| scary moment of brake failure [message #197136] |
Sat, 02 February 2013 14:14  |
bronevaya
Messages: 63
Registered: May 2011
Location: birmingham al
Karma: 0
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Just finished getting the LP gas system leak checked and was happily driving home. No problems but as soon as I get to my hilly neighborhood the trouble started. At stop lights I slowed to coach down and the pedal seemed to travel further down. Holding it in this position the coach would start to inch until I applied full pressure. Then coming to park at the top of the hill the coach did not stop with full brakes applied and me standing on it. I had to throw it into park before I started to gain momentum.
Now here is my question. Should I bleed the brakes or get a new master cylinder and have everything done at once? I have never worked on drum brakes before so I really dont know what I am getting into.
1977 Palm beach
Bham AL
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| Re: scary moment of brake failure [message #197139 is a reply to message #197136] |
Sat, 02 February 2013 14:46  |
bronevaya
Messages: 63
Registered: May 2011
Location: birmingham al
Karma: 0
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just checked. no leaks. after reading some other members posts I am thinking master cylinder so I ordered a new one.
how hard is it to replace? If I replace it myself can I drive it to a shop to have them power bleed it?
1977 Palm beach
Bham AL
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| Re: scary moment of brake failure [message #197143 is a reply to message #197136] |
Sat, 02 February 2013 16:05 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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You need to see if it's an external leak ( hose, caliper, wheel cyl, line) or an internal leak at the master or if its the booster. If the pedal drops I' d say it' one of the first 2 scenarios. If pedal is hard but doesn't fade to the floor it could be the booster. Check vac line and check valve first,
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: scary moment of brake failure [message #197145 is a reply to message #197136] |
Sat, 02 February 2013 16:38 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Here is a booster test (which I think is the problem) that was explained to me by Hubert Rowell a few weeks ago.
With the engine off, press the pedal a few times until rock hard and all stored vacuum is gone. If you are on a slope, block the wheels so it won't move but you can leave it in park too. Now press and hold the pedal down hard while you start the engine. If the pedal goes down further when the engine starts your booster is working.
If you suspect the booster, with the motor running, pull the vacuum line off it and make sure you have a good vacuum in the hose using the thumb test. No vacuum suggests a loose hose somewhere or a major, major vacuum leak that would probably be noticed by a really crappy running engine.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: scary moment of brake failure [message #197149 is a reply to message #197145] |
Sat, 02 February 2013 18:14 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Your symptom could also be caused by rear brake shoes out of adjustment.
Also did you open the cover and look at the master cylinder fluid level? How much fluid was in both chambers of the reservoir?
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: scary moment of brake failure [message #197157 is a reply to message #197136] |
Sat, 02 February 2013 20:52 |
bronevaya
Messages: 63
Registered: May 2011
Location: birmingham al
Karma: 0
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I can confirm that the booster is working via the pedal test. I dont know about the rear brakes but I think I drove with the parking brakes on when I first got it. could that have hurt anything? I doubt it worked when I first got it as it really didnt make a difference (I couldnt tell it was on anyways).
1977 Palm beach
Bham AL
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| Re: scary moment of brake failure [message #197165 is a reply to message #197157] |
Sun, 03 February 2013 00:31 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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The rear brakes are suppose to be self adjusting. But they only adjust when backing up. So if your self adjusters are working, go out in a large parking lot and start backing up and stepping on the brake. I would do this at least 10 times. Then drive forward and see if your pedal is any higher. It is also easy to adjust them manually but if you have never done it then get someone to show you how it is done.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: scary moment of brake failure [message #197170 is a reply to message #197136] |
Sun, 03 February 2013 08:59 |
habbyguy
Messages: 896
Registered: May 2012
Location: Mesa, AZ
Karma: 3
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What Ken said! And don't be afraid if the self-adjusters don't seem to do the job. It really isn't difficult to adjust the rear brakes - but you do need to raise the rear of the coach to do it correctly. That will not only give you a lot more room to get under there and access the adjusters (from the rear of the hub), but will let you spin the wheels to see when you've got 'em adjusted correctly.
On a related note, I see where Harbor Freight has a big sale on their el cheapo infrared non-contact thermometer ($35), which would be a very good way to do a final check on the brakes (a couple stops from speed, and then scan each wheel to see if you're getting good stopping from each brake - the relative temperature of each wheel will indicate how much braking is being done by that wheel, since all that energy x speed is converted into heat by the brakes).
Mark Hickey
Mesa, AZ
1978 Royale Center Kitchen
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| Re: scary moment of brake failure [message #197175 is a reply to message #197170] |
Sun, 03 February 2013 11:55 |
chasingsummer
Messages: 434
Registered: May 2011
Location: asheboro, nc
Karma: 0
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i do know you are not the first to drive with parking brake on.
I second the suggestion to get an ir temp gun.
every thing i stop for gas i use gun on all wheels, and anything else i can hit with it. it helped me find a sticking brake on my rear, (which started after driving with park break on)
brian
asheboro, nc
75 eleganza, 74 build
119k miles and counting,
DOG HOUSE
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| Re: scary moment of brake failure [message #197177 is a reply to message #197136] |
Sun, 03 February 2013 13:00 |
Cadillackeeper
Messages: 464
Registered: October 2012
Location: Fort Lauderdale
Karma: 1
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Guys,What is the Master part number?Is it the same for all years?
I would also think it can't cost too,too much.Mine is kinda soft,
stops good but I have felt the pedal go to the floor a ton of times in the Eldo.It has 4 piston calipers.If you lose 1,fluid goes all over the place and the pedal just goes away.Kinda like a bad master.
77 455 Elaganza II and 67 Animal, Built 500 Powered Eldo
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| Re: scary moment of brake failure [message #197307 is a reply to message #197177] |
Mon, 04 February 2013 09:49 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| Cadillackeeper wrote on Sun, 03 February 2013 14:00 |
Guys,What is the Master part number?Is it the same for all years?
I would also think it can't cost too,too much.Mine is kinda soft,
stops good but I have felt the pedal go to the floor a ton of times in the Eldo.It has 4 piston calipers.If you lose 1,fluid goes all over the place and the pedal just goes away.Kinda like a bad master.
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Anthony,
This is just one of many good reasons to be a member of GMCMI....
You now have one number from one supplier for 73 through 77.
The interchange book (that members get an updated copy of annually) lists about a dozen from different suppliers,
and the numbers for 78 models.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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