Power Brake Booster '70 B Body
#2250019
02/08/17 11:40 PM
02/08/17 11:40 PM
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Joined: Mar 2003
Posts: 4,929 Tri-Cities, Washington
VITC_GTX
OP
master
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OP
master
Joined: Mar 2003
Posts: 4,929
Tri-Cities, Washington
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Lost the brakes in my GTX. I have very low vacuum due to the cam so the brakes are usually sketchy at best but now I have nothing (extremely hard pedal). I believe it can only be the master cylinder or the power booster. All the vacuum lines are OK and I do have an aftermarket reservoir under the battery tray to increase vacuum reserves. Getting ready to dive in so I decided to look for a new power booster in case I need one but I can't find one anywhere for a '70 B body. What options are out there??? I prefer stock-ish look for the GTX but may stray from that if I can find something that will give me good brakes with 6" Hg at idle.
Last edited by VITC_GTX; 02/08/17 11:44 PM.
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Re: Power Brake Booster '70 B Body
[Re: VITC_GTX]
#2250123
02/09/17 01:42 AM
02/09/17 01:42 AM
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Joined: Jan 2003
Posts: 5,357 Rancho Cordova, California (Sa...
hemi71x
master
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master
Joined: Jan 2003
Posts: 5,357
Rancho Cordova, California (Sa...
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Yeah, I don't want to go with the hydro-boost, but it's a good idea.
If I end up not being able to find an original replacement I'll have to see if I can find a place that will rebuild mine. BOOSTER DEWEY
RF-4C Phantom 69-370 Zweibrucken, Germany
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Re: Power Brake Booster '70 B Body
[Re: hemi71x]
#2250145
02/09/17 02:14 AM
02/09/17 02:14 AM
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Joined: Mar 2003
Posts: 4,929 Tri-Cities, Washington
VITC_GTX
OP
master
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OP
master
Joined: Mar 2003
Posts: 4,929
Tri-Cities, Washington
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Yeah, I don't want to go with the hydro-boost, but it's a good idea.
If I end up not being able to find an original replacement I'll have to see if I can find a place that will rebuild mine. BOOSTER DEWEY I had no idea what you were talking about so I searched the net. Not too bad of price and not too far away. Thanks for the information!!!!
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Re: Power Brake Booster '70 B Body
[Re: VITC_GTX]
#2250603
02/09/17 08:31 PM
02/09/17 08:31 PM
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Joined: Jul 2011
Posts: 957 Chicago
PurpleBeeper
super stock
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super stock
Joined: Jul 2011
Posts: 957
Chicago
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I've got a couple more thoughts for you since about 6 months ago my '70 Road Runner lost its brakes (hard pedal, not going to the floor, but no brakes).
1. My car's problem was TWO bad Inline Tube metering valve/proportioning valve (split on '70, can't remember the correct name, but the part where you hold the little pin out to bleed the brakes). The quality control on those parts is TERRIBLE.
2. You can get a pretty close to original looking brake booster (dual diaphragm) which they sell on Ebay. I had to slightly (1/8") enlarge the hole in my firewall (not visible once installed) and I did not need to buy the "heavy duty bracket", maybe because my car was stock front disc.
70 Roadrunner convt. street car
440+6, NOS, 4-spd, SS springs
'96 Mustang GT convt. street car
'04 4.6 SOHC, NOS, auto, lowered
"Officer, that button is for short on-ramps"
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Re: Power Brake Booster '70 B Body
[Re: NANKET]
#2250726
02/09/17 11:40 PM
02/09/17 11:40 PM
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Joined: Mar 2003
Posts: 4,929 Tri-Cities, Washington
VITC_GTX
OP
master
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OP
master
Joined: Mar 2003
Posts: 4,929
Tri-Cities, Washington
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Is it a disc brake or drum brake car? The boosters are different. Do you have a car with 15+ inches of vacuum? Even a new car. Run a long hose from that car to the booster on the GTX and see what it does.
But I will say that your booster is,bad, and the master is not causing this problem.
You might try removing the booster and run in them as manual brakes.
Booster Dewey is the place to go for booster rebuild. It is a disc brake car. When the weather improves enough (foot of snow on the ground now) I'll put another car along side and see what happens then. Thanks for the suggestion.
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Re: Power Brake Booster '70 B Body
[Re: PurpleBeeper]
#2250727
02/09/17 11:42 PM
02/09/17 11:42 PM
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Joined: Mar 2003
Posts: 4,929 Tri-Cities, Washington
VITC_GTX
OP
master
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OP
master
Joined: Mar 2003
Posts: 4,929
Tri-Cities, Washington
|
I've got a couple more thoughts for you since about 6 months ago my '70 Road Runner lost its brakes (hard pedal, not going to the floor, but no brakes).
1. My car's problem was TWO bad Inline Tube metering valve/proportioning valve (split on '70, can't remember the correct name, but the part where you hold the little pin out to bleed the brakes). The quality control on those parts is TERRIBLE.
2. You can get a pretty close to original looking brake booster (dual diaphragm) which they sell on Ebay. I had to slightly (1/8") enlarge the hole in my firewall (not visible once installed) and I did not need to buy the "heavy duty bracket", maybe because my car was stock front disc. Wow, never heard of the metering valves doing that. Must have been preventing the fluid from reaching the caliper/wheel cylinders so it had a hard pedal.
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Re: Power Brake Booster '70 B Body
[Re: cmansell]
#2250728
02/09/17 11:43 PM
02/09/17 11:43 PM
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Joined: Mar 2003
Posts: 4,929 Tri-Cities, Washington
VITC_GTX
OP
master
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OP
master
Joined: Mar 2003
Posts: 4,929
Tri-Cities, Washington
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the airgrabber hood is a good place to lose vacuum and the switch under the dash will also leak. Good call. I think I checked everything for leaks but I will double check before I spend any money on parts.
Last edited by VITC_GTX; 02/09/17 11:43 PM.
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Re: Power Brake Booster '70 B Body
[Re: VITC_GTX]
#2256536
02/20/17 01:06 PM
02/20/17 01:06 PM
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Joined: Jul 2011
Posts: 957 Chicago
PurpleBeeper
super stock
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super stock
Joined: Jul 2011
Posts: 957
Chicago
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I've got a couple more thoughts for you since about 6 months ago my '70 Road Runner lost its brakes (hard pedal, not going to the floor, but no brakes).
1. My car's problem was TWO bad Inline Tube metering valve/proportioning valve (split on '70, can't remember the correct name, but the part where you hold the little pin out to bleed the brakes). The quality control on those parts is TERRIBLE.
2. You can get a pretty close to original looking brake booster (dual diaphragm) which they sell on Ebay. I had to slightly (1/8") enlarge the hole in my firewall (not visible once installed) and I did not need to buy the "heavy duty bracket", maybe because my car was stock front disc. Wow, never heard of the metering valves doing that. Must have been preventing the fluid from reaching the caliper/wheel cylinders so it had a hard pedal. Yep, that's exactly what the mechanic told me. After replacing it twice from two different vendors I was ignoring what was obvious.
70 Roadrunner convt. street car
440+6, NOS, 4-spd, SS springs
'96 Mustang GT convt. street car
'04 4.6 SOHC, NOS, auto, lowered
"Officer, that button is for short on-ramps"
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