80 Series Brake Booster Upgrade (2 Viewers)

[Guu]

What is this 80 series brake upgrade, does it all bolt up without modification. Are there any benefits from changing to 80 series calipers too and likewise will they bolt up to 70 series hubs?

My brake pedal keeps going to the floor, can bleed fine with engine off but soon as it's started pedal goes real soft.

 

[clintnz]

The 80 series came with a dual diaphragm booster which is an almost bolt-in upgrade to the std 70 series single diaphragm booster. There are both 4 bolt & 2 bolt master cylinder to booster attachments so make sure you get the right one there. The 80 series has a shorter pushrod to the brake pedal so you either need to lengthen that, make a longer clevis to screw on, or extend the bracket forward on the brake pedal.

The 80 booster is a great upgrade if you have big tyres/big load & find you are really having to stand on the brakes to slow the rig down. A more powerful booster will not improve your 'pedal to the floor' problem however.

Not sure on what calipers came on what 70 series, but on my LJ71 the rear calipers were fairly similar to an 80 series, piston dia looked like it was the same. Not sure on fronts.

Cheers
Clint

 

[Guu]

Cheers mate

I'm going to replace the booster and master cylinder all at the same time.

 

[jblueridge]

I put on the 80 series master and booster. I have a JDM BJ74 so I had to bend my own brake lines from the master down to the first connections... Maybe 15 cm or so. Had to make a new heat shield for booster.
I also put n 4runner front calipers, 1990 V6 4runner. The bolt holes are the same. The back plate had to be cut for the larger caliper size.
Very easy mod.
The bigest change came from replacing the LSPV. Maybe I could have cleaned up the old one and used it agan. The new lspv let me fne tune the brakes. They work great now.

 

[kbushnz]

I put in an 80 series booster and master cylinder into my KZJ78 Prado.... Bolted straight in. Only issue was the rod needs an extension approx 25mm . Made a difference in pedal feel and overall braking. That was on stock 70 series brakes. Just make sure you get a NON ABS booster.

 

[Dprio34]

So how did you extend the rod 25mm?

 

[jblueridge]

I bought a long coupling nut and sawed the head off a bolt to make the extension.

 

[Dprio34]

Nice!!

 

[clintnz]

I made a longer clevis:

80 series vs 70 series boosters:

Cheers
Clint

 

[kbushnz]

I got an extension. And trimmed it down a bit. Similar to this for a gear stick (threads were the same)

Those radius arms look interesting Clint.... Would you like to share?

 

[jfrench]

For the sake of those considering this upgrade, anybody got part numbers for booster, master cylinder? And where are y'all sourcing these?

Is the booster 44610-60620, -60790, -60791 or -60792?

Is the master 47201-60410 or -60540?

@jblueridge, got a picture of the custom heat shield?

 

[clintnz]

Those radius arms look interesting Clint.... Would you like to share?

Modified Nissan GQ units that I swapped in along with the front axle to match. Details were in my build thread on ORE until photobucket went tits up. Lets just say it's a long way from being a bolt-in mod

For the sake of those considering this upgrade, anybody got part numbers for booster, master cylinder? And where are y'all sourcing these?

Is the booster 44610-60620, -60790, -60791 or -60792?

Is the master 47201-60410 or -60540?

@jblueridge, got a picture of the custom heat shield?

I got my booster new off aussie ebay, seller bxbooster. The master cyl was a non-ABS 80 series one from a local parts store - however that was NOT for std LJ71 brakes. IIRC the original master was smaller to match the smaller piston area of the original front calipers. It would have bolted up to the new booster though, it seems that there are either 2 bolt or 4 bolt master-booster mountings on Landcruisers & if you have the right bolt count there's a good chance it will fit.

Cheers
Clint

 

[jblueridge]

I got the master cylinder and the booster from Rock Auto.
The booster was reman'ed. It was also a POS. A used early 80 series booster has proven to be fine.
Rock Auto master cyl made by Aisin...no prblems.

I will take photo of heat shield. Made it from roof flashing aluminum sheet. Very light.
The master cyl lacks a threaded hole to bolt the shield to.

 

[Dprio34]

Jblueridge, How much of the backing plate had to be cut? Any pics?
Thanks!

 

[jblueridge]

As I recall The backplate needed maybe one inch on one side removed. Perhaps less.
I used my 4.5" angle grinder with a cutoff wheel.
I did not take the backplates off the truck.

 

[Dprio34]

Thanks for the tip. I need to rebuild my calipers, but it would be probably more cost effective to go this route.

 

[jblueridge]

Pic of replacement heat shield. It has held up pretty well for two years. I thought it would vibrate to bits.
Original clutch master heat shield also protects some of brake booster.
Note hand-bent brake line exiting the side of brake MC.

 

[Guu]

I've pulled a few, how do you tell if they are good?

 

[jblueridge]

I would get a vacuum gauge, pull vacuum on the booster and do a leak down test...how long will the booster hold vacuum.
Service manual outlines tests but assumes the booster is installed in vehicle.