Brake vacuum pump question (1 Viewer)

HotBlue

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Hi, I am new to the group. I have a major problem which I hope someone may have a solution for. I own a 1992 Fiat Ducato motorhome. The braking system is very weak due to the vacuum pump not operating. It attaches to the side of the engine and connects directly to the camshaft. It appears that there should be a keyway that fits between the pump and the camshaft to make the pump rotate. This is missing! All the dealers I've checked do not have one. Does anyone have any ideas on this - or even better and actual keyway for sale?
All the best,
HotBlue.
 

jonandshell

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It's probably a standard key available from many engineering suppliers.

I have selection boxes of standard and woodruff keys in the back of my work van.
 

jonandshell

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Have you a photo of the driven shaft?

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HotBlue

HotBlue

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Have you a photo of the driven shaft?
I have a photo of the pump on my engine and a stock photo of the actual pump (a bit awkward to take it off again to photograph!). I hope this helps.
BrakePumpOnMyEngine.jpg
Brake Vacuum Pump.PNG
 

jonandshell

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I see, its a coupling rather than a key in the engineering sense.
It might be main dealer or engine specialist only.

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DBK

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That coupling wouldn't get lost on its own. I suspect it has been removed because the pump might be seized or otherwise broken. Can you check if it will rotate?
 
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are you sure its located properly looking at the picture the flange doesnt seem to be sitting right tho it may be the camera anglewhat ever it locates onto must have an oil feed looking at the o ring on the shaft
 
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HotBlue

HotBlue

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That coupling wouldn't get lost on its own. I suspect it has been removed because the pump might be seized or otherwise broken. Can you check if it will rotate?
It rotates freely and, as a test, I put it into a drill to spin it - it produced a good vacuum!
 
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HotBlue

HotBlue

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are you sure its located properly looking at the picture the flange doesnt seem to be sitting right tho it may be the camera anglewhat ever it locates onto must have an oil feed looking at the o ring on the shaft
The flange sits flush on the engine block and oil doesn't leek out when the engine is running. Sorry about the camera angle.

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HotBlue

HotBlue

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I see, its a coupling rather than a key in the engineering sense.
It might be main dealer or engine specialist only.
Tried dealers and the stock response I get is that Fiat have a 10 year turn around for parts - i.e. not available any more.
 
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Try your local Iveco truck repair centre and take the pump and a photo of the missing part as in your photo No:2 with you or failing that any van repair centre.
 

jonandshell

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I wonder if @Willdbill has such a part left over after his engine rebuilding exploits?

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Dec 12, 2010
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I take it your pump looks exactly like the one in the photo, complete with the tee shaped spigot sticking out the top or is that the bit you need ? If it is exactly the same, then the drive coupling will be a small disc with a hole through the centre and a square cut out groove on one side and square driving lugs on the other, set at 90° to each other. More than likely, someone has removed the pump in the past and the coupling has fallen out and been lost. I think your best bet would be a breakers yard, they will be pretty standard on most any diesel Fiat of that age, not necessarily just on van engines.
Edit.
Just found a picture of the type of thing you need.
Broken Link Removed
 
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Nov 18, 2011
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I have a photo of the pump on my engine and a stock photo of the actual pump (a bit awkward to take it off again to photograph!). I hope this helps.View attachment 116509 View attachment 116510
That pump is not engaged eight take it off and mount it correctly before it brakes sum thing important
Bill

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Nov 18, 2011
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It rotates freely and, as a test, I put it into a drill to spin it - it produced a good vacuum!
I think you should inspect the hose if it producing a good vacuum. It losing vacuums sume whare
Change the hose
Bill
 
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HotBlue

HotBlue

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That pump is not engaged eight take it off and mount it correctly before it brakes sum thing important
Bill
My mechanic put the pump back as we found it and the engine has been running fine. We appear to be missing the part that couples from the cam-shaft to the pump. The link that jockaneezer sent me, it seems clear that we need this coupler for the pump to operate correctly.
 
