Question, New Hydro-boost Pedal pulsing?

[88Stanger]

Ok, i need some help here. I have just installed a brand new hydor-boost conversion kit from POL. All the hydro-boost hoses are installed and no leaks, I already had a Wilwood 1" Master and Adjustable prop valve connected. So i installed the new Hydro-boost and then attached the Master and Prop Valve. i went through the instructions for how to prim the system. after that i started it up and did the turn the steering wheel lock to lock many times. Everything is work with the steering. I also installed a brand new power steering pump. As i hit the brakes hard they pulse. The pedal goes down then comes up a bit. Brakes are not working very well. I pick the truck up on the lift and notice that there is brake fluid on the floor. I believe this is coming from a joint that i did some time ago and l think that it is obviously not a good connection. Could this cause the brakes to act this way?
My plan is to rebuild the front brakes lines with a CPP kit, install the Master and prop valve sent with the Hydro-boost kit, bleed the master and all brakes lines with my pressurized brake tool.
Am i missing anything here? The hydro-boost lines are not leaking at all, no bubbles in the power steering. I happy with that part. lol
Thanks for any help!

[88Stanger]

By the way, i tried to do a search on this and could not come up with anything talking about this issue. Lots of install stuff and how to convert over.

[Rickysnickers]

"I pick the truck up on the lift and notice that there is brake fluid on the floor. I believe this is coming from a joint that i did some time ago and l think that it is obviously not a good connection. Could this cause the brakes to act this way? "

Yes, I believe you found your issue. I suspect once you get that fixed, you shouldn't have any issues with your pedal going to the floor. I'm no expert, with that said, I would pass on the fixed proportioning valve and use one of the adjustable type valves instead, like this one...https://www.amazon.com/Wilwood-4444-.../dp/B003LT619Q

[88Stanger]

Originally Posted by Rickysnickers

"I pick the truck up on the lift and notice that there is brake fluid on the floor. I believe this is coming from a joint that i did some time ago and l think that it is obviously not a good connection. Could this cause the brakes to act this way? "

Yes, I believe you found your issue. I suspect once you get that fixed, you shouldn't have any issues with your pedal going to the floor. I'm no expert, with that said, I would pass on the fixed proportioning valve and use one of the adjustable type valves instead, like this one...https://www.amazon.com/Wilwood-4444-.../dp/B003LT619Q

Yep, that is exactly the one i have, with the Wilwood 1" master.
Thanks for the comments.

[siggyfreud]

It sounds like you also haven't fully bled the hyrdoboost system. You should do about 20-30 turn-to-turn and brake press cycles before even starting up the motor. It took me about 60 cycles to fully bleed the system, but that was also because I started the motor too quickly and let the pump cavitate and suck in a ton of air.

My suggestion is to do the following.

1. 30x of the following: Turn the wheel lock to lock 5 times, pumping the brakes every time to get to full right on the wheel. Top off the powersteering fluid as it goes down.
2. Get a buddy ready to fill the pump quickly. Start the motor and fill the pump as it drains, don't let it cavitate!
3. Do another 20 cycles with the engine running, but stop short of going to full lock on the wheel.

If you complete that you should be fully bled.

The pusling you're feeling is a mix of fluid and air pockets in the hydroboost unit. You wouldn't get pulsing from a brake fluid leak alone in my opinion.

[88Stanger]

Originally Posted by siggyfreud

It sounds like you also haven't fully bled the hyrdoboost system. You should do about 20-30 turn-to-turn and brake press cycles before even starting up the motor. It took me about 60 cycles to fully bleed the system, but that was also because I started the motor too quickly and let the pump cavitate and suck in a ton of air.

My suggestion is to do the following.

1. 30x of the following: Turn the wheel lock to lock 5 times, pumping the brakes every time to get to full right on the wheel. Top off the powersteering fluid as it goes down.
2. Get a buddy ready to fill the pump quickly. Start the motor and fill the pump as it drains, don't let it cavitate!
3. Do another 20 cycles with the engine running, but stop short of going to full lock on the wheel.


If you complete that you should be fully bled.

