Re: [EVDL] Vacuum Pump
Hello Steve,
I do not use any electric driven vacuum pump in my EV. Back in 85, I
purchase a belt driven pump for GMC diesel pick up from a auto parts store
and still running it today only for my heating and A/C units.
Does not make that pumping noise after the vacuum gets up over 15 in.hg.
This unit maintains 20 to 22 in.hg. all the time.
About 2 years ago, my brake master cylinder was acting up, so I went back to
the auto parts store to get a replacement. The clerk happen to have a
different unit that just came in and was setting on the counter, like it was
waiting for me. He said, this is what you need, you can get rid of the
vacuum booster and replace it with this unit.
The unit is call a Hydro-Booster which is a hydraulic unit that replaces the
vacuum booster. It happen to be a re-manufacture unit for a 86 GMC or some
of the pickups back then. It had a steel fire wall mounting plate that
bolted to the same bolt studs that the vacuum booster was mounted on. It
uses the existing power steering pump lines to power this unit.
These units at the GMC dealer cost about $800.00 with a core replacement.
This unit at the auto parts store was $151.00 with a core replacement. For a
core, I went to a savage yard and pick up a 86 hydro-boost with master
cylinder and all the hydraulic lines for it for $50.00. One thing if you
ever do this modification, you need to match these units to about the year
of your vehicle. I am using DOT-3 brake oil in my EV and this unit is
design for DOT-3. You also need to retain the push rod that goes between the
master cylinder and hydra-boost from the old unit.
There is a on line web site call Hydro-Boost Conversion that has photos
details on how to do this conversion. The first problem this guy did was
using a later model hydro-boost which uses a high pressure power steering
pump and DOT-5 oil. He had to change out the power steering unit and all
the brake cylinders.
I did not have the problems they had, because my 1977 El-Camino uses 700 to
1000 psi power steering system that matches the 1986 hydro-boost unit I got.
Roland
----- Original Message -----
From: "Steve Powers" <
[email protected]>
To: "ev" <
[email protected]>
Sent: Tuesday, December 07, 2010 2:52 AM
Subject: [EVDL] Vacuum Pump
I know there is always a lot of discussion on these. I've been using an old
GM pump that is pretty much unobtainable now (early 80's GM cars). It quit
working recently. I was able to rig it up and get it to run, but I don't
know how long it will hold up.
It seems like the electronics in it went bad in it. I ran 2 wires straight
to the brush leads through and external vac switch and it works now. How
long, I'm not sure. What is in there as far as electonics is a lot more
complicated than just a mechanical vac switch, so I don't know if I am
comprimising it by what I did.
What about something line e-bay 320627178191 to be use as an electric vac
pump in an EV. Basically is is an electric vac pump for Ford Diesel trucks.
I'm sure I can buy one for $50-60 and maybe less at a junk yard. I haven't
seen anyone post about these recently. But, I wasn't really looking until
now.
Also, if anyone has an old used GM pump laying around and wants to sell it,
let me know. The car is already setup for that, mounting and all, so I'd
like to keep it that way.
Steve
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