Nov 18, 2011
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The flange sits flush on the engine block and oil doesn't leek out when the engine is running. Sorry about the camera angle.
Nothing wrong with camera angel the bolts are not even more thread showing on top than botum bolt it neds mounting properly first then run up engine with hose removed from servo then put a finger over end of pipe it it sucks its OK if it dosant it probably a hose cracked or broken
Then test your servo it could be losing vacuum or striking a strip down and service should sort it
Lighly oil and grease all working moving parts
Bil

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pappajohn

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All the sites I found don't seem to include a drive key in the published pictures :(.
The drive key is the rectangular bar with nipple stub and comes with the pumps.
The bar slots into a groove in the end of the camshaft.
Oil from the camshafts oil gallery goes through the nipple to lubricate the pump.
There should be no other parts.
 
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pappajohn

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Looking at Jocks link I now see the ADAPTOR which is missing.
Obviously the pump fits more than one fiat engine and the ADAPTOR means they only need make one pump body to fit different engines.

Good luck finding one of those !
 
Nov 18, 2011
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My mechanic put the pump back as we found it and the engine has been running fine. We appear to be missing the part that couples from the cam-shaft to the pump. The link that jockaneezer sent me, it seems clear that we need this coupler for the pump to operate correctly.
OK you might nead the coupling but trust me the pump is not fitted correctly it needs removing and refitting I fitted and removed and removed many of them
IMG_20160723_104330.jpg
look at threads thare not even any mechanical person can she that sack your mechanic and find a another one ASPC before he brake's sum thing (y)

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pappajohn

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OK you might nead the coupling but trust me the pump is not fitted correctly it needs removing and refitting I fitted and removed and removed many of them
View attachment 116650 look at threads thare not even any mechanical person can she that sack your mechanic and find a another one ASPC before he brake's sum thing (y)
I fully agree Bill, except the pump body does look to be fully inserted and straight.
It appears the plate isn't part of the pump body but more of a clamping plate....like an exhaust manifold clamp plate.
Though I don't see how it could be fitted over the pump end to start with.
If the pump was at an angle it would piss oil out as the oil seal/O ring is flat to the mating surface
 
Nov 18, 2011
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I fully agree Bill, except the pump body does look to be fully inserted and straight.
It appears the plate isn't part of the pump body but more of a clamping plate....like an exhaust manifold clamp plate.
Though I don't see how it could be fitted over the pump end to start with.
It is fitted wrong john I done the Sam during my numerous engine rebulds only once it is flush fitting flanged and if not fitted correctly it won't engage their is only 3mm max between engaged and sitting on top of slots that's if the slot I arnt wrecked now
I have had my one on and off more times than a whors drawer's
Bill
 
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HotBlue

HotBlue

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A little more information on the part, which is for a 1993 Fiat Ducato motorhome. From what I can glean from all the kind information, so far, I need a coupler for the brake vacuum pump to make it work. I have attached 2 pictures - the of the top of the pump and the best estimate (the one in the picture is probably not the exact one) of the coupler I am looking for. If anyone has one or knows someone who has one or even a supplier, I would be happy to buy it from them.

Brake Vacuum Pump Top.PNG
Coupler.png

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Nov 18, 2011
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Take your old one off and take a pick when I get home from work I will have a look in my garaged
Bill
 
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HotBlue

HotBlue

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OK you might nead the coupling but trust me the pump is not fitted correctly it needs removing and refitting I fitted and removed and removed many of them
View attachment 116650 look at threads thare not even any mechanical person can she that sack your mechanic and find a another one ASPC before he brake's sum thing (y)
Appreciate your comment. What is the correct position for the pump? If it's not an imposition, do you have a picture / photo of the correct position?
 
Nov 18, 2011
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Appreciate your comment. What is the correct position for the pump? If it's not an imposition, do you have a picture / photo of the correct position?
I am not home yet Ben frighting trafick all day suld have Ben finished at 12am won't get finished til abut 1800 and might have to have night out as I will run out of drivers time
Bill

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