Hydroboost pedal effort

Don W.

Don W.

Stab it and steer it
Hydroboost is installed. Seems to work well. IE the truck stops, doesn't pull or try to lock any wheels.

My question is pedal effort. It takes quite a bit more effort to press the pedal than my original vac assist brakes. Also the pedal returns slowly. Not immediately like the vac brakes did. It's almost as if there is resistance somewhere. The unit is a rebuilt unit, not a junk yard takeout.

All that being said the amount of effort to actually apply the brakes (meaning when resistance is felt and you can tell the brakes are actually being applied) is roughly the same as before. Maybe slightly more. Actuation is linear, no instant on or anything else. Pedal is firm at that point. (No suspicion of air in the system.)

Made one attempt at building boost and brakes held.

So, is this normal?

Thanks!
 
Black Knight

Black Knight

I Glow Therefore I am
Re: Hydroboost pedal effort

On Eviltwins Sy and Cobra198s Ty (both with hydroboost) I never noticed an issue with the pedal returning slowly or more effort. I actually think it takes less effort, and returns about the same speed.

The one thing I love is how much you have to apply the brakes to get the same results from vacuum assisted. You barely touch them and you want to go through the windshield.

Not sure if the fact these are on LSX motors makes a difference or not. Maybe someone with this on a V6 can chime in.
 
TYTILIDIE

TYTILIDIE

METH HEAD
Re: Hydroboost pedal effort

Good to hear you got it done Don. Sounds normal to me. I assume you're on stock brakes? You will find that when you go to launch the truck you wont have to pump the brakes in neutral anymore (if you had to before that is). Have you tried slamming on the brakes? If so, what happens? Mine locked up all four when it would never do that before, especially once I did the Corvette brakes and rear disc.
 
Quickstop [UK]

Quickstop [UK]

Combating adversyty.
Re: Hydroboost pedal effort

When my brakes worked properly, there was very little resistance and only a tiny amount of travel caused the fronts to lock up and slam me through the windshield. Pedal return was fast.

Since I started messing with it and put in a hydratech unit, I can't really say but a lot of cars have hydro assist. Can you compare with another one?
 
Don W.

Don W.

Stab it and steer it
Re: Hydroboost pedal effort

Thanks guys! System is bled. No foaming and steering is exactly as before. I've had one person check the pedal effort (he's done many conversions) and he didn't seem to think it was unusual. Still, it doesn't seem right to me. I'd sure like to be able to "test" another conversion. (The above person has one in his shop but it's not running at the moment.)

BTW I used my original master cyl with housing trimmed to fit into the HB unit.

I think it would be easy to plumb a gauge into the system and see what that shows. Anybody know what the correct pressure should be?

I've also seen kits (expensive!) that include a new, so-called, correct PS pump. Any idea what's different about that pump?

Truck is certainly drivable but hope to sort this out. Just doesn't seem correct. Maybe I'm to anal. Ya think?
 
midnightbluS10

midnightbluS10

Banned
Re: Hydroboost pedal effort

Don W. said:
Thanks guys! System is bled. No foaming and steering is exactly as before. I've had one person check the pedal effort (he's done many conversions) and he didn't seem to think it was unusual. Still, it doesn't seem right to me. I'd sure like to be able to "test" another conversion. (The above person has one in his shop but it's not running at the moment.)

BTW I used my original master cyl with housing trimmed to fit into the HB unit.

I think it would be easy to plumb a gauge into the system and see what that shows. Anybody know what the correct pressure should be?

I've also seen kits (expensive!) that include a new, so-called, correct PS pump. Any idea what's different about that pump?

Truck is certainly drivable but hope to sort this out. Just doesn't seem correct. Maybe I'm to anal. Ya think?
Click to expand...

Ed has a gauge or two plumbed in his hb system. Maybe you could search thru his posts.
 
BoostedSUV

BoostedSUV

Active member
Re: Hydroboost pedal effort

Mine kind of feel the same way. Pedal is stiff, returns slow, and aren't as touchy as expected. If I stab the brakes they do hit hard but normal driving they don't feel all that great. I also have 4 wheel C5 disc brakes. The truck stops and hold boost but the back wheels will push the fronts. Almost like the back doesn't hold as well. I've beld the system a bunch of times so I don't think air in the fluid is an issue. I'm still not impressed with HB brakes.
 
