Pedal placement

[Zandoz]

Once again I'm trying to work on the eventual layout of the interior of my bucket. The point being pondered is the relative positions of the brake and accelerator pedals.

How much distance is needed from the right edge of the brake pedal to the centerline of the accelerator pedal?

Also, how much farther forward should the accelerator pedal be?

I'm looking for minimums I can get by with for safety. Because of my joint issues, driving cars with a long distance between pedals are torture for me. On my Cougar I have had hardware adjustable pedal pads installed. When they were installed, I had them adjusted so that the pedals are even front to back, and close enough together to allow working both pedals by pivoting on my heel. So far that has not worked out well. I frequently accidentally push both pedals together, or hang up the side of my shoe on the brake pedal. Obviously I need to do something different on the bucket...and get the Cougar adjusted to.

I've done some searches and the only numbers I've been able to find is a NHSTA comparison of the generations of Toyota Camrys. They measured pedal edge to pedal edge, and got a range of 2.58" to 3.42". A rough and rounded average of around 3". I have no idea if that is a minimum safe spacing or off one way or the other

 

[EX JUNK]

If it is any help to you, I measured my set up. From the right edge of the brake pedal to the center of the accelerator I get 2 1/2".
From the "face" of the accelerator to the "face" of the brake pedal I get 4 3/4". That measurement could be less if I had power brakes as the brake pedal would be lower. I hope that this helps.



Jim

 

[Zandoz]

Thank you...that certainly does help. I will not have power brakes either. I wish now I had planned on power brakes...but at the time I started acquiring parts it seemed that the consensus was that power brakes were unnecessary.

Also. it appears that my brake pedal and steering column positioning will be similar to yours. Do you have any problems hitting the column with your foot when braking?

 

[EX JUNK]

Thank you...that certainly does help. I will not have power brakes either. I wish now I had planned on power brakes...but at the time I started acquiring parts it seemed that the consensus was that power brakes were unnecessary.

Also. it appears that my brake pedal and steering column positioning will be similar to yours. Do you have any problems hitting the column with your foot when braking?

I've not experienced any problems at all.

Jim

 

[kcline40]

Have you started building the bucket yet? If not why cant you add power brakes? It really isn't a big redesign. They have power kits with Master Cyilinders and brackets for $130 on ebay. You just need a 7" booster. So change it up.

 

[Zandoz]

Have you started building the bucket yet? If not why cant you add power brakes? It really isn't a big redesign. They have power kits with Master Cyilinders and brackets for $130 on ebay. You just need a 7" booster. So change it up.

Building, no...acquiring, yes.

There are a few reasons for not changing directions now.

This car is going to be an unconventional build...partially by necessity and partially by choice. I have mobility issues that I have to design and build to accommodate. The brake system is one of the unconventional design features.

To allow me to do maintenance and ease construction, anything that can be moved from under the floor must be. To facilitate me getting in and out, the car needs to be as low as possible Those combine to leave the only place to put a master/booster/pedal combo is hanging off the firewall. I really don't like that structurally or visually.

Besides all that, I'm on a VERY tight budget...I can't really afford redundant purchases...especially right now (long non car related story). The brake system parts I have acquired are rather pricey to be made redundant.

Once I get this thing built (if I get that far) and it becomes necessary to have a booster, I'll bite the bullet and hang one off the firewall.

 

[tfeverfred]

Zandoz..... please, man, tell us what's REALLY going on. I look at your avatar and I read a bit between the lines of what you've posted, thus far. That being said, is there a physical hindrance that you are attempting to over come in your build? Can you tell us what it is? You'll never get answers, if we really don't know the full question.

 

[Zandoz]

Zandoz..... please, man, tell us what's REALLY going on. I look at your avatar and I read a bit between the lines of what you've posted, thus far. That being said, is there a physical hindrance that you are attempting to over come in your build? Can you tell us what it is? You'll never get answers, if we really don't know the full question.

Well, it's no real secret. I've discussed a lot of it already, but no problem going over some of the biggies.

I have Degenerative Joint Disease. Basically all the cartilage is gone from most of my joints. Additionally, I have a bone spur pinching my spinal cord in my neck. Finally, I am and pretty much always have been a fat guy. What it boils down to is my mobility is both very limited and very painful. I can still walk a few feet if needed with canes or a walker, but for all practical purposes I'm wheelchair bound.

