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Putting heavier duty rear springs on F-100?

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56mulberry
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Putting heavier duty rear springs on F-100?

Post #1 by 56mulberry » Wed Apr 29, 2009 9:15 am

My son is going to start driving his '77 F100 on Monday--he turns 16. He mows a lot of yards--about 20 per week--and has been using my full size Chevy to pull his trailer which is a 12' single axle with a commercial grade Z-turn mower, weedeater, blower etc..

We built a custom hitch w/2" reciever that mounts up under bumper and looks really great and should work great (just didnt want all that weight on bumper only) then sprayed bedliner on bumper/hitch.

Now the question--We are putting on 6ply tirers so should be good with trailering there...but am worried about squatting the rear too much with the trailer on and a load of pine straw or whatever with the tired old stock springs.
Can I replace the stock 33 yr old 4-leaf springs with some heavier duty F150/250 rears maybe to add some payload/bumper sag capacity? OR some 5 leafs? What is the easy bolt on?

I replaced stock 4-leaf rears with F-150 5-leaf rears on my 4wd 83 ford Ranger to help with payload capacity a few years ago.

Anybody? DOUG
"If you ever buy a battery at a place that advertises "free installation" and you own a 2004 Pontiac Montana, go ahead and take 'em up on the offer--while they install it you can go write a novel or solve the world hunger issue or grow some dreadlocks or something...."

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Post #2 by Lazy JW » Wed Apr 29, 2009 9:51 am

"The White OX" 1974 F-350 300-6, Stock single exhaust, Carter YF, T-18A, Dana70 w/4.11, Flatbed dually w/dump bed. "Where no oxen are, the crib is clean, but much increase is by the strength of the ox" (Proverbs 14:4)
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shortbox07
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Post #3 by shortbox07 » Wed Apr 29, 2009 11:37 am

f-150 springs should bolt right in. or you could use some overload shocks on it (basically just a coilover) they are just as easy as bolting in new shocks.
A guy at the local parts store once asked me if i own any vehicles that aren't made up of 10 other vehicles ... i replied whats the fun in that!

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Post #4 by crash-harris » Wed Apr 29, 2009 11:45 am

I'm replacing the 2.5" springs on my '90 F150 with F250 ones (with the 6" lift), but they are 3" and I'll have to change the hangers. I'm willing to bet that you can get some F150 springs for your year and bolt them in. I hate old saggy springs.
Bruiser - 1990 Ford F150...barely...EFI 300 Big Six, 500K+!, converted to 4x4. 4.10 gears and Sterling FF rear w/ Trac-Lok, 37" meats. Undergoing 1 Ton leaf spring SAS. 6BT in the plans.

56mulberry
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Post #5 by 56mulberry » Wed Apr 29, 2009 12:31 pm

Those Timbrens look very cool--are they expensive?

I think a set of F150 springs would be the easiest way to go. I imagine any year would fit as long as width is good?

I am sure 73-79 would be fine to search it out.

On that note--what is the actual spec on payload for SWB F100? vs same model F150? And are SWB springs different than LWB spring load specs for same ?

DOUG
"If you ever buy a battery at a place that advertises "free installation" and you own a 2004 Pontiac Montana, go ahead and take 'em up on the offer--while they install it you can go write a novel or solve the world hunger issue or grow some dreadlocks or something...."

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Post #6 by Lazy JW » Wed Apr 29, 2009 1:28 pm

56mulberry wrote:....

I think a set of F150 springs would be the easiest way to go...


I don't.

They may well be the cheapest route if you can find a good, used set, but rasselin' those old, rusted nasty, stuck bolts and hangers aren't my idea of "easy".

The Timbren's will be the easiest because everything is new and clean; all you are doing is bolting them on and away you go. Plus, you get to keep the soft ride when it is unloaded.

Dunno about the price though, I think you can order them from their website.
Have fun,
Joe
"The White OX" 1974 F-350 300-6, Stock single exhaust, Carter YF, T-18A, Dana70 w/4.11, Flatbed dually w/dump bed. "Where no oxen are, the crib is clean, but much increase is by the strength of the ox" (Proverbs 14:4)
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Post #7 by Harte3 » Wed Apr 29, 2009 1:37 pm

On the other hand, replacing the old springs provides an opportunity to also replace old, worn-out bushings too...might be worth the wrestling match.
'83 F150 300, 0.030 over, Offy DP, Holley 4160/1848-1 465 cfm, Comp Cam 260H. P/P head, EFI exhaust manifolds, Walker Y Pipe, Super Cat, Turbo muffler, Recurved DSII, Mallory HyFire 6a, ACCEL Super Stock Coil, Taylor 8mm Wires, EFI plugs.

