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How to tell is the brake booster is bad in a 1986 dodge D100

We have a leak but it is not in the link, what is the chances it is the booster or master cylinder?

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This is a standard Vacuum operated brake booster.. If you are having fluid leaking at the rod that attaches the brake pedal to the booster it is a bad Master Cylinder. The Brake fluid will eventually destroy the diaphram in the booster if it hasn't already. . Replace or rebuild the Master Cylinder and wash the brake fluid out of the booster. When the booster goes bad the brake pedal will become very hard to push.. because you will have lost "boost" This is not really a hard job. If fluid id leaking somewhere should be very easy to spot.. Brake fluid looks like oil leaking..

Posted on May 14, 2014


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SOURCE: fluid not gushing out brake line

sound like problem is in the combination valve.

Posted on Jul 19, 2009

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1996 Dodge Intrepid with 3.3 engine looses brake pressure. Bled the brakes and changed the master cylinder. Same thing happens. No leaks detected. Brake booster? Or something else?

In most cases I would suspect the master cyl. And you could have a defective unit if you bought a rebuilt part. Its possible one of the calipers or wheel cylinders is leaking internally. But its almost always the master.
The booster only applies extra pressure to the master. It would not have any effect on the fluid.
There might be a chance something is going on with the ABS but I doubt it.
You may have to plug the lines at the master to find out whats going on.

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My brake pedal is spongy, what would cause that? fluid level is good

air in the line or bad booster. try getting the brakes bled if it doesnt fix it probably a bad booster

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There is no way that your proportioning valve is going to affect your engine idle. However, a leaking master cylinder and the resulting damaged diaphram in the vacuum brake booster will. Remove the master cylinder and look for brake fluid in the booster assembly. If there is fluid in there, replac both the master cylinder and the booster.

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1992 dodge grand caravan with ABS has a hard brake pedal and hard to stop, it makes funny chatering sound from the hyd control moduel, how can I tell if the modual or the abs motor are bad

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you should replace the booster and master cylinder. With brake fluid there ,the diaphram in the booster will be damaged .

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Leaking brake fluid

Power boosters don't have fluid in them. This sounds more like your master cylinder is leaking out the back were it joins the booster. Replace the master cylinder, and while you have it off, remove all the excess fluid out of the booster that you can using only towels.

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Replace front brake pads on a 2003 dodge durango,after pumping

could be a bad master cylinder or a power booster the part that the master cylinder attatches to. also check whell cylinders to make sure they are not leaking.

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1 Answer

Brakes brake pedal is hard to push

Chk. to see if you got vacume to break booster, If there is than i would say the booster is bad. When you have to push hard on break peddel means either the booster is bad or there is no vacume to booster. I really don't understand the secound part of your question, Do you mean there are no bleeders on the rear breaks? or you can't get fluid to bleeders in the rear? If you can't get any fluid to the rear breaks, you could have a master cyl. problem too.

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2 Answers

2002 Toyota Sequoia power brake booster % master cylinder are bad

Mr. Clark:
It would be extraordinary for a technician to recommend a booster and a master cylinder with no previous mention from you of a possible problem in this area. In other words, the technician had no business looking at the m/cyl or the booster, unless you told him that your braking was deficient.
Here is what REALLY happened: Somewhere, I'd bet, your brake light came on, and somebody "topped off" the master cylinder, to shut the light off. Now, please understand that the brake fluid level in the master cylinder reservoir DROPS PROPORTIONALLY to the wear of the brake pads. When the tech replaced the front brake pads, he obviously had to squeeze the caliper pistons into the housings to allow the insertion of the new pads. This action forced the brake fluid from the now-compressed caliper pistons BACK into the master cylinder, and it sprayed out from under the cap, coating the cylinder and the booster. Tell that repair service that you do NOT need a booster and a master cylinder, THEY caused the problem with the fluid being everywhere. I am confident that I just saved you a significent amount of money that you do NOT need to spend. Have a great day.

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2 Answers


check your brake booster vacuum pipe for leaks otherwise it sounds like your brake booster has failed

Jun 04, 2008 | 1986 Ford F150 SuperCab

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