I have to make getting in and out as easy and open as possible, with no climbing or extreme movement. I need to arrange the pedals so that the movement to go from one to the other is the minimum possible while maintaining safe separation. I plan on equipping it with hand controls, but I want it driveable by conventional means. For maintenance, I need to minimize things that will require getting down on the ground...nothing under the floor that absolutely does not have to be there. The car needs to be able to handle a wheelchair carrier, and pull a powerchair trailer. Finally, the car needs to be configured so that it can be lifted and moved with a forklift. It will be assembled on a stand to allow me working around it on my powerchair.

The project was started with the realization that there is a good chance it will never be finished. I expected to be in this state before the project was finished, but I've gotten here a couple years sooner than expected.

 

[Screaming Metal]

If it is any help to you, I measured my set up. From the right edge of the brake pedal to the center of the accelerator I get 2 1/2".
From the "face" of the accelerator to the "face" of the brake pedal I get 4 3/4". That measurement could be less if I had power brakes as the brake pedal would be lower. I hope that this helps.

Is there any part of that cotten pickin car that looks like it won't win a trophy in a car show some place?????? ;-)



Jim

 

[Screaming Metal]

Building, no...acquiring, yes.

There are a few reasons for not changing directions now.

This car is going to be an unconventional build...partially by necessity and partially by choice. I have mobility issues that I have to design and build to accommodate. The brake system is one of the unconventional design features.

To allow me to do maintenance and ease construction, anything that can be moved from under the floor must be. To facilitate me getting in and out, the car needs to be as low as possible Those combine to leave the only place to put a master/booster/pedal combo is hanging off the firewall. I really don't like that structurally or visually.

Besides all that, I'm on a VERY tight budget...I can't really afford redundant purchases...especially right now (long non car related story). The brake system parts I have acquired are rather pricey to be made redundant.

Once I get this thing built (if I get that far) and it becomes necessary to have a booster, I'll bite the bullet and hang one off the firewall.

Dude, sorry to hear about the health issues. Ray of hope here, they make some extremely small brake booster for the older import cars. Also, there are some belt driven models, which, all you have to do is mount the pump to the motor, and it amplifies things. Used on some old diesel models....
We maybe need to find some members close by to help you out....

 

[Zandoz]

Dude, sorry to hear about the health issues. Ray of hope here, they make some extremely small brake booster for the older import cars. Also, there are some belt driven models, which, all you have to do is mount the pump to the motor, and it amplifies things. Used on some old diesel models....
We maybe need to find some members close by to help you out....

Thanks!

This is the general design of the pedal/master setup that I have:

My masters will be smaller and have remote reservoirs. The intent is for the setup to mount to a plate on top of the frame rail. Not only is there no room between or below the masters, the right master will be less than an inch from the motor and transmission. Also there would be a length issue to keep from fouling the oil filter. Basically the setup I have planned is kind of a Goldilocks solution...the only one that I could find that's just right.

With all of that, the belt driven units sound interesting. I take it that they would require a special master...correct? If so, they would have to be small, and I wonder how they would function with modern 4 wheel discs.

For now I'm hoping to get by with the manual setup that I've already invested in. But those belt driven units might be a good fallback option. Especially if I could make use of some of the leftover accessory brackets I have...that would offset some of the cost of having to replace the parts I already have.

 

[Screaming Metal]

Heres another option for folks having room problems for their brakes....hope this helps someone out there....

ABS Electric Power Brake System - AMP Up Your Brakes
Written by Ron Ceridono on July 1, 2010Bring Your Hot Rod To A Halt With An Electric Booster
View All 8 Photos
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2/8The ABS electric power brake system generates enough stopping power to bring not only one '57 Ford to a stop but two. Gary Long's Ranchero stops quickly and predictably with or without his blown '57 'Bird tagging along.
Today most street rods have plenty of horsepower to get them going, but they don't always have commensurate stopping power. Ironically, the problem often turns out not to be the brakes themselves, but the hydraulic system that activates them. To improve stopping power it's not unusual for street rods to be equipped with vacuum power boosters, particularly when disc brakes are employed, however sometimes the results don't meet the expectations.

Vacuum boosters use the difference between atmospheric pressure and the engine's manifold vacuum to increase the force delivered to the master cylinder from the pedal. How much of an increase is dependent on two factors: manifold vacuum and the effective size of the diaphragm in the booster. With all things equal (vacuum, pedal ratio, master cylinder bore), an 11-inch booster will raise the pressure in the system as much as three times more than a 7-inch booster. Unfortunately, the tight confines of most street rod engine compartments, or the under floor area that most master cylinders are relegated to, can make it difficult to fit an appropriately sized power unit. However, now there is an alternative to a large-diameter booster for big gains in hydraulic pressure in the form of an electric power brake unit from ABS.

