Brakes pull hard to the left...
12-29-2005, 10:31 PM
#16
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It is my understanding that the master has two independent circuits
1. front
2. rear
When you depress the brake pedal you do 3 things.
1. Open valve to rear circuit (this happens first)
2. Open valve to front circuit
3. If hydraulic pressure in not significant, the pedal will allow you to force the large cylinder behind the valve spool to mechanically create pressure in the system. (This is why you can still stop the vehicle if it is off, you just have to press hard) this goes for power steering also.
You all have driven a vehicle at some point that the pedal “jumps” back at you when you hit it. Especially if it’s about to stall, this is due to not enough hydraulic pressure when you tapped the pedal. Then the spool contacted the cylinder at the same time you gained pressure and the pedal jumped back because the pump then provided more pressure than you physically exerted on the pedal.
Enough of my rambling
My point is, I don’t think a problem with the rear adjusters will cause a problem with the front circuit. I’m not that experienced in automotive, however all hydraulic systems work on the same principles.
1. front
2. rear
When you depress the brake pedal you do 3 things.
1. Open valve to rear circuit (this happens first)
2. Open valve to front circuit
3. If hydraulic pressure in not significant, the pedal will allow you to force the large cylinder behind the valve spool to mechanically create pressure in the system. (This is why you can still stop the vehicle if it is off, you just have to press hard) this goes for power steering also.
You all have driven a vehicle at some point that the pedal “jumps” back at you when you hit it. Especially if it’s about to stall, this is due to not enough hydraulic pressure when you tapped the pedal. Then the spool contacted the cylinder at the same time you gained pressure and the pedal jumped back because the pump then provided more pressure than you physically exerted on the pedal.
Enough of my rambling
My point is, I don’t think a problem with the rear adjusters will cause a problem with the front circuit. I’m not that experienced in automotive, however all hydraulic systems work on the same principles.
12-29-2005, 10:34 PM
#17
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Originally Posted by TIMMY22
You definately have a good argument against them changing your master, here is why.
anybody who understands hydralics knows pascal's law.
Pascal's law [for Blaise Pascal], states that pressure applied to a confined fluid at any point is transmitted undiminished throughout the fluid in all directions and acts upon every part of the confining vessel at right angles to its interior surfaces and equally upon equal areas. Practical applications of the law are seen in hydraulic machines.
so, therfore if the left caliper is working properly, the problem can't be in the master because the two calipers are in the same circuit.
print this out and demand your $ back. You don't diagnose problems by process of elimination at the owners expense!
anybody who understands hydralics knows pascal's law.
Pascal's law [for Blaise Pascal], states that pressure applied to a confined fluid at any point is transmitted undiminished throughout the fluid in all directions and acts upon every part of the confining vessel at right angles to its interior surfaces and equally upon equal areas. Practical applications of the law are seen in hydraulic machines.
so, therfore if the left caliper is working properly, the problem can't be in the master because the two calipers are in the same circuit.
print this out and demand your $ back. You don't diagnose problems by process of elimination at the owners expense!
OK, But. Doesn't the braking system work in 2 circuits that are diagonal, eg: left front and right rear?
12-29-2005, 10:43 PM
#18
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how can you apply pressure to front left and rear right when the two rear wheel cylinders are plumbed together from the same port from the master and the two front calipers are plumbed together from the same port on the master?
to do that you would have to run a line from front right to rear left and so on...
you could do that but thats not how they set it up at the factory.
to do that you would have to run a line from front right to rear left and so on...
you could do that but thats not how they set it up at the factory.
12-29-2005, 11:01 PM
#19
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Thread Starter
Anyyyywwaaayyysss there guys... I tried the emergency brake thing, and it didnt pull to the left, so its not that. It did show me however, that I need to adjust the emergency brake, because it was almost as if I never pushed it when it was to the floor. How do I do that anyways? I am going to try switching the 2 calipers and see if it then pulls to the right. That would tell me if it truely is the caliper thats bad...
12-29-2005, 11:11 PM
#20
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Originally Posted by TIMMY22
how can you apply pressure to front left and rear right when the two rear wheel cylinders are plumbed together from the same port from the master and the two front calipers are plumbed together from the same port on the master?
to do that you would have to run a line from front right to rear left and so on...
you could do that but thats not how they set it up at the factory.
to do that you would have to run a line from front right to rear left and so on...
you could do that but thats not how they set it up at the factory.
