Soft Brake Pedal After New Master Cylinder

Spongy Brake Pedal after caliper rebuilding Hi, to make a long story short I've rebuilt my M calipers (new caliper seals, gaskets, pads, and new flex lines with new "Porsche Genuine" Parts except for brake pads that are Ferodos instead of Textars). Brake Master Cylinder Bleeding. General Brake Booster Installation Instructions. The problem is that despite countless bleedings, the brake pedal remains very soft. By continuing to use this site you consent to the use of cookies on your device as described in our cookie policy unless you have disabled them. Some of this information may not apply to some newer brake systems, which feature integrated electrohydraulic boosting, but the theory is similar. The master cylinder contains rubber seals that maintain fluid pressure while the brake pedal is being applied. Did this procedure 4 times, and all rears are good, front would have a bubble and still soft pedal. Spongy when running. If the pedal is firm (when driving) after taking up the slack at the top, it's possible that you need to adjust the pushrod length on the brake booster. Bruce lancaster Early V8 (1932-53) Sponsored Links (Register now to hide all advertisements). Did you bench bleed the master cylinder before putting it on the. Feels more like a mechanical disconnect from the master cylinder. If the pedal is firm and hard, the master cylinder is good. Re: Brake pedal goes to floor even after replacing master cylinder (vw-gti_1987) 03-28-2009 02:42 AM #10 Ok, may be a stupid question here, but I have seen it before (when I changed out my firts master cylinder). Suddenly, the pedal started to sink. If you have them step on the brake pedal and hold it mid way down to simulate 'initial feel' you will see that the cylinder doesn't move at all. If it breaks or comes out of the clutch master cylinder body, you will be where I am, which is replacing the cylinder with a new OEM one. Spongy brakes, they replaced the master cylinder and still spongy. (He bought the truck less than 6 months ago. NOT! I had. Brake block-off can also isolate which wheel is causing the problem. There is a problem that sometimes crops up from pedal pumping. My first thought was faulty master cylinder or brake booster, but when I went to Autozone the guy there told me I need special scan tool for ABS. Or for that matter, any BMW model. When the pedal feels "soft" the rod may not be pushing the fork meaning theres air in the system still. This is super dangerous and should be addressed as soon as possible. Worn Brake Pads: Your brakes should never wear low enough to cause your brake pedal to feel low, they'll scream at you before then. Need to bleed until all the air is out, not just open the bleeder for a couple seconds. I took my car on a gravel road, got up a little speed and slammed on the brakes, locking the wheels. after this is done, and the pedal feels ok, open the bleeders one last time to let the remaining small amount of air from the calipers. After sitting a few hours it becomes spongy. If the pedal is firm and hard, the master cylinder is good. The brake pedal goes to the floor and must be pump repeatedly to get any pressure. Remove the master cylinder reservoir cap or cover. Soft brake pedal after replacing the brakes and rotors. If you pump the pedal and it goes firm but slowly drops while you hold it you may have an additional leak somewhere or you could have a bad master cylinder. furthest away and in proper sequence. Re: Spongy Brakes After Caliper Replacement? 07/21/2010 6:29 AM Pumping the brake pedal with your foot and holding it while someone opens a bleeder is an invitation to failure of the master cylinder. Why would there be a soft brake with new brakes? I just got new brakes (pads and rotors) for the front of my Ford Escapeit just doesn't feel like there is any change. Three days and $100 later the diagnosis was that it needed a new master cylinder. Unfortunately, the master cylinder can wear out. My problem is brake pedal pressure. Toyota's MSRP for a new master cylinder is around $280. Universal Manual Pedal Assembly Manual Master Cylinder - GM 1994 up 11" Delco Style Dual Diaphragm Power Brake Booster Exact New Delco. After a couple of brake applications, the pedal starts to get hard. In part one in this series, we explain how to test for a low brake pedal by blocking the brake lines. Replaced all rotors, pads, lubed sliders, calipers squeezed in fine and the rears screwed in good. The block-off method shows if the cause of a low brake pedal is at the wheels or the master cylinder. Ive recently upgraded to steel braided brake lines and was having a problem with the brake pedal feel, like the title says my brake pedal feels firm when car is off, but when i start driving the pedal sinks and feels spongy, ive bled all the line and made sure no air is present, i have read online that it might be the master cylinder or brake booster or check valve, is there some way to. The first step is to isolate if the problem is with a wheel or the master cylinder. And when it does as I said the pedal pressure is weak. Whether using our products or those of another company, the first thought people generally have is that they have a bad master cylinder. I bled the brakes by having my wife press the pedal to the floor about 4-5 times per wheel, but no air ever came out - just a solid stream of brake fluid. BMW E53 X5 Brake Fluid Bleed/Flush DIY by hayaku for xoutpost. 