56mulberry
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Post #8 by 56mulberry » Wed Apr 29, 2009 3:16 pm

Anybody tried the "Add-a-Leaf" type like Rough Country or siimilar?
"If you ever buy a battery at a place that advertises "free installation" and you own a 2004 Pontiac Montana, go ahead and take 'em up on the offer--while they install it you can go write a novel or solve the world hunger issue or grow some dreadlocks or something...."

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Post #9 by Luckyman » Wed Apr 29, 2009 3:49 pm

I have used these http://cgi.ebay.com/ebaymotors/70-77-78 ... 240%3A1318 on my vehicles since 1970 and have had no troubles/problems. I put these up from ebay because of the picture. A local parts store could probably order direct from Gabriel for same or better price.

What I like about them is they dont adversly affect the ride too much when the truck is empty and they will help remind you to not overload the truck too much either. They are good for another 500+ lbs which is about all the semi-float axles can handle anyway.

The thing to remember about putting on additional springs is that they can let you severely overload the rear axle if you are not carefull. The F100-150 9" axles are usually rated to carry 3000-4000 lbs which means 1000-2000 lbs in the bed or in my case the very rare/occasional 2500-3000 lb load (which is about the max my 3750 rear springs with the spring shocks added will handle. I had 4500-5000 lbs on the rear axle one time for two weeks. When I finally took the weight off the rear, the axle seals dumped gear oil on my brakes because they had deformed. If you need to carry more than 2000 lbs on a regular basis I would get a truck with a full float rear axle.
Last edited by Luckyman on Mon May 11, 2009 10:22 am, edited 1 time in total.
1 "76" F150 RC, LB, 2WD, 300, NP435, 9" open 3.00, special order 2-76/Delivered 4-76. Still "new".

1 "73-79" F150 RC/SS/SB/4WD, "84"-300, T18, NP205, 9" open 3.50, Dana 44 3.50 open, Offy DP, Holley 470, EFI + single 2.5" exhaust. Gathered from 15+ donor/parts trucks. "Fubar". Runs good, safe, still needs details/project continues.

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Post #10 by 56mulberry » Wed Apr 29, 2009 6:13 pm

That must be the coil over someone else mentioned--and I agree with you all that we are not wanting to overload an axle...but want to be certain we can carry at least what an F150 can carry. I don't think there is much else different in the rear suspension than the springs is there?
"If you ever buy a battery at a place that advertises "free installation" and you own a 2004 Pontiac Montana, go ahead and take 'em up on the offer--while they install it you can go write a novel or solve the world hunger issue or grow some dreadlocks or something...."

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Post #11 by crash-harris » Wed Apr 29, 2009 11:22 pm

Another reason why I'm doing an 8-lug SAS and putting a semi-floating (will go full-float later) Sterling 10.25" in under the backside :lol:
Bruiser - 1990 Ford F150...barely...EFI 300 Big Six, 500K+!, converted to 4x4. 4.10 gears and Sterling FF rear w/ Trac-Lok, 37" meats. Undergoing 1 Ton leaf spring SAS. 6BT in the plans.

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Post #12 by shortbox07 » Thu Apr 30, 2009 10:52 am

56mulberry wrote:
On that note--what is the actual spec on payload for SWB F100? vs same model F150? And are SWB springs different than LWB spring load specs for same ?

DOUG


i think its about a case of beer and a bag of ice :lol:
A guy at the local parts store once asked me if i own any vehicles that aren't made up of 10 other vehicles ... i replied whats the fun in that!



my "six" collection

78' f-100 shortbox 300

67' mustang coupe 200

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Post #13 by Luckyman » Thu Apr 30, 2009 10:53 am

56mulberry wrote:That must be the coil over someone else mentioned--and I agree with you all that we are not wanting to overload an axle...but want to be certain we can carry at least what an F150 can carry. I don't think there is much else different in the rear suspension than the springs is there?


As I noted above the F100-150 axles were rated from approx 3000-4000 lbs. If your F100 has an axle rated at 3000 and you put the springs from an F150 rated at 4000 then you are getting into slightly overloaded territory if you use all the spring there is.

I like the spring shocks because 1. They are so easy to install. 2 They dont ride too bad. 3. They wont let me get too carried away with overloading the semi-float axle. 4. They are not too expensive. 5. They do exactly what I need them to do.
1 "76" F150 RC, LB, 2WD, 300, NP435, 9" open 3.00, special order 2-76/Delivered 4-76. Still "new".

1 "73-79" F150 RC/SS/SB/4WD, "84"-300, T18, NP205, 9" open 3.50, Dana 44 3.50 open, Offy DP, Holley 470, EFI + single 2.5" exhaust. Gathered from 15+ donor/parts trucks. "Fubar". Runs good, safe, still needs details/project continues.

