That's a very comprehensive and convincing explanation, maybe I have learned something today 
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Complete Brake Failure!!
- Thread starter Rookie93
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Pumpy
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yer not filling me wilth confidence about my 80's brakes here lads 
It's OK saying keep it in low range low gear on an auto, but thats proper crawl that is, equal to low range first in a defender, but low range second is too high, equal to about 4th low/1st gear high range on a defender. I can't imagine many people in crawl gear down a real long decent when they feel it's too low, there must be loads in 2nd low using judicious breaking?
mines a 1992 4" EFS lift, 315's, lots of added weight, can the brakes be upgraded to the larger calipers? Would that even help? vented disks? I know previous owner took ceramic pads off as they were worse.
It's OK saying keep it in low range low gear on an auto, but thats proper crawl that is, equal to low range first in a defender, but low range second is too high, equal to about 4th low/1st gear high range on a defender. I can't imagine many people in crawl gear down a real long decent when they feel it's too low, there must be loads in 2nd low using judicious breaking?
mines a 1992 4" EFS lift, 315's, lots of added weight, can the brakes be upgraded to the larger calipers? Would that even help? vented disks? I know previous owner took ceramic pads off as they were worse.
You can go with the bigger rotor/caliper but without wheel spacers you'll probably need 16" rims (unless you already have them). It depends on the offset (or backspace) on the wheels that you're running. A bit more wheel data would help us...
Pumpy
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mine are original alloys, I don't want to go off-set/spacers as it's wide enough already (besides minging up the truck)! I like the look of black steels so could get new rims if it'll mean better brakes, depends on the cost/benefit really.
Someone else may know better.
I tried a 15" rim on my 1995 80 and there was less than a mm clearance to the caliper, too close for comfort for me.
I have new Mr. T OEM discs and rebuilt calipers with Mr. t pads, and the brakes are just fine.
I tried a 15" rim on my 1995 80 and there was less than a mm clearance to the caliper, too close for comfort for me.
I have new Mr. T OEM discs and rebuilt calipers with Mr. t pads, and the brakes are just fine.
stumog
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You only need to run 16" wheels if you have the later rear brakes. I changed mine to later from discs and calipers.
Older disc size are 280mm later 320mm bolt on conversion real easy.
Pumpy you have 16" rims I am sure of it.
Op I would say coasting down a hill and braking just cooked your brakes. If your not used to a diesel use the engine braking on down hills
Much safer
Older disc size are 280mm later 320mm bolt on conversion real easy.
Pumpy you have 16" rims I am sure of it.
Op I would say coasting down a hill and braking just cooked your brakes. If your not used to a diesel use the engine braking on down hills
Much safer
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Did the earlier 80s have 15" alloys Stu? If so, why would you be so sure Pumpy has 16"? (Unless you know his truck, of course
)My 1995 80 had narrow 16" OEM steels on it when purchased, but I know for a fact that 15" steels won't fit on the front with 320mm discs and calipers. I've got drum brakes on the rear, so anything will fit there.
Maybe stock 15" alloys (if there is such a thing) may fit, I wouldn't know that.
The motor is a 95' Gen II 5.9 Cummins. No electronics, the thing will run on two wires. Lol
Good question Frank. I'll look into that. I had the swap done by diesel adaptors so I might have to ask Dustin, but I'm sure that I can figure it out.
Star, great point. I have an Auto and didn't think to drop it into low. But, let me clear the story a bit. I was going down hill, but not on much of a grade. Just a logging road at about 3% when then went out. Thank God I was through the steep stuff by the time they failed.
OK, as requested, here's all I know about my LC at this point.
93' with a fresh 5.9 Cummins diesel. Stock Auto trans. Stock rims with 33" Yoko Geolanders. Stock brakes system. Cheesy spacers as a 1 1/2" lift (soon to be swapped out for a real lift).
I think more and more that it was the fluid. But I'm not liking that the system seems weak to me. I had planned on upgrading the rotors and pads anyway. I think that I will research an oversized MC and use Synthetic Fluid too. The pedal just dropped out, and I had nothing. Pumping did zero good until I was able to let the rig sit for a minute, and returned to full capacity when I got back on the highway. My problem with this is that I wasn't even pushing this rig much. It should be able top handle way more than what I jus put it though. Any thoughts are greatly appreciated.