7L to be specific. Spongy Brake Pedal after caliper rebuilding Hi, to make a long story short I've rebuilt my M calipers (new caliper seals, gaskets, pads, and new flex lines with new "Porsche Genuine" Parts except for brake pads that are Ferodos instead of Textars). If you have to press the brake pedal all the way to the floor to bring your vehicle to a stop, this might be why. So checked the brakes pads and have over 45% of pad left. The problem is that despite countless bleedings, the brake pedal remains very soft. Air trapped in the lines, calipers or wheel cylinders will make the pedal feel soft and spongy. 3) Continue the bleeding process by gravity bleeding the caliper or wheel cylinder at each wheel. Brakes underwent a heavy duty bench bleed after a standard bleed wasn't working, master cylinder was replaced, new brake pads, control rotor. today ive changed discs, pads and fitted two new calipers to the rear. Brake Fluid Leaks: Worn, damaged or rusted components. Stuck brake and no brake are common brake failures encountered when replacing rubber seals or repair kit on a brake master cylinder. If the cylinder isn't level, not all the air will be able to be removed from the master cylinder. In truth, this is a video about how to replace and bleed a master cylinder on a C1500, 1990 5. Pressure brake bleeding is the best way to make sure you get all the air out. A faulty brake master cylinder can reduce braking performance and, in severe cases, cause a brake system failure. My auto shop teacher says I need a new master cylinder, but it was fine before bleeding the brakes. I'm having the same intermittent soft brake pedal problem with my 2008 Mariner. If they were fine before you swapped calipers, they should be fine now. Did this procedure 4 times, and all rears are good, front would have a bubble and still soft pedal. You just keep pumping the brake pedal about 10-15 times, refill the master cylinder, then repeat. I am running the 7/8" master cylinder and proportioning valve is wide open to the rears right now. This is most common in four-piston calipers and four-wheel disc brakes. After releasing the pedal it returns to normal. Got the spongy pedal after new pads were put in. You're driving along and notice your brake pedal seems soft. Took out a few bubbles, still a soft pedal. With tubing end submerged in the brake fluid, there is no need to close the bleed valve after each pedal stroke. (From the master-cylinder down) takes special adapters. Very dry and not a leaker! Tires are matching 31 x 10. The valves keep the fluid in the calipers from siphoning back into the master cylinder when you let up on the brakes. Our tech line often receives calls from customers experiencing a low, soft or spongy pedal. I am trying to locate all the parts and such to make my 1979 Chevy pick-up into a vehicle that has hydro boost brakes as opposed to vacuum. But nothing like before. If you service your own brakes make sure that you fill the master cylinder to the appropriate level and that you bleed the brake lines before use. If the master cylinder is good, most diagnostic procedures recommend blocking the HCU ports next. ) I adjusted the rear brakes and since the pedal still had lots of travel (about 3/4 to the floor) I replaced the master cylinder. You can find excellent coupon codes from each retailers and manufacturers, which could frequently help you save a great deal of cash. Good luck with yours Tony. My pedal seems pretty soft right now. I don't see any drips on the garage floor or wet marks on the wheels near the brake lines. The brake pedal travels all the way to the floor and is SUPER soft. Bled the MC, bled all 4 wheels. There are a few common issues that can be causing this sort of problem. If the level of brake fluid in the master cylinder is low, buy the proper brake fluid for your vehicle and add fluid to the "Full" line on your master cylinder. I'm suspecting the MC is now bad and needs replacement. In a hydraulic clutch, however, the problem may lie in the master or slave hydraulic