47-55.1 Brake pedal return spring - The 1947 - Present Chevrolet & GMC Truck Message Board Network

72Mountaineer · 08-06-2021, 09:17 PM

Can't post pics, but my brake pedal return spring, one of the few I have tried, on my new build isn't working correctly. Truck is a '53, booster and master cylinder mounted on the frame under the cab, stock pedal. Existing spring goes from the pedal where it meets the brake pushrod and to a homemade bracket on a tranny/motor bolt. I've tried a few, none seem to return the pedal completely. Good, stout springs. I'm thinking possibly my design is wrong. What do others have for a return spring?

nvrdone · 08-06-2021, 10:08 PM

I had the same kind of problem with my frame mounted m/c & booster. the problem wasn't the return spring. The pedal where it went thru the floor rubbed on the side of the hole and didnt allow a complete return. Repleced cab mounts & adjusted the pedal. solved the problem.

**mr48chev** · 08-06-2021, 10:17 PM

I've had that happen with the stock pedal. With the same results. Check to make sure that the pedal isn't hanging up in the hole as it goes up and down before you do anything further.

MD2020 · 08-06-2021, 11:19 PM

Do you have these on you break system

https://www.google.com/search?q=resi...hrome&ie=UTF-8

MiraclePieCo · 08-07-2021, 01:03 AM

I used an old dishwasher door spring on mine. I had to keep shortening it until it exerted enough force to pull the pedal back to where the brake lights canceled. It's firewall-mounted however.

72Mountaineer · 08-07-2021, 06:18 PM

Quote:

Originally Posted by MD2020

Do you have these on you break system

https://www.google.com/search?q=resi...hrome&ie=UTF-8

When I first put this system together, I had these on each line and they seemed to work (although I really didn't drive it while building the truck). Then I put on a proportioning unit and was advised that I wouldn't need them. Opinions vary on this. Would they make some kind of difference as per the brake pedal? Also, the pedal is quite free, no obstructions.

nvrdone · 08-08-2021, 12:42 AM

ive got 10# residual check valves on both of my lines, but i'm using a corvette disc brake m/c with front & rear drum brakes. If you are using disc/ drums most m/c's have a check valve built into the port for rear drum brakes. you dont need the valves if you are using a disc / disc set up.

72Mountaineer · 08-08-2021, 08:53 AM

Quote:

Originally Posted by nvrdone

ive got 10# residual check valves on both of my lines, but i'm using a corvette disc brake m/c with front & rear drum brakes. If you are using disc/ drums most m/c's have a check valve built into the port for rear drum brakes. you dont need the valves if you are using a disc / disc set up.

My system is disc front drum rear. I've never heard that the MC has a built-in valve.

MiraclePieCo · 08-11-2021, 11:53 PM

Quote:

Originally Posted by 72Mountaineer

My system is disc front drum rear. I've never heard that the MC has a built-in valve.

I asked this question on the HAMB and was assured by several knowledgeable people that disc/drum MCs do indeed have built-in rear check valves. A second inline one however can't do any harm. 10+10 in this case equals 10, not 20.

72Mountaineer · 08-15-2021, 08:45 PM

Do others have this type of spring/geometry for their pedal?

NeoJuice · 08-18-2021, 01:21 PM

I need to make a brake pedal return spring for my truck with under floor brake booster. That last picture was a pretty good example of what I need to do. Where are people getting there springs from and how tight does the spring need to be to bring the pedal up properly? Homedepot? Lowes?

I found these options online

https://streetrodding.com/forums/brake-return-spring/

https://www.jalopyjournal.com/forum/...rings.1117288/

https://www.speedwaymotors.com/Maste...-Kit,8750.html

If anyone has any more examples of underfloor booster with return spring can post them that would be awesome. Not finding much online because of the under floor.

dsraven · 08-18-2021, 02:59 PM

problem with the return springs on a short belcrank is they don't have enough mechanical advantage to lift the weight of the pedal and all the linkage. maybe a longer belcrank on the linkage where the spring connects would help solve the problem after ensuring the linkage is free of binding anywhere. just spot weld a longer tab onto the spot where the spring connects to the linkage and test/repeat until you get resolve.

dsraven · 08-18-2021, 03:01 PM

possibly a return spring on the actual brake pedal lever would help overcome the weight issue. again, spot weld a tab to the pedal lever and install a spring. test/repeat until it works

dsraven · 08-18-2021, 03:04 PM

or drill a small hole for the spring as high up on the pedal lever as possible to keep it under the floor, then install the spring and tie the other end to something and test. the pedal should also have a definite pedal stop at the top of it's travel range so the pedal stops at the same place every time when released. then adjust the pushrod for the master cylinder so it is sure to be fully released as well.