"All models without ABS have a combination valve and a RWAL valve. A pressure differential switch inside the combination valve is connected to the brake warning light on the dash. This switch monitors fluid pressure in the front and rear hydraulic brake circuits. A decrease or loss of fluid pressure in either circuit will cause the switch valve to move forward or backward in response to the change in pressure. When the valve moves, it pushes the switch plunger up, which closes the electrical circuit to the warning light. The switch valve will remain in this position until the hydraulic system is repaired.
A metering valve is used to balance the braking force between the front disc and the rear drum brakes. The metering valve holds off fully applied pressure to the front disc brakes until the rear drum brake shoes are in full contact with the drums. The valve is designed to maintain front brake fluid pressure between 3 and 30 psi until the hold-off limit of 117 is reached. At this point, the metering valve opens completely, allowing full fluid pressure to the front brakes."
It does mention that the bore diameter for the master cylinders are the same for the 2500's and 3500's, but the stroke length is longer on the cylinder for the 3500. If they are not interchangeable and will cause improper brake balance and diminished braking performance. The code for a 2500 should be 'NL'.
12-30-2005, 07:37 AM
#21
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That valve your refering to keeps the "timing" of the two circuits.
A proportioning valve will send some oil (dot 3) from the front circuit two the rear or vise versa in order to balance the two circuits.
this will only happen once in a blue moon unless there is a leak.
A proportioning valve will send some oil (dot 3) from the front circuit two the rear or vise versa in order to balance the two circuits.
this will only happen once in a blue moon unless there is a leak.
12-30-2005, 08:27 AM
#22
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Originally Posted by MasseyMan1089
Anyyyywwaaayyysss there guys... I tried the emergency brake thing, and it didnt pull to the left, so its not that. It did show me however, that I need to adjust the emergency brake, because it was almost as if I never pushed it when it was to the floor. How do I do that anyways? I am going to try switching the 2 calipers and see if it then pulls to the right. That would tell me if it truely is the caliper thats bad...
Your rears are WAY out of adjustment, and the shop that did it should have adjusted them for you as part of the brake job. Take it back to them and have them do it for free.
12-30-2005, 09:11 AM
#23
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This is getting off the beaten path but here goes, I apologize and don’t want to bore anyone with a lecture.
The braking system itself actually has no “Pump” to move the oil. It actually piggy backs off the power steering circuit.
It does this via a diaphragm in the power booster. There is unpressurized power steering fluid on one side and unpressurized brake fluid on the other (hydraulic over hydraulic). Or, a vacuum of air on one side and brake fluid on the other. (Air over hydraulic)
Remember, air compresses while fluid water, oil etc cannot.
When you start the engine, you pressurize the power steering side which at the same time pressurizes the brake side (pascal’s law).
This is why in certain vehicles when you blow a power steering line, you loose your brakes too!
You wonder, “Why would they separate the two systems and not just use the same oil for both” here is why…
Brake fluid is hydroscopic, meaning that it absorbs or suspends water. The reason they use a fluid that suspends water in a braking system is because if it didn’t, you could end up with several ounces of water all in one caliper or cylinder (big trouble).
The other problem is hydroscopic fluids do not get along well with pumps. The suspended water can cause foaming, and cavitation.
Also, there light properties “thin” do not pump well with the typical, inexpensive, diehard gear or vain pumps typically used in power steering systems.
Another fluid that is hydroscopic is honey! Next time you wife is baking cookies, have her substitute some honey for sugar. This will keep them moist a long time!
So, someone came up with this piggyback system back in the 40’s or 50’s and we have not yet been able to produce a more reliable inexpensive system yet.
Cannot help my college days are coming back to me. I apologize for boring you with the history book!
The braking system itself actually has no “Pump” to move the oil. It actually piggy backs off the power steering circuit.
It does this via a diaphragm in the power booster. There is unpressurized power steering fluid on one side and unpressurized brake fluid on the other (hydraulic over hydraulic). Or, a vacuum of air on one side and brake fluid on the other. (Air over hydraulic)
Remember, air compresses while fluid water, oil etc cannot.
When you start the engine, you pressurize the power steering side which at the same time pressurizes the brake side (pascal’s law).
This is why in certain vehicles when you blow a power steering line, you loose your brakes too!
You wonder, “Why would they separate the two systems and not just use the same oil for both” here is why…
Brake fluid is hydroscopic, meaning that it absorbs or suspends water. The reason they use a fluid that suspends water in a braking system is because if it didn’t, you could end up with several ounces of water all in one caliper or cylinder (big trouble).