cylinders. The excess fluid did return to the master cylinder which I removed via a turkey baster. I picked up a vacuum bleeder a while back to bleed brakes. I had a caliper go bad yesterday and I put my foot on the brake and the pedal went to the floor, fluid all over the driveway. You may be able to temporarily overcome an internal master cylinder leak by pumping the brake pedal, but the only permanent fix is to either overhaul or replace the master cylinder. Bleeding the brakes is always necessary if a brake line has been opened, or if a caliper, wheel cylinder, master cylinder or ABS hydraulic modulator or pump has been replaced. Spongy Brake Pedal after caliper rebuilding Hi, to make a long story short I've rebuilt my M calipers (new caliper seals, gaskets, pads, and new flex lines with new "Porsche Genuine" Parts except for brake pads that are Ferodos instead of Textars). My 93 Eldorado needs some extra effort to stop. These seals wear in time and fluid pressure begins to bypass the seal causing the pedal to sink towards the floor. Using an appropriate tool*, stroke the master cylinder pistons using one-and-a-half-inch strokes. It can happen if part of the master cylinder bore that is unused in normal braking gets corroded. Brake released, opened the rear brake line on the master cylinder until fluid was flowing out, tightened, with the brake pedal pushed, opened that line again, quite fast and as far as possible and closed it again. Allow the master cylinder to gravity bleed. If you have to press the brake pedal all the way to the floor to bring your vehicle to a stop, this might be why. My guesses are the calipers where not bled properly, the master cylinder was not bled properly, an unforeseen leak appeared, or maybe, just maybe, the master cylinder was bad out the box?. CLUTCH-02: Broken. Long brake pedal travel after pad change - RogerL : The front brake pads on my Astra have just been replaced and although the car stops as normal, the pedal travel seems longer / softer than before. did not like the first three-four pump ups to build somewhat pressure. Unlike brake fluid, air is compressible. I took it to Audi who tried to bleed them and they couldn't, they said they'd done the master cylinder and the VAG-COM ABS bleed. Prior to Buying ACDelco 18M391090 Professional Brake Master Cylinder, research websites offering coupon codes, for example coupons. I guess the next step is to replace the master cylinder. The brake pedal sinks a bit when the engine is running. This is to ensure there is no air in the system. 2) If the master cylinder is new or went dry at any time during the installation, begin by bench bleeding the master cylinder. Here's what happened. 7L to be specific. Nissan patrol brake pedal goes down !!! :/ Hi , I need some help please , I have a Nissan Patrol , the problem is when you press the brake pedal it goes half way down (front brakes supposed to work), i have changed the master cylinder , rear wheel cylinders and shoes set brakes and new front caliper pistons and washers. I need some advice on my soft brakes. When the pedal feels "soft" the rod may not be pushing the fork meaning theres air in the system still. I had a new 2012 ram. A sinking brake pedal always used to be a master cylinder problem in days gone by but after the initial garage changed the brake fluid, master cylinder and bled everything with no improvements, two Peugeot dealerships have since checked the car and told me it's perfectly normal for the brake pedal to do. Got the spongy pedal after new pads were put in. Worn or ill. Scared the SHIXNIT out of me. This is likely not the case; the condition can be caused by the piston sticking in bore of the master cylinder during the bleeding process when the brake system is manually bled. The booster will never cause a low or soft brake pedal, check for air or other hydraulic problems. Pedal is still spongy after bleeding brakes and replacing master cylinder 1 Answer. If the master cylinder is good, the pedal won't move. Still soft and squishy! Hint: with engine off, brakes are solid. Need to bleed until all the air is out, not just open the bleeder for a couple seconds. If a clutch fails to disengage fully when the pedal is pressed, the problem may be the clutch itself. Power assist brakes on a 77 LT48. It's time to start suspecting something has gone wrong in. tl;dr Honda says ATE superblue might have weakened the seals in the master cylinder, but when I press the tech, he doesn't really believe it'll get better. From what Ive researched, this sounds like a master cylinder failure, but Im skeptical since I just replaced so much. ABS works fine. Still soft. First, just as you're done with the front and rear brakes, bleed the master cylinder. A defective