75 to later 75 or 79 series axle swap (1 Viewer)

[Peachhead101]

Hi there mud

I've got a 1991 HZJ75 trayback, living in Aus, absolutely loving it (not that it's without its issues haha).

I've got drum breaks on the rear and was considering converting to disc brakes for the extra braking power at the rear and was wondering if a later model 75 diff should bolt straight in? Either that or a 79 model diff (pre-V8). I understand that the 79 diff would have the 5 bolt wheel pattern which would be an issue I can imagine.

The main things I'd like to know are if the spring perches are in the same place on the diff and if the rear disc brakes will work fine with the rear drum brake setup (booster, lines, attachments).

If anyone has any knowledge on this and would like to share, I'd be very grateful.

Many thanks

 

[Indestructible 47]

Hey,

My old 95 hzj75 had disc brakes on the rear end. Imho, the best bet would be to get a 75 rear end that has the disc brakes. You also may need a disc brake hand brake cable to suit. You can also just order all new disc brake components and do it that way but it's probably the most expensive way to do it. Spring perches are the same for all 75s. The master cylinder may be different, I'd have to check the part numbers to confirm but the one you have will still operate rear discs. Not sure a 79 will work, plus it is 5 stud.

 

[Peachhead101]

Fantastic, thank you so much, I'll take a look at part numbers I can find for the master cylinder and hand brake cable

 

[Hulsty]

Discs on the back wont really give you any better braking power over the drums, they will just need less adjustment if doing mud/wet driving. If you want to stop much better, they are a few cheaper options I would try first, adjust the rear LSPV, aggressive pads, 80 series booster, later model HZJ75 calipers and larger master cylinder.

 

[SNLC]

Axles all the same width until the v8 TD was released.

Cheers

 

[roscoFJ73]

Discs on the back wont really give you any better braking power over the drums,

Correct, the drum brakes just need a little more maintenance. And they will stop you as quick as the discs. Most of your braking ability comes from the front brakes.

 

[Peachhead101]

That's some great info, thank you so much, I'll look into the 80 series booster and later model 75 master cylinder and front(?) calipers. I'll read some info about adjusting the brake proportioning valve too and give that a go.
I know that fitting early model IFS Hilux hubs to the front axle can increase the track width, is there anything to increase the rear track width? The wheels that came on the ute are zero offset and with the 285 tires they scrub at the rear when tucking in, I'm thinking I'll have to buy a new set of wheels with negative offset when it comes time to buy new tires (hopefully thinner tires too without loosing the height), but is there any way other than offset rims? I'd like to stick away from spacers, I'd rather just pay for new wheels instead of spacers.

 

[Hulsty]

Can be offset rims easily, in my car I have IFS hubs on the front and a 60 series diff in the back.

 

[Peachhead101]

I've read your thread some time over the past year and it's been great to see what some people are doing with these cars, I actually have 60 series rear springs on the front of mine at the moment due to the front springs snapping (very dangerous but the military wrap at the front saved it, I actually drove on it for a while without realising it was broken before a rego check where they said the bushing were cracked, I lifted the front end on a hoist and what do you know the diff stayed in place, saved me a lot of money at the time, $50 at a wrecker compared to $600 new, just picked up some front parabolics that I'll be installing soon though).

I'll have another read of your thread but did you have to move the spring perch for fitting the 60 series rear axle?

 

[tmarx]

Hi there mud

I've got a 1991 HZJ75 trayback, living in Aus, absolutely loving it ......... and was wondering if a later model 75 diff should bolt straight in? Either that or a 79 model diff (pre-V8). I understand that the 79 diff would have the 5 bolt wheel pattern which would be an issue I can imagine.

The main things I'd like to know are if the spring perches are in the same place on the diff ......

Did you ever come right with this ? My June 1999 75 ser Troopy's left rear bearing just ate the semi floating axle, so I want to upgrade to a full floating unit but the 75 FF axles are very scarce here in ZA - can the 76 or 79 FF axle be used if changing the diff ratio from 4.3 to 4.1 (I already have two 4.1 ring and pinion sets left from my BJ 42) and swapping the hubs to 6 stud ?