Does a mod using a ’39 clutch & brake pedal work correctly?
- Thread starter Robert Dip
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Robert Dip
Senior Member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
TomT.....I guess you and I are in the same boat. ( thought I was alone there for a while ) and yes, your mods on the pedal arm is the direction I am headed for a cure. What PP did you install in this set-up, was it a long type 10" ??
Dick....thanks for the photos...my arm is in an 'S' form for the offset, but I believe that the end result is the same. I measured my arm at exactly 3" hole c/c. What distance do you have on the arms you displayed? Over the years, I have never seen an arm shorter in c/c hole distance than this 3" piece. Robert
TomT.....I guess you and I are in the same boat. ( thought I was alone there for a while ) and yes, your mods on the pedal arm is the direction I am headed for a cure. What PP did you install in this set-up, was it a long type 10" ??
Dick....thanks for the photos...my arm is in an 'S' form for the offset, but I believe that the end result is the same. I measured my arm at exactly 3" hole c/c. What distance do you have on the arms you displayed? Over the years, I have never seen an arm shorter in c/c hole distance than this 3" piece. Robert
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DICK SPADARO
Well-known member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
Robert, Somebody screwed with your arm. The black arm in the picture is correct and
unaltered c-c measurement is 3.5" 35-38 arm measures 3.25, your measurement is 3" with that "S" bend in your set up you cant get enough throw. The correct 39 arm has the throw lever positioned to the outer portion of the casting almost right above the pin holes. refer back to the pictures because your part doesnt match.
Robert, Somebody screwed with your arm. The black arm in the picture is correct and
unaltered c-c measurement is 3.5" 35-38 arm measures 3.25, your measurement is 3" with that "S" bend in your set up you cant get enough throw. The correct 39 arm has the throw lever positioned to the outer portion of the casting almost right above the pin holes. refer back to the pictures because your part doesnt match.
Robert Dip
Senior Member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
Dick..."Somebody screwed with your arm"....I won't doubt that, since I am reviving a 50's built Hot Rod, but, having a shorter arm down to 3" is beneficial for my problem, and not the other way round. Having a 3.5" c/c arm requires even more clutch pedal travel to disengage the clutch, which I don't have. Whatever someone did in the past, this set-up was good with the 9" clutch..????? Go figure??
Dick..."Somebody screwed with your arm"....I won't doubt that, since I am reviving a 50's built Hot Rod, but, having a shorter arm down to 3" is beneficial for my problem, and not the other way round. Having a 3.5" c/c arm requires even more clutch pedal travel to disengage the clutch, which I don't have. Whatever someone did in the past, this set-up was good with the 9" clutch..????? Go figure??
Robert Dip
Senior Member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
Dick...after looking into more detail on your photos, it looks like my arm is the '38 on your photo, reversed and bent back outward for proper rod alignment....IF, that's the case. Interesting, but still at the correct clock position and I'm still better off with the 3" arc.
Dick...after looking into more detail on your photos, it looks like my arm is the '38 on your photo, reversed and bent back outward for proper rod alignment....IF, that's the case. Interesting, but still at the correct clock position and I'm still better off with the 3" arc.