3/8The accumulator attaches to a junction block. The entire assembly is then secured to the car with a single bolt.
Found on a number of contemporary high-end automobiles, electric power brakes are proven to be effective and reliable. No vacuum or belt-driven pumps are required and the entire ABS system consists of three components-a compact electric power supply, a special master cylinder, and an accumulator, which is the source of the boost for the braking system. Measuring only 8x6x6 inches, the power unit can be hidden anywhere in the vehicle, in any orientation, just so long as it is below the brake fluid reservoir. It has two hydraulic connections, the gravity feed from the reservoir and the high-pressure assist line that gets plumbed back to the port on the master cylinder with the accumulator inline. The integral pressure switch and relay come pre-wired, requiring only a ground, a battery connection, and a keyed ignition connection. According to ABS the pump draws 14 amps at maximum pressure and is quieter than most aftermarket electric fuel pumps. The unique master cylinder has a 1-3/16-inch bore, which means the fluid volume is adequate for the most complex systems with multi-piston calipers, while still being able to create 1,600- to 1,800-psi brake line pressure during normal operation and over 2,000 psi at maximum output. Finally there's a hydraulic accumulator that provides for very smooth actuation of the brakes. It also provides reserve pressure to assist the brakes if for some reason the electrical power to the pump is interrupted. The accumulator will supply pressure for as many as 20 brake applications, after that the brakes function as though they were non-boosted. In operation, fluid is delivered from the master cylinder reservoir to an electric pump where it is pressurized and delivered to an accumulator. When the driver steps on the brake pedal and the pushrod moves forward, a valve inside the master cylinder opens and pressurized fluid from the accumulator enters a chamber in the master cylinder behind the piston assembly and helps apply the brakes. A switch monitors the pressure in the accumulator, and turns on the electric pump when pressure drops below a preset minimum and shuts it off when pressure is back up to a preset maximum.

4/8A polished aluminum master cylinder is more or less the brain of the system. Note is has four ports: furthest away from the pushrod is the outlet for the rear brakes, next is the outlet for the front brakes, the third is the inlet for pressurized fluid from the accumulator, and the vertical fitting nearest to the pushrod is the feed supplying fluid from the reservoir to the pump.cylinder
Installing the ABS electric brake booster system is easy enough; the master cylinder is adaptable to most pedal mounts and the only real concern is keeping the reservoir above the pump to provide it with gravity-fed fluid. In cases where the master cylinder is mounted below the floor, remote reservoirs are available. The pump and accumulator can be mounted in virtually any location, then it's simply a matter of connecting all the components with fluid lines. Once in place, ABS recommends DOT5 silicone brake fluid, although the system will work perfectly with DOT3 or DOT4 fluid.

5/8This little device is an accumulator-it stores pressure to provided hydraulic assistance to the master cylinder. Even with the pump off, the system is pressurized.
Electric power brakes are a great option for any application but particularly those with engines that have low manifold vacuum or when the space for a large vacuum booster isn't available. ABS can not only supply the electric booster system, but disc brake kits, hardware, valves, and anything else you made need to bring your hot rod to a halt.

SOURCES
ABS Power Brake
Orange, CA 92866
714-771-6549
www.abspowerbrake.com

 

[Screaming Metal]

With all of that, the belt driven units sound interesting. I take it that they would require a special master...correct? If so, they would have to be small, and I wonder how they would function with modern 4 wheel discs.

Works just fine with regular systems....just do a search, they'll pop up....
And there is one that you can run off a power steering pump also....not expensive....

 

[Zandoz]

I did a bit of looking and didn't find anything that would fit my budget & space. The hydro and electric options bare watching, but I think my first attempt is still going to be with the pedal assembly I already have and manual compact masters...I've already got precious funds invested, and the physical fit is good.

 

[Zandoz]

Now it's time for pedal placement part 2.

Part 2:
I need to know the distance from the center of the brake or clutch pedal to the corner where the left side of the firewall meets the side of the cowl. I want to be sure that as the brake pedal is depressed, the foot will not hit the side of the cowl, pushing the foot off the pedal. It may be an optical illusion (or optical delusion), but in a good number of the pics I've seen it seems that there would barely be enough room for the pedal alone. I'd like to avoid having to do something like the Detroit Speedcraft bulges on the side of the cowl. Right now I'm not seeing how to get safe pedal positioning without something like that.