~PS. I'll post some pics as soon as I'm able to though the site. Didn't someone say I had to post like 15 times or something?
93' with a fresh 5.9 Cummins diesel. Stock Auto trans. Stock rims with 33" Yoko Geolanders. Stock brakes system. Cheesy spacers as a 1 1/2" lift (soon to be swapped out for a real lift).
I think more and more that it was the fluid. But I'm not liking that the system seems weak to me. I had planned on upgrading the rotors and pads anyway. I think that I will research an oversized MC and use Synthetic Fluid too. The pedal just dropped out, and I had nothing. Pumping did zero good until I was able to let the rig sit for a minute, and returned to full capacity when I got back on the highway. My problem with this is that I wasn't even pushing this rig much. It should be able top handle way more than what I jus put it though. Any thoughts are greatly appreciated.
~PS. I'll post some pics as soon as I'm able to though the site. Didn't someone say I had to post like 15 times or something?
If I were you Rook I would do what they call a 'baseline' to the truck before going too far away from stock. I'm not sure when the rotors changed but someone may be able to tell you.
Easiest thing is to change the brake fluid.
Sounds to me like you had some steeper downhill sections that you tackled in high range with the brakes which probably caused the problem.
The system is not especially 'weak' in stock form. Toyota did improve it with bigger rotors and 16" rims and disc brakes all round. Start adding extra weight, bigger wheels and add in uncertainties like what pattern parts or old/ wrong fluid then things can go bad.
There's others on here with far more knowledge on these things on here but getting everything working as it should is a good start before thinking of upgrades. Once baselined, then look at upgrades.
Easiest thing is to change the brake fluid.
Sounds to me like you had some steeper downhill sections that you tackled in high range with the brakes which probably caused the problem.
The system is not especially 'weak' in stock form. Toyota did improve it with bigger rotors and 16" rims and disc brakes all round. Start adding extra weight, bigger wheels and add in uncertainties like what pattern parts or old/ wrong fluid then things can go bad.
There's others on here with far more knowledge on these things on here but getting everything working as it should is a good start before thinking of upgrades. Once baselined, then look at upgrades.
Like thousands of others, my 80 has stock brakes, it's a '95 so has the bigger rotors and calipers.
The rotors wore thin, so I replaced them with stock Mr. T and a couple of sticky cylinders were replaced with new seals all round in the calipers.
The brakes are just fine. In my area, we have several ski resorts, so in the summer I'm often driving down the ski slopes and I can assure you they're more than 3%
No problems. In the past, I have overcooked the brakes on long decents, and I've learned to get the truck down into a suitable low gear before you end up with a runaway, but this is only in extreme cases. Ski slopes are notorious for being "loose" underfoot, they often have a layer of rock chippings under the grass to promote drainage, and driving down them can be just like skiing, but with no snow. That's where locking up all the diffs comes into play and just letting the engine do the braking, feet flat on the floor. 1st or 2nd, low box all locked up, safe as houses...
I appreciate that mine is a manual box so engine braking may be more effective than an auto, I wouldn't know. But I wouldnt be be too much in a hurry to depart from stock, if you upgrade to the bigger rotor (which is just a bolt-on job) 16" rims to clear them (but this is debatable because it depends on rim width and offset) and with fresh fluid and all clean and functioning properly, you won't have any issues. My truck is a European spec, so I only have drum brakes on the rear, but my brakes are fine and have never let me down.
The rotors wore thin, so I replaced them with stock Mr. T and a couple of sticky cylinders were replaced with new seals all round in the calipers.
The brakes are just fine. In my area, we have several ski resorts, so in the summer I'm often driving down the ski slopes and I can assure you they're more than 3%
No problems. In the past, I have overcooked the brakes on long decents, and I've learned to get the truck down into a suitable low gear before you end up with a runaway, but this is only in extreme cases. Ski slopes are notorious for being "loose" underfoot, they often have a layer of rock chippings under the grass to promote drainage, and driving down them can be just like skiing, but with no snow. That's where locking up all the diffs comes into play and just letting the engine do the braking, feet flat on the floor. 1st or 2nd, low box all locked up, safe as houses...