NeoJuice · 08-18-2021, 03:13 PM

The picture that 72Mountaineer posted is not my truck. First I need to acquire some springs in different lengths/strength then do some testing. I'm thinking looking at the picture 72Mountaineer posted I might be able to do something similar but thought other people might have some pictures of there setup with under floor boosters.

dsraven · 08-18-2021, 04:56 PM

brake/clutch return springs are actually pretty beefy, they don't move far and have a decent load to pull. you could fab a hook from threaded rod to be able to hook the spring and then adjust the tension required after.

dsraven · 08-18-2021, 04:57 PM

spring in post 10 looks a little small gauge wire to me.

72Mountaineer · 08-22-2021, 09:28 AM

Quote:

Originally Posted by dsraven

problem with the return springs on a short belcrank is they don't have enough mechanical advantage to lift the weight of the pedal and all the linkage. maybe a longer belcrank on the linkage where the spring connects would help solve the problem after ensuring the linkage is free of binding anywhere. just spot weld a longer tab onto the spot where the spring connects to the linkage and test/repeat until you get resolve.

Where is the belcrank?

dsraven · 08-22-2021, 10:29 AM

The belcrank is the thing that changes motion from rotational to linear. In this case the pedal is welded to a shaft and when the pedal is pushed down the shaft rotates. Welded to the shaft is a short lever with the pushrod attached that pushes the booster/master cylinder. The pedal is basically a lever as well except it is a lot longer and weighs a lot more in comparison to the short lever. Since the spring is attached to the short lever side it has to be a pretty heavy duty spring in order to overcome the weight of the longer lever because it has a very limited mechanical advantage being that the lever it is attached to is a lot shorter than the pedal lever.
As an example, disconnect the pushrod and use a fish scale where your return spring is attached and try to pull the pedal back up to the top of its stroke, like simulating the Springs job. Then you will see how much work the spring needs to do in order to return the pedal. You could then use your fish scale to find a spring that can handle that much weight.

dsraven · 08-22-2021, 10:35 AM

Originally the return spring was attached to the top side of the pedal arm and ran towards the rear of the truck. It was a fairly beefy spring.

dsraven · 08-22-2021, 10:51 AM

You could weld another lever onto your belcrank shaft in an appropriate spot to attach a spring to, where the spring would have a good straight pull and the lever could be a bit longer for better mechanical advantage. Use the fish scale idea to find the weight of spring required. Ensure the pedal arm is not dragging on anything and the shaft is free to rotate and not causing another load cor the spring to overcome. Since the pedal comes up through the floor you should also check for binding caused by the pedal to floor seal, carpet etc. The original pedal arm had a rubber block on it that would bump against the firewall when the pedal was at its upmost position. That, or some other positive pedal stop, should also be intact so your booster/master pushrod can be adjusted properly.

72Mountaineer · 08-22-2021, 03:21 PM

The screwdriver points at the lower leg of the belcrank, I suppose that this is the leg that would be extended downward, that the spring would attach to. Correct? Thanks dsraven for these responses!

dsraven · 08-22-2021, 03:36 PM

Yeah, that's right. If you have room below you could make a piece of flat bar with a rounded out end so that round fits the shaft then drill a hole in the right place to match up to the bolt for the pushrod, then make the lever extension go past the end of the original crank so it will give better mechanical advantage for the return spring. Again, a fish scale would give you a good idea of how string the spring needs to be or just wing it with what you have readily available. Also ensure the pedal stop is in place somewhere as you shouldn't rely on the booster to be your pedal stop.

72Mountaineer · 08-22-2021, 08:16 PM

Sounds good, I'll fab up something and get beck to this forum. Thanks for all the help. I would think that more people would have ran into this problem.

NeoJuice · 08-23-2021, 01:13 PM

That is a great picture 72Mountaineer. I did the exact same thing this weekend. I made a little L bracket and hooked the other end onto a hole in the transmission housing that was right across from the brake pedal. It was a PITA to stretch that spring to get it hooked into place.

See attached video I made of the new spring pedal return spring in action.

https://photos.app.goo.gl/SqMBAJAfVVBipBsj9

08-06-2021, 09:17 PM	#1
72Mountaineer Registered User Join Date: Oct 2010 Location: Where Mountaineers are free Posts: 406	Brake pedal return spring Can't post pics, but my brake pedal return spring, one of the few I have tried, on my new build isn't working correctly. Truck is a '53, booster and master cylinder mounted on the frame under the cab, stock pedal. Existing spring goes from the pedal where it meets the brake pushrod and to a homemade bracket on a tranny/motor bolt. I've tried a few, none seem to return the pedal completely. Good, stout springs. I'm thinking possibly my design is wrong. What do others have for a return spring? Last edited by 72Mountaineer; 08-06-2021 at 10:02 PM.

