| Brake Question [message #66399] |
Wed, 02 December 2009 18:41  |
carnut
Messages: 11
Registered: February 2007
Location: Visalia CA
Karma: 0
|
Junior Member |
|
|
I have a 1976 Elliganza and we took a short trip the other day and I noticed not much power and very low vacuum on the gauge. I stopped for the night after about 5 miles and found the stop somewhat easier and no roll after the brake released. Checking all wheels with my hand they all seemed hot and the drums and rotors could not be touched. (I did not have the laser temp gun) The next morning the brakes were fine and the vacuum was back up and once again had the roll at idle. Drove home with normal conditions. This situation did not return.
Any ideas as to what happened and what ... if anything ... could I do to prevent a future problem ??????
Dave Bockman
Visalia Calif
"76 Eleganza II
Under restoration
|
|
|
|
| Re: Brake Question [message #66428 is a reply to message #66399] |
Wed, 02 December 2009 21:47  |
GMCNUSA
Messages: 283
Registered: August 2006
Location: Indianapolis, IN
Karma: 0
|
Senior Member |
|
|
Dave,
There could be some kind of failure of power brake booster. It uses engine vacuum to operate I don't know the exact conditions that would produce your dragging brakes but I am guessing it is a posibility you had an intermittent problem.
Larry Dilk
Indianapolis, IN
76 Eleganza II
Patterson 455,Turbo City TBI,
Just LOVE It!
|
|
|
|
| Re: Brake Question [message #66438 is a reply to message #66428] |
Thu, 03 December 2009 00:52 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
|
Senior Member |
|
|
| GMCNUSA wrote on Wed, 02 December 2009 21:47 |
Dave,
There could be some kind of failure of power brake booster. It uses engine vacuum to operate I don't know the exact conditions that would produce your dragging brakes but I am guessing it is a possibility you had an intermittent problem.
|
That was my only guess but I have never heard of that failure before. I wonder if their could be some dirt or tust in the Master cylinder preventing the pushrod or valve from returning?
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
|
|
|
|
| Re: [GMCnet] Brake Question [message #66454 is a reply to message #66438] |
Thu, 03 December 2009 07:15 |
GMCWiperMan
Messages: 1248
Registered: December 2007
Karma: 1
|
Senior Member |
|
|
A stuck master cylinder could have held the brakes on, but it shouldn't have
affected the booster since the push rod between the two is free floating --
it can only push.
I vote for some kind of contamination of the booster's valve, allowing the
vacuum to leak continuously from the back side of the diaphragm. I've never
had one apart so I don't know how that could happen. From the history we
know it certainly can't be a common failure mode.
Ken H.
Americus, GA
'76 X-Birchaven
www.gmcwipersetc.com
On Thu, Dec 3, 2009 at 1:52 AM, Ken Burton <n9cv@comcast.net> wrote:
>
>
> GMCNUSA wrote on Wed, 02 December 2009 21:47
> > Dave,
> > There could be some kind of failure of power brake booster. It uses
> engine vacuum to operate I don't know the exact conditions that would
> produce your dragging brakes but I am guessing it is a possibility you had
> an intermittent problem.
>
>
> That was my only guess but I have never heard of that failure before. I
> wonder if their could be some dirt or tust in the Master cylinder preventing
> the pushrod or valve from returning?
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
>
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
|
|
| Re: [GMCnet] Brake Question [message #66467 is a reply to message #66462] |
Thu, 03 December 2009 09:08 |
Carleton Douglas[1]
Messages: 174
Registered: March 2006
Karma: 0
|
Senior Member |
|
|
Look in to quick take up master cylinder, for GM vehicles.
On Thu, Dec 3, 2009 at 7:32 AM, Terry Skinner <gmcnut@gmail.com> wrote:
> My guess from way up here in the cold (22F) Northwest. I am thinking
> you have some sticking brakes dragging you down and requiring more gas
> pedal to maintain the same speed which would cause the lower vacuum
> reading. That's my story and I am sticking to it.
