| brake booster [message #162979] |
Wed, 14 March 2012 12:54  |
skip2
Messages: 544
Registered: September 2011
Location: Winter Haven,FL (center o...
Karma: 3
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Let my coach sit up for 2 weeks and it seems as though the brake booster went out. Have brakes but very hard pedal and very weak, has vacum on booster but hear no vacum leaks under dash like I have heard before on boosters going out, no signs booster working. I've been told I have the upgraded master since the reservoir is rectangular. This is a 74 canyonlands. My big question is has anyone heard of booster going out from sitting or any suggestions to look elsewhwere. Check each wheel and they will all stop rolling if brake applied.
Thanks
Skip Hartline
74 Canyon Lands, FiTech,
3.7 FD LSD, Manny Tranny,
Springfield Distributor,
2001 Chevy Tracker Ragtop Towd
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| Re: brake booster [message #162980 is a reply to message #162979] |
Wed, 14 March 2012 13:17  |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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I had the same thing happen last fall. I thought for sure the booster failed, it was only one summer old. I installed the new booster last May. had the issue at the end of october.
one weekend i was stopping on a dime. the next weekend... the pedal would it a stop point, and it really took a hard push to get any braking. just was goofy. it would sometimes seem better. but just was not really what i thought it was a few weeks back even when I thought it was working.
I thought for sure it was the booster by the way it was acting. just seemed like it had no help on the pedal.
After talking to Jim Bounds, he has seen some boosters go bad. but very rare. And usually right away within the first 1000 miles. He said he has seen alot of the proportioning valves do goofy, unexplainable things in the past couple years. so I decided it was time to change the original proportioning valve out. couldn't hurt, and that would eliminate questioning that part moving forward.
and you know what. Jim was right. After the proportioning valve got changed the the new brass one. we were back in business. and stopping right.
Just my recent(last November). experience.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
[Updated on: Wed, 14 March 2012 13:20] Report message to a moderator |
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| Re: brake booster [message #162984 is a reply to message #162980] |
Wed, 14 March 2012 14:10 |
2-4 the road
Messages: 145
Registered: June 2009
Location: Fulltimers
Karma: 0
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I'm having the same problem. I have disc brakes all the
way around along with a new proportioning valve. I think
I read here sometime ago about someone gutting a P valve.
Would that help?
Thanks
Bill
2-4 the road
77 Kingsley 455
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| Re: brake booster [message #162986 is a reply to message #162984] |
Wed, 14 March 2012 15:15 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Just a comment, the OEM proportiioning valve is probably not a good match for an all-disk set-up. It was designed to pressure the rear drums, before allowing the front disks to engage. (I hope I got the sequence right.)
Ken Henderson, in one of his many posts/photos defeated the valve, by drilling out the oriface. This puts all the line pressure to his disk set-up equally. Might be part of the solution for your braking.
Tom Phipps, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: [GMCnet] brake booster [message #163002 is a reply to message #162992] |
Wed, 14 March 2012 18:17 |
skip2
Messages: 544
Registered: September 2011
Location: Winter Haven,FL (center o...
Karma: 3
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Senior Member |
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do definitely have vacum and noticed the proportioning valve has a piece of metal permanetly attached to depress the button thats uppose to be depressed while bleeding.
the PO put disc on the middle axle and have no brakes on the rear. really never had a stopping problem.
74 Canyon Lands, FiTech,
3.7 FD LSD, Manny Tranny,
Springfield Distributor,
2001 Chevy Tracker Ragtop Towd
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