booster will only cause the pedal to become hard or not return. I bled the brakes by having my wife press the pedal to the floor about 4-5 times per wheel, but no air ever came out - just a solid stream of brake fluid. While both new master cylinders were installed on the truck, removed cap from master cylinder, stepped on brake pedal, brake fluid squirted like a fountain out of the reservoir neared the windshield on both new master cylinders, even after the master cylinder secondary piston moved past the fluid inlet hole located in the reservoir. I saw a brake master cylinder fail where the seal got messed up in a really weird way. Brake lines don't appear to be damaged, one was replaced after wear but still no change. About six months my brakes were really spongy so I replaced the master cylinder. Why is the brake pedal still soft in your 1994 Plymouth Sundance 2. Local master mechanic inspected it and said it's the brake hydraulic control unit (hcu). When bleeding by pumping the brake pedal, it's best to put something like a piece of 2x4. I guess the next step is to replace the master cylinder. Took her for a test drive, brakes still work fine, ABS still kicking in but pedal spongy and with constant foot pressure the pedal will go right to the floor. This leads to a low or soft/spongy brake pedal. I just threw that out there to say everything that could be wrong if you have spongy brakes. It goes down farther than it should and feels spongy. It felt just like a line had let go, soft pedal, weak brakes. I dont see any visible leaks, fluid filled to reccomended. Anything that increases movement, even slightly, will result in a lower brake pedal. I am thinking Master Cylinder but with the inconsistent problem showing up could it be something else?. The bore of the ACU is called a pedal feel emulator and is primarily used to simulate normal brake pedal feel for the driver. Going to try to get a pump bleeder and do it that way. Today, my brakes are working normally again. When the master cylinder was replaced were the brake lines bled? The soft pedal and almost no pedal until pump it, surely sounds like air in the brake lines. I hope the lack of resistance due to not having the cap on didn't dislodge a seal in the master cylinder though, as this. You can use an alternative spacer, if necessary. Brake pedal still spongy after multiple bleeds I have a '97 Nissan XE hardbody pickup that is having brake trouble. I also bleed the brakes and the pedal feels OK and firm when there is no vacum from booster and when the engine is started it will sink an inch or so when it. If your foot slowly sinks to the floor with normal pressure on the brake pedal, the master cylinder is leaking internally. Before I get under there an bleed them all again, is there anything else I need to check?. 2008 Ford Escape - Soft Brake Pedal After Hard Stop Last week, some of the local wildlife decided to test my brakes. Our tech line often receives calls from customers experiencing a low, soft or spongy pedal. I have read so many postings about no brakes, spongy brakes, fading brakes and pedals that go to the floor but have not found my problem or a fix that might work. Then bolt your M/C back into your Cruiser and connect the brake lines to it. How do I tell if it's the master cylinder or a slave cylinder? Thanks, Matt _____. I put new brake pads on the front and bled the front brakes. So this week I got underneath and checked it out. I recently replaced the ABS pump/module and master cylinder with salvage yard parts on the listed above it is the SEL model. Does the pedal go to the floor with pressure on the pedal, if so master cylinder. I just went to Brake Masters this morning and had them replace the Master Cylinder since I was experiencing the pedal very spongy and going to the floor. If your foot slowly sinks to the floor with normal pressure on the brake pedal, the master cylinder is leaking internally. Was your car's brake pedal always spongy and low or just sometimes? My wife's got a 2011 Fiesta 1. On each side, I jacked it up, removed the tire, removed the caliper, removed the old pads, pushed the piston in with a big C clamp, put the new pads on and reattached the caliper. then the problem is a failed seal in the master cylinder. The old original single cylinder master cylinder did its job 50 years ago, but by today’s standards this system is unsafe and unreliable. So I Had it replaced. So what comes first? Glad you asked. However I still have a soft pedal. Ever since I bought my 2003 TDI Jetta with 120K, the brake pedal has been rather soft. Got the spongy pedal after new pads were put in. Have anyone of you had this issue after replacing all the brake lines? If so, how did you fix it? Also, my Yukon has StabliTrak