DICK SPADARO
Well-known member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
Nope, your problem is disengaging the clutch so it doesnt drag on the flywheel when shifting, as you decrease the length of the throw arm it requires a longer stroke to make the pedal operate the required distance. Its distance travel required to disengage the clutch. A 3" lever will only travel xxx inches of the pedal stroke, using a longer clutch lever will now generate a stroke travel of yyy inches. You have three lever arms, one the stock pedal arm, one the clutch arm and one the throw out fork. The pedal arm and the throw out arm are fixed so the only variable is the clutch arm and that is too small to match the required throw distance to fully disengage the clutch. The reason you didnt notice it before with the 9" disc was probably due to the slippage due to the lesser contact area. With the 10" plate there is more area and less slip. Just change the arm to the correct one and jobs done. They are about $20.00
Nope, your problem is disengaging the clutch so it doesnt drag on the flywheel when shifting, as you decrease the length of the throw arm it requires a longer stroke to make the pedal operate the required distance. Its distance travel required to disengage the clutch. A 3" lever will only travel xxx inches of the pedal stroke, using a longer clutch lever will now generate a stroke travel of yyy inches. You have three lever arms, one the stock pedal arm, one the clutch arm and one the throw out fork. The pedal arm and the throw out arm are fixed so the only variable is the clutch arm and that is too small to match the required throw distance to fully disengage the clutch. The reason you didnt notice it before with the 9" disc was probably due to the slippage due to the lesser contact area. With the 10" plate there is more area and less slip. Just change the arm to the correct one and jobs done. They are about $20.00
V8COOPMAN
Well-known member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
Dick....SHORTER the clutch release arm on the trans, the higher number of degrees of clutch release shaft rotation, considering the same amount of PEDAL lever input. Shortening the TRANS arm promotes GREATER fork travel. Sometimes when I don't hold my tongue just right, stuff works-out backwards, too. DD
Dick....SHORTER the clutch release arm on the trans, the higher number of degrees of clutch release shaft rotation, considering the same amount of PEDAL lever input. Shortening the TRANS arm promotes GREATER fork travel. Sometimes when I don't hold my tongue just right, stuff works-out backwards, too. DD
Robert Dip
Senior Member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
Dick...Sorry, your formulae does not equate...the longer the trans clutch shaft arm is, the more travel is needed....not good. If, for example, if I need to rotate the clutch shaft 30 degrees, as per the sketch, I would need more travel with the longer arm.
Dick...Sorry, your formulae does not equate...the longer the trans clutch shaft arm is, the more travel is needed....not good. If, for example, if I need to rotate the clutch shaft 30 degrees, as per the sketch, I would need more travel with the longer arm.
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V8COOPMAN
Well-known member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
Robert...I think Dick's just having a bad day. He'll come-around...he DOES know better. DD
Robert...I think Dick's just having a bad day. He'll come-around...he DOES know better. DD
Robert Dip
Senior Member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
DD....I know that.....and I know Dick, we go back a long ways....but I don't think he's figured out yet who I am.....hell, all of our brains do work backwards at time....How often do I question my own. Are we having fun yet! Robert
DD....I know that.....and I know Dick, we go back a long ways....but I don't think he's figured out yet who I am.....hell, all of our brains do work backwards at time....How often do I question my own. Are we having fun yet! Robert
George/Maine
Well-known member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
To get the max throw, the trans lever has to be at 12 oclock,and the pedal 1/2 way down.
To contact the throwout bearing to soon or late you loose throw.
True short lever more throw.
The arm you have is most likely off location because of the bolt.
To get the max throw, the trans lever has to be at 12 oclock,and the pedal 1/2 way down.
To contact the throwout bearing to soon or late you loose throw.
True short lever more throw.
The arm you have is most likely off location because of the bolt.
DICK SPADARO
Well-known member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
If this is the only mistake I make today I view it as a good day. You Guys you are looking at it the wrong way, your math is correct for a single point but we are dealing with more than one point operation. Robert you answered your problem in post #28.
The Clutch arm is too short to completely disengage the clutch. Maybe I need to explain it as a measure of degrees of rotation not distance traveled. If you need 40 degrees of rotation to disengage the clutch you need 40 degrees. The pedal is hitting the floor and not allowing the clutch to disengage because it is not allowing the clutch shaft to rotate enough. Like you are getting 37 degrees of rotation and then the pedal bottoms. It needs the longer arm to completely disengage the clutch not a shorter one. The shorter arm moves a shorter distance but it means the clutch pedal moves a longer distance during operation, it would be fine if you didn't have a floor board. With your arm the pedal bottoms out on the floor board sooner than it should.
Going to a longer arm on the clutch shaft changes the ratio so the pedal arm has a longer stroke and increases the pedal throw so doesnt bottom out so quick and completes the clutch relaese.
If this is the only mistake I make today I view it as a good day. You Guys you are looking at it the wrong way, your math is correct for a single point but we are dealing with more than one point operation. Robert you answered your problem in post #28.
