WH hydroboost fine tune

[ddm156]

For years I teetered on the hydroboost decision, knowing my rebuild was awesome yet deficient in a few categories. I ended up getting the WH alpine hydro kit + the deluxe power steering upgrade. I've had it out on the road and these brakes are no joke. Should've ponied up years ago. Now I'm just looking to get them perfect. To me, it seems like there has to be some way to adjust my pedal travel. Nothing in the instructions, but I press the brake pedal halfway (or a little more)to floor before anything happens. I'd love to get the pedal in action when I 'tap' on the brakes, as they say. Any ideas?
Some more info:
Front Chevy disc
Rear caddy disc
35" tire
Delphi steering pump
Aware of a break in period- I have probably driven 6-8 miles since installed. Maybe jack up front check steering fluid, pump breaks/turn wheel??
Pedal returns from depress slowly, but I did read that this can improve with break in.

 

[ksagis]

I'm not familiar with the WH alpine hydro kit, does it include a new MC? My rig has front Chevy and back 2.1" piston Caddys, originally with 1.125" Vette MC. My pedal travel was way too much for me. In the middle of sizing up to 1.25" MC bore.

I'm getting around to playing with pedal ratio to get to closer to 5:1 versus factory ratio, but that one is on back burner.

Also, need to be sure your pushrod between the HB and MC doesn't have excessive clearance.

 

[ba123]

I would bet money that you have air in the lines.

I used a motive pressure bleeder and got an additional cap to make it work.

Look here:
https://classicbroncos.com/forums/t...-really-2023-bronco-build.318124/post-3512097

Honestly, I'm just guessing, but I'd still bet. I haven't driven mine yet but the pedal barely moves even with the engine off. Or you have a slight leak somewhere...maybe letting air in.

I love this system, but was not a fan of the WH flares and redid most of them and the ones I didn't, I had to tighten, tighten some more, and then tighten more than I thought was even possible before they sealed.

run your finger under every fitting until you're absolutely sure, they are all dry.

 

[nvrstuk]

IF all air is out of the system, then everything previously mentioned but I need to ask what dia MC.

Also, any play in mechanical linkage connections is greatly amplified in pdeal travel.

 

[ksagis]

I love this system, but was not a fan of the WH flares and redid most of them and the ones I didn't, I had to tighten, tighten some more, and then tighten more than I thought was even possible before they sealed.

@ba123, what material was the WH lines, stainless or NiCop?

Also, I've been battling some leaks at some of my inverted flares, and have been doing similar, but not gone crazy on torque due to fear of maybe "pinching" the flare and causing a weak point. Any guess how much torque you were applying? Feels like my flare nut wrenches slip and "round" off the nut before I applied too much torque.

 

[ba123]

Stainless.

I have Nicop for my fuel and brake lines and I know what you mean, that stuff is soft. I don't think I'd use it again if I could do it all over.

One thing to think about is--if it's leaking, either it's not tight enough, or the flare is no good. So, either way, you need to tighten it more to figure that out. I don't think you're going to cause a weak point my over tightening with a double flare fitting. The only time I've don that was on a Nicop trans line compression fitting that wouldn't stop leaking. A double flare is just going to press against itself only.

How tight? Yes, so tight that I felt like my wrench would slip off but it's a tiny little wrench. Make sure you tighten, loosen, retighten at least once, maybe twice as that helps it seat. Use a flare nut wrench if you can for better grip. If the area is tight, you can't always do that and one thing for some non-brake fittings I had to do was cut a slot into a 12-pt closed end wrench (I used cheap Pittsburg/Harbor Freight ones).

You're never going to to have good brakes if anything is leaking.

 

[nvrstuk]

@ba123, what material was the WH lines, stainless or NiCop?

Also, I've been battling some leaks at some of my inverted flares, and have been doing similar, but not gone crazy on torque due to fear of maybe "pinching" the flare and causing a weak point. Any guess how much torque you were applying? Feels like my flare nut wrenches slip and "round" off the nut before I applied too much torque.

I'm on an "old timer" build your hot rod from scratch forum and the guys there have been mentioning that the pre-flared lines they buy at the stores now seem to leak... come to think of it, the two short lines I bought last summer and used one of them leaked and it took WAY too much torque to seal it. Guess I don't use any premade flared ends anymore...

 

[ksagis]

If the brakes have a lot of throw, but then get firm immediately, I tend to discount air in the lines as the culprit and think more likely to being MC bore, especially if you changed MC and the bore size changed to something smaller.

Did you change MC as part of the HB swap? If so, any idea of bore size before and after? And check the HB rod to MC gap. For example, 0.050" gap translates to 0.300" pedal travel before pushing MC piston. If the HB came with MC, I'd assume WH got the rod right.

Assume you got good bleed on MC if so?

And while asking, which size pistons are your Caddy's? The 2.1 or the 2.5"?

 

[ba123]

It's all a kit. The master comes with it and it's all a PIA to bleed properly. the bench bleed kit that Wilwood supplies with the master even sucks. First set of fittings I tried allowed air and switched which ones I used for a nice mess of a redo.

 

[ksagis]

Per WH site on the bore size

Alpine Aluminum Heavy Duty master cylinder
1 1/8" bore

Not saying it is the cause of OP's problem, but I have not been happy with a 1 1/8" MC with what sounds like the same brake setup (Chevy and Caddy). Including bleeding the crap out of it with a pressure bleeder. Reading multiple articles on CB and looking at piston sizes seems to corroborate that conclusion.

