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runamoc 
Samba Member
Joined: June 19, 2006
Posts: 5601
Location: 37.5N 77.1W
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 Posted: Fri Dec 07, 2018 8:08 am Post subject: Power Brake Booster Vacuum |
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I've searched without out any luck. So I'll ask...for my '81 Mk1 Diesel...
I'm thinking I need either a new power brake diaphragm or just the whole power brake booster 'unit'. I rebuilt the vacuum pump. Second time in 2 years. I understand that's not abnormal. The brake pedal is still hard at first but the farther and the faster I drive it feels a little better. The check valve sounds free when I shake it. Could it be wore out? I replaced it 2 years ago when I did the first pump rebuild.
What different years and/or models of power brake booster/master cylinder combos will work on my 'ol smokey?
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Daily driver: '69 Baja owned 44 yrs - Plan B: '81 Rabbit Diesel LS Deluxe - Plan C: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs-
VW Wiring = It's just wires |
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ps2375
Samba Member
Joined: April 24, 2014
Posts: 2471
Location: Meridian,ID
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| Posted: Fri Dec 07, 2018 8:24 am Post subject: Re: POWER BRAKE BOOSTER VACUUM |
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| Other than "shaking" the check valve, have you tested it? |
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TDCTDI
Samba Advocatus Diaboli
Joined: August 31, 2013
Posts: 12854
Location: North Carolina
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| Posted: Fri Dec 07, 2018 9:42 am Post subject: Re: Power Brake Booster Vacuum |
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Have you checked for vacuum leaks elsewhere in the system?
Disconnect the vacuum line going to the climate controls & cap the tap on the hose to the booster & see if the brakes feel better If so, then you have a leak in the climate system.
_________________
Everybody born before 1975 has a story, good, bad, or indifferent, about a VW.
GOFUNDYOURSELF, quit asking everyone to do it for you!
An air cooled VW will make you a hoarder.
Do something, anything, to your project every day, and you will eventually complete it. |
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Butcher
Samba Member
Joined: December 05, 2015
Posts: 1285
Location: Right Here
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| Posted: Fri Dec 07, 2018 10:10 am Post subject: Re: Power Brake Booster Vacuum |
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Is it that hard to install a vacuum gauge and see where the vacuum is at? You could put a long rubber hose and see what's happening.
Knowing what the vacuum is, would certainly direct you to the problem fairly quick. If it is low, is it because of a leak or because there is not enough capacity? |
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runamoc
Samba Member
Joined: June 19, 2006
Posts: 5601
Location: 37.5N 77.1W
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| Posted: Sun Dec 09, 2018 8:18 am Post subject: Re: Power Brake Booster Vacuum |
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| Quote: |
| Disconnect the vacuum line going to the climate controls & cap the tap |
My Rabbit has cable operated climate control 'flaps'. Straight from the pump to the check valve, then a 3/4" to 1/2" adapter with two 'taps', then the power brake servo.
Looking for leaks, I found the two rubber caps that fit over the two 'taps' in the adapter were dry-rotted and cracked. Found some 1" long screws that threaded right into the holes. Didn't have any rubber hose small enough to make a U connection. Snowing now will test this hack fix later. I'd still like to know what other VW power brake servo/MC combs could be 'swapped'. I've got some spare Mk4 parts.
_________________
Daily driver: '69 Baja owned 44 yrs - Plan B: '81 Rabbit Diesel LS Deluxe - Plan C: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs-
VW Wiring = It's just wires |
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