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Fixing some one elses mistakes. Bleeding brakes


Browning

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It's an 89 mustang. My sisters bf got an idea to bleed brakes, by himself, starting with the front lol. If that wasn't bad enough he some how forgot to put the cap back on after he filled it back up and drove to town after I told my sister to tell him it's a two man job and not to drive it.

 

I went out today to try to bleed them for them since he has no idea what he's doing. I bled them 6-7 times, never letting the master get low and starting from RR, LR, FR, FL. They never got better. It wasn't until then that I realized what it was doin. If you pump it buils pressure but when you hold it slowly sinks to the floor. I didn't see any leaks while I was there but to be honest by the time I got there he had fluid all over the place from trying it himself.

 

Is the pedal sinking to the floor a sign of air still being in the system? The front sprays out a stream of fluid with force while the back doesn't seem to have much force but it comes out heavy, if that makes sense?

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I would keep bleeding them... Sounds like air is still in the system.. IF you can find a hose going to the rear I would pinch it off.. normaly the hose going to the rear axle then splits to both rear wheels..

 

Pinch it off with a pair of pliers or a brake hose pinch off tool..

 

Pump the pedal up and see if it still sinks down. If it does, try each front wheel also.. Typically that will show you front / rear.

 

Sounds to me like the rear needs bled more though

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Did the master run dry? Yes advance rents the bleeder.

he says no but I'd say it's a safe bet that it did. It's awfully hilly around here and he drove it a good 8 miles with the cap off.

I have never had luck with one person bleeders. Especially if there is air trapped in it.

 

There has to be a rubber line somewhere going to the rear as the brakes are mounted to a rear end that goes up and down.....

 

I'll take a look next time I'm there. I got tired of dicking with it today.

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so should I get the same type of pressure/spray at the rear wheels as I do the front?

 

Yes you should get a decent spurt of fluid, maybe not quite as much as the fronts but similar. One of the advantages of being in a shop is using a power bleeder, but without that I'd start by opening the rear bleeders and letting it gravity bleed. If you don't get much you may have the proportioning valve stuck due to air, which on an older car where things weren't bled right may have happened. You can typically free one up by providing very hard fast hits on the brake pedal with the bleeders all closed. I would start by gravity bleeding the system either way and see what happens. It's honestly a very good way to get air out, and finish up with a normal bleed procedure.

 

I have never had much luck with the vacuum type bleeders either, so short of something that can put pressure to it I wouldn't bother. You can always run a hose into a bottle with some brake fluid in it and pump away all by yourself, I do it all the time.

 

Sorry for the rambling, if I can try to answer anything specifically I will. I just always end up typing my thoughts out withut much structure.

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make sure all the bleeders are on the top of the calipers and if all that is good and still have a sinking pedal check and see if the booster is filling up with fluid.

 

Also a longer shot but check the lines buddy had a small hole in one of his lines where it would look like the line was sweating but when you tried to bleed them it would obviously suck in air.

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Possible bad seal in the master cylinder? Could be the reason he felt the need to bleed them in the first place.

 

See I was thinking this from the original post, but I would want to make sure no air was in it first and that there is fluid getting to all the wheels.

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Threads like this make me want to get a Motive Power Bleeder (pressurized brake bleeding system)

 

Do it, I love mine. Gets a little annoying keeping track of all the adapters for different master cylinders but damn itrs nice to just be able to attach the thing to your master, pump it up and go around and crack your bleeders open and just sit back and wait for clean air free brake fluid to start running.

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make sure your bleeding them in the correct order, not every car is RR, LR, RF, LF possible you have a bad master cylinder as stated above. Not sure if the car has ABS or not but on Honda/Acura's sometimes you have to bled that as well or you'll have the same symptoms as your having, if it does have ABS check the ABS modulator/accumulator.

I use a Vacula(one man bleeder) and it works great, I've never had an issue.

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starting to wonder if the MC is bad. With the engine is off, still doesn't hold pressure. If it were air, with the engine off it wouldn't fall to the floor, would it? The pedal drops the same way regardless of the engine running or not. Going back out today to fool with it and check for any leaks in the lines and at the wheel cylinders. As far as I know, there are no fluid losses.

 

Any for sure ways to test a master cylinder? I've read to remove it and look for fluid where it meets the booster. However, that fluid would need to go somewhere, wouldn't it just run down the front of the booster? Or is it a matter of it cycling back and forth passed the seal?

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Got out there today and checked the vacuum for the booster, the lines, etc. I noticed the bottom of the left rear drum was a little wet. Removed the drum and it was a mess. My guess is the wheel cylinder has been leaking for a bit, but it's only gotten worse. Now, whether that is the sole cause of the pressure loss, I'm not sure but the seal was pushed off on one side and the shaft was fairly wet. I wiped it all up, used a screwdriver to lift the seal while he applied the brakes with the engine off. I could see it squirting just a little and the piston wasn't releasing at all. After a couple more times it started flowing quite heavy. Obviously the cylinder isn't functioning like it should, but that wouldn't have anything to do with applying the brake with the drum removed, would it?

 

I would think even with the drum off and applying the brake, that cylinder should not leaked regardless. Not to mention there already being signs of it leaking previously. That was the only wet wheel.

 

Do you see a leaking wheel cylinder accounting for the pressure loss described in the original post? I've already warned them after the cylinder is replaced, an issue could still be present.

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