The Clutch arm is too short to completely disengage the clutch. Maybe I need to explain it as a measure of degrees of rotation not distance traveled. If you need 40 degrees of rotation to disengage the clutch you need 40 degrees. The pedal is hitting the floor and not allowing the clutch to disengage because it is not allowing the clutch shaft to rotate enough. Like you are getting 37 degrees of rotation and then the pedal bottoms. It needs the longer arm to completely disengage the clutch not a shorter one. The shorter arm moves a shorter distance but it means the clutch pedal moves a longer distance during operation, it would be fine if you didn't have a floor board. With your arm the pedal bottoms out on the floor board sooner than it should.
Going to a longer arm on the clutch shaft changes the ratio so the pedal arm has a longer stroke and increases the pedal throw so doesnt bottom out so quick and completes the clutch relaese.
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V8COOPMAN
Well-known member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
OK Folks, this ain't rocket science. Robert Dip...Let's start over, just to be clear. '39 Ford, right? '39 pedal assembly, right? 9" clutch worked properly before you decided to change to a 10" for some reason, correct so far? Is it a fact that the ONLY thing that has changed here is that you've replaced a 9" clutch/PP with a 10" clutch/PP? That's what I get out of all this. I also understand that your clutch release arm is not stock, but I BELIEVE it is the same one that was being used BEFORE the clutch swap......CORRECT?
With ALL these questions answered and confirmed by you ROBERT, we ought to be able to get somewhere without any confusion. IF you had it all working with the 9", and that's ALL that you've changed, I would also have to question SOMETHING being dimensionally and significantly different with the 10" clutch cover/actuating levers as I THINK you seem to be asking. DD
OK Folks, this ain't rocket science. Robert Dip...Let's start over, just to be clear. '39 Ford, right? '39 pedal assembly, right? 9" clutch worked properly before you decided to change to a 10" for some reason, correct so far? Is it a fact that the ONLY thing that has changed here is that you've replaced a 9" clutch/PP with a 10" clutch/PP? That's what I get out of all this. I also understand that your clutch release arm is not stock, but I BELIEVE it is the same one that was being used BEFORE the clutch swap......CORRECT?
With ALL these questions answered and confirmed by you ROBERT, we ought to be able to get somewhere without any confusion. IF you had it all working with the 9", and that's ALL that you've changed, I would also have to question SOMETHING being dimensionally and significantly different with the 10" clutch cover/actuating levers as I THINK you seem to be asking. DD
Robert Dip
Senior Member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
Dick, this is getting funny, and I am not laughing at you, just with you. V8 COOPMAN and I are going to have to sit down with you on this one. What I will be doing to solve this at present, is to leave the clutch shaft arm as is, and increase the pedal lever arm from 1 3/8” to approx. 2”. This will give me the extra throw length needed.
Having said that, it still does not give me an explanation on why there has become a difference going from a 9” to a 10”. Yes, there may an additional frictional difference using a wider surface disc, but not to that degree.
This has me very curious, because so many out there are using the ’39 pedal set-up when converting to hydraulics. Even B. Drake has made available a repop of these pedals. It is just in my professional nature to find the reasons behind this situation. TomT seemed to have this predicament also. I am sure that our discussions here will help others using this set-up….as so many other forums have assisted me in the past.
Dick, this is getting funny, and I am not laughing at you, just with you. V8 COOPMAN and I are going to have to sit down with you on this one. What I will be doing to solve this at present, is to leave the clutch shaft arm as is, and increase the pedal lever arm from 1 3/8” to approx. 2”. This will give me the extra throw length needed.
Having said that, it still does not give me an explanation on why there has become a difference going from a 9” to a 10”. Yes, there may an additional frictional difference using a wider surface disc, but not to that degree.
This has me very curious, because so many out there are using the ’39 pedal set-up when converting to hydraulics. Even B. Drake has made available a repop of these pedals. It is just in my professional nature to find the reasons behind this situation. TomT seemed to have this predicament also. I am sure that our discussions here will help others using this set-up….as so many other forums have assisted me in the past.
