Fl80 Brake pedal fade and overheating (2 Viewers)

[Matt Crandall]

1991 fj80 I’m seriously frustrated. I live in a fairly hilly neighborhood. And but the time I get to the bottom of the hill my pedal is almost to the floor and brakes are hot. I go slow, I don’t hold them the whole time, regulate speed, I’m not riding the brake. Yesterday when out in the woods coming down the hill, was not sure if it was going to stop.

I’ve tried many things to fix this issue. It has had this issue since I’ve owned it for about three years.

First thing obviously swap pads and rotors, rear shoes look good. Flushed all fluid.

Second upgraded to 93 rotors and t100 pads, and cAlipers per a popular thread on this forum. changed hoses to stainless. Also all new correct backing plates

Third upgrade was Ebc Preformance brake pads, again flushed brakes and adjusted rear brakes.

I don’t feel rear brakes are doing much, it will lock up fronts fairly easy.

I am to the point I just don’t feel it very safe for going over mountains and all the Stuff I like to do in it.

It has 16” wheels and 33” bfg’s So not really big tires.

I am up for anything to fix this problem

So to sum up and extended time on brake pedal, they get hot and fade pretty quickly

Happy to provide photos of anything if it helps solve the issue.

Yesterday for the first time I was ready to give up and sell it, help save this fj80!

 

[1911garand]

I feel this is an issue with my truck too :

"I don’t feel rear brakes are doing much, it will lock up fronts fairly easy."

I think there is a way to adjust / modify the rear proportioning valve by simply disconnecting the rod and using a zip tie to hold the lever upward, but i am unable to find a pic (someone please post one).

 

[gnarlytoes]

How steep is this hill and how far to bottom? Do you gear down to let the engine help slow the vehicle or just leave it in drive? You really should check to see if the rear brakes are actually working. Does the parking brake work? The front brakes do the majority of braking and should lock before the rear.

 

[unklwedy]

Change brake fluid. When hot water in hygroscopic brake fluid boils. It acts like air.

 

[Matt Crandall]

Change brake fluid. When hot water in hygroscopic brake fluid boils. It acts like air.

Brake fluid is new and fresh, Motul rb600

 

[Matt Crandall]

How steep is this hill and how far to bottom? Do you gear down to let the engine help slow the vehicle or just leave it in drive? You really should check to see if the rear brakes are actually working. Does the parking brake work? The front brakes do the majority of braking and should lock before the rear.

It’s steep but not terrible, does not effect any of my other cars, even my f350 dually or Disco or lr4. For the big cars at the house

 

[whaler]

How about your soft lines? inspect them, see if they are old and bulging. What about master cylinder, old? It sounds like you have the wheel components and fluid covered so all thats left is MC and your booster.

 

[Desert Dino]

Check and adjust your rear proportioning valve acording to the FSM
i had issues similar to yours that disappear after i replaced the old one that didnt function at all.
and do gear down!!!!

 

[Tools R Us]

Drum brakes are much more susceptible to overheating and fading than disks. Riding the brakes is not great on any vehicle, worse on drum brakes. Best to put it in the needed gear to maintain the desired speed and get off of the brake pedal. Second option, swap a disk brake rear axle.

 

[Desert Dino]

Drum brakes are much more susceptible to overheating and fading than disks. Riding the brakes is not great on any vehicle, worse on drum brakes. Best to put it in the needed gear to maintain the desired speed and get off of the brake pedal. Second option, swap a disk brake rear axle.

I did this swap because of 2 reasons moving from drum to disk brakes and moving from SF Clip to FF

 

[Comet]

In my 1997 there's something like six or seven soft lines. They do not age well, replace them with OEM. LSPV is definitely something to consider too. Don't give up hope, it is not lost!

 

[Matt Crandall]

I have replaced all the lines, some in stainless as well. I'm going to try the LSPV next, seems like that could be it. Seems like removing could be the best option.

 

[Matt Crandall]

Could see Disc brake rear end could be in future, bummer is that I just put an ARB locker in mine...

 

[NV1971FJ40]

Just delete your lspv save your self the head ache

 

[jonheld]

Rear drum brakes require the constant use of the handbrake in order to stay in proper adjustment.
Do you use your handbrake regularly?
Have you set up the rear brakes according to the FSM?
Have you made sure the rear adjusters are working correctly?
Is your LSPV working correctly?

 

[Mark W]

I don't see any mention in your (OP) comments about adjusting the rear brakes. If the parking brake is not used regularly/routinely/(every time you park) then the brakes do not adjust. And even if you begin using it after it has been ignored, the adjusters are often not working properly.

Your symptoms sound like classic "out of adjustment rear brake syndrome".

Mark...

 

[unklwedy]

What happens to brake pedal height when you fire up engine, leave it in park, and apply steady pressure on brake pedal ?

 

[Peru Darrell]

Same problem. Checked everything, changed everything. Next Step LSPV will be changed to a Tee

 

[Matt Crandall]

I disconnected the LSPV, and just zipped tied it up, seems much better, going to take it off.
Brake light keeps staying on now though

 

[jonheld]

Brake light keeps staying on now though

If your dash BRAKE lamp is on, then your fluid is low in the reservoir, or the sensor in the cap is faulty, or the handbrake is on.