Skip to main content
Topic: Re: Vacuum pump under front  (Read 1834 times) previous topic - next topic - Topic derived from Vacuum pump under front

Re: Vacuum pump under front

Hya all, especially to night hawk and old English, my vacuum pump has broken off its mountains but I can't think for the life of me where it was attached to, if could possibly take a photo of there's and send it to me so I can see exactly how it is attached and where too, also can someone remind me what is the purpose of this, I did ask the question sutch a long time ago Ive forgotten, I think it's something to do with air vents, I've noticed there is a fuse under dash for this, does it operate by a switch or does come on automatically when engine is running thanks kev

Re: Vacuum pump under front

Reply #1
Kev, here are a couple of photos of how it was attached on our 93. The pump shown is a replacement. The vacuum pump operates the heater/air conditioner flaps. The bulb in one of the photos is the vacuum canister.
jor

Re: Vacuum pump under front

Reply #2
Jor,
  My pump recently gave up the ghost. 
Don't know yet if it's a fuse or the actual pump yet, but would love to know where you got your replacement - just in case.

Re: Vacuum pump under front

Reply #3
Quote
but would love to know where you got your replacement

Was on the coach when I bought it. Here's a close up of the tag. Probably nothing special about this pump. I would think you could get one pretty cheap.
jor

Re: Re: Vacuum pump under front

Reply #4
Kev, here are a couple of photos of how it was attached on our 93. The pump shown is a replacement. The vacuum pump operates the heater/air conditioner flaps. The bulb in one of the photos is the vacuum canister.
jor
Ah OK thanks very mutch for that, the old bracket had rusted away and I heard a noise one day few years ago and it had fallen as far as the length of cable and hose that is attached, I haven't got a clue if it works or not, my air con isnt working at the mo, because the brackets on that radiator at the front have also rusted and the fans are just dangling there, it's one of the very last jobs I do once I have finished everything else and got it back on road,, it won't affect my normal heater from engine coolant water will it?, I do seem to be able to direct the air flow from screen to floor using dash controls,


Re: Re: Vacuum pump under front

Reply #6
If the flow of air moves from defrost to dash to floor, IT WORKS.  ^.^d

Re: Re: Vacuum pump under front

Reply #7
Kev, here are a couple of photos of how it was attached on our 93. The pump shown is a replacement. The vacuum pump operates the heater/air conditioner flaps. The bulb in one of the photos is the vacuum canister.
jor
Thanks for the photos, looks like like gonna have to make up a new bracket for it to fit, cheers

Re: Re: Vacuum pump under front

Reply #8
The OEM Gast pumps aren't cheap or easy to find. I replaced ours with a Thomas pump off of e-bay, even the rebuild kit that I found for the Gast was close to $200 


Re: Re: Vacuum pump under front

Reply #10
So it worked OK this replacement so it doesn't have to be a gast yeah kev
As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Re: Vacuum pump under front

Reply #11
So it worked OK this replacement so it doesn't have to be a gast yeah kev

It works perfectly.  I got the idea from another forum member about fours years ago, but I can't find the thread.  I think I remember Michelle saying they had put one on their FT and were pleased with the performance but for the noise telegraphing due to being mounted directly on the genset quiet-box sheetmetal, so I mounted mine using a plywood backer and barely notice the sound if at all.

Also, someone else said that that pump didn't last very long so I fooled around with it putting the hoses and vacuum caps on different fittings while powered-up and finally was able to have it work for my application with all fittings covered and air/water tight.  I thought that due to its location on my FT that water ingestion may be what could shorten its life.  As of this posting it's working fine.

Re: Re: Vacuum pump under front

Reply #12
You will find that the vast majority of diesel vehicles with vacuum operated HVAC systems do have an electric vacuum pump. So, these are pretty common.

Yes, there are some that use a mechanical vacuum pump off the engine.

Re: Re: Vacuum pump under front

Reply #13
You will find that the vast majority of diesel vehicles with vacuum operated HVAC systems do have an electric vacuum pump. So, these are pretty common.

Yes, there are some that use a mechanical vacuum pump off the engine.
And a venturi system off the air system.


Re: Re: Vacuum pump under front

Reply #15
It works perfectly.  I got the idea from another forum member about fours years ago, but I can't find the thread.  I think I remember Michelle saying they had put one on their FT and were pleased with the performance but for the noise telegraphing due to being mounted directly on the genset quiet-box sheetmetal, so I mounted mine using a plywood backer and barely notice the sound if at all.

Also, someone else said that that pump didn't last very long so I fooled around with it putting the hoses and vacuum caps on different fittings while powered-up and finally was able to have it work for my application with all fittings covered and air/water tight.  I thought that due to its location on my FT that water ingestion may be what could shorten its life.  As of this posting it's working fine.
OK, I've just checked mine out, it has seized solid, so am thinking of getting this pump from amazon, I have an older 1990 vehicle I noticed yours is a 2003, does this pump you bought just have two wire 1 for earth and 1 for positive and is the air pipe connection on it the same as the gast that I have, and also is this pump running all the time when engine running. Or does it switch itself on and off when operating heater flaps from floor to screen, it's worth giving it a spray with wax oil when. I fit it, kev

Re: Re: Vacuum pump under front

Reply #16
It's two wires and it comes on when vacuum is depleted from the canister. I  reused my old tin can canister as my FT is rust free, but if not you can get a round ball-shaped plastic one at any supply house.

Th pump I linked has a few fittings so you'll have to figure out which to use.

Re: Re: Vacuum pump under front

Reply #17
It's two wires and it comes on when vacuum is depleted from the canister. I  reused my old tin can canister as my FT is rust free, but if not you can get a round ball-shaped plastic one at any supply house.

Th pump I linked has a few fittings so you'll have to figure out which to use.
I didn't realise that their is a canister that attaches to it, so are you saying that the old canister that was on your old gast pump fits on this one that you bought from amazon, I think I understand now how it works, as soon as I move from screen to dash to floor the vacuum operates it and then the pump comes on fills the cannister up with more vacuum then when it is full pump switches off and it's ready for next operation of the flaps, is that correct?

Re: Re: Vacuum pump under front

Reply #18
I didn't realise that their is a canister that attaches to it, so are you saying that the old canister that was on your old gast pump fits on this one that you bought from amazon, I think I understand now how it works, as soon as I move from screen to dash to floor the vacuum operates it and then the pump comes on fills the cannister up with more vacuum then when it is full pump switches off and it's ready for next operation of the flaps, is that correct?
Also, I'm still getting used to abbreviations, what is FT please, is that just short for freightliner kev

Re: Re: Vacuum pump under front

Reply #19
Also, I'm still getting used to abbreviations, what is FT please, is that just short for freightliner kev
I've just had a look at that pump you bought from amazon all the photos, I noticed that their happens to be two air pipe connections , my original gast has only 1 air connection and two wires so a bit concerned where the other air pipe attaches to
Kev