Robert Dip
Senior Member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
V8COOPMAN....well said....correct on all counts.....took the words right out of me....it's gotta be the PP...there is nothing else. Now for the million $$ question....is my 10" PP a weirdo one....or is there really a difference in throw from a 9 to a 10????? Amen.
V8COOPMAN....well said....correct on all counts.....took the words right out of me....it's gotta be the PP...there is nothing else. Now for the million $$ question....is my 10" PP a weirdo one....or is there really a difference in throw from a 9 to a 10????? Amen.
V8COOPMAN
Well-known member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
Robert...You and I are on the same page. IF I were in your shoes, I'd be asking the same question about the PP. What's really interesting here is the fact that your clutch release arm is ALREADY shortened effectively from a stock '39 arm (effectively the same direction you would need to go to fix your problem...just not enough YET). I understand that you intend to correct this fiasco by lengthening the arm on the PEDAL (effectively the same as shortening the clutch release arm).
Since I think you seemed to indicate that you can "kind of" drive the car the way it is, I'd bet you do not need to lengthen the pedal arm to any more than 1 3/4" effective length. Remember, the longer that PEDAL lever gets, the more "leg" it'll take to push that pedal. You know what to do...you're headed in the correct direction. I'd like to hear of your progress. DD
Robert...You and I are on the same page. IF I were in your shoes, I'd be asking the same question about the PP. What's really interesting here is the fact that your clutch release arm is ALREADY shortened effectively from a stock '39 arm (effectively the same direction you would need to go to fix your problem...just not enough YET). I understand that you intend to correct this fiasco by lengthening the arm on the PEDAL (effectively the same as shortening the clutch release arm).
Since I think you seemed to indicate that you can "kind of" drive the car the way it is, I'd bet you do not need to lengthen the pedal arm to any more than 1 3/4" effective length. Remember, the longer that PEDAL lever gets, the more "leg" it'll take to push that pedal. You know what to do...you're headed in the correct direction. I'd like to hear of your progress. DD
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
If both pressure plates are working correctly they require the same amount of travel to release. If the 9" released correctly and the 10" doesn't you have a defective 10" pressure plate or disc.
I think Dick is misunderstanding which lever you are talking about.
The pedal lever has to be longer or the release shaft lever has to be shorter to get more travel of the throwout fork.
Bill
If both pressure plates are working correctly they require the same amount of travel to release. If the 9" released correctly and the 10" doesn't you have a defective 10" pressure plate or disc.
I think Dick is misunderstanding which lever you are talking about.
The pedal lever has to be longer or the release shaft lever has to be shorter to get more travel of the throwout fork.
Bill
DICK SPADARO
Well-known member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
Ok I'll concede you guys are correct I'm wrong. Ford made the throw lever specifically for that combination. Yours is not the correct one its too short and it doesnt work correctly in this application. Does that give you a hint that something might be wrong parts wise. Rather than question my poor math skills and the pressure plate quality look at what you have starting with the situation that the pedal assembly botttoms out on the floor preventing complete release of the clutch!
The clutch should be in full disengagement way before the pedal bottoms on the floor board out. Since the limit factor is the floor board you have to initiate a longer travel in the clutch throw out shaft to increase the distance travel by the throw out fork. You math guys are assuming that the clutch pivot and the trans pivot are on the same plain , they are not, the trans clutch arm pivot point is below the axis of the pedal, the linkage points are at the same plain. Shortening the clutch throw arm moves the linkage points so the throw initiated becomes smaller not larger and requires more clutch pedal input to travel the same distance however the pedal hits the floor before achieving the necessary the throw. The shorter arm cannot rotate far enough to release the clutch.
Additionally making the clutch throw arm arm shorter makes it move more rapidly so you have less of a sweet spot and a hair trigger clutch release with a chatter potential. As I said before the issue was already there just masked by the slippage in the smaller clutch disc. Put the longer correct arm on readjust the pedal to arm rod and problem solved.
Ok I'll concede you guys are correct I'm wrong. Ford made the throw lever specifically for that combination. Yours is not the correct one its too short and it doesnt work correctly in this application. Does that give you a hint that something might be wrong parts wise. Rather than question my poor math skills and the pressure plate quality look at what you have starting with the situation that the pedal assembly botttoms out on the floor preventing complete release of the clutch!