08-06-2021, 10:08 PM	#2
nvrdone Registered User Join Date: Dec 2011 Location: Moxee WA Posts: 1,482	Re: Brake pedal return spring I had the same kind of problem with my frame mounted m/c & booster. the problem wasn't the return spring. The pedal where it went thru the floor rubbed on the side of the hole and didnt allow a complete return. Repleced cab mounts & adjusted the pedal. solved the problem. __________________ 49 chevy 3100 3 window. 327 / m21 4 spd, 12 bolt w/ 3:55's Bought in 1973 for $235.00. Had it longer than my wife & Kids!!

08-06-2021, 10:17 PM	#3
mr48chev Registered User Join Date: Jul 2007 Location: Toppenish, WA Posts: 15,711	Re: Brake pedal return spring I've had that happen with the stock pedal. With the same results. Check to make sure that the pedal isn't hanging up in the hole as it goes up and down before you do anything further. __________________ Founding member of the too many projects, too little time and money club. My ongoing truck projects: 48 Chev 3100 that will run a 292 Six. 71 GMC 2500 that is getting a Cad 500 transplant. 77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around.

08-06-2021, 11:19 PM	#4
MD2020 Registered User Join Date: Sep 2018 Location: Batesville,MISSISSIPPI Posts: 312	Re: Brake pedal return spring Do you have these on you break system https://www.google.com/search?q=resi...hrome&ie=UTF-8

08-07-2021, 01:03 AM	#5
MiraclePieCo Registered User Join Date: Sep 2014 Location: USA Posts: 2,249	Re: Brake pedal return spring I used an old dishwasher door spring on mine. I had to keep shortening it until it exerted enough force to pull the pedal back to where the brake lights canceled. It's firewall-mounted however. __________________ 1951 Chevy Panel Truck

08-08-2021, 12:42 AM	#7
nvrdone Registered User Join Date: Dec 2011 Location: Moxee WA Posts: 1,482	Re: Brake pedal return spring ive got 10# residual check valves on both of my lines, but i'm using a corvette disc brake m/c with front & rear drum brakes. If you are using disc/ drums most m/c's have a check valve built into the port for rear drum brakes. you dont need the valves if you are using a disc / disc set up. __________________ 49 chevy 3100 3 window. 327 / m21 4 spd, 12 bolt w/ 3:55's Bought in 1973 for $235.00. Had it longer than my wife & Kids!!

08-15-2021, 08:45 PM	#10
72Mountaineer Registered User Join Date: Oct 2010 Location: Where Mountaineers are free Posts: 406	Re: Brake pedal return spring Do others have this type of spring/geometry for their pedal? Attached Images

08-18-2021, 01:21 PM	#11
NeoJuice Registered User Join Date: Nov 2016 Location: Beaumont, Alberta Posts: 468	Re: Brake pedal return spring I need to make a brake pedal return spring for my truck with under floor brake booster. That last picture was a pretty good example of what I need to do. Where are people getting there springs from and how tight does the spring need to be to bring the pedal up properly? Homedepot? Lowes? I found these options online https://streetrodding.com/forums/brake-return-spring/ https://www.jalopyjournal.com/forum/...rings.1117288/ https://www.speedwaymotors.com/Maste...-Kit,8750.html If anyone has any more examples of underfloor booster with return spring can post them that would be awesome. Not finding much online because of the under floor.

08-18-2021, 02:59 PM	#12
dsraven Registered User Join Date: Nov 2010 Location: calgary alberta Posts: 8,333	Re: Brake pedal return spring problem with the return springs on a short belcrank is they don't have enough mechanical advantage to lift the weight of the pedal and all the linkage. maybe a longer belcrank on the linkage where the spring connects would help solve the problem after ensuring the linkage is free of binding anywhere. just spot weld a longer tab onto the spot where the spring connects to the linkage and test/repeat until you get resolve.

08-18-2021, 03:01 PM	#13
dsraven Registered User Join Date: Nov 2010 Location: calgary alberta Posts: 8,333	Re: Brake pedal return spring possibly a return spring on the actual brake pedal lever would help overcome the weight issue. again, spot weld a tab to the pedal lever and install a spring. test/repeat until it works

08-18-2021, 03:04 PM	#14
dsraven Registered User Join Date: Nov 2010 Location: calgary alberta Posts: 8,333	Re: Brake pedal return spring or drill a small hole for the spring as high up on the pedal lever as possible to keep it under the floor, then install the spring and tie the other end to something and test. the pedal should also have a definite pedal stop at the top of it's travel range so the pedal stops at the same place every time when released. then adjust the pushrod for the master cylinder so it is sure to be fully released as well.