> Is there a prize for the closest guess??..........Terry
>
> On Wed, Dec 2, 2009 at 4:41 PM, Dave Bockman <carnut123@gmail.com> wrote:
>>
>>
>> I have a 1976 Elliganza and we took a short trip the other day and I noticed not much power and very low vacuum on the gauge. I stopped for the night after about 5 miles and found the stop somewhat easier and no roll after the brake released. Checking all wheels with my hand they all seemed hot and the drums and rotors could not be touched. (I did not have the laser temp gun) The next morning the brakes were fine and the vacuum was back up and once again had the roll at idle. Drove home with normal conditions. This situation did not return.
>>
>> Any ideas as to what happened and what ... if anything ... could I do to prevent a future problem ??????
>> --
>> Dave Bockman
>> Visalia Calif
>> "76 Eleganza II
>> Under restoration
>> _______________________________________________
>> GMCnet mailing list
>> List Information and Subscription Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>
>
>
> --
> Terry Skinner
> 253-686-2624
> Roy. Washington
> '76 GMC
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Carleton Douglas
73 custom, by myself
Prescott, AZ
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
| Re: [GMCnet] Brake Question [message #66488 is a reply to message #66462] |
Thu, 03 December 2009 11:06 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
|
Senior Member |
|
|
We had some coaches that came in to our shop with the brace pedal
shaft sticking .
Once they were freed up there were no more problems.
Someone called me the other day and had a similar problem. I told him
what I thought.
Next day he left us a message that it was the peddle.
On Thu, Dec 3, 2009 at 6:32 AM, Terry Skinner <gmcnut@gmail.com> wrote:
> My guess from way up here in the cold (22F) Northwest. I am thinking
> you have some sticking brakes dragging you down and requiring more gas
> pedal to maintain the same speed which would cause the lower vacuum
> reading. That's my story and I am sticking to it.
> Is there a prize for the closest guess??..........Terry
>
> On Wed, Dec 2, 2009 at 4:41 PM, Dave Bockman <carnut123@gmail.com> wrote:
>>
>>
>> I have a 1976 Elliganza and we took a short trip the other day and I noticed not much power and very low vacuum on the gauge. Â I stopped for the night after about 5 miles and found the stop somewhat easier and no roll after the brake released. Â Checking all wheels with my hand they all seemed hot and the drums and rotors could not be touched. Â (I did not have the laser temp gun) Â The next morning the brakes were fine and the vacuum was back up and once again had the roll at idle. Â Drove home with normal conditions. Â This situation did not return.
>>
>> Any ideas as to what happened and what ... if anything ... could I do to prevent a future problem ??????
>> --
>> Dave Bockman
>> Visalia Calif
>> "76 Eleganza II
>> Under restoration
>> _______________________________________________
>> GMCnet mailing list
>> List Information and Subscription Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>
>
>
> --
> Terry Skinner
> 253-686-2624
> Roy. Washington
> '76 GMC
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
|
|
|
|
| Re: [GMCnet] Brake Question [message #66575 is a reply to message #66467] |
Thu, 03 December 2009 22:43 |
carnut
Messages: 11
Registered: February 2007
Location: Visalia CA
Karma: 0
|
Junior Member |
|
|
Thanks Jim. The master cyl and booster are from from your inventory and appear to be in good condition. The sticky pedal could have very easily be the problem since I did not check it or tap it a few times until I stopped.
I also was curious about the unit which connects all the brake lines behind the left front tire and heard that it has some kind of floating valve. Any chance that it could have gotten stuck ??
Dave Bockman
Visalia Calif
"76 Eleganza II
Under restoration
|
|
|
|
| Re: [GMCnet] Brake Question [message #66593 is a reply to message #66467] |
Fri, 04 December 2009 00:39 |
 |
ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
|
Senior Member |
|
|
What is the benefit of a "quick take up" master cylinder?
Larry Davick
The Mystery Machine
On Dec 3, 2009, at 7:08 AM, Carleton Douglas wrote:
> Look in to quick take up master cylinder, for GM vehicles.
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
