Which mercedes models share our primer pumps?
- Thread starter lostmarbles
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- Thread starter
- #22
Well there aren't any Bosch primers for sale on NZ "Trademe" or on Australian "Ebay". (Edit 9 August 08 - Soon after this thread appeared on MUD, I noticed Bosch primers started appearing for sale on Australian eBay. Whether there is a connection - who knows? )
But I'm sure if I really tried hard I could obtain one here - but then our "marketplace" is tiny in New Zealand. So "vendor competition" in a specialist area like "diesel fuel injection" doesn't exist at all.
I'd have to track down a supplier (by phoning around) and then when I've found one I bet I wouldn't get a cheaper price than my "landed cost from Arizona". So there was no point in trying.
You folks in BIG countries don't know how lucky you are (as far as purchasing goes).
PS. This situation does present "business opportunities" for enterprising people over here to import these cheap goods in bulk and on-sell them. It is a pity more people don't do it. But then such businesses will always flourish better where they are closer to suppliers and/or closer to BIG customer-bases.
But I predict a boom in Internet-purchasing will eventually lower shipping costs. (Or is that just wishful thinking
)
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Yah I know what you mean. I Used to travel around the globe and discovered that shopping in Canada is generally better than most places. Electronics for one, we have the cutting edge stuff the cheapest prices anywhere. Even cheaper than the USA from what I have seen. Some things are higher, but not many.
That's my opinion anyhow.
I think you could have found that primer in your country though. Many diesels run bosch injection, so I'm sure one form or the other is there. But your prices delivered sound fair.
- Thread starter
- #24
Got a break in the weather just before darkness fell this evening so I decided (on the spur of the moment) to install one of these pumps today - That's despite it being bitterly cold outside. (Aren't I a martyr!)
It only took about 15 minutes despite taking photos too and despite having all that water (from the rain) to mop up first (off the hood and fender).
Here are the photos:
Since it is hard to get at "the hex" on this type of pump and since I have no intention of reusing/selling it, I used vicegrips (on the body) to remove it:
I was expecting some diesel to spill so I stuffed a towel in the space below - But I needn't have bothered. With the fuel tank only about 3/4 full and the vehicle parked uphill, none came out.
But interestingly - This pump is able to be dismantled. So all I did with my first attempt at removing it was to open it up at a threaded joint near its base:
And here is the top half:
It only took about 15 minutes despite taking photos too and despite having all that water (from the rain) to mop up first (off the hood and fender).
Here are the photos:
Since it is hard to get at "the hex" on this type of pump and since I have no intention of reusing/selling it, I used vicegrips (on the body) to remove it:
I was expecting some diesel to spill so I stuffed a towel in the space below - But I needn't have bothered. With the fuel tank only about 3/4 full and the vehicle parked uphill, none came out.
But interestingly - This pump is able to be dismantled. So all I did with my first attempt at removing it was to open it up at a threaded joint near its base:
And here is the top half:
- Thread starter
- #25
So here is me removing the bottom half. As you can see - I took pleasure in DESTROYING it:
That left the old copper washer in the seat and I could see the stem of the black check valve (left in the hole) together with its return spring.
Needless to say - I was careful to ensure dirt didn't fall inside and I removed that old copper washer using the tip of my penknife:
I then carefully fitted the new Bosch pump over the spring and valve stem (making sure the new copper washer was in place first - of course).
The new Bosch pump was FAR easier to install than the OEM-type because it requires only a 17mm spanner and the hex is long enough to enable you to angle the spanner upwards (to avoid obstacles) as you turn it. So there is no need for special "crow's foot"-type spanners here:
That left the old copper washer in the seat and I could see the stem of the black check valve (left in the hole) together with its return spring.
Needless to say - I was careful to ensure dirt didn't fall inside and I removed that old copper washer using the tip of my penknife:
I then carefully fitted the new Bosch pump over the spring and valve stem (making sure the new copper washer was in place first - of course).
The new Bosch pump was FAR easier to install than the OEM-type because it requires only a 17mm spanner and the hex is long enough to enable you to angle the spanner upwards (to avoid obstacles) as you turn it. So there is no need for special "crow's foot"-type spanners here:
- Thread starter
- #26
Here's the stuff I had left over.
I'll keep that "plastic-bellows cover". I don't know why really - I guess it's got something to do with the fact that I've always been proud that I've kept it when most are lost very early on in a diesel's life.
I was able to see why that old primer pump was "manufactured to leak". I can wobble the plunger around (side-to-side) readily within the body of the pump. And anyone with engineering background would know (in my opinion) that a seal can't cope with sideways movement of such magnitude.
In contrast, the top (plunger) of the Bosch pump can't be wobbled sideways at all.
Early days yet - But I'm very happy I've made the move to Bosch here!!!!
PS. Interestingly - As well as nil/negligible diesel escaping during this work - nil/negligible air entered. But it will be a while before I "fire it up" (to prove or disprove the validity of this statement) due to "other work in progress".