The clutch should be in full disengagement way before the pedal bottoms on the floor board out. Since the limit factor is the floor board you have to initiate a longer travel in the clutch throw out shaft to increase the distance travel by the throw out fork. You math guys are assuming that the clutch pivot and the trans pivot are on the same plain , they are not, the trans clutch arm pivot point is below the axis of the pedal, the linkage points are at the same plain. Shortening the clutch throw arm moves the linkage points so the throw initiated becomes smaller not larger and requires more clutch pedal input to travel the same distance however the pedal hits the floor before achieving the necessary the throw. The shorter arm cannot rotate far enough to release the clutch.
Additionally making the clutch throw arm arm shorter makes it move more rapidly so you have less of a sweet spot and a hair trigger clutch release with a chatter potential. As I said before the issue was already there just masked by the slippage in the smaller clutch disc. Put the longer correct arm on readjust the pedal to arm rod and problem solved.
Robert Dip
Senior Member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
V8COO........Yes, 1 3/4" on the pedal lever arm would be good, amd the reason I mentioned 2" is because I have designed a piece to add to the existing than can be placed directly in place without taking anything off the car or welding under the car. The slot fork at the pedals is 0.312" ( 5/16" ) and I can fab a piece that will slip in place. This now means that the pedal side will use a fork piece on each end of the adjust rod. ( I am not going to take this engine out again, at least not for a while ) The existing hole in the pedal will be used as one of the bolting points and the existing grease thread centered in the piviting shaft, now a 1/8 NPT can be used and modified to hold as a second mounting point. The .312 thick flat horseshoe style piece will have the hole machined above the existing one, but it needs room for the fork to pivot. Yes, this will bring me close to the floorpan....but we'll see. In this manner, I can experiment on how it works out. Everything I do in building a car goes on the drawing board....I never fit & fiddle....that's me.....design to exact needs and install.
Dick, the next time we meet at a car show....we'll go to the bar and discuss this in-depth...drinks are on me.
V8COO........Yes, 1 3/4" on the pedal lever arm would be good, amd the reason I mentioned 2" is because I have designed a piece to add to the existing than can be placed directly in place without taking anything off the car or welding under the car. The slot fork at the pedals is 0.312" ( 5/16" ) and I can fab a piece that will slip in place. This now means that the pedal side will use a fork piece on each end of the adjust rod. ( I am not going to take this engine out again, at least not for a while ) The existing hole in the pedal will be used as one of the bolting points and the existing grease thread centered in the piviting shaft, now a 1/8 NPT can be used and modified to hold as a second mounting point. The .312 thick flat horseshoe style piece will have the hole machined above the existing one, but it needs room for the fork to pivot. Yes, this will bring me close to the floorpan....but we'll see. In this manner, I can experiment on how it works out. Everything I do in building a car goes on the drawing board....I never fit & fiddle....that's me.....design to exact needs and install.
Dick, the next time we meet at a car show....we'll go to the bar and discuss this in-depth...drinks are on me.
George/Maine
Well-known member
Re: Does a mod using a ’39 clutch & brake pedal work correctly?
I think we all know you have the wrong lever and the shaft has been drilled.
Now the point i,m trying to make is the pin location is very close 1/8" could fix the problem.
Say the lever started at 3 oclock to 1 oclock the movemnet is less, then at 1-11 oclock. this is max travel.
If you look at the lever the pin lacation is not the same. as stock 39.
being the 39 pedal works ok for others,try your idea trial and errror.
Also make sure your pedal is hitting the floor underside for max travel.
I think we all know you have the wrong lever and the shaft has been drilled.
Now the point i,m trying to make is the pin location is very close 1/8" could fix the problem.
Say the lever started at 3 oclock to 1 oclock the movemnet is less, then at 1-11 oclock. this is max travel.
If you look at the lever the pin lacation is not the same. as stock 39.
being the 39 pedal works ok for others,try your idea trial and errror.
Also make sure your pedal is hitting the floor underside for max travel.