W111 fuel pump support

[PeterPortugal]

Hi all,

My 1963 220seb Cabrio has some sort of aftermarket cylindrical type fuel pump fitted. None of the original fuel pump equipment was present on the car when I bought it.

Now that I have sourced and rebuilt a correct early, long style pump I need to fit it. I consulted some parts diagrams and concluded that I needed the brackets shown in the pictures.

I consulted many coupe / cabrio for sale ads and found some which showed this area. Some had the bracket and some didn't. Probably 50/50. I have attached a picture of one which did.

Any early W111 owners out there who can confirm? My boot floor shows no evidence of having any holes drilled in it. I don't want to start drilling holes which shouldn't be there !!

Best Regards

Peter

[wwheeler]

My '68 280SE had the long style pump from the factory as was on the car when I bought it. The brackets that fit to the car are the same whether it be short or long. What attaches to the pump is what is different. So the triangular plate with studs on it is correct and mounts in trunk floor. The two brackets shown are also correct. FYI, be sure to put sealer of some sort around the studs on the plate as they go through the trunk pan. The one piece you are missing is the external pump cover.

The long pump needs a clamp that fits around the pump and has a rubber isolating ring. I think I have the metal clamp, but do not have the rubber ring. I have attached a few pics that show how the brackets mount to the trunk pan. You are also missing the clamps that secure the fuel lines to the on clamp and then to the trunk floor. See second pic. The third pic shows the fuel pump cover.

I hope that helps.

[PeterPortugal]

Hi Wallace,

Thanks for your usual prompt and top notch advice, I will ensure that I seal the plate properly. I have all the other bits and pieces too (thank you Ebay).

Your pictures raise an interesting point which almost passed me by. You have obviously match marked the bottom cover of your short style fuel pump. It states in my W111 workshop manual that after overhaul the pump cover should be re-installed in it's previous position. I never match marked mine, but for the life of me I cannot work out why you would have to. The inside face is a completely flat machined surface and as far as I can tell the bolt holes are all on the same PCD. Some enlightenment in this area could prove very valuable before I install the pump! Do you know why it should be re-installed as removed?

Many Thanks

Peter
 
p.s. That car of yours is not what they call a "driver" is it!

[wwheeler]

I have never torn into one, so I don't know. But I also don't know why it would matter. I believe Baron Youngman rebuilds these and maybe he has insight. I bought that pump years ago and it had the index mark on there already. Mercedes must have owned a marker business back then because they went crazy with the dots. Dotology I believe some one called it.

I drive it about 500 miles a year or so. Rain and dusty roads are strictly verboten. Only sunny skies for this coupe now! Good luck on that and let me know if you need more pictures.

[PeterPortugal]

Thanks Wallace, appreciate the photos which will be of great use.

I bought my last car from Grapevine.....let me know if yours comes up for sale !!

Peter

[BaronYoungman]

To answer the fuel pump question, if the fuel pump has never been pried open or banged on by a hammer to separate the pieces then the orientation of the bottom plate makes no difference.  If it has been ,shall we say persuaded, then it is best to put it back together EXACTLY the same or it might leak or bind.  I am not sure if the original pumps had non tamper marks  on them, but I know all Bosch replacement ones after 1974 had them a dark blue.  I noticed that the ones rebuilt or sold new from the Bosch facility in at the time Broadview Illinois had a much lighter blue which looks like this pump.  Other Re-builders put the marks on the pieces to deter people from opening them as they will void the warranty if opened.  I use to do it because I had a gentleman get my rebuilt pump take out the good impeller and exchange it for his bad one and then return it to me.  Sorry got off on a tangent, again  to answer your question if you separated the pump slowly, easily and correctly then it will make no difference.
Bob

[PeterPortugal]

Bob,

Thanks for picking up on this thread and providing the answer.

My casing cover came off easily so I will hope for the best.

Regards

Peter

[PeterPortugal]

Bob,

What is the implication of a "bad impeller" as you describe?

My newly rebuilt fuel pump is not working. The impeller is spinning freely and quickly and the direction of rotation is correct. The narrow part of the teeth are nearest the motor end of the pump which I understand is correct. There are a few scratches on the impeller and the aluminium casing parts but superficial, not deep scoring.

