Best manual brake setup

[GN SBS]

My powermaster is on the way out and I've decided to swap to manual brakes for safety and simplicity's sake.

Mach.80 has a great post here on his approach that uses a Wildwood manual master (Willwood 260-9439) and a G-body adapter from Drag Race Brakes. His total cost was $340 shipped and:

This modification worked great! The brake has a terriffic feel, not artifficial. The pedel is not too hard like I feared. My 105lb. wife drove the car and had absolutly no problem. Pedel travel is great. A perfect ballance of travel, feel, and pressure.

Are there other good aftermarket manual brake solutions I should consider? Drawbacks to the Wildwood setup I might not be aware of?

For simplicity's sake I'm not inclined to do a junkyard swap from another GM car.

As a reference point, my GN will be pretty darn close to 9.99 on E85 this season. It does see street miles, but not many and I'm not commuting in it or anything.

Thanks for any and all feedback!
Scott

[Scott Atk]

You definitely don't need the adapter no matter which MC you choose. Your powermaster setup already comes with the adapter you need. I went with the S-10 manual master cylinder. It works fine. I have my pedal setup for a 7:1 ratio. Actually I made a spare pedal with an adjustable pushrod... interested?
I'm at work right now. I can post pics of my setup this evening

[turbofabricator]

I run the manual S-10 master cylinder, too. I am going to switch to a Wilwood, though. I am going to sell the car, and don't want the liability of the push rod falling out the back. It has worked great for me, but I want to make it fool-proof. Any mastercylinder will bolt right up the the factory PM firewall adaptor. I also have Wilwood front breaks, and braided hoses front and rear. Pedal pressure is very acceptable, even in stop and go traffic.

[BlackMetal]

I think I am going to try manual soon!

[Scott Atk]

Ken, Do you know what your pedal ratio worked out to?

[blown okie]

this is what i was wanting to do to mine but didn't find all the info i thought i needed and didn't want to tackle it blindly.... looks like i'm gonna have a vac. brake set-up for sale real soon

[BlackMetal]

If someone would be willing to go into detail about modifying a pedal to change the ratio, and creating an adjustable (and SAFE) pushrod, it would be greatly appreciated. Honestly it seems like every brake system out there comes with its own set of headaches and at this point I want it simple and reliable. Manual would be great but I just have a few questions about the things I mentioned above. If you have the time and energy to do a little write-up or take pictures, it would be a great help.

[Scott Atk]

OK, for the sake of the archives, I went out to the garage and did some measurments. These are rough numbers taken with a tape measure.
Vacuum pedal 3.5:1 pedal ratio
Vacuum pedal (unused hole) 5:1 pedal ratio
PM pedal 4:1 pedal ratio
The pic below is a spare pedal that I made, Which I would sell for $60 plus shipping, has a 7:1 pedal ratio and an adjustable pushrod.
The other pic is the stock powermaster adapter. This is why nobody on this site at least should need to buy any billet fancy adapter. You already have one. This one is missing the rubber cup/grommet that also helps in pushrod retention. HTH, Scott

[BlackMetal]

Appreciate the pix. Maybe I can find an aftermarket master cylinder that includes an adjustable pushrod and eliminate one headache. Then I'll just have to work on the pedal.

[RobS]

Try this:
G body with manual brakes - it works! - pics

or

***** MalibuRacing.com - THE 78-83 Malibu Performance Site! ***** click on tech, then on manual brake conversion.

I would like to do this conversion sometime. I would like to find a malibu in the junkyard as a doner car.

[turbofabricator]

Originally Posted by Scott Atk

Ken, Do you know what your pedal ratio worked out to?

Scott,
I used a "PM ratio" (what ever the heck that is ) I.E. I used the stock P/M pivot point for the push rod. I am going to re-locate the pivot point higher (closer to the pedal pivot, to increase travel and ratio) when I install a Willwood M/C. I might just remove the S-10 M/C and drill the rear piston deeper to retain the push rod. My biggest concern is the push rod falling out of the master cylinder (because the S-10 master cylinder only has a drill start in the back of it) and not having any brakes. I have driven my car in rush hour traffic (including about 20 miles today) and the brakes work great. Pedal pressure is a bit high using the stock PM pivot point, though. I also need to lower my pedal (shorten the push-rod) about 3". I adjusted the push rod so that it would return the pedal against the stop and keep about 1/8" of piston depression. I need to just make damn sure the push rod is seated into the rear piston further so it never falls out. Hasn't happened, "yet", though. Been that way for about two years. I really don't drive the car that much. I did start driving it yesterday, and wnat to get a few things sorted out. Brakes being one of them. Just peace of mind is all. (I also want to pull the 3.8 and install a 4.1 and twin 60mm turbos. ) When I pull things apart, I can take pictures if anyone wants them. I just have a few "projects" that are more pressing right now.