 

[fletcherson]

Now it's time for pedal placement part 2.

Part 2:
I need to know the distance from the center of the brake or clutch pedal to the corner where the left side of the firewall meets the side of the cowl. I want to be sure that as the brake pedal is depressed, the foot will not hit the side of the cowl, pushing the foot off the pedal. It may be an optical illusion (or optical delusion), but in a good number of the pics I've seen it seems that there would barely be enough room for the pedal alone. I'd like to avoid having to do something like the Detroit Speedcraft bulges on the side of the cowl. Right now I'm not seeing how to get safe pedal positioning without something like that.

Depends on where your column exits. That's the wild card along with leg room. Mine worked out so the clutch pedal hits it's stop just when the pedal enters the real narrow part of the '23 tub, leaving decent, not ample, foot room. I don't think there is room to worry about my foot slipping off of the pedal, there is just room for it to work the pedal. Short answer, I don't think it's a real concern, comfort it the big issue. If you are using an auto trans, you have a lot of room to jockey the pedal around to either side of the column, whatever feels best to you.

 

[Zandoz]

Depends on where your column exits. That's the wild card along with leg room. Mine worked out so the clutch pedal hits it's stop just when the pedal enters the real narrow part of the '23 tub, leaving decent, not ample, foot room. I don't think there is room to worry about my foot slipping off of the pedal, there is just room for it to work the pedal. Short answer, I don't think it's a real concern, comfort it the big issue. If you are using an auto trans, you have a lot of room to jockey the pedal around to either side of the column, whatever feels best to you.

I will be using an automatic transmission, and a floor mounted pedal/master assembly. So far it's looking like the steering column will not be an issue. With the preferred positioning there would be room for a size 13 shoe to fit under. The fallback position takes the column totally out of the picture.

The problem is that I have no wiggle room with the pedal & master assembly. To begin with, the brake pedal is small...less than 2-1/4" wide. With a 1/2" clearance between the block and the right master cylinder, the left edge of that little pedal is right in line with the corner where the side of the cowl meets the firewall. The side of the cowl does curve away from the pedal, but I'm still worried about the shoe hitting the cowl as the pedal gets close to full travel.

 

[fletcherson]

I will be using an automatic transmission, and a floor mounted pedal/master assembly. So far it's looking like the steering column will not be an issue. With the preferred positioning there would be room for a size 13 shoe to fit under. The fallback position takes the column totally out of the picture.

The problem is that I have no wiggle room with the pedal & master assembly. To begin with, the brake pedal is small...less than 2-1/4" wide. With a 1/2" clearance between the block and the right master cylinder, the left edge of that little pedal is right in line with the corner where the side of the cowl meets the firewall. The side of the cowl does curve away from the pedal, but I'm still worried about the shoe hitting the cowl as the pedal gets close to full travel.

The thing is, if you get full travel, you are in trouble! You should get a couple inches at most if the brakes are adjusted and bled and functioning. The pedal will likely bottom out before you get your foot all the way into the slim space. I just dealt with exactly what you are describing with two pedals, and had the same concerns you have. it worked out. This is one of those things that is hard to conceive on paper, once you get to the actual hands on part, it will be more clear. There isn't any extra room, that's for sure, but it's better than I anticipated. Ps, I do wear a size 13 W, lol!

 

[Zandoz]

The thing is, if you get full travel, you are in trouble! You should get a couple inches at most if the brakes are adjusted and bled and functioning. The pedal will likely bottom out before you get your foot all the way into the slim space. I just dealt with exactly what you are describing with two pedals, and had the same concerns you have. it worked out. This is one of those things that is hard to conceive on paper, once you get to the actual hands on part, it will be more clear. There isn't any extra room, that's for sure, but it's better than I anticipated. Ps, I do wear a size 13 W, lol!

Yeah, I figured that if all else was well there will no bottoming out...but I like to plan for when all else isn't well. It comes from being a lifelong poster boy for Murphy's Law...LOL. The reason I am paying so much attention to the brake pedal placement is that the masters and pedal assembly have to mount to the top of the frame...right where the engine and the transmission meet and are the widest. I'm trying to determine if I am going to have to widen the frame. I'd like to avoid that if at all possible...It's already as wide as the firewall.