I was testing the pump using a bucket of fuel and it would not draw the fuel in, literally zero flow. It is not creating a vacuum. The hose is clear.

Any advice appreciated from the forum..

Regards

Peter

[Mike Hughes]

As installed in a Pagoda, the inlet port of the pump is usually a little bit lower than the bottom of the tank, so the fuel will flow down to prime the pump under normal circumstances.  The pump may not be an efficient pumper of air, but is fairly efficient as a pumper of fluid.  Try priming your pump.  I think you may find it moves the fuel just fine once the impeller has something more substantial to sink its teeth into.

[wwheeler]

I agree with Mike. The pump is partially gravity fed and the tank generates head pressure once there is fuel in there. Once it is primed, it should stay primed.

Air being thinner than fuel, is much harder for a pump to draw and has to be designed for such. Once the fuel is in the pump, it should create enough of a "seal" to continue drawing. The purpose of the partial gravity feed is to get the fuel to the pump so it can start drawing it. 

[PeterPortugal]

Guys,

I followed the excellent section of the technical manual which showed it being tested at the end and the author describes the pump as self priming.

I used a similar arrangement with no success, however I do agree that on the car the connections to the pump would be below the fuel tank.

I shall try a slightly different methodology and report back.

Regards

Peter

[PeterPortugal]

Well that pump would put out a fire in a tower block! It just needed priming properly as suggested.

Bit noisier than I hoped but as I have never heard an original pump running it might be normal.

No leaks through the bottom cover or the mechanical seal so that's a bonus !

thanks for your comments guys.

[BaronYoungman]

Sorry was on holiday for the weekend.  The pump itself once primed will draw from the tank albeit not enough to overcome a large elevation difference. This usually never come into play since the tank is located above the pump inlet.   When not primed a type of froth is created inside the pump continuously breaking the pressure vortex the pump is trying to create.  So by eliminating the air it make the pump work as designed.  This is also why there is the bleeder screw on the side of the pump housing.  Most people never need to use it , but it is good to know where it is in case you ever run empty in a scarry no moon back alley in a seedy neighborhood. Bob

[wwheeler]

...but it is good to know where it is in case you ever run empty in a scarry no moon back alley in a seedy neighborhood. Bob

That's where I hang out with my W111!  Good job Peter and glad to know it works. Those are $$$ these days.

[PeterPortugal]

Thanks again for you photos Wallace. I have started the assembly process.

[PeterPortugal]

Wallace,

When you did that wonderfully detailed restoration of your 280SE did you replace the fuel supply and return lines to the engine?

If so did you find original items or have them made up?

I found a horrible kink in my supply line and had to cut this section out and replace it with some hose temporarily.

I have found off the shelf fuel lines for a Pagoda (in SLS-Shop). These are the correct length and have correctly finished ends but have to be bent to suit. I'd love to find something similar for a W111.

Regards

Peter

[wwheeler]

Peter,

I did replace my fuel lines with stainless from -  http://www.classictube.com/index.php They are in the US, but there must be somebody in Europe who can duplicate lines. I do not know of any off the shelf kits for W111s.

I sent all of my old lines to them and they duplicated them. For the most part it was very close. The long body lines were bent at a point and marked. So when you take it out of the box, you knew what spot was to be straight. Saves on shipping. The fittings worked, but because these do mostly inch sizes, they had a limited assortment of metric fittings. I will do the same for the W128.

I hope that helps!

Wallace

[wwheeler]

Peter,

I did replace my fuel lines with stainless from -  http://www.classictube.com/index.php They are in the US, but there must be somebody in Europe who can duplicate lines. I do not know of any off the shelf kits for W111s.

I sent all of my old lines to them and they duplicated them. For the most part it was very close. The long body lines were bent at a point and marked. So when you take it out of the box, you knew what spot was to be straight. Saves on shipping. The fittings worked, but because these do mostly inch sizes, they had a limited assortment of metric fittings. I will do the same for the W128.

I hope that helps!

Wallace

[PeterPortugal]

Thanks Wallace.

I am having trouble locating a similar company in the UK so I'll put a new post up.

Regards

Peter