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Jacobs vacuum pump
- Thread starter MMeier
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BimmerAgent
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Cummins
My buddy did a couple of months ago. Went to a Cummins distributor. I think he said it was around $125 . Bruce
My buddy did a couple of months ago. Went to a Cummins distributor. I think he said it was around $125 . Bruce
Jacobs Vehicle Systems - Home you can find the Cummins and Dodge part #'s and installation instructions in Acrobat files. I just bought another one from Cummins $165 plus TAX! The solenoid is $300+ !! I think I'll take mine off and put a US Gear unit on!! Goto your parts store and ask for the vacuum pump for a '99 GMC,6. 5 diesel. It MIGHT be the same unit. Good luck
The Cummins part number is:
<TABLE style="WIDTH: 306pt; BORDER-COLLAPSE: collapse" cellSpacing=0 cellPadding=0 width=408 border=0 x:str><COLGROUP><COL style="WIDTH: 306pt; mso-width-source: userset; mso-width-alt: 14921" width=408><TBODY><TR style="HEIGHT: 12. 75pt" height=17><TD class=xl24 style="BORDER-RIGHT: #d4d0c8; BORDER-TOP: #d4d0c8; BORDER-LEFT: #d4d0c8; WIDTH: 306pt; BORDER-BOTTOM: #d4d0c8; HEIGHT: 12. 75pt; BACKGROUND-COLOR: transparent" width=408 height=17>Jacobs exhaust brake vacuum pump 3965925</TD></TR></TBODY></TABLE>
--Eric
<TABLE style="WIDTH: 306pt; BORDER-COLLAPSE: collapse" cellSpacing=0 cellPadding=0 width=408 border=0 x:str><COLGROUP><COL style="WIDTH: 306pt; mso-width-source: userset; mso-width-alt: 14921" width=408><TBODY><TR style="HEIGHT: 12. 75pt" height=17><TD class=xl24 style="BORDER-RIGHT: #d4d0c8; BORDER-TOP: #d4d0c8; BORDER-LEFT: #d4d0c8; WIDTH: 306pt; BORDER-BOTTOM: #d4d0c8; HEIGHT: 12. 75pt; BACKGROUND-COLOR: transparent" width=408 height=17>Jacobs exhaust brake vacuum pump 3965925</TD></TR></TBODY></TABLE>
--Eric
That filter is an air discharge... . remember this is a vacuum pump so the air discharges from the filter an keeps bugs and dirt from moving into the working section of the pump when the engine is not running...
If there was a high volume of air moving through the pump you'd be able to feel the push as it works... since the suction side should be in the high 25's HG (mercury) you won't feel any push from the filter...
Like the vacuum pumps that use to be used on the Fords, we'd pull the suction side(side going to the AC and other controls that needed vacuum (power brake booster) and would drop some 10 w oil into the pump... usually once or twice a year... . no more than a tablespoon or so... this would lubricate the pump action and you'd some of this oil at the filter(discharge).
If there was a high volume of air moving through the pump you'd be able to feel the push as it works... since the suction side should be in the high 25's HG (mercury) you won't feel any push from the filter...
Like the vacuum pumps that use to be used on the Fords, we'd pull the suction side(side going to the AC and other controls that needed vacuum (power brake booster) and would drop some 10 w oil into the pump... usually once or twice a year... . no more than a tablespoon or so... this would lubricate the pump action and you'd some of this oil at the filter(discharge).
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Anybody had to buy the solenoid switch and are there cheaper replacements? What about bypass the solenoid switch altogether?
Oh yeah. The directions say to NEVER let the vacuum pump run "open" as this can shorten the life of the pump. It's been my experience that the pumps last about 100k.
Oh yeah. The directions say to NEVER let the vacuum pump run "open" as this can shorten the life of the pump. It's been my experience that the pumps last about 100k.
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No, if the vacuum pump drew air from someplace else there would be no vacuum... . it draws air from the circuit its attached to and draws the air out of that circuit to make it a vacuum... so the only air that it really pumps once its drawn it down to the level the pump is designed to pump to is air that comes through leaks.....
If you might remember on the old Fords they had a can the size of a tomato juice can (1 qt) that had a nipple on one end of the can... this was a vacuum chamber to supply additional vacuum for braking or the AC controls if the engine speed was low enough so that the pump could not draw enough air...
