Braking issue on fzj70

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

876 Cruisers

876 Cruisers

KZJ70/FZJ70/HJ47/HDJ80²
Joined
Jun 1, 2016
Threads
102
Messages
337
Location
Jamaica
Hi all,

I have seemed to have an issue with my brakes on my fzj70.

Everything was fine before until I did a 2inch dobinsons lift kit and changed the brake lines to longer ones.

When I drive and step on the brake hard the back locks up but the fronts dont.

I am also running 33x12.5r15 mud tires.

Anyone has any idea what can cause this?

Things I've tried:

Changing front brake hoses and front center line.

Tried swapping calipers off a kzj70

Lots and lots of bleeding

Tried smaller tires.

Thanks in advance for any advice.
Dan
 
You didnt really need the extended brake lines. I fitted the dobinsons 2 inch lift and ran 33s with no problems on a FJ73

Did anyone touch the LSPV?

You must have air in the front lines or the LSPV is doing something.
 
If I remember I dont have a lspv on my van. And we have bled the brakes multiple times.
 
Last edited:
I might pull the master cylinder off and test that. Or maybe you could fit a pressure gauge onto it while its on the car.
Either there is no pressure from the master cylinder or the front calipers are faulty.
 
Well 2 mechanics had bled the master cylinder also and both say the pressure seems fine. I had also changed the master cylinder about a year ago to an Aisin 4runner one.

As for calipers i had taken one off my kzj70 and put on it and it did the same thing.
 
876 Cruisers said:
Well 2 mechanics had bled the master cylinder also and both say the pressure seems fine. I had also changed the master cylinder about a year ago to an Aisin 4runner one.
Click to expand...


Well, someones made a mistake. If the MC is making pressure and you have a good caliper, it should work. But its not.
Has the LSPV been removed or was it a model that did not have one fitted?
You said it was working fine before, so whatever is causing your problem must be something you touched or altered
 
My model apparently didnt come with a lspv but I ordered one to put on. I'm changing all hoses and adding the lspv except for mc and calipers. If it still doesnt work properly I guess 2 new calipers and a new mc will just have to be the next thing on the list.


I see Tora calipers for a decent price but idk how good they are. And dont want to have to spend a ton of money.
 
If you truck never had an LSPV the hard brake lines and some of the fittings are different so you will have to deal with that as well.

Cheers
 
That shouldn't be too much of an issue I dont think. Can buy brake lines and bend it according to how it needs to be set and try make it work.
 
Well come to think of it. The lspv does look like a lot of work to add in. Just looked at it on the kzj70 and it has more brake hoses And brackets
 
I wouldnt add an LSPV if it didnt come with one. If you are trying to solve a problem, adding more components only complicates things.
I would disconnect and remove all the components you fitted before it went bad, starting with the hose extensions.
I would also pull the old calipers apart, inspect and add new seals if the bores look ok.
The MC will always pump fluid with no pressure, so it really needs to be examined.
 
Hmm I'll do that and see. Maybe just order a genuine mc for it while I'm at it. I already have caliper seals coming again although I had already rebuilt them few months back
 
I would add one new item at a time, or you wont know which one is causing a problem
If you are getting hard rear brakes, it may not be the MC as It needs something to make them hard.
So I would start with the calipers and removing the extensions.
 
Ok thanks for help. Will do that when new brake lines come. The extended ones I have came from the original brake lines. They cut off the ends and put new hoses. Maybe it wasnt done properly 🤔
 
It doesnt take much air to ruin your brake pressure
 
Hi all. In still having the braking issue and still cant figure out the problem. I've changed one caliper and rebuilt them both and also rebuilt the master cylinder.

I'm left to wonder if maybe the rotors are causing the issue? Is that a possibility?

Also I notice when the van is cold the brake pedal Is softer. After a few mins of driving It starts to get a little on the harder side .

Regards
Dan
 
The rotors have a wear limit of about 2mm( I forget the actual specs). But your brakes were ok before the lift.
I have never been a fan of rebuilt master cyls unless they have had a new bore put in.
 
I went to a Mechanic shop today to get an expert opinion. He was saying the pistons in the Calipers could have an oval shape that isnt really visible causing the piston to not push properly.

Do you know if 60 series calipers will fit on a fzj70?

I have 2 new calipers for the 60 series coming for my hj47 as i did a 60 disc brake conversion
 
I have calipers for a 1990 4Runner 3L V6 on my BJ74.
I had to cut the back plate a little to make room.
They bolted right on otherwise.
 
You must log in or register to reply here.

Share this page

Back
Top Bottom