Outer Limits 4x4 Board

I am thinking of putting some 60s springs in the rear of my1975 fj40 to get more flex, more height and to move the axle rearwards to stop the tyres from rubbing on the floor. from searches it seems that a few of you have done this and are pleased with the results. can anyone advise on potential pitfalls? Also what height increase should i expect? do i go for the flattest 60s springs i can find? roughly how far back will the axle be moved? which shockies would work well with this set-up?
any suggestions appreciated
cheers

The shackle and pin eyes will have to be changed methinks

I haven't done it but looked into it.

From memory you move the front hanger forward by about 150mm and the diff stays where it is but under compression doesn't move forwards.

I think you also have to make up some custom spring packs cause the 60s are a lot heavier than the 40 series. That is an assumption though and I am going to get my flame suit on.

i better method is to turn the rear spring mount around and leave the front mount as it is. As stated if your 40 is a 75 model it will have small sized spring and shackle bushes. The 60 series spring bushes are larger. 60 series springs are very thin and quite soft. You may choose to adjust the pack to suite your needs. I'm running a mixed spring pack with 7 leaves in the back. There are other springs which are longer than 40 series but shorter than 60 series (on the shackle end) which are easier to fit (don't need to change any hanger positions) and work really well.

Tojo wrote:i better method is to turn the rear spring mount around and leave the front mount as it is. As stated if your 40 is a 75 model it will have small sized spring and shackle bushes. The 60 series spring bushes are larger. 60 series springs are very thin and quite soft. You may choose to adjust the pack to suite your needs. I'm running a mixed spring pack with 7 leaves in the back. There are other springs which are longer than 40 series but shorter than 60 series (on the shackle end) which are easier to fit (don't need to change any hanger positions) and work really well.

would they be 55series springs perhaps?

Tojo wrote:i better method is to turn the rear spring mount around and leave the front mount as it is. As stated if your 40 is a 75 model it will have small sized spring and shackle bushes. The 60 series spring bushes are larger. 60 series springs are very thin and quite soft. You may choose to adjust the pack to suite your needs. I'm running a mixed spring pack with 7 leaves in the back. There are other springs which are longer than 40 series but shorter than 60 series (on the shackle end) which are easier to fit (don't need to change any hanger positions) and work really well.

yes mine has the small shackles so was going to put the 60s hangers in.
The other springs (55s?) do they have the small shackle pins?
Do you know if they will move the axle rearwards too? I need to increase the wheelbase slightly for tyre clearance.
thanks

not sure on the size of the 55 series bushes. I think they are the small ones but am unsure. And yes, they will move your axle back. How far depends on how flat they are. what size tyres are you planning on running?

i chucked IFS rears in the back of mine...perfect length for a front drive shaft to go ito the rear, but i think there was two sizes of front drive shafts or something?

Tojo: I am only running 255 85 16s but they rub on the floor in front of the rear wheels.

MY45: IFS rears?? from which vehicle?

Hey guys, reviving this thread ( for favorites menu )

Looks like I am going to do the 60s convo on the old girl.

Any advice before I start would be great.

My front springs are fairly flat and travel pretty well, maybe pull 1 leaf if anything but not really convinced it is worth the hassle, yet.

The rears are obviously the problem and plan to whack the 60s in there. I was going to do the rear mount reversal and leave the front. I am figuring I might need to investigate the rear tailshaft length etc but other than that and maybe brakelines is there anything else to be wary of?

I am also thinking of doing the front shackle reversal as well. I am a little more hesitant with this though as I am worried about stuffing my camber up. The old girl isn't a DD so for onroad handling it isn't really worth it but thinking it may overall improve suspension performance up front.

Comments? advice?

Scott

Tojo wrote:a better method is to turn the rear spring mount around and leave the front mount as it is.

<pauline hanson voice on>

please explain

<pauline hanson voice off>

the stock 40 spring is offset. the short side of the spring towards the center of the vehicle.

you pull em and switch it moves your diffs outwards, increasing your wheelbase.

i put 55 series springs in mine, still getting it right cause gas tank stopped me moving the axle as far back as i wanted to.

but i haven't moved the spring hangers yet, just used a longer shackle

spring eye and bushing are similar between a pre 79 40 and a 55 series... although i'm told the bushings on 55's have a larger shoulder or something

40 lover wrote:

Tojo wrote:a better method is to turn the rear spring mount around and leave the front mount as it is.

<pauline hanson voice on>

please explain

<pauline hanson voice off>

The rear springs in a 40 are about 100mm (150mm I think) ish shorter than a 60s, At the back of your 40s you have the spring mount on a plate with the bush towards the front of the rig. If you cut this off turn it around and put the 60s springs under I think it takes up the length diff. This is what I am hoping and wanting advice on anyways.

Scott

Busiboy wrote:

40 lover wrote:

Tojo wrote:a better method is to turn the rear spring mount around and leave the front mount as it is.

<pauline hanson voice on>

please explain

<pauline hanson voice off>

The rear springs in a 40 are about 100mm (150mm I think) ish shorter than a 60s, At the back of your 40s you have the spring mount on a plate with the bush towards the front of the rig. If you cut this off turn it around and put the 60s springs under I think it takes up the length diff. This is what I am hoping and wanting advice on anyways.

Scott

oh ok i think im getting the picture now...