 

[ba123]

I hear you, but nobody can really know that the problem of their brake system is the size of their master cylinder. In such a system with so many potential faults that I would bet that isn't the problem.

If you have air in your system, are unable to get it out, and put a master with a bigger bore, then yes, certainly, your brakes will feel better with a larger master cylinder because you'll have more power and the air won't affect you as much.

It's not easy getting everything sealed perfectly, esp when people want to use crappy flare tools or deal with flares done by someone not using them. Couple that with how it feels to have a fitting that you know isn't perfect, you know needs to be redone, but the thoughts of that sucks and you're not likely to do it because you're gonna get fluid everywhere, add more air into your system and have to totally rebleed and still be not sure that you're gonna fix the problem.

Brake issues are exhausting and you could do everything right and still have gotten a bad pre-made flare and have problems.

I'm anxious to see for sure how my own brakes work out. Like I said, they feel great but I'm still a little ways off from testing them. Maybe a month or two assuming the dmv lets me drive this thing after being out of the system for so many years.

 

[blade]

The problem with a soft pedal could also be the master cylinder itself. I have a 92 explorer that the pedal that had a lot of take-up for years. No leaks in the system and I tried several ways of bleeding it with no luck. I finally decided to try a new master and immediately had a perfect pedal. The master was probably leaking internally so it never lost fluid, just bled it back to the reservoir or something.

 

[73azbronco]

I'm on an "old timer" build your hot rod from scratch forum and the guys there have been mentioning that the pre-flared lines they buy at the stores now seem to leak... come to think of it, the two short lines I bought last summer and used one of them leaked and it took WAY too much torque to seal it. Guess I don't use any premade flared ends anymore...

I always use the tight, loose tighten loose tighten method to make sure all the play is gone and the surfaces are mated.

 

[ba123]

I always use the tight, loose tighten loose tighten method to make sure all the play is gone and the surfaces are mated.

if the flares are flawed, it doesn't matter how much you do it but no matter what, yes, you should do that. I had a a couple I didn't do, it was more like:

tighten, loosen, tighten, loosen, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten, tighten...

 

[pcf_mark]

With engine off STAND on the brake pedal hard. Hold it for 5-10 minutes. If it does not move / migrate down you do not have a leak.

Start up engine and repeat. It should also not move. If it does you may have a hyrdoboost leak that is bypassing pressure.

All that said - I ended up having to weld up a custom adjustable pushrod that took up the slop in the linkage from the pedal to the hydoboost. When adjusted the pedal is nice and high and I have brakes right at the top. I have never looked back since making this change and it blows people's mind how awesome the brakes are.

 

[ba123]

With engine off STAND on the brake pedal hard. Hold it for 5-10 minutes. If it does not move / migrate down you do not have a leak.

Start up engine and repeat. It should also not move. If it does you may have a hyrdoboost leak that is bypassing pressure.

All that said - I ended up having to weld up a custom adjustable pushrod that took up the slop in the linkage from the pedal to the hydoboost. I have never looked back since making this change and it blows people's mind how awesome the brakes are.

That’s great advice! The WH kit came with an adjustable pushrod.

 

[Wild horse 75]

One thing with double flare fittings is prep is key. Make sure the end of the line is perfectly square. Use a file. Then you need to chamfer both inside and out. Also cheap flare tools result in cheap flares. You can also get a flare lapping tool that helps prep the flare so it will seal the first time.
https://koultools.com/product/flare-lapping-tool/

This is the flare tool I’ve been using for several years now. I’ve never had a tool work as well as this.
https://www.eastwood.com/professional-brake-tubing-flaring-tool.html

 

[nvrstuk]

Another "soft pedal" debacle was the untimely death of my original rear line lock. I am sure that it caused all my grief when upgrading brakes/axles back 7 yrs ago. I could not with the Astro boost 1 1/8" mc pressurize and achieve proper pedal with the Chebby JD6 calipers frt and rear. I used to be a brake tech at a GM dealer about when these calipers were being used all the time so after pressure bleeding, vacuum bleeding at least 6 times each Steve suggested a 1.33" caliper from a HB designed 1 ton Chebby HB system- problem solved. I think the line lock was restricting flow to some degree.

Down the road a bit I noticed that my rear line lock wasn't holding- frt still was and 90% of the time I use both so I didn't notice just the rear not holding (although I have been known to lock the front and smoke the rear 40's) lol

Last summer I upgraded to an alum body mc with a tight fitting lid also designed for JD6 calipers and HB. The new mc is 1.25" mc and works perfect moving enough fluid with a NEW Micolock rear line lock. NO rust & it doesn't weep fluid out the lid (mine didn't after 3 new gaskets, one new lid and to radiator hose clamps.

All this typing just emphasizes that other things (that wouldn't be expected) besides an mc can cause excessive pedal.

I enjoy designing brake systems as there are so many variables and have on a couple local guys old hot rods. There is so much mis-information on brakes floating around out there it's amazing. Especially resto-mod stuff

 

[nvrstuk]

That’s great advice! The WH kit came with an adjustable pushrod.

Totally agree that fabbing up an adj pushrod is beyond important. Like you bax, I always do the same.

 

[Wrightracing]

I picked up the Hydroboost system from a 2010 F350 Superduty. I got the Master cylinder and even the power adjustable pedal assembly. I wanted something semi easy to get parts in the future from a normal auto parts store. It will go in my 72 project with custom bracket to angle the master cylinder out of the way of the coilover's and cage.

I wanted the Bronco to be able to be driven by short people and tall. Thus the reason for the pedal assembly.

David