I appreciate that mine is a manual box so engine braking may be more effective than an auto, I wouldn't know. But I wouldnt be be too much in a hurry to depart from stock, if you upgrade to the bigger rotor (which is just a bolt-on job) 16" rims to clear them (but this is debatable because it depends on rim width and offset) and with fresh fluid and all clean and functioning properly, you won't have any issues. My truck is a European spec, so I only have drum brakes on the rear, but my brakes are fine and have never let me down.
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Just drain and flush the fluid then you can work out what to do. If you decrease the diameter of the master cylinder you will find the brakes are more powerful but you will not have such a firm pedal as there is "spring" in the system which will become more noticeable. A standard set of good brakes should be adequate otherwise you need a different spec truck 
.
The brake system is not a sealed system all the time but only when your foot is on the pedal. When your foot is off the pedal any excess pressure, steam etc is vented back to the fluid reservoir.
.The brake system is not a sealed system all the time but only when your foot is on the pedal. When your foot is off the pedal any excess pressure, steam etc is vented back to the fluid reservoir.
Pumpy
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right O' chaps checked the wheels... 315/75/16
found one of Mals posts from 2012 (I've got Mals old truck)
think the pads have since been changed twice since then, once to ceramic, and then back again.
Is the moral of this "boiled brakes" story a case of changing the fluid on a certain sevice shedule? how often?
found one of Mals posts from 2012 (I've got Mals old truck)
think the pads have since been changed twice since then, once to ceramic, and then back again.
Is the moral of this "boiled brakes" story a case of changing the fluid on a certain sevice shedule? how often?
Yes Pete, but I'm not sure on timing. I have EBC pads in mine and TBH I don't think they are much better than Toyota ones. They are better, just not by much as Toyota ones could lock the wheels quite easily. But then my truck is pretty much stock.
Yep, guilty as charged, it's a bit on the far side for me unfortunately. I miss all the fun of Lincomb and these other meets
ByronJ
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Overheated your brake fluid I suspect (As other have said)
Hi Rookie93. I had the same experience a few days ago.
On Monday I stopped at the top of the long descent into the village of Anergui (Morocco) to take shots of the other guys on the way down. By the time I got to the bottom my brake pedal went to the floor
. Pumping the pedal I came to a stop just outside the village. I expected to find a burst pipe etc. But nothing. The master cylinder was full but the wheels were HOT!
We waited 10 minutes and braking power returned. My car is a '91 so has the smaller brakes, is fitted with 16" tyres and has an auto box so the brakes have to work hard. First time I have overheated them though. Guess I was rushing a bit to catch up so came down in 3rd rather than 2nd. 
. The fluid was changed 2 years ago and looks clean. Very alarming when it happens as one minute they are working and the next nothing. But a lesson learned though.
We then entered the amazing track through the gorge where we sat in the river for lunch (see Georg's pictures). The brakes were fine and have given no trouble since.
Hi Rookie93. I had the same experience a few days ago.
On Monday I stopped at the top of the long descent into the village of Anergui (Morocco) to take shots of the other guys on the way down. By the time I got to the bottom my brake pedal went to the floor
. Pumping the pedal I came to a stop just outside the village. I expected to find a burst pipe etc. But nothing. The master cylinder was full but the wheels were HOT! We waited 10 minutes and braking power returned
. My car is a '91 so has the smaller brakes, is fitted with 16" tyres and has an auto box so the brakes have to work hard. First time I have overheated them though. Guess I was rushing a bit to catch up so came down in 3rd rather than 2nd. . The fluid was changed 2 years ago and looks clean. Very alarming when it happens as one minute they are working and the next nothing. But a lesson learned though. We then entered the amazing track through the gorge where we sat in the river for lunch (see Georg's pictures). The brakes were fine and have given no trouble since.
