Best manual brake setup

[Nick Micale]

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]

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):biggrin:

 

[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]

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.

 

["Turbo-T"]

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]

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.]

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]

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.

 

[Phoneguy]

Subscribed

 

[dentmasters01]

why is the s-10 mc being used over a manual g body mc??

 

[J Banning]

I ended up going with a Wilwood manual master cylinder, stainless braided brake lines, freshly cut rotors and Hawk HP Plus brake pads. I'll post up results once the car is on the road/track in 2-3 weeks (hopefully!).

Wilwood 260-4894
$118.95 from Summit.

Hawk HB119N-594
$68 from Summit.

NOTE: The master cylinder is NOT a direct bolt-on. I was able to use my factory Powermaster mounting bracket, but not before I took it off and moved the two studs inward about 1/8" each. I preferred to do this over ovaling the holes on master cylinder -- weakening it too much, in my opinion.

 

[Boston GN]

I ended up going with a Wilwood manual master cylinder, stainless braided brake lines, freshly cut rotors and Hawk HP Plus brake pads. I'll post up results once the car is on the road/track in 2-3 weeks (hopefully!).

Wilwood 260-4894
$118.95 from Summit.

Hawk HB119N-594
$68 from Summit.

NOTE: The master cylinder is NOT a direct bolt-on. I was able to use my factory Powermaster mounting bracket, but not before I took it off and moved the two studs inward about 1/8" each. I preferred to do this over ovaling the holes on master cylinder -- weakening it too much, in my opinion.

Bringing this back from the dead
Any updates on this Banning? How'd it work out?


On a side note, does anyone make a pushrod for this swap yet or do they all have to be modified??
Seems someone could make some cash making a few of these for people doing this swap

 

[79TurboCutlass]

How much boost can be held at the line with manual brakes?