[BlackMetal]

According to Summit, that Wilwood part number (260-9439) comes with a pushrod. Can it be used? Or would I still need to make an adjustable one?

Wilwood 260-9439 - Wilwood Aluminum Tandem Master Cylinders - summitracing.com

[Scott Atk]

should work. You may need a rod end or something similar to attach to the stud on the pedal. I'm sure that Wilwood master is nice, but I paid like 35.00 for the S-10 manual master that works great.

[GN SBS]

Originally Posted by Turbo6Chicago

According to Summit, that Wilwood part number (260-9439) comes with a pushrod. Can it be used? Or would I still need to make an adjustable one?

Wilwood 260-9439 - Wilwood Aluminum Tandem Master Cylinders - summitracing.com

See this helpful input from the thread I reference above:

So, when I got back from my trip I got to work. The adapter fit perfect to the firewall the MC fit perfect to the adapter. I used a tube bender to swap the location of the brake lines. The MC even came with the adapters and all the fitting to complete the install.

The only fabrication was to the push rod. I had to cut the rod that comes installed in the 7/8" bore MC. I had to cut the rod that came from the PM. I used a die the same thred as the MC pushrod to die the PM shortened rod. I then used a coupler and a locking nut, from your hardware store, to create an adjustable rod.

Now, I also drilled and tapped a hole in the brake pedel and installed a bolt. This gave me a 6:1 ratio instead of the 5:1 the powermaster used. HOWEVER, I did this for nothing because, I had too much pedel travel. So I ended up using the origional PM mounting point.

Scott: did you use a different ratio for the fabbed pedal you actually installed in your car? Trying to zone in on the best ratio for this setup.

Thanks to all, this is a great thread.

[Nick Micale]

Originally Posted by Turbo6Chicago

According to Summit, that Wilwood part number (260-9439) comes with a pushrod. Can it be used? Or would I still need to make an adjustable one?..............]

The pushrod will not work as is, it will fit the MC but the clevis will not work on the pedal.

What we do is remove the exsisting rod from the car, measure what the final installed rod length should be, cut and weld the stock pin end to the MC end.

Also, the Wilwood MC mounting holes will NOT line up with the factory firewall mounting plate from the PM.

[J Banning]

Great thread. I'm looking at this conversion as well.

-Banning.

[GN SBS]

Originally Posted by Nick Micale

The pushrod will not work as is, it will fit the MC but the clevis will not work on the pedal.

What we do is remove the exsisting rod from the car, measure what the final installed rod length should be, cut and weld the stock pin end to the MC end.

Also, the Wilwood MC mounting holes will NOT line up with the factory firewall mounting plate from the PM.

Thanks for that last piece of advice Nick, you're always good for a gem or two. I'll likely order the adapter that Mach0.8 recommends.

Nick, what pedal ratio do you shoot for? Any pearls of wisdom about getting the pedal set up?

What bore size works best: 7/8" or 1" or others?

[GN SBS]

Here's another option from MP Brakes that Frank-G recommended in an old Parts-for-Sale post. Anyone using this, do chime in.

See questions in my post above. -Scott

[Scott Atk]

It's all about preference. Your pedal ratio needs to match up to your MC bore size and what an acceptable "feel" is for you. The 7:1 pedal that I pictured above will give you a nice soft feel but it will have considerably more pedal travel vs. a stock PM pedal ratio. The S-10 MC is I believe a 15/16" bore. HTH, Scott

[Slow91z]

I'm also thinking about doing this.

Can we get a list going on who's using what size master cylinder bore with what pedal ratio, and if they are using manual wheel cylinders, and or oversize piston front calipers.

[Nick Micale]

Originally Posted by GN SBS

Thanks for that last piece of advice Nick, you're always good for a gem or two. I'll likely order the adapter that Mach0.8 recommends.