The rear spring hangar is offset. From the factory the bushing hole is to the front. Remove it from the car by grinding and hammering it off. Then turn it around and weld it back on so that the bushing hole is to the rear of the car. Before you do anything, measure where it is mounted and draw a picture so you can line it back up square. Do one side at a time. This way you can double check the measurements from the one you haven't touched yet before you weld it. Tack it first then double check all your measurements.

yep that helped heaps tojo, would you be able to post pics of your suspension setup showing key parts (i.e. flipped hangers.)

cheers

here is what it might look like finished. I have a shortened LWB rear tailshaft, longer flexible brake line and longer shocks. At the moment i am using standard 75 series rear shocks because i had some brand new ones i got for free. At the front i use GQ rear shocks. My spring pack is a combination from different model Toyotas. Don't forget the issue of the difference in bushing size though if your 40 is an older one.

thanks for the pics tojo.

just another thing though. putting 60s springs in you truck will move your diff back, how much will it move back, its around 150mm i think is it, and is this with or without rotated hangers. So.... if your diff has been moved back then if im right, to put your shockies back in you will have to relocate the crossmember on your chassis so the shockies line up with it, is this right.

cheers

I'm also very keen on this kinda info and was wondering if it would be feasible/possible or even logical to see if you can get fresh (new) soft spring packs made to spec (eg 55 series) from a custom spring place.

I am yet to do any significant research on the subject but I feel this mod is ineviatable (currently running cheap crap springs/shocks)..

I know ih8mud has a heap of info on:
- rear shackle reversals (as explained above)
- front shackle reversals (apparently isn't so good for steering)
- diff spring packs mixes
- SUA and SOA options
- lots of other non QLD DOT friendly mods

I really need to pull my finger out and suss it .. I think there was someone else on this board that posted in a 40 specific thread in regards to minor mods for significant gains in suspenion flex.. let me try and dig it up...

lets keep this thread alive and turn it into a tech article!

cheers guys.

oh it was tojo..

so post all your progress pics dude!

Tojo wrote:Here's mine. Sprung under but using longer springs both ends. Flipped rear hangers. Longer shocks with modified shock mounts on the front. Longer shackles as well. You can get reasonable flex with sprung under.

dude you'll have to post the pic yourself for it to work.
i searched for it a minute ago as well, i immediately thought of that photo looking at this thread!

heres a useful link from ih8mud : http://forum.ih8mud.com/showthread.php?t=381&highlight=flex+40

the question was asked by someone wanting decent flex from SUA so not sure how much it iwll help you out busiboy.. could be good for others.

heres one for you busieboy:
[url=http://forum.ih8mud.com/showthread.php?t=4881&highlight=flex+40]ih8mud re:60 springs in rear
[/url]
both SOA and SUA specific

here are some measurements i took:
my existing 40 rear springs, fixed end to centre bolt 500mm
a 60 front that was lying round, fixed end to centre bolt 550mm.
This means the rear axle would move back 50mm, which is too much for me as its going to interfere with the gas tank
hope this is of use to someone else.....

vraamm wrote:Tojo: I am only running 255 85 16s but they rub on the floor in front of the rear wheels.

MY45: IFS rears?? from which vehicle?

Its from an IFS hilux, then i moved the shackels right to the end of the chassis(and 3/4 elliptic at the same time).

Trying to interpret the info over on Ih8mud,

55 springs are the same (ish) length as a 60s spring but are the same width as a 40s so all I have to do is the rear spring mount on the back of the rig?

Does this sound right?

It seems most people don[t even worry about the front springs? Is this true for you MY45?

front seems to flex pretty easy, but rear sucks as we all know

Comments?

vraamm wrote:here are some measurements i took:
my existing 40 rear springs, fixed end to centre bolt 500mm
a 60 front that was lying round, fixed end to centre bolt 550mm.
This means the rear axle would move back 50mm, which is too much for me as its going to interfere with the gas tank
hope this is of use to someone else.....

i have the same problem with mine, i put 55 series rear springs in mine...

planning on moving the gas tank into the cab, but

you can gain around 40mm by redrilling the spring perch, just a hole the same size as the one in it,

make sure you A measure it well... to get it centered as well as the same distance on both perches

B. note which direction to make the new hole in... i almost drilled mine so it would move the wheelbase back even more.

C. make sure you measure and drill the spring plates as well...

that'll get em almost back in the same place... it's worked so far on mine... but i want more wheelbase, and i didn't measure the holes too well, so i'm moving my gas tank and pushing them back further.

don't forget to leave a little room in there to move, as you don't want your diff to hit the gas tank when your suspension compresses.

and you'll struggle (well i did) to get your shocks to fit between your gas tank and axle tube/ diff...


basically the 55 is a longer spring, with a centered pin compared to the 40 spring.

the 60 spring is about the same as the 55 but has different bushing sizes etc...

the 55's do have a slightly bigger spring pin (the one that holds the leaf packs together)

they are soft packs too...

i haven't done my rear hanger yet, i'm getting away on booty fabbed longer shackles, plus the springs were reset a bit, so the length isn't a problem

Busiboy wrote:Trying to interpret the info over on Ih8mud,

55 springs are the same (ish) length as a 60s spring but are the same width as a 40s so all I have to do is the rear spring mount on the back of the rig?

Does this sound right?

It seems most people don[t even worry about the front springs? Is this true for you MY45?

front seems to flex pretty easy, but rear sucks as we all know

Comments?

Yeah i removed a leaf or to and it flexs fine

Am also interested in this info after reading it, well 55 series springs seem the go for my 75 fj40 as well but by doing this what sort of drive shaft issues can i expect. i.e. is there a model cruiser etc that has a more appropriate shaft or is it a custom job to take up the difference (increased wheelbase)

Thanks in advance

i'll let you in on what i did for driveshaft length...

the front driveshaft out of a 1978 fj55 /(probably the same for ALL 55's with a 4 speed) is about 2 inches longer than the rear shaft on a 4 speed shorty...

so it worked a treat in mine. lucky i had the rest of the 55 that i got the springs out of.