I'll keep that "plastic-bellows cover". I don't know why really - I guess it's got something to do with the fact that I've always been proud that I've kept it when most are lost very early on in a diesel's life.
I was able to see why that old primer pump was "manufactured to leak". I can wobble the plunger around (side-to-side) readily within the body of the pump. And anyone with engineering background would know (in my opinion) that a seal can't cope with sideways movement of such magnitude.
In contrast, the top (plunger) of the Bosch pump can't be wobbled sideways at all.
Early days yet - But I'm very happy I've made the move to Bosch here!!!!
PS. Interestingly - As well as nil/negligible diesel escaping during this work - nil/negligible air entered. But it will be a while before I "fire it up" (to prove or disprove the validity of this statement) due to "other work in progress".
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That's interesting....your original primer pump is completely different from any of the ones that I have had or seen. I second that on the bosch unit being much easier to install. MUCH easier.
I had a fair bit of frustration replacing my primer pump a while ago (of course in the dead of winter). The original pump developed a crack in the plastic plunger which allowed air into the lines, so after trying to source the Bosch, I ended up with an identical looking "Bilstein" - note the quotations. It came in a box labeled made in India and the first one leaked immediately. Two more days and a replacement came, which didn't leak - for a few weeks. So, I managed to jam a wad of paper towel into the plunger which sealed the original long enough to get a Denso shipped to me. In fact, 3 months later I still haven't found the spare 5 minutes for swap the pumps! There will be lots of time to do it on the side of the road in a thunderstorm I imagine...
The Denso looks the same as the pump you've removed, and certainly feels like a quality piece, so I'm hoping for the best.
The Denso looks the same as the pump you've removed, and certainly feels like a quality piece, so I'm hoping for the best.
- Thread starter
- #29
I've probably accidentally misled you in that the pump I've just removed was not OEM. It was a recently installed (7 months ago) "aftermarket" pump that has no brandname. The only identification that came with it was on the packaging box. (A toyota part number and the words "made in Taiwan".)
I'm sure you'll recognise this one. It is the one that was fitted to my vehicle by the Toyota factory in Japan:
- Thread starter
- #30
I have confidence in the Denso brand so I reckon that pump should last you at least as long as the original Toyota one before it begins to leak. (And my original Toyota one lasted more than 20 years.)
- Thread starter
- #31
I decided to open up that primer pump (that I removed) just to check on the "engineering" in it.
Here a photo:
PS. - I was sloppy with taking this photo. The piston actually enters the cylinder when it is facing the other way from how it is shown here
As I suspected,it uses an O-ring on the plunger/piston to TRY to accomplish a seal while you're priming with it. (When "stowed" -the plunger/piston pushes that big black sealing washer against those holes in the base to seal them off. - So there's no danger of it leaking "while stowed". And I admit - some people may be happy with a primer that drips ONLY when in use.)
IMO - Using an O-ring (rather than a "lip-type seal") when the piston must slide such a long way is pushing your luck to start with. Put when the plunger/piston is such a sloppy fit in the cylinder -- it is nigh impossible. I believe ALL these "unbranded" primers will drip diesel during operation. (If not the first time you use it, then probably the second or third time you do.)
IMO - The cutaway view I posted earlier shows the sealing system in the Bosch is much more "engineeringly sound".
Here a photo:
PS. - I was sloppy with taking this photo. The piston actually enters the cylinder when it is facing the other way from how it is shown here
As I suspected,it uses an O-ring on the plunger/piston to TRY to accomplish a seal while you're priming with it. (When "stowed" -the plunger/piston pushes that big black sealing washer against those holes in the base to seal them off. - So there's no danger of it leaking "while stowed". And I admit - some people may be happy with a primer that drips ONLY when in use.)
IMO - Using an O-ring (rather than a "lip-type seal") when the piston must slide such a long way is pushing your luck to start with. Put when the plunger/piston is such a sloppy fit in the cylinder -- it is nigh impossible. I believe ALL these "unbranded" primers will drip diesel during operation. (If not the first time you use it, then probably the second or third time you do.)
IMO - The cutaway view I posted earlier shows the sealing system in the Bosch is much more "engineeringly sound".
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- Thread starter
- #33
Bore: 20.2mm Piston: 20.0mm (Just using vernier callipers.)
So there's 0.2mm clearance Dougal. I know it doesn't sound much but when the piston is only 14mm high that amount of clearance allows it to wobble very noticeably in the bore.
But then again, perhaps I'm wrong to point the finger at "sloppy piston fit" as being responsible for the leakage?
I guess I really find it hard to believe that you could create a good seal when you're dragging an O-ring up and down a 20mm bore repeatedly over a 30mm stroke with a liquid as thin as diesel. The bore is not "highly finished" either. It has been cadmium plated just like the outside of the pump. (Well - Maybe a tad better finish - It looks like the manufacturer did spin some wet&dry in there - or did something similar. But it is NOTHING like the finish inside a new brake cylinder.)
Hey - I think I'll cut open the OEM primer pump and see what was done there. I suspect it uses an O-ring in the bore instead of on the piston/plunger. ...................................
