Fuel pump (leaks!!!)

[peter9423]

Hi,
I have a mercades w111 (220 se 1963).
in the fuel pump (Bosch fp esb 5rc 25/12/1 ) there is a berrow seal, but i dont understand its operation, because my pump has many leaks from vent. I haven't the number part 37 and i dont know that it is.
When i removed the impeller i dont marked the verse. Can you help me ? Can you indicate me the verse of the impeller and can you explain me as the bellow seal work???

thank you !

[peter9423]

I have seen that the surface of the teeth on the side (a) is smaller than the side (b). Thanks to this difference I can know what is the correct verse. Please, can someone check the orientation of the impeller based on this difference in surfaces?

thank you!!!

[dirkbalter]

Hey there,
The bellow seal, once installed acts like a spring, sealing the faces and preventing fuel leakage. Insure the bellow seal itself is ok. There are rebuild instructions on the pump in the technical manual.
Yes, it is important to install the impeller correctly. I believe the fins are tapered slightly. Unless someone else can give you an instant answer, I will check my notes and photos tonight and get back to you. I did mine a little while back.
Dirk

[peter9423]

my bellow seal is not stretched and flows freely coming to touch the black plastic on one side and the c-clip on the other, disconnecting from the black washer that has two tabs. it's normal? Thanks for the interest!

[BaronYoungman]

I can tell you on short pumps the thicker side of the impeller (vane) is on the bottom and the thinner tapered side is up.  This forces the gasoline up when spinning.  I would assume that is the same on the tall pump.
Bob

[dirkbalter]

Agreeing with Bob, it’s the same on the long one. Don’t know if you can see it on the picture.
Dirk

[peter9423]

Hi,
thanks to you i have knowed the correct verse of the impeller.
I see that there is a metallic O-ring in your photo that there isn't  in the manual, and your bellows seal is longer than my, finally my driving disc (black washer) has only two tabs while yours has three .
why?
Can you tell me the order of these parts?
thank you for all
 

[rgafitanu@gmail.com]

Peter,
The metallic clip that you see in Dirk's picture is not the original retaining clip but it will do the job. The original is a simple retaining ring in a C shape. You must have it because it holds in place the bellows, o-ring and shaped washer to the shaft.
The shaped washer must have 2 external tabs and one internal to engage the bellows in rotation together with the shaft and the impeller. Check if the internal tab is probably bent under.
If you have all these then check the bellows for leaks. Cover one end with your finger and blow into the other. There should be no air escaping.
To assembly, first is the rubber o-ring on the shaft then you push down the bellows (try to stretch the bellows ~5 mm), the 3 tab shaped washer and the retaining ring. Sometimes a 1 mm thick rubber o-ring may not be sufficient to seal the bellows. The bellows should go slightly forced over the o-ring. I had success with 1.5 mm thick o-rings.

A few drops are not unusual and sometimes if there is an impurity caught between the bellows and the sealing surface there will be a leak that should go away. I just had a situation like this maybe due to cold.

[peter9423]

Thanks so much!
My black washer has only two tabs, I think it's broken.
Can you tell me how to fix it or can you tell me a website from which i can buy it?

[rgafitanu@gmail.com]

If your washer has one external tab and one internal tab it may still work. If you are missing the internal tab then you have a problem. These pumps are not available anymore and rebuilt are very expensive.You need to make that washer. I made a drawing of it a while ago but I couldn't find a reasonable sheet metal shop to make them for me. Another option is to watch eBay.de for a damaged one and if you are lucky both the washer and the bellows are in good condition. I remember there was a member of this forum that these washers made but I forgot who.

[PeterPortugal]

Radu,

I just pulled apart a 1963 fuel pump and mine did not have the internal tab on the washer either.

I followed the good set of instructions in the technical manual, so I was looking out for it and I know that I didn't break it off.

Are you 100% convinced that all pumps should have the 3 tabs?

Regards

Peter

[dirkbalter]

Having the internal as well as external tabs on the washer, makes perfect sense to me as it will insure that the bellow rotates with the shaft.

That being said, the first pump that I rebuild, I bought in parts from George Des. He supplied the tab washer that you see in the pic.
After that, I took my original pump apart and recognized that my washer did not have the internal tab. I doubt, but I don’t know if it broke off at one point or was never there.

Dirk

[rgafitanu@gmail.com]

I know that the internal tab may be missing because it is very thin. In my case it was bent almost invisible. The internal tab goes into the machined groove on the shaft. The motion is transmitted from the shaft through the internal tab, to the washer and through the external tabs to the bellows. Because there is friction between the bellows and the o-ring the bellows will be engaged in rotation and may still work even with the washer internal tab broken. However, the smallest slippage and the bellows will cease to rotate, no longer filling with gas that pushes against the seal. Result, continuous leak. Leaks coming from that spout come only from the loss of sealing between the bellow upper flange and a black plastic flange in the lower chamber of the pump. Loss of sealing comes from: 1- perforated/leaking bellows or 2- bellows not rotating therefore not creating centrifugal force required for sealing.
I would contact George Des for the washer.

[dirkbalter]

Agreed, I would not rebuild the pump without the taps on the washer either. There is no down side, aside from getting or finding one.

[PeterPortugal]

Thanks guys, I will not reassemble mine until I investigate further. The answer from Radu makes perfect sense that it is to drive the rotating part of the seal (the bellows).

If anybody does know where to get the washers then I would be grateful to hear.

Regards

Peter

[dirkbalter]

I would contact George Des. He is a member here. I believe he had them manufactured and might have some left.

[neelyrc]

According to this recent post, George Des no longer has these pump parts.  There is reference to the shop that made the tabbed washers for him.

See here:
https://www.sl113.org/forums/index.php?topic=27035.msg193878#msg193878

[swood1]

If you give me the dimensions I can make one assuming it either spring steel or gauge plate.

One of my interests is watchmaking.



Steve

[peter9423]

I scratched the surface of the washer then I cut out a tab tin from a box of cookies (on the edge bent that ago corner because there the material is incrudito and then harder) after flattened the new tab the I welded pond on the washer putting it in the right place. all OK, tongue rebuilt and very durable because the tin is a alloy steel sweet and pond for this binds well with the pond time. I have resolved well and works well. I hope to be been help.

[swood1]

Hope you ate the cookies .....  no one likes a soggy cookie!

[neelyrc]

In the thread referenced in my post #16 above, you will see that fellow Forum member "Scoot" had some kits for sale last month which contained the three tab washer. Don't know if he has any left.

[rgafitanu@gmail.com]

Those kits were auctioned on eBay and I partnered with a member to split them but I was outbid by a lot. I have the correct drawing for the washer, maybe a member has access to a good sheet metal shop to make some. Being made from thin material the shop must have a really good NC press or a laser machine. If there is enough interest from the members I can talk with a shop that I know and make the setup costs acceptable.

[George Des]

Hey guys I posted my drawings for the tab washer today. The drawing is correctly dimensioned and I'm sure EMS has it on file somewhere as well. My drawing is up in General Discussion section. Emachineshop.com made them for me several years ago and they lasted me quite a long time. I had these made using the EDM process and they were difficult to tell apart from the originals. I do not have any of those left but I did have a second batch made that did not turn out so well but do work. They were made using a water jet process and the cut is just not as clean as my original batch. Only a few of these left somewhere in the garage.  My first batch back in 2007 cost me about $175.00 US for about 120 of these. The second batch cost about the same but was ordered several years after the first. Not sure what they would charge today but the price per piece goes way down the more you order. The key price determinants are the process, material, tolerances and finish which are all electable.