Bad brake job....?
#1
Bad brake job....?
I have been reading some posts on changing brake pads and noticed a few things that i did not do, and am afraid it may have caused some problems. When changing my pads all the way around I did not open my master cylinder cap or the bleeder valve when using a C-clamp.
Now when i step on the brake the pedal is not as sensitive i stop just fine but the pedal has to travel a llittle ways to get any feel, and i do have alot of brake dust being made on my fron wheels. My brake fluid is fairly dark as well.
Does anyone have ideas or as to what could be wrong?
The pads were not all that old when i cjanged them either maybe a year, cant remeber if they were worn evenly or not. I'll be checking this week.
Now when i step on the brake the pedal is not as sensitive i stop just fine but the pedal has to travel a llittle ways to get any feel, and i do have alot of brake dust being made on my fron wheels. My brake fluid is fairly dark as well.
Does anyone have ideas or as to what could be wrong?
The pads were not all that old when i cjanged them either maybe a year, cant remeber if they were worn evenly or not. I'll be checking this week.
#2
Join Date: May 2004
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Have you given the new pads a few miles to seat in fully? Did you resurface the rotors with the new pads?
Dirty brake fluid has a heavy influence on pedal feel and quality. The idea behind opening the bleeders before compressing the caliper pistons in is to minimize the chance of forcing crud into the (expensive) ABS valve assembly or compromising a seal in the master cylinder.
Depending on how lousy your pedal really feels, I'd try bleeding it first. Failing that, out with the old, in with the new; have the system flushed and refilled with fresh brake fluid.
Dirty brake fluid has a heavy influence on pedal feel and quality. The idea behind opening the bleeders before compressing the caliper pistons in is to minimize the chance of forcing crud into the (expensive) ABS valve assembly or compromising a seal in the master cylinder.
Depending on how lousy your pedal really feels, I'd try bleeding it first. Failing that, out with the old, in with the new; have the system flushed and refilled with fresh brake fluid.
#3
Brake fluid is ...here it goes Big word...Hydroscopic. This means it will draw moisture right out of the air. To prevent this brake systems in newer cars are sealed. But because it is Hydroscopic it is recommended to flush your brake system every year with fresh fluid.
The color gets darker because rust forms in the Calipers, Wheel Cylinders, ABS Valve, and Master Cylinder. Anywhere iron is present. Heck even in the Stainless brake lines. Yeah, I know they are stainless, but over time a small amount of iron comes from them too.
By flushing out the system, it will remove the iron/rust from the system and keep the hydraulic portion of your brakes happy and free moving.
Next...SCOLD....you should never push brake fluid back into the brake system with any type of clamp during a brake job. The correct way to do it is to clamp off the correcponding brake line, open the bleeder screw before compressing the caliper. This way the old fluid in the caliper is expelled, not pushed back to the master via the ABS valve.
Second...there is a hat valve in the ABS assembly/valve that when fluid flows the wrong way for any lenght of volume can flip over, causing a permanent failure in the ABS valve until replaced.
So if you get someone else to flush your system for you, please tell them you did a brake job and "forgot" to expell the fluid, and pushed it back into the system. I once spent almost a week working on a car to regain good pedal pressure, until they came clean and told me that they did what you did. After replacing the ABS valve, all was good again.
I'm not saying you have this problem....just that it's possible.
Change you fluid boys!
The color gets darker because rust forms in the Calipers, Wheel Cylinders, ABS Valve, and Master Cylinder. Anywhere iron is present. Heck even in the Stainless brake lines. Yeah, I know they are stainless, but over time a small amount of iron comes from them too.
By flushing out the system, it will remove the iron/rust from the system and keep the hydraulic portion of your brakes happy and free moving.
Next...SCOLD....you should never push brake fluid back into the brake system with any type of clamp during a brake job. The correct way to do it is to clamp off the correcponding brake line, open the bleeder screw before compressing the caliper. This way the old fluid in the caliper is expelled, not pushed back to the master via the ABS valve.
Second...there is a hat valve in the ABS assembly/valve that when fluid flows the wrong way for any lenght of volume can flip over, causing a permanent failure in the ABS valve until replaced.
So if you get someone else to flush your system for you, please tell them you did a brake job and "forgot" to expell the fluid, and pushed it back into the system. I once spent almost a week working on a car to regain good pedal pressure, until they came clean and told me that they did what you did. After replacing the ABS valve, all was good again.
I'm not saying you have this problem....just that it's possible.
Change you fluid boys!
#4
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For the longest time, like a jackass, I'd stick a prybar in between the outside pad and the caliper and jam the caliper home to compress the pistons without opening the bleeder.
That stopped the day I did that on a friend's Mustang and had no brake pedal afterwards. Another thing too, after replacing pads, when you're pumping the brake pedal up, don't stomp on it trying to send it through the floorboard. This can over-extend the piston in the master cylinder and compromise a seal in it. Little by little, pump the pedal up until you've got a firm pedal. Same idea goes for bleeding, don't let the pedal fall all the way to the floor.
That stopped the day I did that on a friend's Mustang and had no brake pedal afterwards. Another thing too, after replacing pads, when you're pumping the brake pedal up, don't stomp on it trying to send it through the floorboard. This can over-extend the piston in the master cylinder and compromise a seal in it. Little by little, pump the pedal up until you've got a firm pedal. Same idea goes for bleeding, don't let the pedal fall all the way to the floor.
#6
They make brake line clamps that look like mini c-clamps, or you can use locking pliers. Be careful, a lot of pressure is NOT necessary. Just enough to pinch the hose, not enough to leave marks on the line. If you are worried that the locking pliers will dig into the line you can use masking tape on the plier teeth to make them less abrasive.
#7
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#10
Hi Quintin - Where is the ABS valve located? Is it in the proportioning valve or master cylinder? Just curious as I was looking at the system breakdown in AllData & I dont see just an ABS valve (though Im sure it has one).
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Thanks
Last edited by LittleTow; 06-09-2005 at 05:31 PM. Reason: Typo
#11
#12
While the plastic may allow air to be absorbed into the fluid through the bottle the situation is a "catch 22" - the metal containers will rust & contaminate the fluid....besides do they even sell brake fluid in small containers that arent plastic? I think the thing is to buy only the amount you need and no more so you dont end up keeping around "forever".
#13
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Originally Posted by LittleTow
Hi Quintin - Where is the ABS valve located? Is it in the proportioning valve or master cylinder? Just curious as I was looking at the system breakdown in AllData & I dont see just an ABS valve (though Im sure it has one).
Thanks
Thanks
While the plastic may allow air to be absorbed into the fluid through the bottle the situation is a "catch 22" - the metal containers will rust & contaminate the fluid....besides do they even sell brake fluid in small containers that arent plastic? I think the thing is to buy only the amount you need and no more so you dont end up keeping around "forever".
#14
Free is good - They could be good for a long time depending on where you live & the conditions in which their stored, I used to live a couple of miles from the ocean in an old house W/a really poor excuse for a garage, needless to say things corroded quickly out there. Remember folks if you ever get stranded in the middle of nowhere with a hydraulic fluid leak just about anything will work & get you going again (albeit for a short time since whatever you put in will leak out again). Just be sure to flush the sytem well after especially if you were to put pee in it as our auto shop instructor suggested, its gonna corrode FAST!
#15
Originally Posted by 69aries
One more thing. Brake fluid sold in plastic bottles will absorb air through the plastic. So while it's sitting on the shelf at the store it's already absorbing air. Buy fluid in metal containers only.