.......Maybe we've got too much time on our hands farting around like this Dougal?
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- #34
Well. Looky here! I think I can see why this OEM primer lasted 20 years before leaking its first drip. No little wee O-ring here! We have a proper seal.
(OK - so I was wrong and the seal was indeed on the plunger itself just like the other pump.....
)
And what's more - The finish on that bore is more towards "brake-cylinder-standard"!
By the way - I was so rough in hacksawing it apart, I accidentally cut the end off the plunger by mistake. (-- It is not supposed to have that hole right through the bottom there.) And that thread at the bottom screws into a matching female thread in the base of the unit when you are "stowing it". In this way, it pulls the plastic plunger firmly down and seals the whole unit from leakage via that black sealing washer beneath the plunger knob/wheel at the top.
So even if you find the clearance for the O-ring in that dodgy primer pump is "within spec" Dougal - I think I can still see why it is a "flawed design".
(OK - so I was wrong and the seal was indeed on the plunger itself just like the other pump.....
)And what's more - The finish on that bore is more towards "brake-cylinder-standard"!
By the way - I was so rough in hacksawing it apart, I accidentally cut the end off the plunger by mistake. (-- It is not supposed to have that hole right through the bottom there.) And that thread at the bottom screws into a matching female thread in the base of the unit when you are "stowing it". In this way, it pulls the plastic plunger firmly down and seals the whole unit from leakage via that black sealing washer beneath the plunger knob/wheel at the top.
So even if you find the clearance for the O-ring in that dodgy primer pump is "within spec" Dougal - I think I can still see why it is a "flawed design".
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No you're quite right, that's at least double what the clearance needs to be to get a good seal. That's without being able to wobble around like that one can.
I can't find the quick reference table I had previously for some hydraulic cylinder components I've done, but here's a link to the Parker O-ring Handbook. It contains more than you ever need to know.
http://phonon.phys.unm.edu/tiki/tiki-download_file.php?fileId=67
If it wasn't for interesting stuff like this, I'd be reduced to something really boring, like watching TV.
- Thread starter
- #36
I'll wait till I get my mastercard bill and then I'll PM you offering the other one "at my landed cost price" if you still want it Dougal.
I think my new Bosch pump is going to be so reliable that I'm stupid to want to carry a spare. (But I don't really care whether I carry it as a spare or get rid of it.)
Hey.... Marbles....... What a silly thing to say! If you were to think about it properly - You'd realise that the Bosch pump probably uses "internal spring pressure" to seat the same type of valve used in the "screw-to-stow" primer pumps. And there is very little in the way of "fuel pressure" there to force diesel out. In fact - It a damned vacuum you idiot!!!!!
...If it wasn't for interesting stuff like this, I'd be reduced to something really boring, like watching TV.
Heaven forbid!!!!
- Thread starter
- #38
Here's a link to a thread that has just appeared on MUD where a new Bosch primer has been found to be leaking:
https://forum.ih8mud.com/diesel-tech-24-volts-systems/237255-bosh-primer-pump.html#post3594388
I'm adding it here in the interests of providing a "balance".
Clearly my posts so far have indicated that I think the Bosch primer is "a good product". ........ And my new one hasn't given me any problems and is performing well so far.
I just want people who decide to buy one on the basis of this thread to be aware of "all the facts".
https://forum.ih8mud.com/diesel-tech-24-volts-systems/237255-bosh-primer-pump.html#post3594388
I'm adding it here in the interests of providing a "balance".
Clearly my posts so far have indicated that I think the Bosch primer is "a good product". ........ And my new one hasn't given me any problems and is performing well so far.
I just want people who decide to buy one on the basis of this thread to be aware of "all the facts".
I can confirm that Marbles spare primer pump fitted my Isuzu 4BD1T pump and is a real pleasure to use.
I can't believe how long I put up with the crappy original, especially since these cost less than an oil change.
I can't believe how long I put up with the crappy original, especially since these cost less than an oil change.
Hi Guys,
I just noticed this thread and thought I would toss my opinion in:
I replaced my OEM 12HT priming pump with a metal Denso pump from 4wheelauto.com. I suspect that LostMarbles pump was a cheap, asian knockoff of the high-quality Denso unit. Because I have been playing with my fuel lines/filters, I have had to use the pump on a dozen occasions and after 4800 miles I have not had any leakage during pumping or when stowed. Here is the pump I purchased (was about $50+shipping):
Product link:
4Wheel Auto Wholesale
I just noticed this thread and thought I would toss my opinion in:
I replaced my OEM 12HT priming pump with a metal Denso pump from 4wheelauto.com. I suspect that LostMarbles pump was a cheap, asian knockoff of the high-quality Denso unit. Because I have been playing with my fuel lines/filters, I have had to use the pump on a dozen occasions and after 4800 miles I have not had any leakage during pumping or when stowed. Here is the pump I purchased (was about $50+shipping):
Product link:
4Wheel Auto Wholesale
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