new master, bled out and still bad pedal and poor brakes, what next?
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new master, bled out and still bad pedal and poor brakes, what next?
The title says it all, I replaced my master cyl. the other night, bench bled it then totally re bled the entire system. The pedal gets nice and solid until I start the engine then it turns to mush. I'm leaning toward the booster but its not hissing or anything, correct me if I'm wrong but doesn't the rod push from the pedal strait through the booster and push the master??? Even with the brakes bled out and good pads / shoes etc. I still couldn't stop this thing if I had too. I jumped the brakes HARD and still cant lock a wheel, it does stop but I would think without ABS I should be able to lock a wheel!!! Any thoughts?? Id hate to replace the booster now and still have no pedal. The pedal engages at the halfway point then is very spongy the rest of the stroke, but with the engine off it gets rock solid!! Wouldn't the booster hiss like crazy if the diaphragm was bad?? How do these old boosters work anyway?
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I didnt bleed that
The rear shoes are new, the front rotors and pads have about 20,000 miles on them but look good. I didnt know that I had to bleed the prop. valve... Even with the rear circuit out of whack if thats the case should I be able to lock a front wheel if needed??? The pedal just firmly compresses to the floor!
#5
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yup the lspv can be a PITA to bleed. if your drivers front is locking up on gravel if you mash on them, then it is air in your lines over on the pass side/rear lines.
on another note i was in shepherdstown a while ago at the fish and wildlife services nctc campus for fisheries training. fun little town.
on another note i was in shepherdstown a while ago at the fish and wildlife services nctc campus for fisheries training. fun little town.
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had the same thing going on. replaced master and no good. went to a junk yard pulled a brake booster for like 13 bucks slaped it in and im all good to go. i guess if your MC goes bad it can leak break fluid into the BB and destroys the stuff inside that makes a brake booster work.....
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Ill try that next!
yup the lspv can be a PITA to bleed. if your drivers front is locking up on gravel if you mash on them, then it is air in your lines over on the pass side/rear lines.
on another note i was in shepherdstown a while ago at the fish and wildlife services nctc campus for fisheries training. fun little town.
on another note i was in shepherdstown a while ago at the fish and wildlife services nctc campus for fisheries training. fun little town.
Last edited by Ilovemountains; 08-20-2009 at 11:55 AM. Reason: missed a thought
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#8
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i did not see that you adjusted the rear brakes . Even new Brakes need to be adjusted.
Does the emergency brake work . That should stall the vehicle trying to pull out if it doesn`t adjust the rear shoes . there should just be a slight drag on the drum.
If I missed any of this I am sorry!! Hope it does fix the problem
Does the emergency brake work . That should stall the vehicle trying to pull out if it doesn`t adjust the rear shoes . there should just be a slight drag on the drum.
If I missed any of this I am sorry!! Hope it does fix the problem
#9
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i had same prob in 2 different vehicles, ended up being that i didint get all the air, i bled like an entire quart and a half out of the system and its good now on both
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Sounds to me like air in the system somewhere as stated earlier. Does NOT sound like a booster at all. If you eliminate a booster completely (like stopping without the engine running) you have a high, hard pedal. It won't stop well but the pedal won't sink. Its a hydraulic problem.
The brake booster amplifies your foot/pedal pressure applied to the master cyl. A failing booster will just keep the pedal feeling hard at all times.
To feel this yourself, try holding your truck on a hill with the engine off. You will have to push harder than normal. I bet the pedal sinks then and watch out that your don't run into anything.
The brake booster amplifies your foot/pedal pressure applied to the master cyl. A failing booster will just keep the pedal feeling hard at all times.
To feel this yourself, try holding your truck on a hill with the engine off. You will have to push harder than normal. I bet the pedal sinks then and watch out that your don't run into anything.
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Thanks for all the help.. I did install the bracket between the prop valve and axle... Im betting its air in the lines from the PV.... Im going to re-bleed it again tomorrow.. I did adjust the rear shoes when I put them on a few months back but will re check them tomorrow as well as the parking brake! Ill let you know what happens. I bet its air though, I used a friends massive vacuum bleeder and pulled fresh fluid through the system but didn't know about the LSPV bleeder! Ive since had the rear hubs out to replace the rear diff and wheel bearings and just swapped the master with a fresh rebuilt unit, I did pull a lot of fluid through the system when I installed the new master but there must be a lot of air still in the system! I thought the LSPV just had an affect on the rear drums not the front brakes as well!
#13
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It could be possible that somewhere on the connections you had apart . there is one or more that is tight enough to not to leak fluid but will suck air.
Seems strange but i have seen it a few times.
For what it`s worth on these Toyotas i have never bled more then the rear wheel cylinders and calipers unless replacing the Master Cylinder which I just bench bleed I also ended up with great brake pedal feel
Seems strange but i have seen it a few times.
For what it`s worth on these Toyotas i have never bled more then the rear wheel cylinders and calipers unless replacing the Master Cylinder which I just bench bleed I also ended up with great brake pedal feel
#14
This is whats above the rear axle right? I just bought a truck with a 3 inch body lift. Should this be raised in some way? I noticed when bleeding my brakes that a lot more fluid bleeds through the front brakes then when I am bleeding the rear brakes.
#15
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I have the exact same problem! I just got a second master cylinder thinking i had a bad one out of the box? Will put on this weekend.
I'm curious what people think of what I experience when bleeding the system. I get no build up of pressure when pumping the brakes (rather when the GF is pumping them). THen when she holds down the pedal, very small amounts of fluid come out. When I tried a vaccum bleed, I pulled air bubles and a pint of fluid and the air bubbles never stopped. This lead me to believe the rebuilt master cylinder is leaking. I've checked all over for leaks and found none.
I'm curious what people think of what I experience when bleeding the system. I get no build up of pressure when pumping the brakes (rather when the GF is pumping them). THen when she holds down the pedal, very small amounts of fluid come out. When I tried a vaccum bleed, I pulled air bubles and a pint of fluid and the air bubbles never stopped. This lead me to believe the rebuilt master cylinder is leaking. I've checked all over for leaks and found none.
#17
I'm curious what people think of what I experience when bleeding the system. I get no build up of pressure when pumping the brakes (rather when the GF is pumping them). THen when she holds down the pedal, very small amounts of fluid come out. When I tried a vaccum bleed, I pulled air bubles and a pint of fluid and the air bubbles never stopped. This lead me to believe the rebuilt master cylinder is leaking. I've checked all over for leaks and found none.
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