Bucky92 Posted January 26, 2007 Share Posted January 26, 2007 As most of you know I have temporarily retired my beloved Loyale mainly due to brake failure...he has always had brake issues. Anyway..started him up yesterday to run him ( I hate letting cars sit) and I noticed when he is idling and you step on the brakes ..he wants to stall...I am thinking brake booster/master cylinder..Peddle goes to floor even after pumping them a few times...I have a spare one so I may just swap it out and see if that helps ( cause I miss my boy). Anyway..what do you guys think? TIA Quote Link to comment Share on other sites More sharing options...
joostvdw Posted January 26, 2007 Share Posted January 26, 2007 As most of you know I have temporarily retired my beloved Loyale mainly due to brake failure...he has always had brake issues. Anyway..started him up yesterday to run him ( I hate letting cars sit) and I noticed when he is idling and you step on the brakes ..he wants to stall...I am thinking brake booster/master cylinder..Peddle goes to floor even after pumping them a few times...I have a spare one so I may just swap it out and see if that helps ( cause I miss my boy). Anyway..what do you guys think? TIA sounds like brake master cilinder to me too, since it's vacuum operated and your engine stalls when you brake, seems logical to me you could unplug the vacuumline to the brakebooster and then see if you car stalls if you brake, if it doesn't (you have to close the line!) the master cilinder is the problem Quote Link to comment Share on other sites More sharing options...
Turbone Posted January 26, 2007 Share Posted January 26, 2007 The booster is vacume assisted. Theres a one way valve in the hose from the manifold that can go bad with time (and elements). Theres a flow chart in the FSM to check the system but I'm not in my office right now:rolleyes: I'll try and scan it later in the morning. Quote Link to comment Share on other sites More sharing options...
daeron Posted January 27, 2007 Share Posted January 27, 2007 I second the idea of checking the check valve first. The check valve is inserted to ensure two things: 1. No positive manifold pressure goes into the brake booster (bad for the booster) 2. no negative pressure escapes the brake booster, once past the check valve. The check valve is easy to identify, remove, and test. Its (usually) a small roundish thing in the rather large vacuum line going from the manifold to the brake booster. All you have to do is unclamp the line from either side, make sure you note the direction air flows through it, put your lips on the engine side, and suck. you should be able to pull air through it freely. then, with your lips still on the engine side, blow. you shouldn't be able to move any air. if it fails that test, replace it. I say usually because while I have been here, and done this, on a few cars.. the soob is NOT yet one of them. No brake issues yet, knock on wood. Well, pad replacement, rear shoe replacement, accompanying rear bearing catastrophic failure (thanks haynes!! the haynes book lists rear bearing nut torque at like 150 lb-ft in the chart.. then in the actual directions for the 2wd rear bearings, it tells you "oh yah, THESE only get re torqued to like, 35 lb-ft...") but I mean, what all THAT?? nothing! Quote Link to comment Share on other sites More sharing options...
TomRhere Posted January 27, 2007 Share Posted January 27, 2007 Quick check for bad booster is; engine "off", pump brake pedal until it firms up. Hold foot on pedal and start engine. Pedal should "fall away" from your foot. In other words, pedal should move towards floor as engine vacuum works the booster. If it doesn't, bad booster. Diaphram has a hole in it is most likely cause there. But I would check thehose going from intake to booster for cracks also. If the pedal is stiff feeling after letting car sit for a while, chances are checkvalve is bad, or as above, booster diaphrem is holed and not holding a vacuum like it should. A good booster should hold vacuum for 3-4 brake applications without the engine running. If the pedal is wanting to go towards the floor every time you push on it, chances are you have air in the lines, or the Master Cylinder is worn. Quote Link to comment Share on other sites More sharing options...
Turbone Posted January 27, 2007 Share Posted January 27, 2007 Quick check for bad booster is;engine "off", pump brake pedal until it firms up. Hold foot on pedal and start engine. Pedal should "fall away" from your foot. In other words, pedal should move towards floor as engine vacuum works the booster. If it doesn't, bad booster. Diaphram has a hole in it is most likely cause there. But I would check thehose going from intake to booster for cracks also. If the pedal is stiff feeling after letting car sit for a while, chances are checkvalve is bad, or as above, booster diaphrem is holed and not holding a vacuum like it should. A good booster should hold vacuum for 3-4 brake applications without the engine running. If the pedal is wanting to go towards the floor every time you push on it, chances are you have air in the lines, or the Master Cylinder is worn. Thats basically how the manual tells you how to check the booster and check valve. Also correct on the MC going to the floor being bad. Quote Link to comment Share on other sites More sharing options...
Bucky92 Posted January 27, 2007 Author Share Posted January 27, 2007 Thanks guys..checking all this right now. 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.