The other problem is hydroscopic fluids do not get along well with pumps. The suspended water can cause foaming, and cavitation.
Also, there light properties “thin” do not pump well with the typical, inexpensive, diehard gear or vain pumps typically used in power steering systems.
Another fluid that is hydroscopic is honey! Next time you wife is baking cookies, have her substitute some honey for sugar. This will keep them moist a long time!
So, someone came up with this piggyback system back in the 40’s or 50’s and we have not yet been able to produce a more reliable inexpensive system yet.
Cannot help my college days are coming back to me. I apologize for boring you with the history book!
12-30-2005, 10:33 AM
#24
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Using the ebrake won't tell you if the rear brakes are out of adjustment as the ebrake is driven by one cable that balances the force between the wheels mechanically.
When you are using the the foot brake it's hydraulic.
I've been though this more times than I can count fixing pull. It's very common that at least one side doesn't self adjust correctly.
Just jack up the rear and adjust the brakes, no need to remove the wheels, it will take less than 5 minutes.
Remove the rubber cap at the bottom back of the wheel and turn the starwheel under the cap upwards with a screwdriver or brake tool while spinning the tire. When you hear the brakes just starting to drag-- stop, you are done, do the other side.
You've had enough work done on the front that it seems it should be fine.
When you are using the the foot brake it's hydraulic.
I've been though this more times than I can count fixing pull. It's very common that at least one side doesn't self adjust correctly.
Just jack up the rear and adjust the brakes, no need to remove the wheels, it will take less than 5 minutes.
Remove the rubber cap at the bottom back of the wheel and turn the starwheel under the cap upwards with a screwdriver or brake tool while spinning the tire. When you hear the brakes just starting to drag-- stop, you are done, do the other side.
You've had enough work done on the front that it seems it should be fine.
12-30-2005, 11:16 AM
#25
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Originally Posted by TIMMY22
try holding the release for the parking brake up while you use the parking brake pedal to stop. try this in a vacant parking lot or somewhere you won't get hurt.
if it still pulls the problem is in the rear mechanisim. if not the trouble is in the hydralic rear or front.
if it still pulls the problem is in the rear mechanisim. if not the trouble is in the hydralic rear or front.
01-01-2006, 03:09 PM
#27
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Thread Starter
I got the brakes fixed. I ended up replacing the right caliper, and it helped. Then the left one pulled, so I replaced it, and now they are fine. Thanks for all the help!
01-01-2006, 03:49 PM
#28
Registered User
I have gone through my share of calipers. Seems to me when they rehab them they must not do a very good job. Seems like the rebuilt ones don't last very long, and it starts pulling again in a year or so. But now you know how to fix it.
01-01-2006, 04:58 PM
#29
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Thread Starter
Yeah, because I took it to the brake place a few months ago to have the pulling fixed and they said they replaced the calipers...so I guess it was one of two things. Either they didnt replace them, or they went bad again. O'Reilly's offers the lifetime warranty with their calipers, so I should be ok from now on, although its a pain to bleed the system and change everything. One more thing, has anyone ever heard of the sensor on the proportioning valve to short out? I was taking my black dash trim off, and I saw some smoke. Then I looked in the floor board and the whole thing was full of smoke!!! 
I quick unhooked the batteries and took the kick panel out and found that a wire from the harness, up to the steering column burnt! It burnt all the way up the column to the ignition area, it was in the 7 wire plug in. It went down into the jumper thing by the harness, then into the harness, then stopped. So we found the same color outside on the proportioning sensor and unplugged it, put a new wire, but fused it this time, and as soon as we popped the fuse in, it blew it. So we left it unhooked. Anyone ever hear of something like this?! 
I quick unhooked the batteries and took the kick panel out and found that a wire from the harness, up to the steering column burnt! It burnt all the way up the column to the ignition area, it was in the 7 wire plug in. It went down into the jumper thing by the harness, then into the harness, then stopped. So we found the same color outside on the proportioning sensor and unplugged it, put a new wire, but fused it this time, and as soon as we popped the fuse in, it blew it. So we left it unhooked. Anyone ever hear of something like this?!
01-15-2006, 10:29 AM
#30
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Thread Starter
Update: I've noticed now that when I am driving and I put the brakes to the floor going around 40 or so, it doesnt stop hardly, it just keeps going. It feels like ABS I guess, but Im not sure. I'd hate to be near an accident and not be able to suddenly stop. The distance it takes me does not seem short enough to be ABS. What do I look for?
