Troubleshooting brakes

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(New page: Right you have a car that has a brake pedal that goes to the floor, maybe a little pumping on the pedal gives some braking.Here is how i go about establishing what needs doing in a logical...)
 
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Right you have a car that has a brake pedal that goes to the floor, maybe a little pumping on the pedal gives some braking.Here is how i go about establishing what needs doing in a logical order, on a level floor or better still on a car lift , raise car and if necessary use axle stands that will safely support the weight of your car, obviously you dont need axle stands for car ramp/lift.With the help of a friend and firstly make sure the brake master cylinder is filled with good quality ,preferably new and from a sealed container , brake fluid.I usually surround the master cylinder with some clean rags just in case of any accidental spillage of brake fluid.On most cars- trucks -pick ups etc.you will find four flexible brake hoses one on each brake caliper or drum on the front then one or two between rear axle and floor at the rear.If you have the correct brake pipe clamps use them to clamp the flexy pipes , or with great care vice grips could be used instead, one word of caution here do not try this on aftermarket braided piping [Aeroquip etc.]Now your helper who is in the drivers seat presses the brake pedal if the pedal still goes to the floor then bleed the master cylinder by opening the one or more brake pipes at least halfway out the threads,get your helper to pump the brake pedal slowly,hopefully brake fluid will appear and be asorbed by the rags you positioned earlier, now tighten up the brake pipes on the M/C.If you still have no firmness on the brake pedal then either replace the M/C. with a known good one or a new one. Some times a re buid kit for the M/C. is available, so you have options.Once again i bleed the new M/C.before i proceed. The second possibility ie your helper says the brake pedal is rock hard ie. no travel,you then remove one clamp and your helper presses the pedal again ,if the pedal remains hard then proceed and remove the next clamp, remove the next clamp and so on .If removing any of the clamps results in too much brake pedal travel bingo you have discovered the fault area .If it were the back axle the remove the drums as per Chilton or Haynes manual and carry out reconditioning as per book.Quite often all that is needed is the dust removing with an aerosol brake cleaner then manually adjusting the brakes.If your vehicle has a brake proportioning valve of any type then make sure you understand its function , maybe do a google search on it.
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Right now you have a car that has a brake pedal that goes to the floor, maybe a little pumping on the pedal gives some braking.Here is how i go about establishing what needs doing in a logical order, on a level floor or better still on a car lift , raise car and if necessary use axle stands that will safely support the weight of your car, obviously you dont need axle stands for car ramp/lift.
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With the help of a friend and firstly make sure the brake master cylinder is filled with good quality ,preferably new and from a sealed container , brake fluid.I usually surround the master cylinder with some clean rags just in case of any accidental spillage of brake fluid. On most cars- trucks -pick ups etc. You will find four flexible brake hoses one on each brake caliper or drum on the front then one or two between rear axle and floor at the rear. If you have the correct brake pipe clamps use them to clamp the flexy pipes , or with great care vice grips could be used instead, one word of caution here do not try this on aftermarket braided piping [Aeroquip ].  
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Now your helper who is in the drivers seat presses the brake pedal if the pedal still goes to the floor then bleed the master cylinder by opening the one or more brake pipes at least halfway out the threads,get your helper to pump the brake pedal slowly,hopefully brake fluid will appear and be absorbed by the rags you positioned earlier, now tighten up the brake pipes on the master cylinder.
 +
 
 +
If you still have no firmness on the brake pedal then either replace the master cylinder with a known good one or a new one. Some times a re build kit for the Master cylinder is available, so you have options. Once again i bleed the new master cylinder  before i proceed.  
 +
 
 +
The second possibility is your helper says the brake pedal is rock hard with no travel, you then remove one clamp and your helper presses the pedal again ,if the pedal remains hard then proceed and remove the next clamp, remove the next clamp and so on . If removing any of the clamps results in too much brake pedal travel bingo you have discovered the fault area. If it were the back axle the remove the drums as per Chilton or Haynes manual and carry out reconditioning as per book. Quite often all that is needed is the dust removing with an aerosol brake cleaner then manually adjusting the brakes. If your vehicle has a brake proportioning valve of any type then make sure you understand its function , maybe do a google search on it.

Revision as of 12:02, 26 April 2009

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