Quickstop [UK]

Quickstop [UK]

Combating adversyty.
Re: Hydroboost pedal effort

BoostedSUV said:
Mine kind of feel the same way. Pedal is stiff, returns slow, and aren't as touchy as expected. If I stab the brakes they do hit hard but normal driving they don't feel all that great. I also have 4 wheel C5 disc brakes. The truck stops and hold boost but the back wheels will push the fronts. Almost like the back doesn't hold as well. I've beld the system a bunch of times so I don't think air in the fluid is an issue. I'm still not impressed with HB brakes.
Click to expand...

My rears would go before the fronts (C5s up front) so I was going to try and get a different proportioning valve to compensate.
 
BoostedSUV

BoostedSUV

Active member
Re: Hydroboost pedal effort

Quickstop [UK] said:
My rears would go before the fronts (C5s up front) so I was going to try and get a different proportioning valve to compensate.
Click to expand...

I was always under the impression that a disc/drum prop valve put more break pressure to the back. (more pressure is needed to apply drum brakes). I figured I'd have issues with my rears locking up with discs in the back which is the complete opposite of what I have going on.
 
Quickstop [UK]

Quickstop [UK]

Combating adversyty.
Re: Hydroboost pedal effort

I'm not even sure our truck has a prop valve. There is that bit under the MC but that holds the sensor in it that tells you if you have lost front or rear brakes. It's not adjustable at any rate. Have a look under the hood but I think the rear lines are a smaller diameter and it's the fronts that get most of the braking force applied. When you brake, you want the front to plant and give you more grip - same as a motorbike - hence the fronts have more force to hold them and the rears break free and push the truck.
 
BoostedSUV

BoostedSUV

Active member
Re: Hydroboost pedal effort

Tom Renzo said:
The rear shoes are self energizing so they require less pressure. There for the need for a proportioning valve

Gm uses 1100 LBS
FORD 850 LBS
CHRYSLER 1100 LBS
Click to expand...

well that would certainly explain why my rear disc brakes don't do much for stopping and holding power.
 
Jimmy

Jimmy

Banned
Re: Hydroboost pedal effort

Don you are 85 years old stuff gets harder to do (like pushing down on the brake,seeing ect)
 
P

Poconojoe

Donating Member
Re: Hydroboost pedal effort

Tom Renzo said:
Why are you guys converting to hydro boost????

You can actually install an electric booster from an olds if you have vacuum issues or an external vacuum electric pump. Just curious on why Thanks
Click to expand...

Hydra-boost is a lot smaller and works a lot better then any vacuum based system
 
BoostedSUV

BoostedSUV

Active member
Re: Hydroboost pedal effort

I think I remember reading somewhere that brake pedal fulcrum on our trucks is different than a vehicle equipped with hydroboost. Therefore we don't have as much leverage with our brake pedal thus the HB brakes are stiffer to use. I could be wrong though
 
Don W.

Don W.

Stab it and steer it
Re: Hydroboost pedal effort

Jimmy said:
Don you are 85 years old stuff gets harder to do (like pushing down on the brake,seeing ect)
Click to expand...

Not quite... :rotf::rotf: Buuuttt I will be 70 this year. Or as I sometimes say: I've got a 50 year old brain trapped in a 69 year old body. :rotf:

BTW:

Renzo; you're correct on self energizing for drums. Disks are not self energizing, (Exception: complex system on early Chryslers.)

Quickstop: That IS a proportioning valve. As well as the front/rear failure switch.

And

BoostedSUV Sorry, but you had it backwards. More pressure is required for disks. Because, BTW, of the aforementioned self energizing feature on drum brakes.

Great conversation, brakes haven't changed...:roll: I wonder if on startup something got into the spool valve?
 
Last edited:
Maxtor

Maxtor

New member
Re: Hydroboost pedal effort

Don, I have an ABS powerbrake system and mine feels the same way as you describe.

I tried a vacuum pump before hydroboost and the constant noise drove me nuts no matter where I put it.
 
Don W.

Don W.

Stab it and steer it
Re: Hydroboost pedal effort

Thanks Tom. If there self energizing disk brakes out there now I'd appreciate a link or something. Sounds cool. Automotive tech, not counting large truck tech, is just unbelievable. I vote for points and condensers but they were a PITA also. :rotf:
 
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