Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 11-05-2019, 12:39 PM   #1
M2M
Senior Member
 
M2M's Avatar
 
Join Date: Jul 2012
Location: AUSTRALIA/USA/EU/RUSSIA
Posts: 821
Question Replacing only the main leaf spring with a new one?

I noticed that spring guru Travis Cook is selling just the main leaf for both front and rear. Much cheaper than buying a whole new spring. Does it make sense to replace just the main leaf on your springs if you feel they've lost their bounce or height?
__________________

M2M is offline   Reply With Quote
Old 11-05-2019, 02:01 PM   #2
Rusty Sills
Junior Member
 
Join Date: Aug 2019
Location: Apple Valley CA
Posts: 10
Default Re: Replacing only the main leaf spring with a new one?

I presume you are seeking a 'real' answer to your specific question. So I provide the following with an assumption (since you didn't say) that you are not working on a 100 point restoration ... and the fact that something is only "original,' once", anyway.



I have done this several times, successfully. However, I had several solid and complete springs to work from in selecting well inspected replacement leaves. To my eye, which is the only one I can speak of, one has to have some idea of what would constitute those leaves which seem 'iffy'. Obviously, leaves that are cracked, corroded or significantly(?) gouged ... or showing considerable 'de-arching(?) (in relationship to those in succession in the stack) would not be in the running. But that is where the 'several complete springs come into play, as you can make comparisons of tension, arch, etc.


As far as a complete 'new' replacement spring ... the aftermarket supplier would have to have actually engineered each leaf to Ford engineering spec, for it to be factually, "right". So the question is, would the complete replacement be much better than a reconstituted (for lack of a better term) assembly. But, I cannot speak to other's ability to make a adequate guestimation as I have a mechanical engineering background.



It has been my experience that many 'aftermarket' parts are very often 'sorta close', but not to spec with the original Ford engineering (in spite of what is touted), ie., cotter pin holes mislocated in "u" bolts, brake spring wire to heavy guage, off the shelf castle nut sent as proper(?) replacement to the much taller 'real' spindle nuts, etc. I could go on for awhile on that issue ... but that does not address your question.


Bottom line. If you think you have the 'eye' for a good assessment, or if you have someone nearby to collaborate with, it's your call. You will know fairly quickly when you put the car on the ground.
Rusty Sills is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 11-05-2019, 03:04 PM   #3
Rusty Sills
Junior Member
 
Join Date: Aug 2019
Location: Apple Valley CA
Posts: 10
Default Re: Replacing only the main leaf spring with a new one?

M2M.


In addressing your question, it seems that I overlooked that you stated that your car had been in constant usage 24/7/365 for the past 90 years.



My apologies for stating my opinion .... misguided as it was.


RS
Rusty Sills is offline   Reply With Quote
Old 11-05-2019, 03:14 PM   #4
ryanheacox
Senior Member
 
ryanheacox's Avatar
 
Join Date: Apr 2013
Location: Northwest CT
Posts: 664
Default Re: Replacing only the main leaf spring with a new one?

My opinion, obviously replacing the spring outright would be better and a longer lasting fix. Changing just the bottom leaf still leaves you with 9 old leaves on top of it.



However, if replacing the bottom leaf works, keeps the car going down the road well AND you are okay with the knowledge that it might not be the longest lasting repair then go for it.


If it were me and I was going through the time to pull the spring, front or rear, I'd just replace it. For the time you take disassembling the old spring and fitting the new bottom leaf it might make more sense just to buy a new spring. I'd rather not do the job twice.
ryanheacox is online now   Reply With Quote
Old 11-05-2019, 03:28 PM   #5
M2M
Senior Member
 
M2M's Avatar
 
Join Date: Jul 2012
Location: AUSTRALIA/USA/EU/RUSSIA
Posts: 821
Default Re: Replacing only the main leaf spring with a new one?

Quote:
Originally Posted by Rusty Sills View Post
M2M.


In addressing your question, it seems that I overlooked that you stated that your car had been in constant usage 24/7/365 for the past 90 years.



My apologies for stating my opinion .... misguided as it was.


RS

Where did I state that???
__________________

M2M is offline   Reply With Quote
Old 11-05-2019, 03:41 PM   #6
Rusty Sills
Junior Member
 
Join Date: Aug 2019
Location: Apple Valley CA
Posts: 10
Default Re: Replacing only the main leaf spring with a new one?

M2M,


My bad. I see that it wasn't you ... but another member who made that comment.