The pusling you're feeling is a mix of fluid and air pockets in the hydroboost unit. You wouldn't get pulsing from a brake fluid leak alone in my opinion.

I really appreciate the idea! That makes sense now that you mention that. I was very curious why the pedal would do what it was from just a brake line leak. The air in the system sounds like a very possible issue and something i should do. So, i will follow your suggestions after i re-plumb the new lines. I ordered a new set or lines for the front.

[siggyfreud]

Originally Posted by 88Stanger

I really appreciate the idea! That makes sense now that you mention that. I was very curious why the pedal would do what it was from just a brake line leak. The air in the system sounds like a very possible issue and something i should do. So, i will follow your suggestions after i re-plumb the new lines. I ordered a new set or lines for the front.

Not going to lie, bleeding my hydroboost was a pain. I put Netflix on my phone and leaned it on the dash to kill the time as I did it.

I forgot to mention, but ensure your tires are in the air when you do this. Obviously they'd be nearly impossible to turn with the car off and on the ground, but just thought I'd mention it .

Once it's bled though hydroboost is AWESOME. I'm running it with a Baer brake system and very wide tires, and this truck stops incredibly well.

[Steeveedee]

Originally Posted by siggyfreud

Not going to lie, bleeding my hydroboost was a pain. I put Netflix on my phone and leaned it on the dash to kill the time as I did it.

I forgot to mention, but ensure your tires are in the air when you do this. Obviously they'd be nearly impossible to turn with the car off and on the ground, but just thought I'd mention it .

Once it's bled though hydroboost is AWESOME. I'm running it with a Baer brake system and very wide tires, and this truck stops incredibly well.

The factory manuals always say to have the front tires off the ground, or do not make more than five cycles from lock to lock without moving the vehicle, to avoid flat-spotting the tires. Having the tires off the ground also helps for that reason (above needing Hulk-smash arms).

[KQQL IT]

Wait overnight they'll bleed themselves. Always was my experience in our squarebodys with hydro boost

[57taskforce]

I agree you’ve still got air in the system, I had to fill my pump with the engine running, I fought and fought cavitation until I filled it and kept topping it off with it running. As mentioned above keep turning the wheels and pumping the pedal and it’ll eventually get there. It’s a bit of a pain in the ass I’m not gonna lie. However it is one of the top two best things I’ve done to my K20 thus far. It’s stops better than I ever really thought it could honestly.

[88Stanger]

Originally Posted by 57taskforce

I agree you’ve still got air in the system, I had to fill my pump with the engine running, I fought and fought cavitation until I filled it and kept topping it off with it running. As mentioned above keep turning the wheels and pumping the pedal and it’ll eventually get there. It’s a bit of a pain in the ass I’m not gonna lie. However it is one of the top two best things I’ve done to my K20 thus far. It’s stops better than I ever really thought it could honestly.

I really appreciate all you comments from you all! This site is the best with the best help and guys and gals willing to help whenever possible.
I plan to fix the brake lines, then using the pressure bleeder i have, bleed all the brakes and then as many of you have mentioned, have truck on lift, pick it up and lock to lock pushing on the brakes. I assume i am to work the pedal while turning the wheel and not just keep it pressed down while turning.
This is all i have to do and the truck is done! LS was dyno tuned to 352hp at the rear wheels and now i want to go cruise but damn these brakes. LOL
I am also building a 1966 C10 that is on hold for this to be done.

[siggyfreud]

Originally Posted by 88Stanger

I really appreciate all you comments from you all! This site is the best with the best help and guys and gals willing to help whenever possible.
I plan to fix the brake lines, then using the pressure bleeder i have, bleed all the brakes and then as many of you have mentioned, have truck on lift, pick it up and lock to lock pushing on the brakes. I assume i am to work the pedal while turning the wheel and not just keep it pressed down while turning.
This is all i have to do and the truck is done! LS was dyno tuned to 352hp at the rear wheels and now i want to go cruise but damn these brakes. LOL
I am also building a 1966 C10 that is on hold for this to be done.

Sounds awesome . Definitely let us know how the brakes turn out!