Nick, what pedal ratio do you shoot for? Any pearls of wisdom about getting the pedal set up?

What bore size works best: 7/8" or 1" or others?

Wilwood recommended an 1-1/8" bore MC. Rick Elam at Baer Brakes said 1" should work fine too.

I am not interested in manual brakes on a street driver. With more pedal travel it gives a slower response time for a panic stop. Some one familiar with operating a manual brake vehicle may not have an issue. I would not put my wife behind the wheel with a manual set up on a GN

To answer the question about ratio, seems like the stock GN PM pedal works fine with this conversion. I would never use an adjustable rod on any car unless it is just for testing and fit. Then I would weld it so it cannot move.

On the race cars I have converted, it is really best that the stock rubber flex hoses are replaced with stainless lines. I love the solid brake pedal feel at 140+ MPH.

Based upon info here, I just ordered a S-10 MC to try on a local GN. I will modify the stock push rod to try and simplify this job. Should be done this weekend. [Any interest in a working PM? Hope the owner reads this thread so he will know about this before he picks up his GN! ]

[BlackMetal]

Originally Posted by GN SBS

Here's another option from MP Brakes that Frank-G recommended in an old Parts-for-Sale post. Anyone using this, do chime in.

See questions in my post above. -Scott

I also emailed Master Power and they pointed me to that part number. Will it really work since it says it's for full size GM 1955-1970?

[Scott Atk]

Here's another tip for you guys. Next time you go to a pick-a-part, Take a hammer and punch. Remove any old G body vacuum booster. Take the hammer and punch and go to town. You can remove the pushrod and it's a perfect fit for a PM pedal. (I think)

[gnxtc2]

I'm using the kit from Drag Race Brakes. I also have Wilwood Rear Discs. I did not change the fronts yet, still stock.

Just had the car at BG this past week and the brakes preformed flawlessly. The manual brakes are way better than the PM. I used the same brake pedal as the PM.

I mounted the master along with the adapter to the firewall and the rod landed exactly were the PM pivot point was. I knocked the stud out, threaded some 1/4 NPT threads and install a 1/4 NPT - 1/8 NPT brass reducer. I drilled out the brass reducer for the 3/8 bolt for the heim joint. The rod can not fall out unless the brake pedal falls out.

The hardest part of the mod is reaching up the dash to remove the brake pedal for the mod.

Here are some pics:
Manual Brake Conversion pictures from friends & fun photos on webshots

Billy T.
gnxtc2@aol.com

[GN SBS]

Two more questions:

• Are folks using a residual pressure valve as Wildwood recommends with drum brake setups? In theory a 10 lbs valve (their recommendation) should help to reduce pedal travel, but has anyone used RPV's in their setup?
  
• blank line
• Did anyone's setup require an adjustable proportioning valve, or does the stocker keep fore/aft bias correct?

Thanks again!
Scott

[turbofabricator]

For drag racing, (only) I swapped the front and rear brake lines on the master cylinder. I learned this from NHRA Stock Eliminator guys. It puts more pressure to the rear brakes. I also used an adjustable prop. valve, too. The brakes (even with swapped lines) works great on the street. My only concern with the S-10 manual MC is that there is no real way to positively retain the push rod in the master cylinder. It just has a small drilled countersink to position the push rod. I just lengthend the push rod so it was at full mechanical stop (the pedal), which makes the pedal pretty high. As soon as I can get back to working on MY car, that is one thing that I am going to adress. I am going to try and drill the rear piston deeper so the rod cannot fall out of the back of the mastercylinder. I might even build a sliding guide inside the car. But, the best way would be to use a Willwood or other manual mastercylinder. I also need to look at a factory service manual on the S10 to see how they retained the push-rod. Maybe the rebuild company used the wrong rear piston?? One other concern is the possibility that the increased load on the firewall might cause a cracking condition over time. The fire wall on our cars is paper thin in that area. The next time I pull the engine, I am going to add some re-inforcement to the fire wall. It might be time for a dash bar and some added pedal support tubing. Have someone step on your manual brakes, while you watch the firewall/mastercylinder move. I also used Willwood front brakes and larger S-10 wheel cylinders along with braided DOT brake lines. My local hydraulic shop makes DOT legal brake lines in just about any configuration. Not dirt cheap, but I'm worth it. (barely)

[Scott Atk]

Ken,
Are you using the rubber boot with the PM adapter? The rubber seems to be stiff enough to ensure pushrod retention. Similar to the Wilwwod that everyone is making reference to:
Wilwood 260-9439 - Wilwood Aluminum Tandem Master Cylinders - summitracing.com

As far as residual pressure valves, etc. I'm not using anything like that. Our cars have the same brakes as S-10 trucks. So basically I'm running the same system That GM has already engineered.