On the old cars were vacuum wipers... one side of the system had air pressure at 15. 7 psi, room pressure... and vacuum on the other side... the air pressure would push the wipers one direction and the valve would switch, and there would now be air pressure on the other side of the valve and the pump would have to draw down again to move the wipers...
If and when there was a leak... . hose loose or bad connection the system would not work...
On the early dodge trucks we used vacuum from a pump to power the brakes and exhaust brake... I used to have several of those as well as the fords... .
I hope this answers the questions... .
If you might remember on the old Fords they had a can the size of a tomato juice can (1 qt) that had a nipple on one end of the can... this was a vacuum chamber to supply additional vacuum for braking or the AC controls if the engine speed was low enough so that the pump could not draw enough air...
On the old cars were vacuum wipers... one side of the system had air pressure at 15. 7 psi, room pressure... and vacuum on the other side... the air pressure would push the wipers one direction and the valve would switch, and there would now be air pressure on the other side of the valve and the pump would have to draw down again to move the wipers...
If and when there was a leak... . hose loose or bad connection the system would not work...
On the early dodge trucks we used vacuum from a pump to power the brakes and exhaust brake... I used to have several of those as well as the fords... .
I hope this answers the questions... .
Maybe this will help
Photo of intake (best I can get, coolant reservoir is in the way)
#ad
Drawing of operation. (at least what I think the valve does)
No , no, no, no!! You have it completely wrong, read up on the thing some !!
AH64ID
Your right to some extent... a gasoline engine usually has a high state of vacuum because the throttle plate is closed... however on the old cars as you would go up a hill, and open the throttle the vacuum would fall off... . most of those owners would buy an additional vacuum pump so that when they pulled a hill the wipers would still work... and for years class 8 trucks back in the 50's had vacuum wipers powered by a pump since a diesel has no vacuum from the engine... .
Hope this helps... .
Your right to some extent... a gasoline engine usually has a high state of vacuum because the throttle plate is closed... however on the old cars as you would go up a hill, and open the throttle the vacuum would fall off... . most of those owners would buy an additional vacuum pump so that when they pulled a hill the wipers would still work... and for years class 8 trucks back in the 50's had vacuum wipers powered by a pump since a diesel has no vacuum from the engine... .
Hope this helps... .
Okay, What about the vacuum chamber/valve on the elbow behind the turbo? I put on the new vacuum pump. When it still didn't work,I removed the hoses and plumbed direct to the vacuum chamber itself. The arm starts to move upward and then stops. can pry the arm upward with a bar and the chamber works as it should. sprayed some PB Blaster on the rod and pivot but it still won;t close the butterfly valve as it should.
Jelag, where did you put the 10 wgt oil? I guess I will find out how much the vac chamber costs now!
The rebuild kit referenced above is for the 2002 and older models for the vac pump that mounted direct on the engine. There is a kit for those that can be found at DODGE DIESEL VACUUM PUMP REPAIRING /TRANSMISSIONS REPAIR.
There is no core on these pumps and the price has almost doubled in the past year.
Jelag, where did you put the 10 wgt oil? I guess I will find out how much the vac chamber costs now!
The rebuild kit referenced above is for the 2002 and older models for the vac pump that mounted direct on the engine. There is a kit for those that can be found at DODGE DIESEL VACUUM PUMP REPAIRING /TRANSMISSIONS REPAIR.
There is no core on these pumps and the price has almost doubled in the past year.
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On our early dodge and ford trucks with the vac pump on the enigne we would pull the hose to the vac booster for the power brake... . and drop the oil in this line with the engine running...
If we were installing an exhaust brake on the engine we would test the vac with a gauge before doing the installation... there is no reason to install an exhaust brake if the vac system can't make it work... .
If we had a good system we'd install the tee for the vac circuit and before we connected the brake we'd drop the oil into that hose... .
Often we'd see a rise of 2-3" hg in the vac gauge from before and after the oil... and you can't believe the dirt that the oil would flush out of the circuit... .
If we were installing an exhaust brake on the engine we would test the vac with a gauge before doing the installation... there is no reason to install an exhaust brake if the vac system can't make it work... .
If we had a good system we'd install the tee for the vac circuit and before we connected the brake we'd drop the oil into that hose... .
Often we'd see a rise of 2-3" hg in the vac gauge from before and after the oil... and you can't believe the dirt that the oil would flush out of the circuit... .
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