DBA 4000 rotors/pads - 1990 HDJ81

[Super 70]

Hi,

I recently bought a 1990 HDJ81. My rotors and pads need to be replaced. Anyone running the DBA 4000 series rotors and pads on an early (1990) HDJ81? MAF shows a part kit: 4000-FZJ80KITXSC or 4000-FZJ80KITXS but lists 08/92-97 as the models... I assume this is directed at the US destined 80 series trucks.

Are there brake differences between my 1990 HDJ81 and a 1992 FZJ80?

Anyone know for sure if these parts will or will not fit on a RHD 1990 HDJ81.

I used the search and found lots of brake info and discussions on OEM vs. various aftermarket options, running 100 series brake pads on the 80... etc.... all very helpful.

I will try to run the 100 Series pads.

Thanks!

Rob

 

[jasonmt]

Pads will work, rotors will not.

Both the front and rear discs on 90 to ~8/92 JDM 81's were smaller than the ones used post ~8/92 in both the US and JDM models.

The front rotors went from 286mm OD and 25mm thick to 311mm OD and 32mm thick which is the same as the US market trucks.

Rear rotors went from 312mm OD and 18mm thick to 336mm OD and 18mm thick, the post 8/92 rear rotors are the same as the US market ones while pre 8/92 the US market rear brakes were drums.

Front and rear pads are the same for F&R disc braked trucks for 1990-1997.

Pre ~8/92 front rotor on top, post ~8/92 front rotor on the bottom.

 

[Super 70]

Jasonmt,

Thanks!

Stupid question. I am assuming the bigger brakes on the later models are better. Has anyone else upgraded their early JDM brakes? Can i just switch rotors/calipers/pads.... everything, the whole brake setup, to the newer style to get the bigger brakes and lose the early JDM stuff completely? Custom work or bolt on?

Cheers!

Rob

 

[Sarmajor]

Brakes

Asfar as I know this should be a straight bolt on swap. I know of at least one 1991 VX hdj81 Landcruiser that has had the later years larger front brakes bolted on. Not sure about the rears though. You might have to replace more than the rotors on the back end as the Hand Brake (E Brake) is a drum brake inside the disk and is larger in the 8/92 on build vehicles.

 

[nicholas]

If you do the swap to bigger rotors I would use OEM product. I have been very satisfied with my OEM rotors and 100 series pads up front.

 

[jasonmt]

The front should swap over with post 8/92 rotors, calipers and brake backing plates, the actual brake caliper piston bore size is the same between the two calipers so there is no worries there as far as changing the hydraulic ratio. Finding someone who stocks rotors for the earlier (smaller) front discs for a reasonable price can be a bit of a chore in Canada, I ended up ordering out of the States from Rock Auto. For what the local shop wanted for one rotor I got 2 rotors, 2 caliper rebuild kits, 2 hardware kits and a set of pads shipped to my door for less money and in a faster manner.

I do not think swapping over the rears to the larger rotors is going to make enough difference to make it worthwhile, as well the larger rotors in the rear generally precludes using 15" wheels. The JDM specific 312x18 rear rotors run about $135 for AM and $160 for OEM.


https://forum.ih8mud.com/80-series-tech/174459-caliper-question.html

 

[M23TLC]

If there is no change in the piston bore size across the range and the post '92 rotors are larger, the only place the newer setup will perform better is an environment that generates a lot of heat in the brakes like long hill decents or towing. Meaning, the larger rotors will take longer to heat up to a point where brake fade becomes an issue (or, in other words, they soak up the heat better). Otherwise, you are better off with the smaller rotors as there is less rotating mass to slow down.

Your choice of pad makes more of an issue with our 80's than anything else will unless, as I said, you subject your truck to extreme conditions. For wheeling, the thing to be concerned about is cold bite since there is no real heat in the brakes. Hope that helps.

