Completely lost brakes while driving - master, or booster?
05-14-2017, 06:24 AM
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Completely lost brakes while driving - master, or booster?
I replaced my front calipers with 13WLs off a Tundra a few months ago and had no issues. New rotors, pads, etc. Fully flushed and bled the system and it braked great. Occasionally I would need to double-pump to brake shorter, but they would always bite great toward the end of the pedal and I didn't consider them unsafe - I chalked this up to the MC being stock where the calipers were bigger. Yesterday they just completely went dead. It would take 5+ pumps to even begin to slow the vehicle down. I was really lucky this happened right as I was leaving a parking lot, and not on a highway, or I may not be typing this right now.
I don't have any ABS lights on and in general, everything else seems normal. No leaks and the fluid level is where I left it a few months ago. It just doesn't build or maintain pressure in the system. I'm inclined to think the MC has had it - but are there any culprits it could be? It's a '99 Limited 4WD with stock rear drum brakes. I'm selling this rig soon (I have too many cars) and want to be sure I'm not selling an unsafe car to a fellow human.
I don't have any ABS lights on and in general, everything else seems normal. No leaks and the fluid level is where I left it a few months ago. It just doesn't build or maintain pressure in the system. I'm inclined to think the MC has had it - but are there any culprits it could be? It's a '99 Limited 4WD with stock rear drum brakes. I'm selling this rig soon (I have too many cars) and want to be sure I'm not selling an unsafe car to a fellow human.
05-14-2017, 07:15 AM
#2
you can undo the master cylinder from the booster with out disconnecting the brake lines, move it forward as far as you can and inspect the inside of the booster for any corrosion that could be a result of the MC having a slight leak inside the booster. Not sure if the booster would need to be replaced, but something to check since it would be indicating the MC has a slight leak.
Other thing to check is the vacuum line to the booster to make sure it is still in good condition.
Other thing to check is the vacuum line to the booster to make sure it is still in good condition.
05-14-2017, 07:45 AM
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Can do, thanks. Even if the booster was completely shot, wouldn't I still have at least some level of usable brakes? Having to pump 5+ times to barely slow the vehicle down sounds like a failure in the hydraulic system. If the master was failed, would that always manifest as fluid leaking out the backside? The fluid level is correct.
