oceanrunner Posted October 27, 2007 Share Posted October 27, 2007 I have a LS 400 90 model. Just recently, the brake pedal just went to the flood. Remind you, I havent driven the car in a while(garage kept). I start it up periodically. I replaced the master cyclinder and bleed brakes. I have a hard pedal after bleeding, but when I start it up, the pedal rides to the flood again. What are the chances it may be the brake booster? If so, how do I check to see if working properly. Perhaps, any other suggestions. Quote Link to comment Share on other sites More sharing options...
pishta Posted October 27, 2007 Share Posted October 27, 2007 I have a LS 400 90 model. Just recently, the brake pedal just went to the flood. Remind you, I havent driven the car in a while(garage kept). I start it up periodically. I replaced the master cyclinder and bleed brakes. I have a hard pedal after bleeding, but when I start it up, the pedal rides to the flood again. What are the chances it may be the brake booster? If so, how do I check to see if working properly. Perhaps, any other suggestions.pump brakes a few times to get a hard pedal with motor off. Push brake and start car, brake should sink a little, not go to floor. Stop car and wait about 30 seconds. push brakes again, you should feel the assist, ie. it should go down a few like you were idling. If it doesnt, you have a leak somewhewre, it could be as simple as the vacuum one way valve thats pushed into the brake booster, a cheap part to fix. It could be an air pocket somewhere but if you bled them that is not likely. Sometimes you can hear a brake booster hissing when you put the brakes on. a booster is not that hard to replace, just getting it in and out may be a hassle. I did my Suburbans for less than 120 bucks but that was a truck...with a large engine compartment. Hardest part was getting the nuts loose behind the dash. Quote Link to comment Share on other sites More sharing options...
en11871 Posted January 15, 2008 Share Posted January 15, 2008 I have a LS 400 90 model. Just recently, the brake pedal just went to the flood. Remind you, I havent driven the car in a while(garage kept). I start it up periodically. I replaced the master cyclinder and bleed brakes. I have a hard pedal after bleeding, but when I start it up, the pedal rides to the flood again. What are the chances it may be the brake booster? If so, how do I check to see if working properly. Perhaps, any other suggestions.pump brakes a few times to get a hard pedal with motor off. Push brake and start car, brake should sink a little, not go to floor. Stop car and wait about 30 seconds. push brakes again, you should feel the assist, ie. it should go down a few like you were idling. If it doesnt, you have a leak somewhewre, it could be as simple as the vacuum one way valve thats pushed into the brake booster, a cheap part to fix. It could be an air pocket somewhere but if you bled them that is not likely. Sometimes you can hear a brake booster hissing when you put the brakes on. a booster is not that hard to replace, just getting it in and out may be a hassle. I did my Suburbans for less than 120 bucks but that was a truck...with a large engine compartment. Hardest part was getting the nuts loose behind the dash. Hi, What is that part called exactly? I believe I need that part, but have heard different names. Thanks. Quote Link to comment Share on other sites More sharing options...
rich13 Posted January 21, 2008 Share Posted January 21, 2008 I have a LS 400 90 model. Just recently, the brake pedal just went to the flood. Remind you, I havent driven the car in a while(garage kept). I start it up periodically. I replaced the master cyclinder and bleed brakes. I have a hard pedal after bleeding, but when I start it up, the pedal rides to the flood again. What are the chances it may be the brake booster? If so, how do I check to see if working properly. Perhaps, any other suggestions. First thing check for a leakin the system. I do not think that is the problem. @nd rebleed the brakes you more than likly have a air bubble in the line somewhere. If you do not have a pressure bleeder then fill the master cylinder then remove the bleeder screw from each caliper one at a time and pump the brakes (engine off) and run a bowl of fluid to each caliper. Just opening the bleeder will not always move a air bubble since not alot of fluid come from the bleeder. Take your time. The booster does not sound like the problem. air in the lines sounds like a problem. If there is a local parts store that rents pressure bleeders that would work also. Rich Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.