Wilwood Disc on a 73 Challenger

[Wanda73]

Hydro boost was my answer, but that's not the only one. The pedal ratio on bower brake cars is less than manual brake cars, and I think that contributed some oddities. My adapter is nothing but aluminum plate machined to fit, that was specific to the mustang master and booster, that has a longer pushrod than factory. As you can see in my thread it's a snug fit, and requires rerouting lines and changing fittings. All of that I listed before. If you don't want to fabricate buy a kit. If you don't mind playing and tinkering tons of cars have hydro boost, anything with a turbo or supercharger, almost all 3/4-1 ton trucks, and old Chevy astro vans are just a start. If your not in a hurry I might could build your adapter, but I'm about to move to California in July, so I don't have time right now.

 

[Steve340]

Those levers are not standard - the brake light switch should run against the lever bar that goes on to the brake pedal. That being said they may not be the problem.
I have some diagrams I could draw up for you to give you a few ideas. If I try and explain my thoughts in words it will be to complicated.
PM me your email address if interested
The hydro boost is good if you need to change but I believe it is worthwhile to try and sort the current system if you can. After all it works on millions of cars. Your problem is a bit unusual.

 

[Hemi Steve]

Steve340
I don't see a function specifically called private message on this forum so I sent a message to you with my email address via "conversations".

 

[Hemi Steve]

Update.
I got my brake pressure gauge and measured the hydraulic pressure at the front calipers. First I measured the pressure with engine idling at 14 to 15 in. vacuum and heavy foot force on the pedal. Got 500 psi. Next removed the engine vacuum and temporarily installed a Stainless Steel Brakes brand diaphragm vacuum pump and measured 25 in of vacuum at the booster. With heavy foot force the hydraulic pressure at the caliper was 750 psi. My leg is not a calibrated force member but I pushed as hard as I thought I would in a panic stop. Pressures are marginal at best in my opinion.

I Re measured and calculated the booster pushrod to the master cylinder clearance. I have 0.072" clearance. I'll make a spacer to install between the pushrod end and the reaction pad to increase the length of the non adjustable rod. Everything I read suggests that this adjustment will not increase the booster force.

Steve

 

[Cudafor36]

Old post but thought I'd chime in. I've just ordered my hydroboost system today. The third new master cyl booster assembly with my gen III 392 ain't cutting it. Hard pedal all the time with new four disc Wilwoods.

 

[Cudafor36]

I ordered my hydroboost setup from Matt in Cali as well. A real nice guy and stands behind his work. I'll let y'all know how she stops once installed.

 

[Hemi Steve]

For a variety of reasons this project got delayed. I decided to go with a hydroboost system from Hydratech. There were delays in getting the system delivered but the wait was definitely worth it. After installing the unit I have fantastic brakes. This is the only change I made and I could not be happier. From an installation perspective, the only problem was getting the upper two nuts off of the vacuum booster. They are way up under the dash and barely visible. For anyone doing this installation on an E body the tool combination I used for those nuts is as follows:
1. 5/8"deep socket 3/8" drive
2. 3/8"universal adapter with a rubber band wrapped around the universal part to keep the socket from flopping around as you try to get it on the nut.
3. 10" X 3/8 drive extension
4. 3/8" ratchet
you need really good lighting under the dash to even see the nuts. The best strategy is to remove the drivers seat to allow room for your body. I did not do that and my 72 yo body struggled.

 

[Cudafor36]

Thanks for the Intel on your install. I've had my booster out a dozen times and apparently I'm limber for a 47yr old. Lol. My hydroboost is going in next weekend. The Wilwoods suck in my opinion. I'd go with stock next time around and stock discs in back as well. The best pedal feel I've gotten was using a 15/16" bore MC. But then you have lots of pedal travel.

 

[Hemi Steve]

Well, actually I'm 6'-1" and 195 lbs and still not flexible enough. Mine is a 3 pedal car and it is really busy under there with all of the pedal linkages. Anyway, with the hydrobooster the brake travel is about the same as before but the feel is a little softer at the heavy application end of the stroke. I like it better. Also the supplied adjustable rod end coming out of the hydrobooster to the pedal arm allowed me to increase the step-over dimension which I also like.
Even with the 7" booster the clearance to the GenII hemi valve cover was too close to get the valve cover off. the hydrobooster fixes that problem also. The Hydratech people recommend a 1-1/8" master cylinder and I have a 1". They said to try the system with the 1" bore piece and see if I like it before I go through the aggravation of switching to the 1-1/8 bore. I find the 1" bore just fine with my setup. The fact that the Hydrobooster is the same length as the vacuum booster said all of my plumbing was good also. I'm very please with the brakes now . Steve

 

[Hemi Steve]

Well, actually I'm 6'-1" and 195 lbs and still not flexible enough. Mine is a 3 pedal car and it is really busy under there with all of the pedal linkages. Anyway, with the hydrobooster the brake travel is about the same as before but the feel is a little softer at the heavy application end of the stroke. I like it better. Also the supplied adjustable rod end coming out of the hydrobooster to the pedal arm allowed me to increase the step-over dimension which I also like.
Even with the 7" booster the clearance to the GenII hemi valve cover was too close to get the valve cover off. the hydrobooster fixes that problem also. The Hydratech people recommend a 1-1/8" master cylinder and I have a 1". They said to try the system with the 1" bore piece and see if I like it before I go through the aggravation of switching to the 1-1/8 bore. I find the 1" bore just fine with my setup. The fact that the Hydrobooster is the same length as the vacuum booster said all of my plumbing was good also. I'm very please with the brakes now . Steve

 

[Cudafor36]

Yeah that clutch assembly up in there would be a pain to get around. Glad I'm hearing good Intel on the hydroboost. I am putting in the 1 1/8" bore cylinder. I'll advise on the outcome.

 

[Hemi Steve]

I'm sure it will be good for you
Steve

 

[Cudafor36]

Did your booster linkage hook up ok to the stock linkage or was the rod to long. Mine is and I'm out of adjustment. Can you hook it up directly to the brake pedal arm and bypass the link.

 

[AUSTA]

That's how i done my TA connected the hydro boost shaft directly to the pedal arm great feel only needs light pressure

 

[Cudafor36]

Thank you for the quick reply. I'll line it up tonight. Again ty.

 

[Hemi Steve]

Austa is correct, the rod connects directly to the pedal arm. The Hydratech unit adapter plate is quite thick due to the need to get the pushrod that comes out of the hydrobooster properly aligned and spaced to make the connection to the pedal arm and still have sufficient length adjustment to allow you to set the pedal height that you want.

Steve