[dennislbrooks]

As Steveedee said lift weight off front wheels. I have never had a problem bleeding a hydroboost with or without a power steering gear.

Even if you only have power steering, take weight off front wheels before bleeding.

Sneak up on lock and do not hold it there before reversing direction.

[jessemthompson]

I have been on the fence about going hydroboost for a couple of years now. I think it would be one of the better brake upgrades to do.

[57taskforce]

Originally Posted by jessemthompson

I have been on the fence about going hydroboost for a couple of years now. I think it would be one of the better brake upgrades to do.

It’s well worth it. It will plant you against the windshield if you so desire... it will will also lock all four tires on asphalt pretty easily.

[siggyfreud]

Originally Posted by 57taskforce

It’s well worth it. It will plant you against the windshield if you so desire... it will will also lock all four tires on asphalt pretty easily.

I'm still tuning my bias, but with big brakes, 315 tires, and the hyrdo I can validate this. This truck can brake pretty hard. To the point where I (illogically) worry about my cab bolts sheering and my cab taking off as the frame stays put haha.

[jessemthompson]

I’m gonna hit a pick and pull this Saturday and start collecting the parts for this.

[jaros44sr]

do you have a small vent in the cap to the tank, spoke with jim at hydratech because i was having the same conditions. he advised me to drill one as the air has no where to escape. he also said to drive it for 100-150 miles to let all the micro bubbles to escape(only if your streering and brakes are working properly. he said the pulsing is similar to putting your steering to full lock and your putting excess pressure on the pump

you dont need a lot of pedal pressure for this system to work, try driving around the yard and youll see what Im talking about. I was used to my old vacuum system, so my driving style had to change, much less pedal pressure

If your pedal is going to the floor, then you have air in your brake lines, its not in your hydro boost.

[88Stanger]

I really appreciate all the info from you all!!
So a little update:
Note sure i mentioned it, but i am running Wilwood D52 & D154 upgraded dual brake calipers on all 4. I installed the 1" master cylinder and 4 wheel disc brake prop valve, the new hard lines, one from the prop valve down for each, the front and rear brakes. Front is one size smaller than rear at 3/16" and rear is 1/4", they both go to a tee, front is just at the front part of the frame, then goes to each caliper, and the rear does this but at the rear axle. I was a bit concerned with the front only having one line then to a tee, i am used to having one for each caliper which i may go back to.
I called Wilwood just to ask what they suggested. They said they do not like the 1" master and that a 1.125" master is best due to the upgraded size of the caliper pistons on the front needing more volume, so now i have a new 1.125" bore master on the way. They said that they are not worried about the single 3/16" line down to a tee, which surprised me. Would not be hard to build a new line to the driver side and just plug off the one side of the tee.
What do you all think?
I will take the advice Jaros44sr and drive it around a bit after i get the new master installed.
I will say this, you can tell it is working though. With a motor that only really puts out about 10" of vacuum, this is in my opinion the best option, Hydroboost.

[Rickysnickers]

Sounds like you got it all worked out . I wouldn't worry about a single line and the T. It will be fine, which is confirmed by Wilwood. To me, there's really no sense in making new lines. There's really no benefit from it.

[siggyfreud]

Glad to hear it's working! I think either master you'll be fine. The bigger master will reduce pedal pressure a bit, but shouldn't be that much of an issue with the hydro. I believe I'm running a 1" Baer on my setup.

Let us know how it continues to perform!

[88Stanger]

Well, Update: I went with what Wilwood said and installed a 1.125" bore master cylinder and tada, everything is working great!! Love me some hydroboost!! Thanks again everyone for all the help and suggestions!! You all are awesome.

[57taskforce]

Glad you got it worked out. It’s hands down one of the best improvements that can be made to these old trucks.

[88Stanger]

Originally Posted by 57taskforce

Glad you got it worked out. It’s hands down one of the best improvements that can be made to these old trucks.

Thanks and i fully agree!

[jessemthompson]

I picked up a hydroboost from a 95 suburban last weekend along with the lines for $22. So I’m about to start this journey as well.