[gnxtc2]

Originally Posted by GN SBS

Two more questions:

• Are folks using a residual pressure valve as Wildwood recommends with drum brake setups? In theory a 10 lbs valve (their recommendation) should help to reduce pedal travel, but has anyone used RPV's in their setup?
  
• blank line
• Did anyone's setup require an adjustable proportioning valve, or does the stocker keep fore/aft bias correct?

Thanks again!
Scott

You don't need the residual valves unless the master is below the brakes. The valves are used to prevent the brake fluid from gravity bleeding back into the master.

I got rid of the factory porportioning valving and replaced it with an adjustable one for the rear brakes. I believe the Wilwood master already is already porportioned.

Billy T.
gnxtc2@aol.com

[Slow91z]

Actually the residual valve for drum brakes is so the springs don't pull the shoes back off of the drums, which would create excessive pedal travel.

[87Regal3.8SFI]

Originally Posted by Scott Atk

OK, for the sake of the archives, I went out to the garage and did some measurments. These are rough numbers taken with a tape measure.
Vacuum pedal 3.5:1 pedal ratio
Vacuum pedal (unused hole) 5:1 pedal ratio
PM pedal 4:1 pedal ratio

If I may ask, I take it these are different spots on the brake pedal where the hole would be drilled?

And are these critical to what you use them on?

For example, I hear the PM and vac brake holes are not the same, you have to use PM with PM, vac with vac, etc. But then I see some have taken their PM MC rods and shortened them to use on a vac set up, could you run a PM brake pedal on a vac MC if the rod were short or long enough?

One other thing I see some of you run an S-10 MC, forgive me for asking but does the S-10 MC offer more braking PSI than a G body MC?

[GN SBS]

Originally Posted by Slow91z

Actually the residual valve for drum brakes is so the springs don't pull the shoes back off of the drums, which would create excessive pedal travel.

Yes, that is correct-- we wouldn't need a front RPV for the reasons stated above, but wildwood recommends a rear one to work against the drum springs and I'm going to run one unless someone recommends otherwise.

[Louie L.]

Originally Posted by GN SBS

Yes, that is correct-- we wouldn't need a front RPV for the reasons stated above, but wildwood recommends a rear one to work against the drum springs and I'm going to run one unless someone recommends otherwise.

On that same note using one on the rear brakes especially when using aftermarket (ex. Aerospace 4 piston) racing drag calipers is recommended by many racers.. After the primary brake pressure spike, some of these calipers will try and force fluid back into the MC.

[GN SBS]

Originally Posted by 87Regal3.8SFI

If I may ask, I take it these are different spots on the brake pedal where the hole would be drilled?

This is a good question-- let's get this info into the thread.





This tech brief from Stoptech is very informative. The illustration on page 1 better illustrates what exactly you're measuring along the pedal, which is the distance from the pivot point to the 90* (perpendicular) line of movement/force that your foot creates.

What pedals are people using?

[65wagone]

Nick,
Any update to the conversion you mentioned? I would like to hear any advice you have.
I've installed Wilwood rear discs and still have stock discs up front. I also want to go with manual brakes.
Thanks.

[Nick Micale]

The GN I installed with the S-10 MC just installed has stock front disks and Wilwood disks in the rear. The brakes are awesome!

A local GN owner made a pass with it and did not even know it had been converted until I told him a couple days later. He thought is was still the PM. Will be changing his vac system over next week.

Using the PM pedal gives a good "ratio" for pedal pressure and will stay with that.

I very much like the GM look under the hood and that the S-10 MC works with the PM firewall plate. The Wilwood or Mopar MC does not fit the adapter w/o modifications.

Still working on the "best" pushrod or parts to build one. The one we just did was a PM pushrod that was welded up with a 3/8" union and piece of threaded rod. A simpler solution may be to replace the pin on the PM pedal to a size to fit a conventional clevis end?

There are a couple more GN's to covert this summer and will update when done.