| Loss of front brakes [message #250145] |
Mon, 19 May 2014 19:12  |
Bruce Hart
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
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Senior Member |
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I had a blow out on the passenger side front rear tire. After changing out the tire I got an occasional
brake light with no front brakes being applied. The light would come on after depressing the brakes two or three times and stay on and no front brake. I have checked all four rear drums for a leak nada and checked the front calipers for a leak and that was negative as well. I have a Powermaster for my master brake cylinder and found that one side was a bit low in fluid (Dot 5). Filled reservoir and still get the light.
Something with the combination valve is sticking. I tried to push on the front end of combination valve but could not get any movement.
Once when we were traveling home the brake light would flicker off and on.
I am at a loss any ideas from the forum.
Bruce Hart
1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
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| Re: Loss of front brakes [message #250147 is a reply to message #250145] |
Mon, 19 May 2014 19:25  |
stick miller
Messages: 1036
Registered: March 2010
Location: Americus, Georgia
Karma: 0
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Senior Member |
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Bruce- I don't know the answer to your question but, just for information, what was the DOT date on your tire?
Stick Miller
'78 Royale - "White Trash" - she left me for another man
'76 Eleganza - "Cousin Eddie" Sold
'84 Bluebird Wanderlodge - "Past Tents"
Americus, GA
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| Re: [GMCnet] Loss of front brakes [message #250153 is a reply to message #250150] |
Mon, 19 May 2014 20:09 |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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Senior Member |
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Did you check the wire to the top of the combination valve?
The teinal might be loose.
Emery Stora
> On May 19, 2014, at 6:24 PM, James Hupy wrote:
>
> I also suspect the combination valve. Perhaps you might have applied the
> brakes harder than usual when the tire blew, moving the piston assy. in the
> combo Valve into some gunk. Try a tap with a heavy hammer head on the
> plunger to see if it moves. If not, I suspect that is where the trouble can
> be found. That valve assy. can be unscrewed and inspected. DON'T LOSE ANY
> PIECES AND RE-ASSEMBLE IT IN THE REVERSE ORDER OF DIS-ASSEMBLY.
> JIM HUPY
> SALEM , Or
> 78 GMC ROYALE 403
>> On May 19, 2014 5:12 PM, "Bruce Hart" wrote:
>>
>> I had a blow out on the passenger side front rear tire. After changing
>> out the tire I got an occasional
>> brake light with no front brakes being applied. The light would come on
>> after depressing the brakes two or three times and stay on and no front
>> brake. I have checked all four rear drums for a leak nada and checked the
>> front calipers for a leak and that was negative as well. I have a
>> Powermaster for my master brake cylinder and found that one side was a bit
>> low in fluid (Dot 5). Filled reservoir and still get the light.
>>
>> Something with the combination valve is sticking. I tried to push on the
>> front end of combination valve but could not get any movement.
>>
>> Once when we were traveling home the brake light would flicker off and on.
>>
>> I am at a loss any ideas from the forum.
>> --
>> Bruce Hart
>> 1976 Palm Beach
>> Milliken, Co
>> _______________________________________________
>> GMCnet mailing list
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>>
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| Re: [GMCnet] Loss of front brakes [message #250156 is a reply to message #250153] |
Mon, 19 May 2014 20:37 |
Bruce Hart
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
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Senior Member |
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I did, and I unplugged and plugged in a couple of times to clean up the
connection
Letting the coach set for a while, I turn the engine over and give it some
gas and the brake light will go out if it isn't out all ready. As soon as
I hit the brake peddle three times the light comes on. When the light is
out I have very good peddle pressure, but when the light is on the peddle
is very stiff and won't move very far.
On Mon, May 19, 2014 at 7:09 PM, Emery Stora wrote:
> Did you check the wire to the top of the combination valve?
> The teinal might be loose.
>
> Emery Stora
>
>> On May 19, 2014, at 6:24 PM, James Hupy wrote:
>>
>> I also suspect the combination valve. Perhaps you might have applied the
>> brakes harder than usual when the tire blew, moving the piston assy. in
> the
>> combo Valve into some gunk. Try a tap with a heavy hammer head on the
>> plunger to see if it moves. If not, I suspect that is where the trouble
> can
>> be found. That valve assy. can be unscrewed and inspected. DON'T LOSE
> ANY
>> PIECES AND RE-ASSEMBLE IT IN THE REVERSE ORDER OF DIS-ASSEMBLY.
>> JIM HUPY
>> SALEM , Or
>> 78 GMC ROYALE 403
>>> On May 19, 2014 5:12 PM, "Bruce Hart" wrote:
>>>
>>> I had a blow out on the passenger side front rear tire. After changing
>>> out the tire I got an occasional
>>> brake light with no front brakes being applied. The light would come on
>>> after depressing the brakes two or three times and stay on and no front
>>> brake. I have checked all four rear drums for a leak nada and checked
> the
>>> front calipers for a leak and that was negative as well. I have a
>>> Powermaster for my master brake cylinder and found that one side was a
> bit
>>> low in fluid (Dot 5). Filled reservoir and still get the light.
>>>
>>> Something with the combination valve is sticking. I tried to push on
> the
>>> front end of combination valve but could not get any movement.
>>>
>>> Once when we were traveling home the brake light would flicker off and
> on.
>>>
>>> I am at a loss any ideas from the forum.
>>> --
>>> Bruce Hart
>>> 1976 Palm Beach
>>> Milliken, Co
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
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Bruce Hart
1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
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| Re: Loss of front brakes [message #250171 is a reply to message #250145] |
Mon, 19 May 2014 23:15 |
Bullitthead
Messages: 1411
Registered: November 2013
Karma: 5
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Senior Member |
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You have an air bubble in the line that has made it's way to the combo valve. As it moves back and forth through the valve there will be all kinds of strange brake behavior. You may be able to get it out at the top of the system by adjusting the rear brakes up and then applying the parking brake to push that fluid back up the lines and then compressing the front calipers to push that fluid back up the lines also. Watch for the bubbles to come up in the master cylinder during this whole process and while just barely tapping the brake pedal and releasing quickly. Otherwise, bleed it out the long way at each wheel and keep the master cylinder full of clean fluid.
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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| Re: Loss of front brakes [message #250185 is a reply to message #250145] |
Tue, 20 May 2014 09:47 |
kingd
Messages: 592
Registered: June 2004
Karma: 2
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Senior Member |
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I wonder if it is an air bubble, one of those DOT 5 things. I've heard
TOO many bad stories about DOT 5. As it is not hydroscopic one
can actually get enough water in one place in the system that the
water will freeze in cold weather and NO brakes.
It sounds more like a combo valve problem than a Power Master
problem. My Yukon has factory hydraulic assist(not vacuum) brakes.
DAVE KING
lurker, wannabe
Toronto, Ontario, Canada
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