75 series diffs under 40 series

[Barney7779]

Looking at getting a set of late model 75 series diffs to put under my 40

Is this possible?

Have heard that the 40 and 75 share the same housing and that they are the same track width? Is this true?


Are the spring perches in the same position


Cheers

[ZOOK60]

if you go for a late model front 75s diff it will be a hilux centre.Save yourself the trouble and got 60s diffs and get a little more track while your at it

[Barney7779]

Must be thinking of early 75s then

I thought about going 60s but isnt there alot of stuffing around with the driver side spring because of the diff center


Was more looking for something that will bolt straight in to give me disc brakes, dont wanna stuff around with parts from different models, prefer complete diff so if i break it i dont need to remember what model the broken bit came from

[bad_religion_au]

Must be thinking of early 75s then

I thought about going 60s but isnt there alot of stuffing around with the driver side spring because of the diff center


Was more looking for something that will bolt straight in to give me disc brakes, dont wanna stuff around with parts from different models, prefer complete diff so if i break it i dont need to remember what model the broken bit came from

late model 40 series have discs and are the right width. take your pick after 1976

and a disc conversion isn't that bad... just a knuckle off a 60, an early 75, a 40, or a solid axle hilux... most the seal kits are the same part, cv's are interchangeable, i think it'll be the rotor that will be the OnLY part you'll have to "remember"....

[Barney7779]

Must be thinking of early 75s then

I thought about going 60s but isnt there alot of stuffing around with the driver side spring because of the diff center


Was more looking for something that will bolt straight in to give me disc brakes, dont wanna stuff around with parts from different models, prefer complete diff so if i break it i dont need to remember what model the broken bit came from

late model 40 series have discs and are the right width. take your pick after 1976

and a disc conversion isn't that bad... just a knuckle off a 60, an early 75, a 40, or a solid axle hilux... most the seal kits are the same part, cv's are interchangeable, i think it'll be the rotor that will be the OnLY part you'll have to "remember"....

So if i just take the whole swivel hub off a hilux it will all bolt up no probs????

What mods will be needed for the master cylinder to get correct front to back bias?

By the way mine is a 78 BJ40

[Shadow]

Get a 60 series swivel hub as they have vented rotors where as earlier hilux ones are solid.

It would probably be worthwhile fitting a late 40 series or any 60 series master cylinder aswell. This should just bolt into the same spot no mods required and should work with your rear drums fine.

[Barney7779]

Get a 60 series swivel hub as they have vented rotors where as earlier hilux ones are solid.

It would probably be worthwhile fitting a late 40 series or any 60 series master cylinder aswell. This should just bolt into the same spot no mods required and should work with your rear drums fine.

Cool thanx for that mate

Just to throw a spanner in the works, looking into this conversion aswell for the rear ...... looks to be a pretty simple conversion ..... anyone done it????

http://www.employees.org/~dirttrak//rea ... ersion.htm

[beanz2]

75 diffs will be the right width but the spring perches are about 10mm farther apart. You can easily grind the old ones off and weld them back in place closer to the centre, but the one on the dirver's side needs a bit grinding so it would ride up the pumpkin, otherwise the cruiser would lean as the drivers side perch ends up a little higher.

Like bad_religion says, the easiest ones to use are 40 series front diffs with disc brakes. 45 series fronts still have drums. If you get a 1979 or later diff you get the larger steering arm bolt pattern suitable for high steer arms like those sold by Snake Racing.

The conversion in the link above was done by a mate of mine. His was possible because of the bolt pattern on the pre 1981 diff housings. The 1981 or later rear diffs have a different pattern, but an adapter can be made and welded directly to the housing.

Dave

[bad_religion_au]

Get a 60 series swivel hub as they have vented rotors where as earlier hilux ones are solid.

It would probably be worthwhile fitting a late 40 series or any 60 series master cylinder aswell. This should just bolt into the same spot no mods required and should work with your rear drums fine.

yep this is the prime way of doing it, but if hilux solid rotors come up cheap enough, there isn't a massive difference in vented if you don't drive like a loon. both'll be an improvement.

a master cyl from a disc brake 40 will get your bias right. i've heard of people doint this and keeping their old master too so :S

and yeah, Fj's got discs, Bj's didn't get discs till the 42's i think

[beanz2]

It is not the brake bias as much as the brake residual pressure valve. Drum brakes need a higher residual pressure to keep the brake springs form collapsing the brake cylinders, discs don't. If you run a drum brake master on a disc brake diff, the calipers will always be under excessive residual pressure, so the pads will drag on the rotor causing rapid wear and brake fade.

Dave

[Barney7779]

Cool thanks for that fella's


I have a M/C from a 40 that was running a disc front so that should be ok


Time to look around and see what parts i can find at what price

Cheers again

[bad_religion_au]

It is not the brake bias as much as the brake residual pressure valve. Drum brakes need a higher residual pressure to keep the brake springs form collapsing the brake cylinders, discs don't. If you run a drum brake master on a disc brake diff, the calipers will always be under excessive residual pressure, so the pads will drag on the rotor causing rapid wear and brake fade.

Dave

yep that's what i assumed he meant by bias. i've heard you can pull the residual valve out of the master.

[beanz2]

yep that's what i assumed he meant by bias. i've heard you can pull the residual valve out of the master.

Yes, on the older ones are removable and RPVs from different Toyota models of similar vintage also suit the master.

Dave