Have a 92 FJ. All pads have just been replaced and been using them for about 500 miles now. All of a sudden in the summer heat, I feel the pedal smush to the floor and I start to loose brake pressure. I turn my A/C off and braking increased alittle but but not up to par so I drove home slowly. I though that My Brake booster was going bad or my master cylinder. I checked the brake fluid and reservoir is still full. I am also thinking my fluid is old and needs to be bleeded and replaced. Any suggestons?
Brake Effectiveness has ben lost! help!!
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Possible vacuum leak at the booster.
I experienced brake failure last summer after a hot decent. Changed the brake fluid and that helped some. Changed rotors and pads and that fixed the rest. If the fluid change doesn't work then Dan is probably right.
92 brake issues
I feel like my brakes are normal,....until I turn on the A/C...then they suck A$$! Everything else is up to par, so if Dan is right, I wonder why it is only noticable with the A/C on?
I feel like my brakes are normal,....until I turn on the A/C...then they suck A$$! Everything else is up to par, so if Dan is right, I wonder why it is only noticable with the A/C on?
Wild speculation would be that you have a minor vacuum leak and the additional load of the A/C drops the manifold vacuum down to a point where it can't keep up with the leak.
I suspect the pistons in the MC. They do get worn out after a time. I also suspect the brake improvement after turning off the AC was imaginary. You can more or less verify this by pumping the pedal. If Brakeing improves, it's proof to me. Likewise another way is to panic step the pedal and that too can show the effect. I'm thinking that you probably have brakes that still work, albeit, at floor level and probably very scary.
Try replaceing the pistons. They don't cost much. Be sure to check that there are no grooves inside the MC when you change them.
Kalawang
Try replaceing the pistons. They don't cost much. Be sure to check that there are no grooves inside the MC when you change them.
Kalawang
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Guys,
I am thinking maybe my Brake Booster is bad as well. I've done the works: pads, rotors, bleed, new fluid, new master cylinder, and the brakes still suck. I had a buddy check them tonight and he said it felt like the booster when his when out on his FJ40. How often does the Brake Booster go out on an 80? I have a 1997, well maintained FZJ80. The pedal just goes to the floor and it is almost like there is now power behind the brakes, It is like a 1:1 ratio. If it is possibly a vacuum leak, how do I check for this other than putting a new hose on?
What goes wrong with the Booster? Can it be rebuilt? How much is a new one CDan?
I'm getting tired of this poor braking issue. And NO, it isn't just because it is a big heavy Land Cruiser. I've driven 3 other 80s this week and they all feel better (like mine felt the first year I owned it)
I am thinking maybe my Brake Booster is bad as well. I've done the works: pads, rotors, bleed, new fluid, new master cylinder, and the brakes still suck. I had a buddy check them tonight and he said it felt like the booster when his when out on his FJ40. How often does the Brake Booster go out on an 80? I have a 1997, well maintained FZJ80. The pedal just goes to the floor and it is almost like there is now power behind the brakes, It is like a 1:1 ratio. If it is possibly a vacuum leak, how do I check for this other than putting a new hose on?
What goes wrong with the Booster? Can it be rebuilt? How much is a new one CDan?
I'm getting tired of this poor braking issue. And NO, it isn't just because it is a big heavy Land Cruiser. I've driven 3 other 80s this week and they all feel better (like mine felt the first year I owned it)
The brakes are a hydraulic system. As far as I can tell the booster only assists in movement of the piston in the system. I just don't understand how a bad booster would cause the peddle to go to the floor with no braking going on. That should mean that the piston is moving which is moving the fluid to the calipers. The only thing I can think of is air being in the lines somewhere, or the pads aren't gripping the calipers like they should.
D,
That is exactly it! The brake booster is to the Brake System as the Power Steering Pump is to the steering system. I feel like the brakes don't have any power assist which is what the booster provides. I just read a previous post that the Booster goes for $800
I think I will check the hose for leaks and do all the FSM troubleshooting tomorrow.
BTW, did you get a canine yet?
That is exactly it! The brake booster is to the Brake System as the Power Steering Pump is to the steering system. I feel like the brakes don't have any power assist which is what the booster provides. I just read a previous post that the Booster goes for $800
I think I will check the hose for leaks and do all the FSM troubleshooting tomorrow.BTW, did you get a canine yet?
As a "box it in" exercise, do this: With the truck at idle and foot on the brake, if you apply a touch of throttle (like an A/C idle-up or more), do you rapidly sink to the floor and loose boost power? If so, it's going to be a vacuum issue. If not, it's going to be a master cyliinder/air in the lines type of problem.
DougM
DougM
Before we condemn the booster it could also be the line, connection, etc to the booster. I had mine fail in my 91 and you could hear the hiss of the vacuum at the booster when it did fail. If you stick your head under the dash you could easily hear it when you hit the brakes.
If you don't, it could be a failure internal to the booster, or a vacuum line that has failed. Since there is a vacuum take off of #5 that hose could be bad, but I suspect the engine would be giving you more signs if this was the case.
If you don't, it could be a failure internal to the booster, or a vacuum line that has failed. Since there is a vacuum take off of #5 that hose could be bad, but I suspect the engine would be giving you more signs if this was the case.
On other cars when the booster failed I had a hard time getting the pedal to move. I actually had better braking with the engine off. If the pedal moves down and there is no braking you have air in the line or possibly a bad master cylinder. A check for a master cylinder problem we used to do is to pull the boot back off from inside the foot well and feel for fluid leaking out the back of the master cylinder.
D,
That is exactly it! The brake booster is to the Brake System as the Power Steering Pump is to the steering system. I feel like the brakes don't have any power assist which is what the booster provides. I just read a previous post that the Booster goes for $800
BTW, did you get a canine yet?
So is the pedal hard to push on or does it readily go to the floor? I would think (like landtank said) if the booster was bad the brakes would feel the same with the engine off or on. If the brake pedal is "softer" with the engine on then I would say the booster is doing it's thing.
Nope no canine yet... were waiting till we get into out own house.
Landtank,
The pedal moves just fine. That seams to be the issue, it moves so well that I hit the floor when trying to stop and I don't have much room for error. BTW, Leffe is my new favorite Belgian Beer. You can get a nice Belgian pack at Costco right now.
D, The pedal is softer, there for I think it must be operating correctly. I need to go out there and listen for an air leak. It is hard with the rain right now. All I hear are rain drops.
The pedal moves just fine. That seams to be the issue, it moves so well that I hit the floor when trying to stop and I don't have much room for error. BTW, Leffe is my new favorite Belgian Beer. You can get a nice Belgian pack at Costco right now.
D, The pedal is softer, there for I think it must be operating correctly. I need to go out there and listen for an air leak. It is hard with the rain right now. All I hear are rain drops.
I think your booster is fine as well as any vacuum connections. A booster problem will only effect "effort" in applying brakes.
Your problem is in 1 or more of three areas.
1. excessive pad wear, with the caliper pistons at here limits from worn pads you can have this situation. Have you added brake fluid recently?
2. air in the lines or old fluid. Old fluid will act like this and that should be flushed once a year. When was that last done?
3. Master cylinder, if the other two don't yield positive results that it's most likely this. Rebuild or replace are the two options.
Leffe is some good tasting beer
. Anyone out there who hasn't tried it is missing out. Hard to explain the taste as there really isn't anything out there like it. While in Belgium I had it as a draught which is always better than bottle or can.