Please disregard my opinion and experience, for as a junior member, it is fitting that I defer to the opinions and experience of senior members.


RS
Rusty Sills is offline   Reply With Quote
Old 11-05-2019, 04:00 PM   #7
woofa.express
Senior Member
 
woofa.express's Avatar
 
Join Date: Jan 2018
Location: Tocumwal, NSW, Australia
Posts: 1,015
Default Re: Replacing only the main leaf spring with a new one?

Hi M2M. Tell me please, is the truck you posted last year doing a rebuild?


Sorry all. I posted the above on the wrong thread. gary
__________________
I know many things,
But I don't know everything,
Sometimes I forget things.

And there are times when I have a long memory.
woofa.express is offline   Reply With Quote
Old 11-05-2019, 04:26 PM   #8
alexiskai
Senior Member
 
alexiskai's Avatar
 
Join Date: Apr 2018
Location: Mebane NC
Posts: 365
Default Re: Replacing only the main leaf spring with a new one?

It occurs to me that there are a ton of companies in the US (or wherever you are) that specialize in repairing leaf springs for trucks, trailers, RVs, etc., and I bet you could call up a couple of them and get an answer much more informed by the engineering and behavior of leaf springs then you're likely to get here.
alexiskai is online now   Reply With Quote
Old 11-05-2019, 05:22 PM   #9
Patrick L.
Senior Member
 
Patrick L.'s Avatar
 
Join Date: May 2010
Location: Upstate NY and western Florida
Posts: 5,204
Default Re: Replacing only the main leaf spring with a new one?

I think Rusty covered this pretty well.

I've been rebuilding springs on things from baby carriages to heavy trucks for decades. I have no issues with a repaired spring as long as its a quality repair.

I replaced broken leaves on my 'A' 45 yrs ago when I got it, with no issues since. You just need a good spring to get the extra leaves from, thats usually the tricky part.
Patrick L. is offline   Reply With Quote
Old 11-05-2019, 11:40 PM   #10
dumb person
Senior Member
 
dumb person's Avatar
 
Join Date: Apr 2011
Location: South pacific island
Posts: 1,585
Default Re: Replacing only the main leaf spring with a new one?

The bottom leaf holds to the axles. If you have doubts to it's strength, then replacing it is a good option.
It's only a bad option of the other leaves are rather poorly, as they do the heavy lifting.
So to answer your question, if you feel you lost bounce, the bottom one is only the first one to change out. Uppers may vary.
__________________
<Link> This is how we roll<Link>

"I'm Convinced that no one really reads posts anymore; they just fabricate what they think the post says then ramble on about red herrings."--Bob
Outcasts rules of old cars
#1 Fun is imperative, mainstream is overrated
#2 If they think it is impossible, prove them wrong
#3 If the science says it impossible you are not being creative enough.
#4 No shame in recreating something you never had
#5 If it were not for the law & physics you would be unstoppable
dumb person is offline   Reply With Quote
Old 11-07-2019, 12:25 AM   #11
SSsssteamer
Senior Member
 
SSsssteamer's Avatar
 
Join Date: Nov 2010
Location: Sedro-Woolley, WA
Posts: 944
Default Re: Replacing only the main leaf spring with a new one?

On my 1929 Tudor, I had sorted out the best leaves from many different used spring sources and I still had too much body roll and a soft spring at that. I even added an additional leaf spring to firm it up. After many years (50 years) of fighting the soft springs, I bought a whole new spring for the front. A world of difference. Seams that all the old spring leaves had lost their tension and they were allowing our Tudor to sag out on every opportunity. My advice, don't screw around with replacing the main leaf. For not much more money you can replace them all and do the job right.
SSsssteamer is offline   Reply With Quote
Old 11-07-2019, 02:24 AM   #12
Randy in ca
Senior Member
 
Randy in ca's Avatar
 
Join Date: May 2010
Posts: 1,215
Default Re: Replacing only the main leaf spring with a new one?

Quote:
Originally Posted by M2M View Post


......... With these two facts in mind, let me ask you 2 questions:

1. Of the ten leaves in a Tudor spring isn't the main leaf the most important one as far as forming the arch (and height) and supplying the flex to the spring?

2. If the answer to question 1 is "yes"; wouldn't adding a new main leaf be better than not adding one? As far as matching leaves, in such a scenario 9 of the 10 leaves are already matched, with all of them sitting on the new main leaf.