if that info helps. Today he replaced me the brake pads and rotors with I bought Akebono Brake Pads and Centric rotors and today he installed it for me, Now after the replacement my brake pedal soft and when I try to make an emergency stop the pedal drops to the floor and the car stops slowly and not like before. I have bleed them and the pedal keeps going to the floor. And I bench bled the master cylinder. bleed the brakes using the scanner. Help me with Soft Brake Pedal after Upgrade on me to keep the master cylinder topped off. This is needed so you do not bottom out pistons in the master cylinder and cause internal master cylinder leakage. Things I have done so far. The pedal works great after being bleed, but after driving it for a few minutes the pedal go back down to the floor. Took out a few bubbles, still a soft pedal. They said it could be the HCU. In order to remove your old worn out master cylinder first, be sure to disconnect all brake lines from the master cylinder. Right WASIM I hope this helps you - After changing my pads the last time I has exactly the same problem as you. The New Soft Brake Pedal Thread. Check Brake Fluid Levels. This usually goes away after the first couple of stops. Another sign of neglect is brake fluid that has a dark or murky brown color. Remove the master cylinder reservoir cap or cover. I'm suspecting the MC is now bad and needs replacement. My mothers 99 4runner and fathers 04 Tacoma feel night and day compared to my truck. (It took more pressure on the pedal for the brakes to actually work) Your master doesnt have to be leaking for it to be bad and not working efficiently. Brake lines don't appear to be damaged, one was replaced after wear but still no change. You can use an alternative spacer, if necessary. The first place I took it to said it was bad master cylinder. I raised the same issue with the garage I bought my 407 SW from after my first test drive. I did replaced my master cylinder 3 years ago because it was leaking but then parked the car for 3 years because of other mechanical issues. The valves keep the fluid in the calipers from siphoning back into the master cylinder when you let up on the brakes. I'm suspecting the MC is now bad and needs replacement. Remove the nuts from the master cylinder, and slide the master cylinder off the brake booster. The master cylinder is supposed to be for a power brake booster, but in this case, it's used manually without a booster. I have replaced both calipers,pads,brake line and the master cylinder. Something is obviously wrong, and you need to find out the cause. I dont have the firm brake feel you get when the pads stick to the rotor. When I put the brake on to start the pedal moves about an inch, inch and a half but is not rock hard. If the master cylinder is replaced, care must be taken to prime the new master cylinder by removing all of the air and completely filling it with. a new vacuum booster, new rotors, new front dual piston calipers, a rear brake adjustment and bleeding the system with the battery disconnected I still have a soft brake pedal. When the pedal feels "soft" the rod may not be pushing the fork meaning theres air in the system still. I have read so many postings about no brakes, spongy brakes, fading brakes and pedals that go to the floor but have not found my problem or a fix that might work. It recovers right away but this is not a consistent problem although it happened to my daughter today. The only thing left I can think of is maybe the ABS control module. There will be variables from one shop to another, but I would suspect about a 2 hr charge for this (troubleshooting, replacing master cylinder, & bleeding brakes). If I pump the brakes it becomes hard and if I continue to hold the pedal it sinks down a bit. It looks like ABS could make a soft pedal if some of the return/relief valves are leaky. Need to bleed until all the air is out, not just open the bleeder for a couple seconds. The most common cause of pedal problems is failure to bench bleed a new master cylinder. I'm 99% sure there are no leaks, I've left her sit for a couple weeks after bleeding the brakes and there isn't a drop of fluid anywhere on the cement under the car, and the level has remained full in the master cylinder. So I have 06 OR Xterra MT. When I put the brake on to start the pedal moves about an inch, inch and a half but is not rock hard. This will cause your soft pedal. Still soft. WD 40 and 13mm socket and ratchet + 13mm closed end wrench. We ran out of light, so tomorrow we're going to. If the master cylinder is good, the pedal should be rock hard—barely moving—with the ports blocked. Possible the master cylinder is bad to but not likely since it was ok before you loosened the bleeders. Rear