78 series brake booster

I would be checking your lpsv valve on the rear diff

adjust that first.
but i do agree.
standard the brakes are woefull without a load on.
I have done both a master cylinder and brake booster upgrade.
but on a hj47
And highly recommend it.
Totally different vehicle and brakes awesome, vehicle at full gvm and towing 1.4t

you might want talk to a suspensionshop and engineer to actually to get a real cost and whats involved.
I can recommend a brake shop who did my work...
But no good if your in another state

as i have driven a hdj79 towing a 1.4t boat with nothing on the ute and it struggles to pull up.

Check out Bramac Brakes, in Rockhampton, for their double diaphragm (?) brake booster. Think the kit is around $600-800, depending whether you get braided brake lines as well.

JMACX does a kit too, albeit a little dearer. Marks Adapters do a hydraulic kit, using power from power steering pump as well. Both these kits nudge the wallet to some degree.

Lot of good reports about Bramac.

Bob

Couple ways you can go.
80series booster upgrade
Very cheap and many people have done it
As you buy a used booster from a wrecker

Or you can go the big coin way
Jmax brake booster for alot more money.

I personally did the slotted rotors in the front
New pads

But still wasnt great
The bigger booster and master cylinder was well worth the cost
He modified the lpsv again..
As i adjusted it higher
But he went another 25 - 35mm higher
Pressure checked the brake lines for brake pressure and brake bias.
With a custom pressure guage he made up to see what pressures im getting at the diff ends
Checked the slotted rotors for wear
Brake pads were scorched and cooked.
Replaced them

Mounted a toyota surf booster and a 80series master cylinder

Best money i ever spent on the cruiser
Being all of $1200 - 1300

( And very timely as the original booster failed when i actually had all the brakes upgraded..
Failed while the brake shop took it for a test drive
After i handed cruiser over !! )

Make sure your load proportioning valve has been adjusted if you have a lift or airbags in the rear and drive to the conditions. they are not a sports car but a 2.5t 4wd.... In saying that i think mi e stops pretty well with standard brakes

The 70 series brakes are well known for being a bit underwhelming.

Its well worth the trouble of upgrading the booster, wether you go with a modified 80 series booster (cheap) or one of the upgrade kits available from some suppliers like Bramac or Marks (expensive).

You will find that it will transform the car and restore your confidence in it, especially if you are doing a GVM upgrade.

Thanks folks.

I've just email Bramac for a price. Already changed out pads and front rotors to slotted. This helped a little.
ARB have installed the bracket to allow for ride height difference.

Anyone done this upgrade themselves and if so was it easy?

Thanks

Lyndon

Ive played a bit....the front calipers of a 105 series have larger pistons and bolt straight on.
The booster of a 80 series or a 1990- cressida are double diaphram, and alot more powerful than std....the cressida has a 1.125 inch master, larger than 80 series....but nothing beats a 105 electric master.....bolts in, needs some mods to pipework, and needs power to run the motor, but they are a truely progressive booster, the more you push the more they brake.

Hi Lyndon, I have driven both a 76 series and a 79 series one with a bigger brake booster (Jmax i think it was) which was definitely better than standard. I also have driven a 76 and 79 with the Marks hydraulic kit.I put the Marks kit in my 79 ute with upgraded rotors, brake lines and the hydraulic conversion on the steering pump. Not a cheap option and you can here the pump operating some times however to me was by far the better option as my ute is heavy with a full tray camper and all the other gear on it.
In saying that either are better than the original.

Regards Sludgie

The place to start for normal braking use is to test the vacuum pump and see if it is really doing what it should do.
If it isn't up to, or better than specification, then no brake booster, apart from an electric one is going to perform it's push/boost duty as designed to do.
After you test and verify the vac pump works satisfactorily, both HOT and COLD, then perhaps look at hydraulic system/booster system.
Just my opinion.
Different engine oils seal rings better than others do, ie, cleaner sump oil for longer is a definite indicator that is so. The SAME oil is used to run through the vanes of the vacuum pump. So if the oil is sus or cheaper crap brand, it probably won't seal the vanes of the vacuum pump to make it work as intended. It is the oil film seal which really makes the vacuum. Pehaps the oil restrictor to the vacuum pump is half blocked and the vanes are simply starving of oil to be able to seal properly. All these things are cheaper to do or check BEFORE doing brake work.
Everyone heads for slotted everything, harder pads/softer pads, bigger this and double that, before checking the basics.

Get the Bramac booster it changed our Troopy to sedan braking. Super easy to install, 6-8 bolts and 45 minutes. The only important thing is to set the actuator rod length to match the OEM rod length That\s only a screw link adjustment and locking nut. Great helpful people at Bramac too. Like others noted if you have changed the lift adjust the proportioner too.