56mulberry
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Post #14 by 56mulberry » Thu Apr 30, 2009 12:57 pm

I found that Monroe also offers a similar product at a similar price as Gabriel's--AM definitely going with that coil spring/shock combo--because we still have original 1977 shocks on it too!!! and they need replacing.
"If you ever buy a battery at a place that advertises "free installation" and you own a 2004 Pontiac Montana, go ahead and take 'em up on the offer--while they install it you can go write a novel or solve the world hunger issue or grow some dreadlocks or something...."

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Post #15 by Luckyman » Thu Apr 30, 2009 1:01 pm

56mulberry wrote:I found that Monroe also offers a similar product at a similar price as Gabriel's--AM definitely going with that coil spring/shock combo--because we still have original 1977 shocks on it too!!! and they need replacing.


I'm pretty sure you wont be sorry with either the Monroe or Gabriel spring overload shocks. Dont squash the rubber bushings too much.
1 "76" F150 RC, LB, 2WD, 300, NP435, 9" open 3.00, special order 2-76/Delivered 4-76. Still "new".

1 "73-79" F150 RC/SS/SB/4WD, "84"-300, T18, NP205, 9" open 3.50, Dana 44 3.50 open, Offy DP, Holley 470, EFI + single 2.5" exhaust. Gathered from 15+ donor/parts trucks. "Fubar". Runs good, safe, still needs details/project continues.

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Re: Putting heavier duty rear springs on F-100?

Post #16 by Frankford6 » Fri Jun 26, 2009 11:17 am

I carry a camper on my F150, and I installed Firestone airbags on it to deal with the extra weight. Best addition I ever made to the suspension. They're adjustable for pressure, and took less that two hours to install.
Frank

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Re: Putting heavier duty rear springs on F-100?

Post #17 by Luckyman » Fri Jun 26, 2009 11:30 am

Frankford6 wrote:I carry a camper on my F150, and I installed Firestone airbags on it to deal with the extra weight. Best addition I ever made to the suspension. They're adjustable for pressure, and took less that two hours to install.


Inspect the frame rails frequently where the upper brackets bolt through the rails. The rails more probably than not had to be drilled for the brackets. This is in a place where the stresses on the rails cause the rails to crack and break. I once had one in our shop that was so bad the entire frame had to be replaced (for liability/insurance reasons, not that it couldnt be repaired, the shop would not undertake the liability for a frame repair of that sort, with the truck being used to carry the loads that it had been)

I'm not saying that yours will break, I'm just saying keep an eye on it and dont load your truck past its axle capacity.
1 "76" F150 RC, LB, 2WD, 300, NP435, 9" open 3.00, special order 2-76/Delivered 4-76. Still "new".

1 "73-79" F150 RC/SS/SB/4WD, "84"-300, T18, NP205, 9" open 3.50, Dana 44 3.50 open, Offy DP, Holley 470, EFI + single 2.5" exhaust. Gathered from 15+ donor/parts trucks. "Fubar". Runs good, safe, still needs details/project continues.

SNRusnak

Re: Putting heavier duty rear springs on F-100?

Post #18 by SNRusnak » Fri Jun 26, 2009 6:42 pm

We put "heavy duty F150" leaf springs on my 81 F100, don't remember where we bought them tho. Somewhere between a 1/2 ton and 1 ton spring, very rough ride however with those and the air shocks at full capacity. F100 was a 1/4 ton truck and F150 was a 1/2 ton truck. Easiest/cheapest would be to get either F150 or F250 leafs from a junkyard they will bolt right up(keep in mind this will lift the rear a little and ford trucks already have a bit of a rake to them)(front coils also interchange), or use new coilover shocks, i did this with my s10 also worked great and still rides smooth, although only will support a few extra hundred pounds comfortably; i have put 1 ton in my s10 with the coilovers and it just about hit the overload springs, the poor little 2.2L(89hp @ wheels) sure didn't like that. As for the axle, we did blow out the seals once and when we put 1 ton in it, then just replaced with better seals, my f100 had a 9" rear :). Never had a problem with the rear 12 bolt axle on the s10 even with the 1 ton. Feel free to ask more if you want as I have been through this on my truck.

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Re: Putting heavier duty rear springs on F-100?

Post #19 by frank b » Thu Jul 02, 2009 9:56 am

I would suggest the bolt on load helper springs, the ones that are good for 500-1000 pounds. The problem with using the bigger springs is that you'll overload the axle and frame without realizing it. The best and obvious indicator of an overloaded suspension is the springs. The axle and frame may not be able to handle what the springs can, especially when we're talking about a 28 year old truck?? You want some movement in the suspension. If your trailer is loaded properly, with the load over the axles, you can limit the amount of load on your truck. If you load all the weight onto the front of the trailer, you'll put too much weight on the truck. My 82 F150 2wd has some soft springs, I used the add on helper springs and it does help a bit, but a good load will still squish it so I know if I'm asking too much of it. the truck can pull more than it can carry in my experience, so it would be better to build the truck to handle well with a trailer than with a loaded bed.

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