There’s no doubt that the shape and condition of the leaves above the main leaf has a definite effect on the overall shape and performance of the spring assembly. Each leaf moving from bottom to top should have a tighter curvature. That means that every time you add/clamp another leaf above, more curvature should be forced into the leaves below and the main leaf spring eyes become closer together. By example, all rear main leaves should have the same eye-to-eye distance when loose, but by the time they’re assembled those springs with 2 or 3 more leaves should measure up to 2” shorter eye-to-eye due the additional force applied by the curvature of the additional top leaves. The Roadster spring, with the least number of leaves, should have the flattest appearance when assembled as well as the largest eye-to-eye distance. An old catalogue I have shows the assembled Roadster rear spring eye-to-eye dimension as being 40" to 40-3/16" while those for other models range from 37-7/8" to 39-11/16" eye-to-eye when assembled.


Randy in ca is offline   Reply With Quote
Old 11-07-2019, 12:44 PM   #13
alexiskai
Senior Member
 
alexiskai's Avatar
 
Join Date: Apr 2018
Location: Mebane NC
Posts: 365
Default Re: Replacing only the main leaf spring with a new one?

Quote:
Originally Posted by Randy in ca View Post
An old catalogue I have shows the assembled Roadster rear spring eye-to-eye dimension as being 40" to 40-3/16" while those for other models range from 37-7/8" to 39-11/16" eye-to-eye when assembled.
Is there a resource online showing the factory standard unweighted dimensions for the various front and rear springs? This would be a good resource for those of us looking at used springs or trying to assess the condition of our current springs.
alexiskai is online now   Reply With Quote
Old 11-07-2019, 01:24 PM   #14
M2M
Senior Member
 
M2M's Avatar
 
Join Date: Jul 2012
Location: AUSTRALIA/USA/EU/RUSSIA
Posts: 821
Default Re: Replacing only the main leaf spring with a new one?

Quote:
Originally Posted by dumb person View Post
The bottom leaf holds to the axles. If you have doubts to it's strength, then replacing it is a good option.
It's only a bad option of the other leaves are rather poorly, as they do the heavy lifting.
So to answer your question, if you feel you lost bounce, the bottom one is only the first one to change out. Uppers may vary.
Quote:
Originally Posted by Randy in ca View Post
There’s no doubt that the shape and condition of the leaves above the main leaf has a definite effect on the overall shape and performance of the spring assembly. Each leaf moving from bottom to top should have a tighter curvature. That means that every time you add/clamp another leaf above, more curvature should be forced into the leaves below and the main leaf spring eyes become closer together. By example, all rear main leaves should have the same eye-to-eye distance when loose, but by the time they’re assembled those springs with 2 or 3 more leaves should measure up to 2” shorter eye-to-eye due the additional force applied by the curvature of the additional top leaves. The Roadster spring, with the least number of leaves, should have the flattest appearance when assembled as well as the largest eye-to-eye distance. An old catalogue I have shows the assembled Roadster rear spring eye-to-eye dimension as being 40" to 40-3/16" while those for other models range from 37-7/8" to 39-11/16" eye-to-eye when assembled.

Good answers that directly address my question about replacing only the main leaf with a new one.
__________________

M2M is offline   Reply With Quote
Old 11-07-2019, 03:45 PM   #15
WHN
Senior Member
 
Join Date: Mar 2017
Posts: 1,071
Default Re: Replacing only the main leaf spring with a new one?

Quote:
Originally Posted by M2M View Post
A spring is NOT running gear. If a leaf in a spring breaks at 45mph there's no way on earth it will result in any harm to your children and grandchildren.

Interesting that you take this view with springs (it must be new, correct and perfect) while in another thread you advise the use of a 50/50 mix of STP and the fake "600w" oil the suppliers sell in transmissions. A transmission IS running gear. STP is NOT meant for transmissions. The oil the suppliers sell is NOT 600w. Using YOUR logic, you're risking the safety of your grandchildren.

You don't seem to have a coherent strategy/ideology about safety, restoration and maintenance.
As stated earlier, you and I seem to not be on the same plane.

I would just add that a broken main leaf in either a front or rear spring has the potential to create a REAL problem. Someone that doesn’t think that is the case really does not understand how these cars are set up.

I don’t know what I have said or done that has gotten you so upset. That’s your issue not mine.

Check with Webster’s. Running Gear is a noun, definition, wheels, axels, and springs. Sorry.

Please reframe from addressing me further.

Last edited by WHN; 11-07-2019 at 04:30 PM.
WHN is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 04:17 PM.