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Alaskaberrys Samba Member
Joined: June 19, 2016 Posts: 1001 Location: SE Alaska
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Posted: Sun May 16, 2021 1:27 pm Post subject: Vacuum system on a diesel syncro question |
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Hi all,
I went to exercise the front and rear lockers on my ‘91 diesel doka (European) as I do every few months (surprised how little I use either front or rear lockers) and this last go around I got nothing. Pull knobs, front, back, both, in, out and no sign of anything happening. Usually get a bit of noise or slight resistance when pulling the knob and then after a bit can feel the lock and light comes on.
Figured I’d check the vacuum lines, the bulbs, tee, check valve underneath and start with the easy stuff - lots muddy rutty roads this winter and easy to see something get plugged off with dirt.
Then I realized I have no idea what produces the vacuum on this diesel in the first place
1.9l AAZ TD (originally 1.6TD) _________________ '91 Westfalia, Bordeaux Red Pearl 2.1L 2wd Auto
'91 T3 Syncro Doka, Escorial Green 1.9L TD AAZ “Gremian” (to provoke, irritate, exasperate, vex...) |
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17155 Location: Retired South Florida
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Posted: Sun May 16, 2021 1:51 pm Post subject: Re: Vacuum system on a diesel syncro question |
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There is a vacuum pump on the Diesel engine. Follow the brake booster hose in the engine compartment. _________________ ☮️ |
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Alaskaberrys Samba Member
Joined: June 19, 2016 Posts: 1001 Location: SE Alaska
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Posted: Sun May 16, 2021 2:31 pm Post subject: Re: Vacuum system on a diesel syncro question |
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MarkWard wrote: |
There is a vacuum pump on the Diesel engine. Follow the brake booster hose in the engine compartment. |
Thanks MarkWard - I’ll trace it down. Is it driven mechanically then? _________________ '91 Westfalia, Bordeaux Red Pearl 2.1L 2wd Auto
'91 T3 Syncro Doka, Escorial Green 1.9L TD AAZ “Gremian” (to provoke, irritate, exasperate, vex...) |
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17155 Location: Retired South Florida
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Posted: Sun May 16, 2021 2:39 pm Post subject: Re: Vacuum system on a diesel syncro question |
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I’ve not really paid attention to the 1.9, but the 1.6 had a pump where the distributor would fit the block on a gas engine. My TDI has a vacuum pump driven by the cam shaft on the back of the head.
You really need a vacuum gauge to test the lockers. Each outer nipple should have vacuum when off. On, vacuum is routed to the inner nipples on the servo. I temporarily disconnect the vacuum tank when troubleshooting. It takes too long to fully recover when you are connecting and disconnecting. _________________ ☮️ |
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Alaskaberrys Samba Member
Joined: June 19, 2016 Posts: 1001 Location: SE Alaska
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Posted: Sun May 16, 2021 2:47 pm Post subject: Re: Vacuum system on a diesel syncro question |
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I see. So a possibility is having vacuum at the pump, but signal not getting to it to re-route a vacuum to the reservoir?
Sounds like I best route it out to get a better understanding of what lines run to where first. Hadn’t dived into the locker rabbit hole yet.....I guess it’s time _________________ '91 Westfalia, Bordeaux Red Pearl 2.1L 2wd Auto
'91 T3 Syncro Doka, Escorial Green 1.9L TD AAZ “Gremian” (to provoke, irritate, exasperate, vex...) |
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