describing sounds more squishy than normal.

 

[laserjock]

It's possible. I have vacuum bled the brakes but I'm sure they may need bled some more.

 

[Golden Helmet]

When I first put my hydroboost in it sounded worse than in your video and it did the kicking back thing too. In my case it was a DOA power steering pump though, so both the steering and the pedal were stiff. When I put the 300k mile pump back in everything worked like it should, no noise from the hydroboost, no kicking back, and a firm brake pedal with almost no dead travel in it.

 

[laserjock]

The power steering pump i used is the one that came with the hydroboost. I hope it's all good. I looked for leaks last night just briefly. Didn't see anything. I'll go back over things when I get a minute.

 

[junk]

Is the hydroboost used? If so it might need seals. Pretty easy to do. I just did my crewcab a couple weeks ago. It was a 35$ kit off eBay and I followed instructions off FTE.

I think the kick back can be a symptom of a bad seal.

My unit was acting like great manual brakes. So no power assist. After being rebuilt it works much better.

 

[Cruiseomatic]

Could be hooked up backwards...Seen that once.

 

[towcat]

if the hydro is a used unit, chances are the nitrogen charge in the reserve accumulator is no good. trust me on this, when you panic brake, the sinking pedal is normal. that's the calm before it kicks back and all hell breaks loose.
you really quick find out what's tied down and WHAT'S NOT.

 

[laserjock]

I think that may be the case. That's sure how it seems like it's acting. It is a used unit. Great. May be time to find a reman.

 

[ifrythings]

You can change the accumulator if it's bad that's what I did.

Two ways to check if it's bad, start the truck then turn it off and see if you have a few brake assists, the other way is the accumulator should not be loose or wiggle around.

When mine was bad I couldn't find a new one so I went to the auto wreckers with a c clamp and small pin punch and pulled one off of a chevy truck, the color of the accumulator is supposed to tell you what pressure is in it so try to get the same color.

 

[chillman88]

I can tell you that the internals are almost identical between all the different hydroboost units.

I want to say it took me 2-3hrs to reseal be the one on my Chevy. That includes pulling it out and cleaning it very very well. Simple job if you're mechanically inclined.