brake shoes adjustment. Master Cylinder (MC) The one standard to most all Studebaker brake systems is the 1” bore MC, which was mounted on the frame below the driver’s feet and has a one inch bore. Tests to find causes of a low brake pedal. I question the master cylinder, brake booster, and ABS brake system (only because I'm not familiar with it). Flushed completely with new Brake fluid, until all air bubbles came out. Any thoughts? Seems like it would involve the vacuum servo since it happens with the car running. This included: new master cylinder(was bench bleed), new brake lines, new rubber hoses to front calipers, new calipers, new pads, and new rotors. Sinking/Spongy Brake Pedal???? With ABS SYSTEM!!Watch this before you buy a master cylinder!!It does happenIts Not always a Master Cylinder Issue! Must Watch! Check out My Amazon Auto. I also replaced the master cylinder thinking that was the problem but 2 days after i changed the cylinder the pedal became soft again and the car seems like its only braking on one wheel (hence it is pulling to the left when braking). On a journey, sometimes the brakes are fine, other times the pedal sinks with very little braking effect. Home Brakes, Steering & Suspension Brake Hardware & Components Brake Master Cylinder Parts Brake Master Cylinder Parts A sure sign of master cylinder trouble is a tendency for the brake pedal to gradually go to the floor while you hold the vehicle at a stop, in gear, as it leaks hydraulic pressure and can't hold the vehicle. This is to ensure there is no air in the system. However I still have a soft pedal. You can find excellent coupon codes from each retailers and manufacturers, which could frequently help you save a great deal of cash. Basically the first half of the pedal movement is worthless. I then bled them. So, now I'm thinking fluid must be squeezing by a cylinder. 2008 Ford Escape - Soft Brake Pedal After Hard Stop Last week, some of the local wildlife decided to test my brakes. 015” 1) Remove both brake lines from master cylinder. With engine running, brakes are squishing. If your master cylinder isn't that low or is slightly above the calipers, it can still happen if you're parked on a hill! If you ever have to press on the brake pedal twice to get a hard pedal, you need them. Check out these three tips for dealing with a soft brake pedal as safely as possible. The master cylinder is the usual suspect due to the internal seals having failed. I tried bleeding the brakes 3-4 times each, no lucky. The brake pedal sinks a bit when the engine is running. Brake pedal goes soft after pad replacement. During normal use brake fluid can become contaminated and the master cylinder wears internally but only for the length of your brake pedal travel. This is usually centered around the master cylinder but can also be contributed to other components in the brake system like wheel cylinders or calipers. To disconnect the master cylinder tie bar, loosen the master cylinder then free the Tie bar from the cross shaft. Today, my brakes are working normally again. Power assist brakes on a 77 LT48. Truck had a bad 6 banger. When bleeding by pumping the brake pedal, it's best to put something like a piece of 2x4. If the master cylinder is replaced, care must be taken to prime the new master cylinder by removing all of the air and completely filling it with. Open a front caliper bleed fitting and depress the brake pedal to the floor. Brake pedal soft Has new pads and mastercylinder? Unanswered Questions. Just pull them out of the top of the master cylinder and watch the fluid run out. Help! Installed new Calipers, Brake Pedal Sinks Help! I installed new calipers on Sunday and bled the master as usual, as well as the lines but the brake pedal is soft as hell and moves all the way to the floor. A soft brake pedal is the result of a loss of. Pressure brake bleeding is the best way to make sure you get all the air out. After new installing rotors and pads when I'm braking the car pulls to the right. Did this procedure 4 times, and all rears are good, front would have a bubble and still soft pedal. After suspecting a bad master cylinder, I bit the bullet and got a new one and changed it over (hell of a job). After bleeding the master cylinder, proceed to check the brake pedal. Bled the whole system but the pedal still feels soft (like it did before the new parts) plenty of vacuum on the motor. I then did a bench bleeding on the master cylinder, well sort of, I did it with the master cylinder still in the car, not on the bench. The master cylinder is the component that generates all of the pressure. If the pedal still feels soft, additional bleeding at the master cylinder or wheels may be needed. Suddenly, the pedal started to sink. A