08-18-2021, 03:13 PM	#15
NeoJuice Registered User Join Date: Nov 2016 Location: Beaumont, Alberta Posts: 468	Re: Brake pedal return spring The picture that 72Mountaineer posted is not my truck. First I need to acquire some springs in different lengths/strength then do some testing. I'm thinking looking at the picture 72Mountaineer posted I might be able to do something similar but thought other people might have some pictures of there setup with under floor boosters.

08-18-2021, 04:56 PM	#16
dsraven Registered User Join Date: Nov 2010 Location: calgary alberta Posts: 8,333	Re: Brake pedal return spring brake/clutch return springs are actually pretty beefy, they don't move far and have a decent load to pull. you could fab a hook from threaded rod to be able to hook the spring and then adjust the tension required after.

08-18-2021, 04:57 PM	#17
dsraven Registered User Join Date: Nov 2010 Location: calgary alberta Posts: 8,333	Re: Brake pedal return spring spring in post 10 looks a little small gauge wire to me.

08-22-2021, 10:29 AM	#19
dsraven Registered User Join Date: Nov 2010 Location: calgary alberta Posts: 8,333	Re: Brake pedal return spring The belcrank is the thing that changes motion from rotational to linear. In this case the pedal is welded to a shaft and when the pedal is pushed down the shaft rotates. Welded to the shaft is a short lever with the pushrod attached that pushes the booster/master cylinder. The pedal is basically a lever as well except it is a lot longer and weighs a lot more in comparison to the short lever. Since the spring is attached to the short lever side it has to be a pretty heavy duty spring in order to overcome the weight of the longer lever because it has a very limited mechanical advantage being that the lever it is attached to is a lot shorter than the pedal lever. As an example, disconnect the pushrod and use a fish scale where your return spring is attached and try to pull the pedal back up to the top of its stroke, like simulating the Springs job. Then you will see how much work the spring needs to do in order to return the pedal. You could then use your fish scale to find a spring that can handle that much weight.



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08-22-2021, 10:35 AM	#20
dsraven Registered User Join Date: Nov 2010 Location: calgary alberta Posts: 8,333	Re: Brake pedal return spring Originally the return spring was attached to the top side of the pedal arm and ran towards the rear of the truck. It was a fairly beefy spring.

08-22-2021, 10:51 AM	#21
dsraven Registered User Join Date: Nov 2010 Location: calgary alberta Posts: 8,333	Re: Brake pedal return spring You could weld another lever onto your belcrank shaft in an appropriate spot to attach a spring to, where the spring would have a good straight pull and the lever could be a bit longer for better mechanical advantage. Use the fish scale idea to find the weight of spring required. Ensure the pedal arm is not dragging on anything and the shaft is free to rotate and not causing another load cor the spring to overcome. Since the pedal comes up through the floor you should also check for binding caused by the pedal to floor seal, carpet etc. The original pedal arm had a rubber block on it that would bump against the firewall when the pedal was at its upmost position. That, or some other positive pedal stop, should also be intact so your booster/master pushrod can be adjusted properly.

08-22-2021, 03:21 PM	#22
72Mountaineer Registered User Join Date: Oct 2010 Location: Where Mountaineers are free Posts: 406	Re: Brake pedal return spring The screwdriver points at the lower leg of the belcrank, I suppose that this is the leg that would be extended downward, that the spring would attach to. Correct? Thanks dsraven for these responses! Attached Images

08-22-2021, 03:36 PM	#23
dsraven Registered User Join Date: Nov 2010 Location: calgary alberta Posts: 8,333	Re: Brake pedal return spring Yeah, that's right. If you have room below you could make a piece of flat bar with a rounded out end so that round fits the shaft then drill a hole in the right place to match up to the bolt for the pushrod, then make the lever extension go past the end of the original crank so it will give better mechanical advantage for the return spring. Again, a fish scale would give you a good idea of how string the spring needs to be or just wing it with what you have readily available. Also ensure the pedal stop is in place somewhere as you shouldn't rely on the booster to be your pedal stop.

08-22-2021, 08:16 PM	#24
72Mountaineer Registered User Join Date: Oct 2010 Location: Where Mountaineers are free Posts: 406	Re: Brake pedal return spring Sounds good, I'll fab up something and get beck to this forum. Thanks for all the help. I would think that more people would have ran into this problem.

08-23-2021, 01:13 PM	#25
NeoJuice Registered User Join Date: Nov 2016 Location: Beaumont, Alberta Posts: 468	Re: Brake pedal return spring That is a great picture 72Mountaineer. I did the exact same thing this weekend. I made a little L bracket and hooked the other end onto a hole in the transmission housing that was right across from the brake pedal. It was a PITA to stretch that spring to get it hooked into place. See attached video I made of the new spring pedal return spring in action. https://photos.app.goo.gl/SqMBAJAfVVBipBsj9

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