HBoost - "No Brakes" - Resolved

[KentuckyV6]

Mounting is correct.
Envision the bleeder at the top.
Jack the back of the car up high. The bleeder rotates fwd and down. To get it to the top, the caliper has to he rotated towards the back.
Just the detail I am forced to go through. . .

Got it, I have the visual of what you are going through now. Hopefully the end is near and you get it resolved. Although I bought a new accumulator for my PM last summer I want better and more dependable brakes and have been thinking about this conversion myself.

 

[Jerryl]

the only thing i didnt see you mention......are the front calipers/pads in goodshape? my stockers where half froze....is the rear wheel cyl's / hardware items good?

Calipers moved in when placing vacuum on the mc. Disk and pads <50 miles.
Everything worked with the PM. Lol. Matter of fact, PM accumulator held pressure for +4 months.
Pic of disk and caliper rotation.

 

[Coelacanth]

Interesting problem; in this series of 4 videos documenting the Powermaster-to-Hydroboost swap, they clearly mention reversing the brake lines going into the master cylinder, because they're opposite compared to the PM MC. I saw others mentioning reversing lines to the power steering, but I don't think anyone mentioned this. Here's part 1 of the series:

I don't know if this is your problem, but it could explain the problem of having weak brakes; the bigger cylinder is for the fronts as they do most of the work; and if your front brake line is going into the smaller rear cylinder, that could logically cause weak brakes.

 

[haywire4130]

I could be wrong but i think the fittings are 2 different sizes to prevent this from happening (pretty sure mine were)

 

[turbo87regal]

I could be wrong but i think the fittings are 2 different sizes to prevent this from happening (pretty sure mine were)

Not on that Wilwood master cylinder. It has interchangeable adapter fittings that can easily be put on the wrong way witch is why I asked that question early on.

 

[Jerryl]

Not on that Wilwood master cylinder. It has interchangeable adapter fittings that can easily be put on the wrong way witch is why I asked that question early on.

Wilwood stated that the MC is 50/50. I explicitly asked about the port bias and was told it will work either way.
Now. . . I have had a few sleepless nights over the connections AFTER discussing with Wilwood.
Understand that on a disk/drum setup, the front = larger bowl because of the volume required when moving the pistons.

However, the primary circuit should also be the front circuit, and I had to decide which makes the most sense.
I am a firm believer that Buick had the setup right. I followed the same as stock setup and will live with the consequences. Thanks for the reply.

 

[Toby_Goodmk]

My brakes are badass. If I were you. I would replace the MC with a stock good old cast iron setup. I have an older cast iron setup here, pay the shipping and you can have it for testing. Ditch any aftermarket valving setups that you may be running. Put the brass block back down by the frame and enjoy. On my cast iron MC the larger lines feed the back, front are in the front. Since I ran into my dumbass moment, the brakes sure are one of the best performing items on the car.

 

[Toby_Goodmk]

pic

 

[bison]

Id attempt to plug the front and rear individually at the proportioning valve and see if the peddle changes. Maybe even bypass the valve to further diagnose.


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[No disintegrations]

Are you wrenching on this today?

 

[Jerryl]

It was slow going today in the 99F heat . . . Swapped the HB unit and made no other changes. Result:

Brakes are firm and work as expected. Thanks to all who replied and hope this helps someone.

 

[No disintegrations]

Are you wrenching on this today?

It was slow going today in the 99F heat . . . Swapped the HB unit and made no other changes. Result:

Brakes are firm and work as expected. Thanks to all who replied and hope this helps someone.

Great news!

 

[Danster]

So I was correct, it was the HB. Been there done that 2-3 times myself.

I do wonder what is wrong with them? There's something they are not doing correctly when they rebuild them.

Glad this one worked for you. It such a pain to swap these out!

 

[TexasT]

Awesome!
So we can expect to see this car at the next event?
I am glad you got it worked out.

 

[Cryptic]

Tagging onto this as I'm experiencing similar issues.

Brand new Hydratech hydroboost setup
Brand new master cylinder from Hydratech
New front brake lines from Inline tube
SS braided lines
New PV from Highway stars
Bench bled Master Cylinder
Manually bled with a friend (countless times)
Pressure bled with a Motive Power bleeder (countless times)
No bubbles visible after bleeding a full Coke bottle full of fluid from each wheel

With the car turned off the pedal is still soft and spongy even after pumping the brakes a dozen times. With the car on the pedal drops some and is extremely slow to fully come up.

I initially thought I had caught the problem at the proportioning valve (brass) as there were leaks there but I replaced both it and the front brake lines which were where the leaks were coming from. I'm at my wit's end. Any suggestions?

 

[No disintegrations]

See post 51 and 53

 

[Cryptic]

See post 51 and 53

I have considered that but have people had issues with the non-parts store units? Also, my understanding is that when the car is off you should be able to get a firm pedal outside of the HB unit because the car effectively has manual brakes at this point?

 

[1KWIKSIX]

I also installed new front hard brake lines from inline tube too and needed to use my mightyvac vacuum pump on the front bleeder screws in order to pull fluid through & get the fluid moving. Power bleeder pushing on the master cylinder brake fluid reservoir afterwards did the trick, followed by an assistant in the car pumping and releasing brake pedal in sync with my opening and closing bleeder valve on brake caliper. My HydroBoost work great now! Will literally throw you thru the windshield stopping from 60mph. I did remove the factory brake proportioning valve and installed a Wilwood adjustable unit so I’m able to adjust front / rear brake bias.

 

[No disintegrations]

I had a Silverado with hydroboost and it had an odd pedal feel. Always kind of soft but had excellent braking power. Haven't delt with any converted Buicks first hand.
The hydroboost unit doesn't seem to have a direct connection to the brake fluid and the pedal.
Going by memory there is valving in it between the master which can be problem area.

 

[Cryptic]

I also installed new front hard brake lines from inline tube too and needed to use my mightyvac vacuum pump on the front bleeder screws in order to pull fluid through & get the fluid moving. Power bleeder pushing on the master cylinder brake fluid reservoir afterwards did the trick, followed by an assistant in the car pumping and releasing brake pedal in sync with my opening and closing bleeder valve on brake caliper. My HydroBoost work great now! Will literally throw you thru the windshield stopping from 60mph. I did remove the factory brake proportioning valve and installed a Wilwood adjustable unit so I’m able to adjust front / rear brake bias.View attachment 335632

That's a beautiful looking setup. Getting fluid moving and things to bleed has never been an issue. Just getting the pedal right at all. How much line modification did it take to get the adjustable PV in place?


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