few simple tools and an understanding of the system are required for finding the cause of a low brake pedal. The brakes worked ok-ish but only towards the bottom of the pedal. After that I felt a spongy brake pedal, hissing sound, and abnormal braking movement. Feels more like a mechanical disconnect from the master cylinder. It has the 6 cylinder and automatic transmission so everyone in the family can use it. They ended up replacing the master cylinder and bleeding the system. Braking got a little better, but still really soft low pedal. Jack the front of the car up and have someone watch the slave/rod and watch it while you depress the clutch pedal. After replacing master cylinder and still having the problem I decided that it could only be the brake booster so I replaced it, bled the brake lines one more time and it finally fix the soft pedal. I have a feeling its the master cylinder but I haven't ever worked on brakes before. Going to try to get a pump bleeder and do it that way. So this week I got underneath and checked it out. I drove several other new and used Foresters because I didn't believe the dealership. (4) When, after proper mechanical adjustment of all brake shoes, the brake pedal feels spongy, indicating presence of air in the system. It pushes the brake fluid where it needs to be to help bring your car to a stop. Scared the SHIXNIT out of me. Best Answer: Normally a soft or spongy feel to the clutch when the pedal is depressed is the result of air in the system. If you use a drum brake master for disc brakes you would move an insufficient volume of fluid and the disc brakes would drag because of the residual valves. new lines, calipers, master cylinder, proportioning valve, everything) and I've pumped fluid through the system going through the bleeder valves to the M/C and I still don't have any pressure in the system when I pump the brake pedal???. Hey Guys, I am been plagued by a spongy brake pedal ever since I built my car. Took out a few bubbles, still a soft pedal. In some cases, a leak near the vacuum booster or inside the. If the pedal remains firm then the problem is not coming from the front brakes. New front lines, pads, rotors, rear shoes, rear cylinders, drums, springs, adjusters, and levers have all been changed. If the master cylinder is bypassing, the pedal will go down. there is a. Spongy brakes, they replaced the master cylinder and still spongy. I bled the master cylinder on the truck with the plugs in where the lines would go and had someone push the brake pedal till no more bubbles came up in reservoir. Unlike brake fluid, air is compressible. Brake Brake pedal feels soft (already bled the system Dmctalk. Install plugs in both ports of the master. Then when you bleed the brakes manually the seal passes over this corroded area and chews itself up. Engine 350 4 bolt main. can it be the adjusting rod in the brake booster going to the master cylinder when brake pedal is pressed. If a firm pedal can not be achieved after bleeding the system, the master cylinder may not be properly sized for the brake system. Drum brake masters have 10 lb residual valves at the outlet to keep a residual pressure on the drums. Add Complaint but after that activation the brake pedal felt very soft and would not engage the brakes until the very end of the pedal travel. After changing all this I had a very soft pedal. If the pedal is hard to push then maybe booster. While both new master cylinders were installed on the truck, removed cap from master cylinder, stepped on brake pedal, brake fluid squirted like a fountain out of the reservoir neared the windshield on both new master cylinders, even after the master cylinder secondary piston moved past the fluid inlet hole located in the reservoir. Next go ahead and disconnect the electrical plugs from the brake pressure switches. But yea, take it back, get him to bleed it again (preferably with a pressure bleeder and not the manual press the pedal way and see how it goes. The first place I took it to said it was bad master cylinder. There are a few common issues that can be causing this sort of problem. Brake fluid can absorb up to 7% moisture, but after that you get water and that means problems will develop. I saw a brake master cylinder fail where the seal got messed up in a really weird way. It felt just like a line had let go, soft pedal, weak brakes. Now they are saying that after bleeding the brakes, it still doesn't work. There is a problem that sometimes crops up from pedal pumping. A few simple tools and an understanding of the system are required for finding the cause of a low brake pedal. The excess fluid did return to the master cylinder which I removed via a turkey baster. 2005 Sprinter Brake pedal falls away or soft.