 

[jasonmt]

Those of us running larger tyre/wheel combinations (37" Iroks/15x10" steelies in my case) obviously are not going to be concerned about the additional rotating mass from the larger rotors.

 

[Super 70]

Thanks.

So I can buy the later (08/92-97) rotors/calipers/backing plates and 100 series pads for the front and i am good to go.... if I decide to go that way.

On the rear: I am running 17" wheels so going to the newer and larger rotors wouldn't be an issue as far as fitting, as I have no plans to run a smaller diameter wheel. So if I did buy the later (08/92-97) rear rotors/calipers/backing plates and brake pads. This too should work, correct? Would I have a parking brake dilemma by going newer/larger on the rear?

I know that I don't NEED this but if I am going to replace most of these parts anyway... and if I can improve things, at all... why not. The truck is only going to get heavier with a lift, bigger tires, bumpers, winch, new roof rack... etc. etc. I also have a trailer that I will be towing sometimes.

And if it is bolt on... that is even better... Cuz most of my pre 80 series cruiser stuff, has been a little more on the custom side of things.

The hdj81 will end up getting upgrades but I am trying to keep this from getting out of hand other than "bolt on" level upgrades...

Unfortunately, like most guys on mud, I have a tendency to go overboard...

To illustrate my point...

Here are the new brakes (on a custom axle) going into my 85 BJ70 right now...


and a couple of pictures of the HDJ81 like I bought it (with too much chrome )

 

[jasonmt]

Thanks.

So I can buy the later (08/92-97) rotors/calipers/backing plates and 100 series pads for the front and i am good to go.... if I decide to go that way.

On the rear: I am running 17" wheels so going to the newer and larger rotors wouldn't be an issue as far as fitting, as I have no plans to run a smaller diameter wheel. So if I did buy the later (08/92-97) rear rotors/calipers/backing plates and brake pads. This too should work, correct? Would I have a parking brake dilemma by going newer/larger on the rear?

I am running 15" wheels so I never looked at swapping the rears that closely even though I have a complete set of post ~8/92 Aimco cross drilled rotors that came with my 1990 81.

On the rear the calipers themselves are the same, I believe that you would need new "Torque Plates" (see parts numbered 47721C & 47722A in the image below), backing plates and rotors to do the rear. The post ~8/92 "Torque Plates" should move the caliper 12mm radially outward to accommodate the bigger rotors.

I am not at home right now but I am pretty sure that in the past I had checked and the rear parking brake shoes were the same for 1990-1997, if you download the EPC you can check the parking brake shoe part number for models they apply to, this picture shows it done for the rear disc pads:

 

[Super 70]

jasonmt,

Thanks a lot for all the info.

I ordered the new style 08/92-97 rotors (SLEE),calipers (New Toyota),pads for the front and rear. I ordered the slee axle to caliper brake kit as well. I ordered the newer style backing plates for the front and rear. I am just waiting for a phone call to see if buying new Toyota rear calipers come with the torque plates (included) or if I will order them separately.

Appreciate the advice.

Cheers!

Rob

 

[RHDieselCruiser]

I am running 15" wheels so I never looked at swapping the rears that closely even though I have a complete set of post ~8/92 Aimco cross drilled rotors that came with my 1990 81.

On the rear the calipers themselves are the same, I believe that you would need new "Torque Plates" (see parts numbered 47721C & 47722A in the image below), backing plates and rotors to do the rear. The post ~8/92 "Torque Plates" should move the caliper 12mm radially outward to accommodate the bigger rotors.

I am not at home right now but I am pretty sure that in the past I had checked and the rear parking brake shoes were the same for 1990-1997, if you download the EPC you can check the parking brake shoe part number for models they apply to, this picture shows it done for the rear disc pads:

View attachment 261230

Where you able to find the torque plates (parts # 47721C and 47722A). Have the same Land Cruiser as You and now need to do the rear brakes. but been struggling to find the parts. Any help is much needed and even more appreciated. I have 15" rims though.